PART III (B): Other selected scientific reports

UN@) 
environment
programme 
Too Little, Too Slow
Climate adaptation failure
puts world at risk
Executive Summary
Adaptation Gap Report 2022
Adaptation Gap Report 2022: Too Little, Too Slow
© 2022 United Nations Environment Programme 
ISBN: 978-92-807-3982-4 
Job Number:  DEW/2480/NA
This publication may be reproduced in whole or in part and in any form for educational or non-profit services without
special permission from the copyright holder, provided acknowledgement of the source is made. The United Nations
Environment Programme would appreciate receiving a copy of any publication that uses this publication as a source.
No use of this publication may be made for resale or any other commercial purpose whatsoever without prior
permission in writing from the United Nations Environment Programme. Applications for such permission, with
a statement of the purpose and extent of the reproduction, should be addressed to the Director, Communication
Division, United Nations Environment Programme, P. O. Box 30552, Nairobi 00100, Kenya.
Disclaimers
The designations employed and the presentation of the material in this publication do not imply the expression of any
opinion whatsoever on the part of the Secretariat of the United Nations concerning the legal status of any country,
territory or city or area or its authorities, or concerning the delimitation of its frontiers or boundaries. 
Some illustrations or graphics appearing in this publication may have been adapted from content published by third
parties. This may have been done to illustrate and communicate the authors’ own interpretations of the key messages
emerging from illustrations or graphics produced by third parties. In such cases, material in this publication do not
imply the expression of any opinion whatsoever on the part of United Nations Environment Programme concerning the 
source materials used as a basis for such graphics or illustrations.
Mention of a commercial company or product in this document does not imply endorsement by the United Nations
Environment Programme or the authors. The use of information from this document for publicity or advertising is
not permitted. Trademark names and symbols are used in an editorial fashion with no intention on infringement of
trademark or copyright laws.
The views expressed in this publication are those of the authors and do not necessarily reflect the views of the United
Nations Environment Programme. We regret any errors or omissions that may have been unwittingly made.
© Maps, photos, and illustrations as specified
Suggested citation
United Nations Environment Programme (2022). Adaptation Gap Report 2022: Too Little, Too Slow – Climate adaptation
failure puts world at risk — Executive Summary. Nairobi. https://www.unep.org/adaptation-gap-report-2022
Co-produced with:
UNEP Copenhagen Climate Centre and the World Adaptation Science Programme (WASP) 
UN@ 
WASP 
environment
programme 
copenhagen
climate centre 
s3l 
. 
Supported by:
U 
MINISTRY OF FOREIGN AFFAIRS
OF DENMARK 
.
. 
9 
I I Sweden 
Belgium 
partner in development 
n Sverige 
UNEP promotes
environmentally sound 
practices globally and
in its own activities. Our 
II
distribution policy aims to reduce 
UNEP's carbon footprint.
Too Little, Too Slow
 
Climate adaptation failure
puts world at risk
Executive Summary
Adaptation Gap Report 2022
III
Adaptation Gap Report 2022: Too Little, Too Slow
Executive summary
Climate risks are increasing as global warming
accelerates. Strong mitigation and adaptation are
both key to avoiding hard adaptation limits.
the world will face severe climate risks before the end of
this century, even under low-emission scenarios
(figure ES.1). 
Climate impacts are increasing across the globe. A
multi-year drought in the Horn of Africa, unprecedented
flooding in South Asia, and severe summer heat and
record-breaking droughts across multiple regions of the
northern hemisphere, among others, point to mounting
and ever-increasing climate risks. According to the recent
Intergovernmental Panel on Climate Change (IPCC)
Working Group II Sixth Assessment Report (IPCC WGII AR6),  
Ambitious, accelerated action to adapt to climate change
is therefore paramount, together with strong mitigation
efforts. However, even ambitious investment in adaptation
cannot fully prevent climate change related impacts.
Hence, dealing with losses and damages cannot be avoided
and must be addressed adequately at the United Nations
Framework Convention on Climate Change (UNFCCC) and
at national levels. 
Figure ES.1 Reasons for Concern as assessed in IPCC WGII AR6
A. Global surface temperature change
     Increase relative to the period 1850–1900
B. Reasons for Concern (RFC)
     Impact and risk assessments assuming low to no adaptation
°C
5.0
Risk/impact
Projections for different scenarios
4.0
SSP1-1.9
SSP1-2.6 (shade representing very likely range)
SSP2-4.5
SSP3-7.0 (shade representing very likely range)
SSP5-8.5
Very high
High
Moderate
Undetectable
3.0
2.0
1.5
1.0
0.0
2100
1950
2000
2050
RFC1
RFC2
RFC3
RFC4
RFC5
Global
aggregate
impacts
Unique and
threatened
systems
Extreme
weather
events
Distribution
of impacts
Large scale
singular
events
Source: IPCC (2022). Climate Change 2022: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Sixth Assessment
Report of the Intergovernmental Panel on Climate Change. Pörtner, H.-O., Roberts, D.C. , Tignor, M., Poloczanska, E.S., Mintenbeck, K.,
Alegría, A. et al. (eds.). Cambridge, UK and New York, NY, USA: Cambridge University Press. 3056. doi:10.1017/9781009325844.
Adaptation must not be sidelined because of largescale,
non-climate
and
compounding
factors.
term investments in adaptation are urgently needed to
avoid the adaptation gap from widening. It is critical that
the international climate community build on the Glasgow 
The war in Ukraine, global supply shortages and the global 
Climate Pact, agreed during the twenty-sixth session of the 
COVID-19 pandemic have all contributed to an evolving
energy and food security crisis, with the cost of living as
well as inflation surging in many countries across the world.
However, unprecedented political will and many more long-
United Nations Climate Change Conference of the Parties
to the UNFCCC (COP 26) in 2021, and deepen collective
commitments on net-zero, adaptation, climate finance, and
loss and damage.
•
••
•••
••
••
•••
••
•••
••••
•••
••••
••••
IV
••
••
••
Transition range
Confidence level
assigned to
transition
range
Low
•
••
•••
Very high
••••
Historical average
temperature increase
in 2011–2020 was
1.09°C (dashed line),
range 0.95–1.20°C
Executive Summary
Global efforts in adaptation planning, financing
and implementation continue to make incremental
progress but fail to keep pace with increasing
climate risks. 
which people and ecosystems are more resilient or less
vulnerable to climate change. Countries are also increasing
the implementability of adaptation planning instruments by
defining objectives, determining time frames, considering
future climate change, strengthening the science base, and
improving the capacity and partnerships needed to ensure
effective implementation. Moreover, nearly 90 per cent of
planning instruments analysed display consideration for
gender and/or historically disadvantaged groups, such as
indigenous peoples.
This calls for groundbreaking acceleration in scientific
research, innovative planning, more and better finance
and implementation, increased monitoring and evaluation,
and deeper international cooperation. Current processes
under the United Nations climate negotiations, including
the Glasgow–Sharm el-Sheikh work programme on the
global goal on adaptation and the global stocktake, present
an important opportunity to act upon the conclusions of
this report and the IPCC WGII AR6.
The adaptation finance gap in developing countries
is likely five to 10 times greater than current
international adaptation finance flows and continues
to widen.
More than eight out of 10 countries now have at
least one national adaptation planning instrument,
and they are getting better and becoming more
inclusive of disadvantaged groups.
International adaptation finance to developing countries
continues to rise, reaching US$28.6 billion in 2020. This
represents a 34 per cent share of total climate finance to
developing countries in 2020 and is a 4 per cent increase 
At least 84 per cent of Parties to the UNFCCC, up 5 per 
from 2019. Combined adaptation and mitigation finance 
cent from last year, have established adaptation plans,
strategies, laws and policies, and about half of those have
two or more planning instruments in place (figure ES.2).
More than a third of all 198 Parties to the UNFCCC have
incorporated quantified and time-bound targets, which
are an increasing part of national adaptation planning.
However, the majority of these targets do not capture
the outcomes of adaptation action, such as the degree to 
flows in 2020 fell at least US$17 billion short of the
US$100 billion pledged to developing countries, even by
climate finance providers' own accounting. If the annual
increase from 2019 persisted in the coming years, the
US$100 billion target would not be met until 2025. This
calls for significant acceleration in adaptation finance,
especially if doubling of 2019 finance flows by 2025 is to
be met, as the Glasgow Climate Pact urges.
Figure ES.2 Status of adaptation planning worldwide, as at 31 August 2022 
V
!
National plan, strategy, law or policy in place
Yes
No
N/A
In progress
■ 
■ 
■ 
Adaptation Gap Report 2022: Too Little, Too Slow
Accounting for inflation, estimated annual adaptation
costs/needs are in the range of US$160–34 0 billion by 2030
and US$315–565 billion by 2050. This range is in line with
new findings estimating finance needs of US$71  billion
per year between now and 2030 based on 76 developing
countries’ nationally determined contributions (NDCs) 
and national adaptation plans (NAPs) (figure ES.3). Based
on this assessment, estimated adaptation cost/needs
are currently between five and 10 times higher than
international adaptation finance flows, and the adaptation
finance gap continues to widen.
Figure ES.3 Information on adaptation finance needs included in developing countries' NDCs or NAPs 
Adaptation implementation is increasing but not
keeping up with climate impacts.
However, without a step change in financial support,
adaptation actions could be outstripped by accelerating
climate impacts, which would further widen the adaptation
implementation gap. In addition, only three out of
10 principal adaptation actions (reflecting around 40 per
cent of the funding volume) reported by climate finance
providers to the Organisation for Economic Co-operation
and Development (OECD) are explicitly targeting climate
risk reduction, while the degree to which all other actions
address adaptation is unclear. Better labelling of financial
support could help clarify its contribution to adaptation.
!
� f 
m. 
4 
; 
7a%. 
Adaptation finance needs included
in developing countries' NDCs or NAPs
Yes
No
N/A
■ 
■ 
The number and volume of adaptation actions supported
through international climate funds (Adaptation Fund [AF],
Green Climate Fund [GCF], and the Global Environment
Facility’s [GEF] Least Developed Countries Fund [LDCF]
and Special Climate Change Fund [SCCF]), multilateral
finance and bilateral donor support continue to increase,
though the rate may be slowing (figure ES.4). Actions
are concentrated in the agriculture, water, ecosystems
and cross-cutting sectors and primarily address rainfall
variability, drought and flooding. 
VI
Executive Summary
Figure ES.4 Number of new adaptation projects per start year, size and combined annual funding value under the Adaptation
Fund, Green Climate Fund and the Least Developed Countries Fund and Special Climate Change Fund of the Global
Environment Facility, as at 31 August 2022 
Number of projects
60
600
50
500
5
40
400
4
5
3
1
8
5
30
300
20
200
10
100
0
0
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022 
(until August 31)
US$0.5–10 million
US$10–25 million
US$25–50 million
> US$50 million
Extrapolated 2022 value
Total value of projects
Current adaptation practice falls woefully short
of what is required, but following best practices
in adaptation planning and implementation can
improve effectiveness.
 ●
inadequate metrics reflecting what is easily
measurable but often difficult to validate and
interpret in terms of climate risk reduction.
Adaptation actions remain largely incremental in nature,
typically do not address future climate change, and may
reinforce existing vulnerabilities or introduce new risks,
particularly for the most vulnerable. The main reasons for
these shortcomings are: 
 ●
inadequate involvement of stakeholders through elite
capture of resources and exclusion of marginalized
groups, including women, indigenous peoples and
local communities
 ●
Data to quantify adaptation effectiveness and adequacy
are limited yet urgently needed, especially for higher levels
of warming and complex or cascading risks. However,
existing evidence shows that hybrid solutions addressing
multiple dimensions of climate-related risks – for example
by bringing together climate information, infrastructure,
and nature-based and institutional solutions – tend to
be more effective than single solutions. To be effective
and adequate in the longer term, solutions must also
be context-specific and address the root causes of
vulnerability, such as underlying structural inequities and
gendered disadvantages, in addition to reducing climaterelated
exposures
and
vulnerabilities
to
climate
hazards.
inadequate attention to local contexts and ownership
through genuine local participation in adaptation
design and implementation
There are a number of general principles of good adaptation
practice to ensure that adaptation actions are relevant,
appropriate, sustainable, equitable and effective. These
principles are quite consistent across the literature and
can broadly be summarized as:
 ● retrofitting development activities as adaptation
actions without specifically addressing climate
risks, often resulting in marginal resilience benefits
or maladaptation
 ● short-term focus and neglect of future climate risks
resulting in inadequate attention to the long-term
viability of adaptation solutions
 ● genuine inclusion of stakeholders as well as local
communities, indigenous peoples, women and
other marginalized groups into decision-making
and co-development of adaptation planning
and implementation to reflect differing values,
perspectives and interests and to produce equitable,
fair and just adaptation outcomes
 ● narrow definitions of adaptation success that
neglect diverse views regarding the purpose and
effectiveness of adaptation interventions among
those targeted and that miss elements encompassing
social transformation and climate justice
 ● transparency, accountability and predictability
of support and integration of adaptation into
national development priorities, strategies and the
Sustainable Development Goals (SDGs)
US$ million
3
1
9
1
13
5
5
3
25
48
37
35
35
29
32
30
1
19
22
20
20
2
15
13
2
8
8
1
■ 
■ 
■ 
■ 
VII
Adaptation Gap Report 2022: Too Little, Too Slow
 ●
flexible programming and adaptative management of
implementation to consider feedback and learnings
and to enhance efficiencies
 ●
integration of local, traditional, indigenous and
scientific knowledge into design, implementation
and monitoring and evaluation to enhance buy-in
and ownership
 ●
investment in local capabilities, capacity-building
and democratic governance structures in support
of climate risk management and empowerment for
long-term sustainability
 ● tackling inequalities and structural drivers of
vulnerability in addition to reducing exposure and/
or vulnerabilities to climate hazards to embark on
climate-resilient development pathways.
 ● consideration of future risks, including climate
trajectories and uncertainties, to minimize
unintended consequences and maladaptation, while
enhancing adaptation ambition
Paying attention to these principles when designing,
implementing and assessing adaptation interventions
increases the likelihood of effective, adequate and
sustained outcomes (figure ES.5).
Figure ES.5 An ‘architecture’ of risk reduction, including principles, actions and outcomes that can be used as a basis for
assessing actual or likely adaptation effectiveness  
Principles
Actions
Outcomes
Good practices
based on
adaptation
principles:
Mitigation and 
adaptation actions
that modify
hazards directly
Enhanced
resilience/
reduced risk
• Inclusion
• Co-production
• Transparency
• Equitability
• Devolved
and adaptive
governance
• Local ownership
• Knowledge
and integration
• Avoiding
maladaptation
• Addressing
future risks
• Minimizing
mitigation and
development
trade-offs
• Flexible
• Addressing
structural drivers 
Reduced
hazards
$ 
Adaptation
action to
reduce exposure
to hazards
(infrastructure,
nature-based,
behavioural,
institutional)
lli% 
Improved human
& ecosystem
well-being,
reduced losses
and damages,
compared with
the no-adaptation
baseline
Reduced
exposure
Action on 
structural drivers
of vulnerability
(power, inequality,
marginalization,
politics), improved
institutions, 
Reduced 
vulnerability
governance 
of vulnerability
and policies
Considering interlinkages of adaptation and
mitigation action from the outset in planning,
finance and implementation can enhance
co-benefits.
and damages will occur if mitigation is insufficiently
ambitious. Given this interrelationship and to enhance
synergies while limiting trade-offs, this report devotes
a section in the planning, finance and implementation
chapters to adaptation–mitigation interlinkages. 
Strong mitigation action is needed to limit global warming 
to 1.5°C above pre-industrial levels and avoid reaching 
Taking adaptation and mitigation jointly into account 
most hard adaptation limits. Enhanced adaptation support
is needed to minimize climate impacts, and more losses 
in planning, finance and implementation enhances
opportunities for co-benefits, including ancillary and non-
VIII
Executive Summary
market benefits, and limits trade-offs and maladaptation
(such as hydropower reducing food security or irrigation
increasing energy consumption). Moreover, some climate
solutions effectively reduce climate risk and contribute to
mitigation simultaneously (figure ES.6). However, while
nature-based solutions such as planting and conserving
mangroves, restoring salt marshes or protecting peatlands
effectively reduce climate risks and remove carbon from
the atmosphere, accelerating climate change is also heavily
affecting their ability to provide these climate services.
Data from planning, finance and implementation show
that adaptation–mitigation co-benefits are mainly sought
in the agriculture, forestry, ecosystems, water and energy
sectors. However, possible barriers, trade-offs and risks
are frequently missed, and adaptation and mitigation
actions are often implemented independent of each other.
Addressing these shortcomings will be important to
contribute to the Paris Agreement’s article 2.1(c) goal of
making finance flows consistent with low greenhouse gas
(GHG) emissions and climate-resilient development.
Figure ES.6 Aligning climate change mitigation and adaptation action: differences, synergies and trade-offs 
SYNERGIES
Adaptation solutions that reduce exposure to climate hazards while
simultaneously sequestering carbon (e.g. mangrove restoration that
reduces coastal hazards; increasing urban green spaces to reduce urban
heat island effect).
Mitigation solutions that reduce GHG emissions or enhance carbon
sequestration while simultaneously reducing exposure to climate hazards
(e.g. reforestation that reduces landslide hazard; hydroelectric power that
reduces downstream flood or drought risk).
DIFFERENCES
TRADE-OFFS
Mitigation actions 
I T
I G
A T I O N
Different knowledge
and information required
to inform policymaking
M
that increase exposure
and vulnerability to
climate change 
(e.g. hydropower investments
in hazard-prone areas)
Adaptation actions that 
Distinct stakeholders
Distinct distributional
impacts
(global mitigation 
vs. local adaptation benefits)
(e.g. air conditioning
investments)
A
D
A
P
TA T I O N
undermine mitigation efforts
Source: Adapted from OECD (2021a). Strengthening adaptation-mitigation linkages for a low-carbon, climate-resilient future. OECD
Environment Policy Papers, No. 23. Paris: OECD Publishing. https://doi.org/10.1787/6d79ff6a-en. 
In summary, despite positive signs we must do
much more towards net-zero climate-resilient
development.
 ● Current adaptation practice falls woefully short of
what is required, and following best practices in
adaptation planning and implementation is needed
to improve effectiveness.
 ● Accelerating global warming is increasing climate
impacts and puts countries at serious risk of
experiencing adaptation limits and intolerable losses
and damages. 
 ● Despite the potential for substantial co-benefits to
be realized when considering adaptation-mitigation
interlinkages from the outset, more must be done to
overcome silos and avoid potential trade-offs.
 ● Avoiding hard adaptation limits requires the urgent
scaling-up of mitigation and for adaptation to go
beyond incremental change.
 ● Although efforts in adaptation planning, finance
and implementation are continuing to increase,
signifi cant acceleration and shif ts in scale are needed
to avoid the adaptation gaps from widening further.
 ● Large-scale, non-climate and compounding factors
continue to jeopardize adaptation investments and
outcomes, and strong political will is needed for
the international climate community to build on the
Glasgow Climate Pact, agreed during COP 26 in 2021,
and to deepen collective commitments on net-zero,
adaptation, climate finance, and loss and damage.
IX
UN@» 
environment
programme 
United Nations Avenue, Gigiri
P O Box 30552, 00100 Nairobi, Kenya
Tel +254 720 200200
[email protected]
www.unep.org
[JUE 
EIIE.IT 
IEIlE 
The Closing Window
Climate crisis calls for rapid transformation
of societies
Executive Summary
Emissions Gap Report 2022
Emissions Gap Report 2022: The Closing Window
© 2022 United Nations Environment Programme
ISBN: 978-92-807-3979-4
Job number: DEW/2477/NA
This publication may be reproduced in whole or in part and in any form for educational or non-profit services without
special permission from the copyright holder, provided acknowledgement of the source is made. The United Nations
Environment Programme would appreciate receiving a copy of any publication that uses this publication as a source.
No use of this publication may be made for resale or any other commercial purpose whatsoever without prior permission
in writing from the United Nations Environment Programme. Applications for such permission, with a statement of the
purpose and extent of the reproduction, should be addressed to the Director, Communication Division, United Nations
Environment Programme, P.O. Box 30552, Nairobi 00100, Kenya.
Disclaimers
The designations employed and the presentation of the material in this publication do not imply the expression of any
opinion whatsoever on the part of the Secretariat of the United Nations concerning the legal status of any country,
territory or city or its authorities, or concerning the delimitation of its frontiers or boundaries.
Some illustrations or graphics appearing in this publication may have been adapted from content published by third
parties. This may have been done to illustrate and communicate the authors’ own interpretations of the key messages
emerging from illustrations or graphics produced by third parties. In such cases, the material in this publication does not
imply the expression of any opinion whatsoever on the part of the United Nations Environment Programme concerning
the source materials used as a basis for such graphics or illustrations.
Mention of a commercial company or product in this document does not imply endorsement by the United Nations 
Environment Programme or the authors. The use of information from this document for publicity or advertising is not 
permitted. Trademark names and symbols are used in an editorial fashion with no intention on infringement of trademark
or copyright laws.
The views expressed in this publication are those of the authors and do not necessarily reflect the views of the United
Nations Environment Programme. We regret any errors or omissions that may have been unwittingly made.
© Maps, photos and illustrations as specified
Suggested citation
United Nations Environment Programme (2022). Emissions Gap Report 2022: The Closing Window — Climate crisis calls
for rapid transformation of societies — Executive Summary. Nairobi. https://www.unep.org/emissions-gap-report-2022
Co-produced with:
UNEP Copenhagen Climate Centre (UNEP-CCC) and CONCITO – Denmark’s green think tank.
('..;;..) 
UN
8.09.
� 
CONCITO 
environment
programme 
copenhagen
climate centre 
DENMARK'S GREEN THINK TANK 
Supported by:
( climateworks 
(((] FoNATioN 
�I 
The 
W Federal Government 
U 
MINISTRY OF FOREIGN AFFAIRS
OF DENMARK 
.
. 
I 
I 
Sweden 
Government of the Netherlands 
n Sverige 
UNEP promotes
environmentally sound 
practices globally and
in its own activities. Our 
II
distribution policy aims to reduce 
UNEP's carbon footprint.
The Closing Window
 
Climate crisis calls for rapid
transformation of societies
Executive Summary
Emissions Gap Report 2022
III
Emissions Gap Report 2022: The Closing Window
Executive summary
1.
 Testimony to inadequate action on the climate
crisis and the need for transformation
of opportunity to limit global warming to well below 2°C,
preferably 1.5°C. Every fraction of a degree matters.
This thirteenth edition of the Emissions Gap Report is
testimony to inadequate action on the global climate crisis,
and is a call for the rapid transformation of societies. Since
the twenty-sixth United Nations Climate Change Conference
of the Parties (COP 26), there has been very limited progress
in reducing the immense emissions gap for 2030, the
gap between the emissions reductions promised and the
emissions reductions needed to achieve the temperature
goal of the Paris Agreement, illustrated in the following:
At COP 26 last year, this dire situation was recognized,
and countries were called upon to “revisit and strengthen”
their 2030 targets by the end of 2022. Consequently, a key
question for this edition of the Emissions Gap Report is,
what progress has been made in ambition and action since
COP 26, and how can the necessary transformations be
initiated and accelerated?
 ▶ Countries’ new and updated nationally determined
contributions (NDCs) submitted since COP 26
reduce projected global greenhouse gas (GHG)
emissions in 2030 by only 0.5 gigatons of CO2 
The report considers transformations required in the
sectors of electricity supply, industry, transport and
buildings. It furthermore investigates cross-cutting systemic
transformations of food systems and the financial system,
illustrating that there is immense potential to reduce
emissions beyond current mitigation pledges.
equivalent (GtCO2e), compared with emissions 
projections based on mitigation pledges at the time
of COP 26.
The climate crisis is part of the triple planetary crisis of
climate change, pollution and biodiversity loss. This year, the
world is witnessing compounding energy, food and cost of
living crises, exacerbated by the war in Ukraine, all of which
are causing immense human suffering.
 ▶ Countries are off track to achieve even the globally
highly insufficient NDCs. Global GHG emissions
in 2030 based on current policies are estimated
at 58 GtCO2e. The implementation gap in 2030
between this number and NDCs is about 3 GtCO2e
for the unconditional NDCs, and 6 GtCO2e for the
conditional NDCs.
 ▶
Several methodological improvements and updates have
been made this year to improve the estimates and ensure
consistency across the chapters of this report. These
changes, along with their implications for the interpretation
of the report results, are described in detail in the report
chapters and online appendices. However, it is important
to note that these improvements imply that the estimates
presented are not directly comparable to those of
previous reports.
The emissions gap in 2030 is 15 GtCO2e annually
for a 2°C pathway and 23 GtCO2e for a 1.5°C
pathway. This assumes full implementation of
the unconditional NDCs, and is for a 66 per cent
chance of staying below the stated temperature
limit. If, in addition, the conditional NDCs are fully
implemented, each of these gaps is reduced by
about 3 GtCO2e.
2.
 Global GHG emissions could set a new record
in 2021
 ▶
Policies currently in place with no additional action
are projected to result in global warming of 2.8°C
over the twenty-first century. Implementation
of unconditional and conditional NDC scenarios
reduce this to 2.6°C and 2.4°C respectively.
 ▶
Estimates of land use, land-use change and forestry (LULUCF)
are currently only available up to 2020, limiting our analysis
of total global GHG emissions for 2021. However, global GHG
emissions for 2021, excluding LULUCF, are preliminarily
estimated at 52.8 GtCO2e, a slight increase compared to
2019, suggesting that total global GHG emissions in 2021 will
be similar to or even break the record 2019 levels (fi gure ES.1). 
To get on track for limiting global warming to 1.5°C,
global annual GHG emissions must be reduced by
45 per cent compared with emissions projections
under policies currently in place in just eight years,
and they must continue to decline rapidly after
2030, to avoid exhausting the limited remaining
atmospheric carbon budget.
This confirms earlier findings that the global response to the
COVID-19 pandemic led to an unprecedented but short-lived
reduction in global emissions. Total global GHG emissions 
dropped 4.7 per cent from 2019 to 2020. This decline was 
As these headline findings illustrate, incremental change
is no longer an option: broad-based economy-wide
transformations are required to avoid closing the window 
driven by a sharp decline in CO2 emissions from fossil fuels
and industry of 5.6 per cent in 2020. However, CO2 emissions
rebounded to 2019 levels in 2021, with global coal emissions
exceeding 2019 levels. Methane and nitrous oxide emissions
remained steady from 2019 to 2021, and fluorinated gases
continued to surge.
IV
Emissions Gap Report 2022: The Closing Window
3.
Global GHG emissions have continued to grow in the past
10 years, but the rate of growth has slowed compared to the
previous decade. Between 2010 and 2019, average annual
growth was 1.1 per cent per year, compared to 2.6 per cent
per year between 2000 and 2009. Thirty-five countries
accounting for about 10 per cent of global emissions have
peaked in CO2 and other GHG emissions, but their reductions
have been outweighed by global emissions growth elsewhere.
 GHG emissions are highly uneven across
regions, countries and households
The top seven emitters (China, the EU27, India, Indonesia,
Brazil, the Russian Federation and the United States
of America) plus international transport accounted for
55 per cent of global GHG emissions in 2020 (figure ES.1).
Collectively, G20 members are responsible for 75 per cent
of global GHG emissions. 
Estimates of LULUCF emissions and sinks are substantial,
but also deeply uncertain. Based on national inventories, the
LULUCF sector was a net sink in 17 of the G20 member States
in 2020, including in China, the United States of America,
India, the EU27 and the Russian Federation. GHG emissions
excluding LULUCF in these countries are therefore higher, by
as much as 33 per cent in the Russian Federation, 17 per cent
in the United States of America, 9 per cent in India, and about
8 per cent in China and in the EU27. By contrast, the LULUCF
sector is a net emitter in Indonesia and Brazil, accounting for
44 per cent and 22 per cent of their emissions respectively.
Per capita emissions vary greatly across countries
(figure  ES.1). World average per capita GHG emissions
(including LULUCF) were 6.3 tons of CO2 equivalent (tCO2e)
in 2020. The United States of America remains far above
this level at 14 tCO2e, followed by 13 tCO2e in the Russian
Federation, 9.7 tCO2e in China, about 7.5 tCO2e in Brazil
and Indonesia, and 7.2 tCO2e in the European Union.
India remains far below the world average at 2.4 tCO2e.
On average, least developed countries emit 2.3 tCO2e per
capita annually.
Figure ES.1 Total and per capita GHG emissions of major emitters in 2020, including inventory-based LULUCF
Total GHG emissions
China
USA
India
EU27
Indonesia
Russian
Federation
LULUCF CO2
Brazil
Fossil CO2 FFI,
CH4, N2O, F−gases
International
transport
-3
0
3
6
9
12
15
0
GtCO2e
Per capita GHG emissions
USA
Russian
Federation
China
Brazil
Indonesia
EU27
_I 
_ 
World
3 
India
0
3
6
9
12
15
tCO2e/capita
V
Emissions Gap Report 2022: The Closing Window
Consumption-based emissions are also highly unequal
between and within countries. When emissions associated
with both household consumption and public and private
investments are allocated to households, and households
are ranked by GHG emissions (excluding LULUCF), the
bottom 50 per cent emit on average 1.6 tCO2e/capita and
contribute 12 per cent of the global total, whereas the top
1 per cent emit on average 110 tCO2e/capita and contribute
17 per cent of the total. High-emitting households are
present across all major economies, and large inequalities
now exist both within and between countries.
revisit and strengthen their 2030 mitigation targets to align
with the temperature goal of the Paris Agreement. Between
1 January 2020 and 23 September 2022 (the cut-off date
used for this report), 166 parties representing around 91 per
cent of global GHG emissions had submitted new or updated
NDCs, up from 152 parties as of COP 26. As the European
Union and its 27 member States submit a single NDC, 139
new or updated NDCs have been submitted. Relative to
initial NDCs, a larger share includes GHG emission targets,
coverage of sectors and gases is generally greater, and more
include unconditional elements.
4.
 Despite the call for countries to “revisit and
strengthen” their 2030 targets, progress since
COP 26 is highly inadequate
In total and if fully implemented, the new or updated
unconditional NDCs are estimated to result in an annual
additional reduction of 4.8 GtCO2e by 2030 relative to the
initial NDCs. Progress since COP 26 amounts to about
0.5 GtCO2e, mainly resulting from new or updated NDCs
from Australia, Brazil, Indonesia and the Republic of Korea
(figure ES.2).
As part of the Paris Agreement’s five-year ambition-raising
cycle, countries were requested to submit new or updated
NDCs in time for COP 26. The Glasgow Climate Pact,
adopted in 2021 at COP 26, further requested countries to 
Figure ES.2 Impact on global GHG emissions in 2030 of new and updated unconditional NDCs relative to initial NDCs 
MtCO2e
0
-500
-1,000
-1,500
-2,000
- 
-2,500
• - ■ mp 
-3,000
-3,500
-4,000
-4,500
-5,000
Impact of new and updated NDCs (decrease in emissions)
Impact of new and updated NDCs (increase in emissions)
Impact since COP 26
Total impact
Zero impact, no new or updated NDC
VI
Argentina
Australia
Brazil
Canada
China
EU27
India
Indonesia
Japan
Mexico
Russian Federation
Saudi Arabia
South Africa
Türkiye
United Kingdom
United States
of America
Non-G20
Other factors
Other factors
T otal T otal
Republic of Korea
•
• 
• 
• 
Emissions Gap Report 2022: The Closing Window
5.
 G20 members are far behind in delivering
on their mitigation commitments for 2030,
causing an implementation gap 
Current commitments by countries as expressed in their
unconditional and conditional NDCs for 2030 are estimated
to reduce global emissions by 5 and 10 per cent respectively,
compared with current policies and assuming that they are
fully implemented. To get on track for limiting global warming
to below 2.0°C and 1.5°C, global GHG emissions must be
reduced by 30 and 45 per cent respectively, compared with
current policy projections.
Most of the G20 members that have submitted stronger NDC
targets since 2020 have just started the implementation
of policies and actions to meet their new targets. Those
that are currently projected to meet their NDC targets are
countries that have either not updated their original NDCs,
or did not strengthen or only moderately strengthened their
target levels in their updated NDCs. All other G20 members
will need additional policies to achieve their NDCs.
The central estimate of aggregate emissions projections
for G20 members in 2030 under current policies decreased
by 1.3 GtCO2e compared with the 2021 assessment, mainly
due to the projected emission reductions from the Inflation
Reduction Act in the United States of America (about
1 GtCO2e).
Collectively, the G20 members are not on track to achieve 
Full implementation of unconditional NDCs is estimated to
result in a gap with the 1.5°C scenario of 23 GtCO2e (range:
19–25 GtCO2e) (table ES.1, table ES.2 and figure ES.3). This
estimate is about 5 GtCO2e smaller than in the 2021 edition
of the Emissions Gap Report. However, this difference is
almost entirely due to methodological updates and updates
to the 1.5°C scenarios. The emissions in 2030 are higher
under the updated 1.5°C scenarios, because they start their
reductions from the most up-to-date historical emissions,
which have increased over the past 5 years. This does not
come without consequences, as on average these scenarios
have a lower chance of effectively keeping warming to 
their new or updated NDCs. Based on current policies 
1.5°C. If the conditional NDCs are also fully implemented, 
scenario projections in independent studies, there is an
implementation gap, defined as the difference between
projected emissions under current policies and projected
emissions under full implementation of the NDCs. This
implementation gap is 1.8 GtCO2e annually by 2030 for
the G20 members. For two G20 members, the Russian
Federation and Türkiye, the projected emissions under their
NDCs have consistently been significantly above current
policies projections, thereby lowering the implementation
gap compared to what can reasonably be expected. If NDC
projections are substituted by current policies scenario
projections for these two members, the G20 members
would collectively fall short of achieving their NDCs by 2.6
GtCO2e annually by 2030.
the 1.5°C emissions gap is reduced to 20 GtCO2e (range:
16–22 GtCO2e).
The emissions gap between unconditional NDCs and below
2°C pathways is about 15 GtCO2e (range: 11–17 GtCO2e),
which is about 2 GtCO2e larger than that which was reported
last year. The main reason for this increase is that this year’s
report corrects for discrepancies in historical emissions
through harmonization. If the conditional NDCs are also fully
implemented, the below 2°C emissions gap is reduced to 12
GtCO2e (range: 8–14 GtCO2e).
Beyond G20 members, the global implementation gap
for 2030 is estimated to be around 3 GtCO2e for the
unconditional NDCs and 6 GtCO2e for the conditional NDCs.
Emissions under current policies are projected to reach 58
GtCO2e in 2030. This is 3 GtCO2e higher than the estimate
of last year’s report. About half of the increase is due to
the harmonization, about one quarter to the change of
global warming potentials (GWPs), and the remainder to the
methodological choice of only selecting model studies that
explicitly account for the most recent current polices and
NDC estimates.
6.
     Globally,    the    NDCs    are    highly    insufficient,    and    
the emissions gap remains high
The emissions gap for 2030 is defined as the difference
between the estimated total global GHG emissions resulting
from the full implementation of the NDCs, and the total
global GHG emissions from least-cost scenarios that keep
global warming to 2°C, 1.8°C or 1.5°C, with varying levels of
likelihood.
VII
Emissions Gap Report 2022: The Closing Window
Figure ES.3 Global GHG emissions under different scenarios and the emissions gap in 2030 (median estimate and tenth
to ninetieth percentile range) 
GtCO2e
70
Current policies scenario
Unconditional NDC scenario
Conditional
NDC scenario
15
2°C
range
Blue area shows pathways
limiting global temperature 
increase to below 2°C with 
about 66% chance
1.8°C
range
1.5°C
range
Table ES.1 Global total GHG emissions in 2030 and the estimated emissions gap under different scenarios
GHG emissions in 2030
(GtCO2e)
Estimated emissions gap in 2030 (GtCO2e)
Below 2.0°C 
Below 1.8°C
Median and range
Below 1.5°C
Year 2010 policies 
66 (64–68)
-
-
-
Current policies 
58 (52–60)
17 (11–19)
23 (17–25)
25 (19–27)
Unconditional NDCs
55 (52–57)
15 (12–16)
21 (17–22)
23 (20–24)
Conditional NDCs 
52 (49–54)
12 (8–14)
18 (14–20)
20 (16–22)
VIII
Note: The gap numbers and ranges are calculated based on the original numbers (without rounding), and these may differ from the
rounded numbers in the table. Numbers are rounded to full GtCO2e. GHG emissions have been aggregated with global warming potential
over 100 years (GWP100) values of the Intergovernmental Panel on Climate Change Sixth Assessment Report (IPCC AR6).
Green area shows pathways
limiting global temperature
increase to below 1.5°C with
a 66% chance by 2100 and
minimum 33% chance over
the course of the century
Conditional NDC case
Unconditional NDC case 
GtCO2e
23
GtCO2e
20
Remaining
gap to stay
within 2°C
Remaining
gap to stay
within 2°C
GtCO2e
Conditional NDC case
Unconditional NDC case 
limit
limit
Median
estimate
of level
consistent
with 2°C:
41 GtCO2e
(range: 37–46)
Median
estimate
of level
consistent
with 1.5°C:
33 GtCO2e
(range: 26–34)
2010 policies scenario
60
50
GtCO2e
12
40
30
20
2015
2020
2025
2030
Emissions Gap Report 2022: The Closing Window
Table ES.2 Global total GHG emissions in 2030 and global warming characteristics of different scenarios consistent with
limiting global warming to specific temperature limits 
Global total GHG
emissions (GtCO2e)
Estimated temperature outcome
Closest
approximate
Scenario
Number of
scenarios
In 2030
In 2050 50% chance 66% chance 90% chance
IPCC AR6 Working
Group (WG) III
scenario class
Peak:  
Peak:  
Peak:  
Below 2.0°C 
(66% chance)*
41  
20 
195
(37–46)
(16–24)
1.7–1.8°C
In 2100: 
1.4–1.7°C
1.8–1.9°C
In 2100: 
1.6–1.9°C
2.2–2.4°C
In 2100: 
2.0-2.4°C
C3a
Peak:  
Peak:  
Peak:  
Below 1.8°C 
(66% chance)*
35  
12  
139
(28–40)
(8–16)
1.5–1.7°C
In 2100:
1.3–1.6°C
1.6–1.8°C
In 2100: 
1.4–1.7°C
1.9–2.2°C
In 2100: 
1.8–2.2°C
N/A
Below 1.5°C
(66% in 2100 
Peak:  
Peak:  
Peak:  
33  
8  
50
with no or limited 
(26–34)
(5–13)
overshoot)*
1.5–1.6°C
In 2100: 
1.1–1.3°C
1.6–1.7°C
1.9–2.1°C
C1a
In 2100:  
In 2100:  
1.2–1.5°C
1.6–1.9°C
* Values represent the median and tenth to ninetieth percentile range across scenarios. Percentage chance refers to peak warming at
any time during the twenty-first century for the below 1.8°C and below 2.0°C scenarios. When achieving net-negative CO2 emissions
in the second half of the century, global warming can be further reduced from these peak warming characteristics, as illustrated by
the “Estimated temperature outcome” columns. For the below 1.5°C scenario, the chance applies to the global warming in the year
2100, while the “no or limited overshoot” characteristic is captured by ensuring projections do not exceed 1.5°C with more than 67 per
cent chance over the course of the twenty-first century or, in other words, that the lowest chance of warming being limited to 1.5°C
throughout the entire twenty-first century is never less than 33 per cent. This definition is identical to the C1 category definition used by
the IPCC AR6 WG III report. Compared to IPCC (2022), the Emissions Gap Report analysis also selects scenarios based on whether or
not they assume immediate action.
Note: GHG emissions in this table have been aggregated with GWP100 values of IPCC AR6.
7.
 Without additional action, current policies
lead to global warming of 2.8°C over this
century. Implementation of unconditional and
conditional NDC scenarios reduce this
to 2.6°C and 2.4°C respectively
A continuation of the level of climate change mitigation
effort implied by current unconditional NDCs is estimated
to limit warming over the twenty-first century to about 2.6°C
(range: 1.9–3.1°C) with a 66 per cent chance, and warming
is expected to increase further after 2100 as CO2 emissions
are not yet projected to reach net-zero levels.
Global warming levels only get close to the Paris Agreement
temperature goal if full implementation of the highly
uncertain net-zero pledges is assumed. Achieving net-zero
targets in addition to unconditional NDCs results in keeping
projected global warming to 1.8°C (range: 1.8–2.1°C) with
a 66 per cent chance. Assuming that conditional NDCs
and pledges are achieved and followed by net-zero targets,
global warming is similarly projected to be kept to 1.8°C
(range: 1.7–1.9°C) with a 66 per cent chance. However, in
most cases, neither current policies nor NDCs currently
trace a credible path from 2030 towards the achievement
of national net-zero targets.
Continuing the efforts of conditional NDCs lowers these
projections by around 0.2°C to 2.4°C (range: 1.8–3.0°C) with
a 66 per cent chance. As current policies are insufficient
to meet even the unconditional of NDCs, a continuation of 
8.
 The credibility and feasibility of the net-zero
emission pledges remains very uncertain
current policies would result in about 0.2°C higher estimates 
Globally, 88 parties covering approximately 79 per cent of 
of 2.8°C (range: 1.9–3.3°C) with a 66 per cent chance.
global GHG emissions have now adopted net-zero targets, 
IX
Emissions Gap Report 2022: The Closing Window
either in law (21), in a policy document such as an NDC or a
long-term strategy (47), or in an announcement by a highlevel
government
official
(20).
This
is
up
from
74
parties
at

COP
26.
An
additional
eight
parties
covering
an
additional

2
per
cent
of
global
GHG
emissions
have
another
(nonnet-zero)
GHG
mitigation
target
as
part
of
their
long-term

strategies.
made. This will require not just incremental sector-bysector
change,
but
wide-ranging,
large-scale,
rapid
and

systemic
transformation.
This
will
not
be
easy,
given
the

many
other
pressures
on
policymakers
at
all
levels.
Climate

action is
imperative
in
all
countries
but
must
be
achieved

simultaneously
with
other
United
Nations
Sustainable

Development
Goals.
Focusing on the G20 members, 19 members have
committed to achieving net-zero emissions, up from 17
at COP 26. These targets vary in a number of important
respects, including their legal status; time frame; explicit
consideration of fairness and equity; which sources, sectors
and gases they cover; whether they will allow the use of
international offsets to count towards their achievement;
the level of detail they provide on the role of CO2 removal;
and the nature of planning, review of and reporting on target
implementation.
The transformation towards zero GHG emissions in the
sectors of electricity supply, industry, transportation and
buildings is under way. However, increased and accelerated
action is needed if these are to happen at the pace and
scale required to limit global warming to well below 2°C,
preferably 1.5°C.
Figure ES.4 visualizes the necessary direction for countries
to move from their current emission levels to their NDC 
Of these four sectors, electricity supply is the most
advanced, as the costs of renewable electricity have
reduced dramatically. Still, major obstacles continue to exist,
including ensuring that transformations are just and deliver
energy access for people who are currently not served.
Furthermore, the impacts on communities and nations, and 
targets for 2030, and indicates the net-zero targets for each 
existing fossil energy companies and supply chains, must 
G20 member that has a net-zero target (noting that France,
Germany and Italy are only assessed as part of the European
Union). Those G20 members whose emissions have already
peaked will need to further accelerate their emission
declines to their net-zero target year, while members whose
emissions will continue to increase through 2030 under the
NDCs will require further policy shifts and investments –
including adequate support to developing countries, where
applicable – to achieve the emissions reductions implied by
their national net-zero targets.
be handled, and grid integration of large shares of renewable
energy must be prepared. For building operations and road
transport, the most effi cient technologies currently available
need to be applied, while for industry, and shipping and
aviation, zero-emissions technologies need to be further
developed and deployed. 
The following broad portfolio of key actions to initiate and
advance the transformation must be undertaken, tailored to
the specific context of each of the four sectors:
This illustration does not consider the relative merits
in terms of equity or fairness of the choices countries
make regarding their NDCs or their nationally determined
pathways to net-zero. However, it brings to the fore the
discrepancies between short-term policy implementation,
midterm targets and long-term targets. It also serves as an
important reminder that current evidence does not provide
confidence that the nationally determined net-zero targets
will be achieved.
 ▶
avoiding lock-in of new fossil fuel intensive
infrastructure
 ▶
enabling the transition by further advancing zerocarbon
technologies,
market
structures
and
plans
for

a
just
transformation
 ▶
applying zero-emissions technologies and promoting
behavioural change to sustain and deepen reductions
to reach zero emissions 
9.
 Wide-ranging, large-scale, rapid and systemic
transformation is now essential to achieve the
temperature goal of the Paris Agreement
The task facing the world is immense: not just to set more
ambitious targets, but also to deliver on all commitments 
All actors have roles to play in initiating and accelerating
the transformation, including in the removal of barriers
that stand in the way of progress (table ES.3). While any
individual actions may not amount to significant enough
change, taken together they can spur more far-reaching,
durable, systemic change.
X
Emissions Gap Report 2022: The Closing Window
Figure ES.4 Emissions trajectories implied by NDC and net-zero targets of G20 members.
National emissions in MtCO2e/year over time. 
Argentina
Australia
Brazil
Canada
400
600
1500
800
]·=. 
0
0
0
0
ls. 
2020 2040 2060
2020 2040 2060
2020 2040 2060
2020 2040 2060
China
EU27
Mexico
India
Indonesia
@ 
@ 
d. 
- 
@ 
... 
15000
I 
3500
5000
2500
0
0
0
0
2020 2040 2060
2020 2040 2060
2020 2040 2060
2020 2040 2060
·- : 
I 
L 
• 
6 
Japan
Republic of Korea
Russian Federation
Saudi Arabia
• 
'·; 
• 
e 
1500
800
2500
800
0
0
0
0
2020 2040 2060
2020 2040 2060
2020 2040 2060
2020 2040 2060
I,�',,��
• • • 
@ 
South Africa
Türkiye
United Kingdom
USA
$ 
(I 
• 
6 
­ 
600
I 
1000
600
6000
0
0
0
0
I\\,({� 
.,�--,� 
2020 2040 2060
2020 2040 2060
2020 2040 2060
Net-zero GHG targets
Historical data
Net-zero CO2 targets
Emissions trend until 2030 implied by NDC targets
Net-zero with unclear or 
Linear continuation of the emissions trend implied 
CO2-only coverage
by NDC targets
XI
2020 2040 2060
• '­ 
...._,, 
...._,, 
@ 
• 
6) 
• 
...._,, 
@ 
Emissions Gap Report 2022: The Closing Window
Table ES.3 Important actions to accelerate transformations in electricity supply, industry, transportation and buildings by
different actors
XII
1
Table ES1 Important actions to accelerate transformations in electricity supply, industry, transportation 
  and buildings by different actors
• l >S 
{ 
0° 
 
ELECTRICITY SUPPLY
INDUSTRY
TRANSPORTATION
BUILDINGS
National
governments
R
Remove fossil fuel
subsidies in a socially
acceptable manner
R Support zero-carbon
industrial processes
R Promote circular
material flow
R
R Set mandates to
switch to zeroemissions
road

vehicles
by
specific

dates
R Regulate towards
zero-carbon building
stock
Remove barriers
to expansion of
renewables
R Incentivize zerocarbon
building
stock
R Promote
electrification
R
R Regulate and
incentivize zerocarbon
fuels
for

aviation
R Facilitate zero-carbon
building stock
Stop expansion
of fossil fuel
infrastructure
R Support alternative
carbon pricing
mechanisms
R
Plan for a just fossil
fuel phase-out
R Adjust taxation/
pricing schemes
R Support research and
innovation
R
Adapt market rules
of electricity system 
R Invest in zeroemissions
transport
R Promote low-carbon
products 
for high shares of 
infrastructure
renewables
R Plan for a just
transformation
International
cooperation
R
Cooperate on a just
coal phase-out 
R Cooperate on
zero-carbon basic
materials
R Cooperate on
financing and policy
development
R Provide access and
favourable conditions
to finance
R
Support initiatives
on emissions-free
electricity, power
system flexibility
and interconnection
solutions
R Cooperate on
hydrogen
R Coordinate on target
setting and standards
R Support skills and
knowledge growth
R Share best practice
Subnational
governments 
R
Set 100 per cent
renewable targets 
R Engage in regional
planning and
regulations
R
R Plan infrastructure
and supporting
policies that reduce
travel demand
R Implement zeroemissions
building

stock
plans
Plan for a just fossil
fuel phase-out
R Cooperate with
various stakeholders
R Adjust taxation/
pricing schemes
R Integrate lowemissions
requirements
in
urban

planning
R Add requirements
that go beyond the
national level 
Businesses
R Support a 100 per
cent renewable
electricity future
R Plan and implement
zero-emissions
transformation
R Work towards
zero-emissions
transportation
R Construction and
building material
companies review
business models 
R Design long-lived
products 
R Reduce travel in
operations
R Achieve zero-carbon
owned or rented
building stock
R Create circular
supply chain 
Investors,
private and
development
banks 
R Engage with or
divest from fossil
fuel electricity utility
companies
R Engage with or divest
from emissionsintensive
industry
R Invest in zeroemissions
transport

infrastructure
R Adjust strategy and
investment criteria for
zero-carbon building
stock 
R Invest in low-carbon
energy and process
technologies
R Support zeroemissions
vehicles,

vessels
and
planes
R Do not invest in or
insure new fossil fuel
infrastructure
R Support building
renovation
 
R Drive awareness of
climate risks
Citizens
R Purchase 100 per cent
renewable electricity
R Consume sustainably 
R Adopt active mobility
practices
R Retrofit for improved
carbon footprint
R Lobby
R Use public
transportation
R Tenants challenge
landlords
R Use zero-emissions
vehicles
R Adopt energy-saving
behaviour 
R Avoid long-haul flights
Emissions Gap Report 2022: The Closing Window
10.
 The food system accounts for one third
of all emissions, and must make a large
reduction 
(5.7 GtCO2e, 32 per cent), and supply chain activities (5.2
GtCO2e, 29 per cent). The latter includes retail, transport,
consumption, fuel production, waste management,
industrial processes and packaging.
Food systems are major contributors not only to climate
change, but also to land-use change and biodiversity loss,
depletion of freshwater resources, and pollution of aquatic
and terrestrial ecosystems. Adopting a food systems lens
implies a cross-sectoral approach that explicitly connects
supply and demand sides, and all actors of the food supply
chain. It facilitates identifying synergies and trade-offs
across interconnected environmental, health and economic
dimensions, but the inclusion of several sectors makes
computation of emissions more difficult, and increases
risks of double counting. 
Projections indicate that food system emissions could reach
ca 30 GtCO2e/year by 2050. To get on an emissions pathway
aligned with the Paris Agreement temperature goal, food
systems will have to be rapidly transformed across multiple
domains. Required transformations include shifting diets,
protecting natural ecosystems, improving food production
and decarbonizing the food value chain. Each transformation
domain includes several mitigation measures. The potential
to reduce GHG emissions is up to 24.7 GtCO2e/year in 2050
(figure ES.5).
The food system is currently responsible for about a third
of total GHG emissions, or 18 GtCO2e/year (range: 14–22
GtCO2e). The largest contribution stems from agricultural
production (7.1 GtCO2e, 39 per cent) including the production
of inputs such as fertilizers, followed by changes in land use 
Transforming food systems is not only important for
addressing climate change and environmental degradation,
but also essential for ensuring healthy diets and food security
for all. Actions by all major groups of actors is required to
drive transformations forward and to overcome barriers.
Figure ES.5 Food systems emissions trajectory and mitigation potentials by transformation domain
XIII
GHG emissions (GtCO2e)
30
Demand-side
changes
25
Less loss and waste
Flexitarian diets
Pescatarian diets
Vegetarian diets
Vegan diets
Reduce conversion of
coastal wetlands
20
J 
■
■
■
■
■ 
Protection of
ecosystems
Reduce conversion of
peatlands
15
Reduce conversion of
grasslands
-, 
■
■ 
Farm-level
improvements
iiiiii 
Reduce deforestation
■ 
10
Decarbonizing
supply chain
- - 
5
■
■
■
■
■ 
2°C
Manure management
Crop nutrient management
Rice management
Feed composition
Soil carbon management
in grassland
Soil carbon management
in croplands
0
2015 2030 2050
Target
Decarbonize supply chains
■
■ 
Emissions Gap Report 2022: The Closing Window
11.
 Realignment    of    the    financial
system is a critical enabler
of the transformations needed 
Development banks, including green banks, can play
a more active role to stimulate financial markets
as newer product markets are being accelerated.
Multilateral development banks can support market
creation through shifting financial flows, stimulating
innovation and helping to set standards (e.g. for fossil
fuel exclusion policies, GHG accounting and climate
risk disclosure).
A realignment of the financial system is vitally important
to enable the transformations needed are to be achieved.
The financial system is a network of private and public
institutions such as banks, institutional investors and
public institutions that regulate the safety and soundness
of the system, but also co-lend or finance directly. A global
transformation from a heavily fossil fuel- and unsustainable
land use-dependent economy to a low-carbon economy is
expected to require investments of at least US$4–6 trillion
a year, a relatively small (1.5–2 per cent) share of total
financial assets managed, but significant (20–28 per cent)
in terms of the additional annual resources to be allocated.
The IPCC assesses that global mitigation investments
need to increase by a factor of three to six, and even more
for developing countries (figure ES.6). Financial systems
change is required to enable such a global transformation.
 ▶ Mobilize central banks. Central Banks are increasingly
addressing the climate crisis. In December 2017,
eight central banks and supervisors established the
Network for Greening the Financial System, which
has now grown to 116 members and 18 observers.
Mandates of central banks in developing countries are
often broader than those of central banks in developed
countries; more concrete action towards this approach
can therefore be observed. For example, the Reserve
Bank of India requires that commercial banks allocate a
certain proportion of lending to a list of “priority sectors”,
including renewable energy, and Bangladesh Bank has 
To date, most financial actors have shown limited action on 
introduced a minimum credit quota of 5 per cent that 
climate change mitigation because of short-term interests
and conflicting objectives, and because climate risks are not
adequately recognized. Six approaches to bringing about a
financial system that is capable of the shifting of finance
flows needed for systemic transformation are identified: 
financial institutions must allocate to green sectors. 
 ▶
 ▶
Set up climate clubs and cross-border finance initiatives.
These can include just transition partnerships, and can
alter policy norms and change the course of finance
through credible financial commitment devices
on cross-border financial flows, such as sovereign
guarantees. 
Increase the efficiency of financial markets.
Key interventions include the provision of better
information, including taxonomies and transparency,
on climate risks. In developing country contexts,
priorities will include capacity-building and
strengthening institutions.
 ▶
Evidence on the effectiveness of the six approaches above
suggests that there is no single “silver bullet”. Instead, nested
and coordinated approaches are needed, tailored to contexts,
and implemented across major groups of countries, with
equity and “just transition” within and between countries.
The success of such coordinated and cooperative action,
depend, ultimately, on public support and pressures to avert
the significant risks of inaction, and the willingness of key
financial system actors to take on their roles.
Introduce carbon pricing. This can be done through
policy instruments such as carbon taxes or capand-trade
systems.
Emissions-trading
schemes

and
carbon
taxes
now
cover
30
per
cent
of
all
global

emissions,
with
a
global
average
price
of
US$6
per

ton
of
CO2.
Both
the
coverage
and
the
price
are

insufficient
for
transforming
the
financial
system:
the

International
Monetary
Fund
has
suggested
a
global

average
price
of
US$75
as
required
by
2030.
 
 ▶ Nudge financial behaviour. Climate finance markets
are subject to deep information asymmetry, risk
aversion and herd behaviour, all of which result in
inefficient choices. Policy “nudges” can achieve
better results, with strong public policy interventions,
taxation, spending and regulations positively
influencing behaviour.
 ▶ Create markets. Public policy action can remove
existing market distortions and accelerate new
product markets for low-carbon technology, pushing
innovation through public finance, and replacing
older, inefficient and fossil fuel-based technology. 
XIV
Emissions Gap Report 2022: The Closing Window
Figure ES.6 Finance flows and mitigation investment needs per sector, type of economy and region (averaged until 2030) 
Actual yearly flow compared to average annual needs (billion US$2015/year)
Sector
0
500
1000
1500
2000
Energy efficiency
(IEA)
Average flows
(2017–2020)
x2
x7
Transport
•
• 
Annual mitigation
investment needs
(averaged until 2030)
x7 x7
Electricity
x2
Multiplication factors
x5
Agriculture,
forestry and
low
other land use
x10 x31
high
CO 
0
0 
Actual yearly flow compared to average annual needs (billion US$2015/year)
0
1000
2000
3000
Type of
economy
Value GDP share
Developing
countries
x4
x7
4%
9%
Developed
countries
2%
4%
x3
x5
low
high
Actual yearly flow compared to average annual needs (billion US$2015/year)
Region
0
300
600
900
1200
East Asia
x2
x4
North America
= 
m. 
x3
x6
Europe
x2
x4
»Omo 
South Asia
x7
x14
CO 
Latin America
and Caribbean
x4
x8
-»OO 
Japan, Australia
x3 x7
and New Zealand
CO 
Eastern Europe and
West-Central Asia
x7
x15
Africa
x5
x12
CO
CO 
South-East Asia and
developing Pacific
x6
x12
»IO 
x14
Middle East
x28
»OIO 
XV
UN@» 
environment
programme 
United Nations Avenue, Gigiri
P O Box 30552, 00100 Nairobi, Kenya
Tel +254 720 200200
[email protected]
www.unep.org
of the Global Climate 
State of the Global Climate
2021
WMO-No. 1290
WEATHER CLIMATE WATER
(») ; 
woauD, 
,ociCAL 
deg.a 
ORGANI 
WMO-No. 1290
© World Meteorological Organization, 2022
The right of publication in print, electronic and any other form and in any language is reserved by WMO. 
Short extracts from WMO publications may be reproduced without authorization, provided that the complete source
is clearly indicated. Editorial correspondence and requests to publish, reproduce or translate this publication in
part or in whole should be addressed to:
Chair, Publications Board
World Meteorological Organization (WMO)
7 bis, avenue de la Paix 
Tel.: +41 (0) 22 730 84 03
P.O. Box 2300 
Fax: +41 (0) 22 730 81 17
CH-1211 Geneva 2, Switzerland 
Email: [email protected]
ISBN 978-92-63-11290-3
Cover illustration from Adobe Stock: Icebergs (Photo credits: z576); Forest fires, red and orange forest fires at night in the dry season (Photo credits:
prirach); Shallow Coral Reef and Island in Raja Ampat (Photo credits: ead72); Flooded terrain in lowlend of Great river (Photo credits: Vladimir Melnikov).
iSTOCK:
Terre
de
sécheresse
au
coucher
du
soleil.
Ciel
dramatique
de
désert.
changement
climatique
(Photo
credits:
mycola).
NOTE
The designations employed in WMO publications and the presentation of material in this publication do not imply the expression of any opinion
whatsoever on the part of WMO concerning the legal status of any country, territory, city or area, or of its authorities, or concerning the delimitation
of its frontiers or boundaries.
The mention of specific companies or products does not imply that they are endorsed or recommended by WMO in preference to others of a similar
nature which are not mentioned or advertised.
The findings, interpretations and conclusions expressed in WMO publications with named authors are those of the authors alone and do not necessarily 
reflect those of WMO or its Members.
B
Contents
Key messages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Global climate indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Baselines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Greenhouse gases  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Ocean  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Cryosphere  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12
Stratospheric ozone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .19
Drivers of short-term variability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
High-impact events in 2021 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Heatwaves and wildfires . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Cold spells and snow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25
Precipitation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26
Flood . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27
Drought  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .28
Tropical cyclones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
Severe storms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
Attribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31
Risks and impacts  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
Food security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33
Humanitarian impacts and population displacement  . . . . . . . . . . . . . . . . . . .35
Climate impacts on ecosystems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38
Northern hemisphere summer extremes: the role of the quasi-stationary 
Northern hemisphere summer extremes: the role of the quasi-stationary
planetary waves and the Arctic warming amplification 
planetary waves and the Arctic warming amplification  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 
 .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 
4040
Observational basis for climate monitoring
Observational basis for climate monitoring   .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 
  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  .  . 4444
Can sub-seasonal-to-seasonal predictions improve disaster risk preparedness for 
Can sub-seasonal-to-seasonal predictions improve disaster risk preparedness for
the South-east Asia region? A review of the 20–26 September 2021 case study
the South-east Asia region? A review of the 20–26 September 2021 case study  .  .  .  .  .  .  . 
  .  .  .  .  .  .  . 4646
Data sets and methods  . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .47
List of contributors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .53
1
Key messages
The global mean temperature in 2021 was around 1.11 ± 0.13 °C above the 1850–1900
pre-industrial average. This is less warm than some recent years due to the influence of
La Niña conditions at the start and end of the year. The most recent seven years, 2015 to 2021,
were the seven warmest years on record.
Global mean sea level reached a new record high in 2021, rising an average
of 4.5 mm per year over the period 2013–2021.
The Antarctic ozone hole reached a maximum area of 24.8 million km
2 
in 2021. This unusually deep and large ozone hole was driven by
a strong and stable polar vortex and colder-than-average conditions
in the lower stratosphere.
Greenland experienced an exceptional mid-August melt
event and the first-ever recorded rainfall at Summit Station, 
the highest point on the Greenland ice sheet at an altitude 
of 3 216 m. 
Exceptional heatwaves broke records across western
North America and the Mediterranean. Death Valley,
California reached 54.4 °C on 9 July, equalling a
similar 2020 value as the highest recorded in the
world since at least the 1930s, and Syracuse in Sicily
reached 48.8 °C.
Hurricane Ida was the most significant of the North
Atlantic season, making landfall in Louisiana on
29 August, equalling the strongest landfall on
record for the state, with economic losses in the
United States estimated at US$ 75 billion.
Deadly and costly flooding induced economic losses of
US$ 17.7 billion in Henan province of China, and Western
Europe experienced some of its most severe flooding
on record in mid-July. This event was associated with
economic losses in Germany exceeding US$ 20 billion.
Drought affected many parts of the world, including areas in Canada,
United States, Islamic Republic of Iran, Afghanistan, Pakistan, Turkey
and Turkmenistan. In Canada, severe drought led to forecast wheat and
canola crop production levels being 35%–40% below 2020 levels, while
in the United States, the level of Lake Mead on the Colorado River fell in
July to 47 m below full supply level, the lowest level on record. 
The compounded effects of conflict, extreme weather events and economic shocks, 
further exacerbated by the COVID-19 pandemic, undermined decades of progress
towards improving food security globally. 
2
Hydro-meteorological hazards continued to contribute to internal displacement. The
countries with the highest numbers of displacements recorded as of October 2021
were China (more than 1.4 million), Viet Nam (more than 664 000) and the Philippines
(more than 600 000). 
Foreword
than the average annual growth rate over
the last decade. This is despite a decrease
in fossil fuel CO2
 emissions of approximately
5.6% in 2020 due to restrictions related to the
COVID-19 pandemic. 
Stabilizing global mean temperature at 1.5 °C
to 2 °C above pre-industrial (1850–1900)
levels by the end of this century will require
an ambitious reduction of greenhouse gas
emissions, which must accelerate during
this decade. 
Early warning systems are critically required
across sectors for climate adaptation. However,
less
than
half
the
Members
report
having

early
warning
systems
in
place.
WMO
and
its

Members
are
working
closely
to
substantially
The release of the World Meteorological
Organization State of the Global Climate 2021
report comes a few months after the release
of the Working Group I, II and III contributions
to
the
Sixth
Assessment
Report
of

the
Intergovernmental
Panel
on
Climate

Change
(IPCC).
The
present
WMO
report

provides
an
update
on
the
annual
state
of

the
climate
observed
in
the
year 2021,
and

shows
continued
trends
(also
reported
in

the
IPCC
reports)
in
terms
of
key
indicators.

These
include
concentrations
of
greenhouse

gases,
global
annual
mean
surface
temperature,
global
mean
sea
level,
ocean
heat

content,
ocean
acidification,
sea-ice
extent

and
changes
in
mass
of
the
ice
sheets
and

glaciers.
While
the
key
indicators
show
that

climate
continues
to
change,
information

on
socioeconomic
impacts
highlights
the

vulnerability
of
populations
to
current
weather

and
climate
events.
Loss
and
damages
of
improve this situation in the near future.
I take this opportunity to congratulate the
experts and the lead author, who compiled
this report using physical data analyses and
impact assessments. I thank all the contributors,
particularly
WMO
Member
National

Meteorological
and
Hydrological
Services

and
Regional
Climate
Centres
and
United

Nations
agencies,
for
their
collaboration
and

input.
The
present
report
is
intended
to
help

our
organizations
to
update
world
leaders
and

citizens
on
the
latest
information
about
the

state
of
the
Earth
system,
the
weather
and

climate
conditions
in
2021,
and
the
impacts

of
weather
and
climate
events.
WMO
remains

committed
to
supporting
this
publication
and

communicating
it
widely
for
this
purpose.
more than US$ 100 billion, as well as severe 
impacts on food security and humanitarian
aspects due to high-impact weather and
climate events have been reported. 
The increase in atmospheric concentration of
CO2
 from 2019 to 2020 was slightly lower than
that observed from 2018 to 2019, but higher 
(Prof. Petteri Taalas)
Secretary-General
3
Global climate indicators
Global climate indicators
1
 provide a broad
view of climate change at a global scale,
encompassing the composition of the atmosphere,
energy
changes,
and
the
response
of

the
land,
ocean
and
ice.
These
indicators
are

closely
interrelated.
For
example,
the
rise
in

CO2

and
other
greenhouse
gases
in
the
atmosphere
leads
to
an
imbalance
of
energy
and

thus
warming
of
the
atmosphere
and
ocean.

Warming
of
the
ocean
in
turn
leads
to
rising

sea
levels,
to
which
is
added
the
melting
of
ice

on
land
in
response
to
increasing
atmospheric

temperatures.
The
global
indicators
draw
on

a
wide
range
of
data
sets
that
are
listed
at

the
end
of
the
present
report
and
which
are

based
on
multiple
observing
systems
(see

Observational
basis
for
climate
monitoring).

Together,
the
indicators
build
a
consistent
used in this report, and these are specified
in the text and figures where appropriate.
Where possible, the WMO climatological
standard normal, 1981–2010, is used as a
baseline for consistent reporting.
2
 For some
indicators, however, it is not possible to
use this baseline, due to either a lack of
measurement during the whole period, or
because a longer period is needed to calculate
representative statistics.
There are two notable exceptions. Firstly,
for global mean temperature, a baseline of
1850–1900 is used. This is the baseline used in
recent IPCC reports (Sixth Assessment Report,
3

Special Report: Global Warming of 1.5 °C
4
) as
a reference period for pre-industrial temper-
picture of a warming world that touches all 
atures, and is relevant for understanding 
parts of the Earth system.
progress relative to the goal of the Paris
Agreement. Secondly, for greenhouse gases,
atmospheric concentrations can be estimated
much further back in time, using gas bubbles
trapped in ice cores. The year 1750 is therefore
used in this report to represent pre-industrial
greenhouse gas concentrations.
The connections between global climate
indicators and the Sustainable Development
Goals were highlighted in Climate Indicators
and Sustainable Development: Demonstrating
the Interconnections (WMO-No. 1271). That
report traces the links and feedback loops
among the key climate indicators as a physical
system
and
the
cascading
risks
to
most

of
the
17 Sustainable
Development
Goals.

Monitoring
the
global
climate
indicators,

as
well
as
their
related
risks
and
impacts,
is

therefore
of
critical
importance
for
achieving

the
Sustainable
Development
Goals
by
2030.
GREENHOUSE GASES
BASELINES
Atmospheric concentrations of greenhouse
gases reflect a balance between emissions
from human activities, natural sources, and
sinks in the biosphere and ocean. Increasing
levels of greenhouse gases in the atmosphere
due
to
human
activities
have
been

the
major
driver
of
climate
change
since
the

mid-twentieth
century.
Global
average
mole
Baselines are specific periods, usually span-
fractions of greenhouse gases are calculated 
ning one or more decades, that are used as a
fixed period against which current conditions
can be compared. A variety of baselines are 
from in situ observations made at multiple
sites in the Global Atmosphere Watch (GAW)
Programme of WMO and partner networks. 
1 
Trewin, B.; Cazenave, A.; Howell, S. et al. Headline Indicators for Global Climate Monitoring, Bulletin of the
American Meteorological Society 2021, 102 (1), E20–E37. https://journals.ametsoc.org/view/journals/bams/102/1/
BAMS-D-19-0196.1.xml. 
2 
1981–2010 is used in preference to 1991–2020, for consistency with climate reports from WMO Members, not all of whom 
have yet transitioned to using the more recent period.
3 
Intergovernmental Panel on Climate Change (IPCC), 2021: AR6 Climate Change 2021: The Physical Science Basis, 
https://www.ipcc.ch/report/ar6/wg1/. 
4 
Intergovernmental Panel on Climate Change (IPCC), 2018: IPCC Special Report: Global Warming of 1.5 °C, 
https://www.ipcc.ch/sr15/. 
4
 420
 1950
 335
 410
 1900
 1850
 1800
 1750
 1700
 1650
 1600
 1985  1990  1995  2000  2005  2010  2015  2020
In 2020, greenhouse gas mole fractions reached
new highs, with globally averaged surface
mole fractions of carbon dioxide (CO2
) at
413.2 ± 0.2 parts per million (ppm), methane (CH4
)
at
1889 ± 2 parts per billion
(ppb)
and

nitrous
oxide
(N2
O)
at
333.2 ± 0.1 ppb,
respectively
149%,
262%
and
123%
of
pre-industrial

(1750)
levels
(Figure 1).
The
increase
in
atmospheric
concentration
in
CO2

from
2019
to
2020

was
slightly
lower
than
that
observed
from
2018

to
2019,
but
higher
than
the
average
annual

growth
rate
over
the
last
decade.
This
is
despite

a
decrease
in
fossil
fuel
CO2

emissions
of

approximately
5.6%
in
2020
due
to
restrictions

related
to
the
COVID-19
pandemic.
Atmospheric methane (CH4
) increase is an
issue of concern because it is not only a powerful
greenhouse
gas,
but
it
is
also a
precursor

of
tropospheric
ozone,
with
implications
for

human
health,
agriculture
and
ecosystems.
6
5

The mean annual increase of CH4
 decreased
from approximately 12 ppb per year during
the late 1980s to nearly zero between 1999
and 2006. Since 2007, atmospheric CH4
 has
been increasing, and in 2020 it increased by
11 ppb over 2019 levels. Studies using GAW
CH4
 measurements indicate that increased
CH4
 emissions from wetlands in the tropics
and from anthropogenic sources at the
mid-latitudes of the northern hemisphere are 
 For CH4
 
and N2
O, the increase from 2019 to 2020 was 
the likely causes of this recent increase.
7
 These 
higher than that observed from 2018 to 2019
and also higher than the average annual growth
rate over the last decade. 
studies have also pointed to the short-term
climate benefits and cost-effectiveness of
mitigating CH4
 emissions. Such mitigation
measures were presented in the United
Nations Environment Programme (UNEP)
methane assessment
Real-time data from specific locations, including
Mauna
Loa
(Hawaii)
and
Cape
Grim

(Tasmania)
indicate
that
levels
of
CO2
,
CH4

and
N2
O
continued
to
increase
in
2021.
8
 and address major
emitting sectors, namely oil and gas, agriculture
and
waste
management.
5 
https://public.wmo.int/en/resources/united_in_science; https://library.wmo.int/index.php?lvl=notice_display&id=21946
6 
https://www.unep.org/resources/report/global-methane-assessment-benefits-and-costs-mitigating-methane-emissions
7 
Nisbet, E. G.; Manning, M. R.; Dlugokencky, E. J. et al. Very Strong Atmospheric Methane Growth in the 4 Years
2014–2017: Implications for the Paris Agreement. Global Biogeochemical Cycles 2019, 33 (3), 318–342. https://doi.
org/10.1029/2018GB006009.
8 
CO
 mole fraction (ppm)
CO
 growth rate (ppm/yr)
2
https://www.unep.org/resources/report/global-methane-assessment-benefits-and-costs-mitigating-methane-emissions
2
CH
 mole fraction (ppb)
 330
 325
 320
 315
 310
4
 305
 300
 1985  1990  1995  2000  2005  2010  2015  2020
Year
Year
4.0
 20
 15
3.0
 10
2.0
 5
1.0
 0
0.0
-5
 1985  1990  1995  2000  2005  2010  2015  2020
 1985  1990  1995  2000  2005  2010  2015  2020
Year
CH
 growth rate (ppb/yr)
4
Year
N
O mole fraction (ppb)
 400
 390
 380
 370
 360
2
 350
 340
 1985  1990  1995  2000  2005  2010  2015  2020
Year
N
O growth rate (ppb/yr)
2
2.0
1.5
1.0
0.5
0.0
 1985  1990  1995  2000  2005  2010  2015  2020
Year
Figure 1. Top row:
Globally averaged mole
fraction (measure of
concentration), from
1984 to 2020, of CO2
 in
parts per million (left),
CH4
 in parts per billion
(centre) and N2
O in
parts per billion (right).
The red line is the
monthly mean mole
fraction with the
seasonal variations
removed; the blue
dots and line show
the monthly averages.
Bottom row: The growth
rates representing
increases in successive
annual means of mole
fractions are shown
as grey columns
for CO2
 in parts per
million per year (left),
CH4
 in parts per billion
per year (centre)
and N2
O in parts per
billion per year (right).
Source: WMO Global
Atmosphere Watch.
5
TEMPERATURE
remains the warmest year on record in most
of the data sets surveyed.
The global mean temperature in 2021 was
1.11 ± 0.13 °C above the 1850–1900 average
(Figure 2). The six data sets used in the analysis
(see
Global
temperature
data)
place
2021

between
the
fifth
and
seventh
warmest
year

on
record
globally,
and
all
six
show
that
the

most
recent
seven
years,
2015
to
2021,
were

the
seven
warmest
years
on
record.
The method for calculating global temperature
anomalies
relative
to
the
1850–1900

baseline
has
been
updated
from
previous

state
of
the
global
climate
reports.
The
new

method
uses
the
assessment
of
temperature

change
and
its
uncertainties
from
the
IPCC

Sixth
Assessment
Report
as a
foundation

for
estimating
changes
since
1850–1900.

Details
are
given
in
the
section
on
Global

temperature
data.
The year 2021 was less warm than some
recent years due to the influence of moderate
La Niña events at the start and end of the
year, known as a “double-dip” La Niña (see
Drivers of short-term variability). La Niña
has a temporary cooling effect on the global
mean temperature, which is strongest in the
year following an event. Aside from the weak
La Niña of 2018, the last significant La Niña
event was in 2011. The year 2021 was around
0.22 °C to 0.29 °C warmer than 2011. The year
2016, which started during a strong El Niño, 
In the IPCC Sixth Assessment Report,
Summary for Policymakers,
9
 temperature
crossing points – the point at which longterm
warming
exceeds
a
particular
level

–
were
assessed
using a
20-year
average

centred
on
the
crossing
point.
For
the
period

2001–2020,
the
average
was
estimated
10
 to be
0.99 [0.84–1.10] °C. The provisional 20-year
average for the period 2002–2021, based on 
1.4
1.2
1.0
0.8
HadCRUT5 analysis
NOAAGlobalTemp
GISTEMP
ERA5
JRA-55
Berkeley Earth
0.6
0.4
0.2
0.0
–0.2
1850              1875              1900              1925              1950              1975             2000              2025
Year
© Crown Copyright. Source: Met Oce
9 
Intergovernmental Panel on Climate Change (IPCC), 2021: Summary for Policymakers. In: AR6 Climate Change 2021:
The Physical Science Basis, https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_SPM_final.pdf.
10 
Intergovernmental Panel on Climate Change (IPCC), 2021: Summary for Policymakers, A.1.2. In: AR6 Climate Change 2021:
The Physical Science Basis, https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_SPM_final.pdf.
The IPCC average was based on four data sets: HadCRUT5, NOAAGlobalTemp—Interim, Berkeley Earth and Kadow, C.;
Hall, D. M.; Ulbrich, U. Artificial Intelligence Reconstructs Missing Climate Information. Nature Geoscience 2020, 13 (6),
408–413. https://doi.org/10.1038/s41561-020-0582-5. Bracketed values indicate the 5%–95% confidence range.
6
°C
Figure 2. Global annual
mean temperature
difference from
pre-industrial conditions
(1850–1900) for six
global temperature data
sets (1850–2021). For
details of the data sets
and processing see
Data sets and methods.
Source: Met Office,
United Kingdom of Great
Britain and Northern
Ireland.
the average of the six data sets used in the
present report, was 1.01 ± 0.12 °C above the
1850–1900 average.
Near-surface temperatures in 2021 were
above the 1981–2010 average across a broad
swath of North America and Greenland,
Northern and Tropical Africa, the Middle
East and Southern Asia (Figure 3). Areas with
below-average temperatures included parts
of Northern Asia, Australia, Southern Africa
and North-west North America. The imprint
of La Niña can clearly be seen in the Tropical
Pacific. Cooler conditions in Southern Africa,
India, and eastern Australia are characteristic
of La Niña. The cooler-than-average area in
Northern Asia stands in contrast to 2020,
which saw exceptionally high temperatures 
–10.0  –5.0   –3.0  –2.0   –1.0  –0.5       0      0.5    1.0     2.0    3.0    5.0   10.0  °C
in the region. This is partly associated with 
CO2
 in the ocean. This affects ocean chemistry, 
the different phases of the Arctic Oscillation
in early 2020 (strongly positive) and early
2021 (strongly negative, see the section on
Arctic Oscillation (AO)), which had an imprint
on the average for the whole year.
lowering the average pH of the water, a process
known
as
ocean
acidification.
All
these

changes
have
a
broad
range
of
impacts
and

interactions
11
 in the ocean and coastal areas.
OCEAN HEAT CONTENT
OCEAN
Figure 3. Near-surface
temperature differences
relative to the 1981–2010
average for 2021.
The map shows the
median anomaly
calculated from five
data sets: HadCRUT5,
E R A 5 , GI S T E MP,
NOAAGlobalTemp and
Berkeley Earth. 
Source: Met Office,
United Kingdom.
Increasing human emissions of CO2
 and other
greenhouse gases cause a positive radiative
imbalance at the top of the atmosphere – the
Earth energy imbalance (EEI) – leading to
an accumulation of energy in the form of
heat in the Earth system which is driving
global warming.
Most of the excess energy that accumulates
in the Earth system due to increasing concentrations
of
greenhouse
gases
is
taken
up

by
the
ocean.
The
added
energy
warms
the

ocean,
and
the
consequent
thermal
expansion

of
the
water
leads
to
sea-level
rise,
to
which

is
added
melting
land
ice.
The
surface
layers

of
the
ocean
have
warmed
more
rapidly
than

the
interior,
mirrored
in
the
rise
of
global

mean
sea-surface
temperature
and
in
the
12,13,14
 Around 90% of this accumulated
heat
in
the
Earth
system
is
stored

in
the
ocean,
which
is
measured
through

ocean
heat
content
(OHC). A
positive
EEI

signals
that
the
Earth’s
climate
system
is

still
responding
to
the
current
forcing
15
 and 
increased incidence of marine heatwaves. As 
that more warming will occur even if the 
the concentration of CO2
 in the atmosphere
increases, so too does the concentration of 
forcing does not increase further.
16
 This in
turn is reflected in a continued increase of 
11 
Gruber, N.; Boyd, P. W.; Frölicher, T. L. et al. Biogeochemical extremes and compound events in the ocean. Nature 2021,
600, 395–407. https://doi.org/10.1038/s41586-021-03981-7. 
12 
Hansen, J.; Sato, M.; Kharecha, P. et al. Earth’s energy imbalance and implications. Atmospheric Chemistry and Physics
2011, 11 (24), 13421–13449. https://doi.org/10.5194/acp-11-13421-2011.
13 
Intergovernmental Panel on Climate Change (IPCC), 2013: Climate change 2013: The physical science basis, Chapter 3,
https://www.ipcc.ch/report/ar5/wg1/.
14 
von Schuckmann, K.; Palmer, M. D.; Trenberth, K. E. et al. An imperative to monitor Earth’s energy imbalance. Nature 
Climate Change 2016, 6, 138–144. https://doi.org/10.1038/nclimate2876.
15 
Hansen, J.; Nazarenko, L.; Ruedy, R. et al. Earth’s Energy Imbalance: Confirmation and Implications. Science 2005,
308 (5727), 1431–1435. https://doi.org/10.1126/science.1110252. 
16 
Hansen, J.; Sato, M.; Kharecha, P. et al. Young people’s burden: requirement of negative CO2
 emissions. Earth System
Dynamics 2017, 8 (3), 577–616. https://doi.org/10.5194/esd-8-577-2017. 
7
at depth.
18
 With the deployment of the Argo
network of autonomous profiling floats, which
first achieved its target near-global coverage
in
2006,
it
is
now
possible
to
routinely

measure
OHC
changes
down
to a
depth
of

2 000 m.
100
50
0
19,20
OHC 0–300 m
OHC 0–700 m
OHC 0–2 000 m
OHC 700–2 000 m
Ensemble mean 
–50
Various research groups have developed
estimates of global OHC, and all results
show continued ocean warming (Figure 4).
Differences between the estimates at annual
to decadal scale arise from the various statistical
treatments
of
data
gaps,
the
choice
of

climatology
and
the
approach
used
to
account

for
instrumental
biases.
21,22,23
 A concerted
effort has been established to provide an
international view on the global evolution of
ocean warming up to the year 2021.
24
 
ocean heat content. The IPCC concluded that
it is unequivocal that human influence has
warmed the atmosphere, ocean and land,
and that it is extremely likely that human
influence was the main driver of the ocean
heat increase observed since the 1970s.
The upper 2 000 m depth of the ocean continued
to
warm
in
2021
and
it
is
expected
that
it

will
continue
to
warm
in
the
future – a
change

which
is
irreversible
on
centennial
to
millennial
timescales.
25,26
17
Historical measurements of subsurface
temperature back to the 1940s mostly rely
on shipboard measurement systems, which
constrain the availability of subsurface temperature
observations
at a
global
scale
and
 The ocean heat content in
2021 was the highest on record, exceeding
the 2020 value by 14 ± 9 ZJ (Figure 4). All
data sets agree that ocean warming rates
show a particularly strong increase in the
past two decades. Ocean warming rates for
the 0–2 000 m depth layer (relative to the
ocean surface) reached 1.0 (0.6) ± 0.1 W m
-2 
17 
Intergovernmental Panel on Climate Change (IPCC), 2021: Summary for Policymakers. In: AR6 Climate Change 2021: The
Physical Science Basis, https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_SPM_final.pdf.
18 
Abraham, J. P.; Barlinger, M.; Bindoff, N. L. et al. A review of global ocean temperature observations: Implications for
ocean heat content estimates and climate change. Reviews of Geophysics 2013, 51 (3), 450–483. https://doi.org/10.1002/
rog.20022.
19 
Riser, S. C.; Freeland, H. J.; Roemmich, D. et al. Fifteen years of ocean observations with the global Argo array. Nature
Climate Change 2016, 6 (2), 145–153. https://doi.org/10.1038/nclimate2872. 
Figure 4. 1960–2021
ensemble mean time
series and ensemble
standard deviation
(2 standard deviations,
shaded) of global OHC
anomalies relative to
the 2005–2017 average
for the 0–300 m (grey),
0–700 m (blue),
0–2 000 m (yellow) and
700–2 000 m (green)
depth layers. The
ensemble mean is
an update of the
outcome of a concerted
international data
and analysis effort
(see footnote 24),
and all products used
are referenced in the
section on Ocean heat
content data. Note that 
20 
Roemmich, D.; Alford, M. H.; Claustre, H. et al. On the Future of Argo: A Global, Full-Depth, Multi-Disciplinary Array. 
values are given for 
Frontiers in Marine Science 2019, 6, 439. https://www.frontiersin.org/article/10.3389/fmars.2019.00439.
21 
Boyer, T.; Domingues, C. M.; Good, S. A. et al. Sensitivity of Global Upper-Ocean Heat Content Estimates to Mapping
Methods, XBT Bias Corrections, and Baseline Climatologies. Journal of Climate 2016, 29 (13), 4817–4842. https://doi.
org/10.1175/JCLI-D-15-0801.1. 
22 
von Schuckmann, K.; Palmer, M. D.; Trenberth, K. E. et al. An imperative to monitor Earth’s energy imbalance. Nature
Climate Change 2016, 6, 138–144. https://doi.org/10.1038/nclimate2876. 
23 
Cheng, L.; Abraham, J.; Goni, G. et al. XBT Science: Assessment of Instrumental Biases and Errors. Bulletin of the
American Meteorological Society 2016, 97 (6), 924–933. https://journals.ametsoc.org/view/journals/bams/97/6/
bams-d-15-00031.1.xml.
24 
the ocean surface area
between 60°S and 60°N
and limited to the 300 m
bathymetry of each
product. The ensemblemean
OHC
(0–2
000
m)

anomalies
for
2021
have

been
added
as
separate

points,
together
with
the

ensemble
spread,
and

are
based
on
the
four
von Schuckmann, K.; Cheng, L.; Palmer, M. D. et al. Heat stored in the Earth system: where does the energy go? Earth
System Science Data 2020, 12 (3), 2013–2041. https://doi.org/10.5194/essd-12-2013-2020. 
25 
products listed in Ocean 
Intergovernmental Panel on Climate Change (IPCC), 2021: Summary for Policymakers. In: AR6 Climate Change 2021: The
Physical Science Basis, https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_SPM_final.pdf.
26 
Intergovernmental Panel on Climate Change (IPCC), 2019: Summary for Policymakers. In: IPCC Special Report on the
Ocean and Cryosphere in a Changing Climate, https://www.ipcc.ch/site/assets/uploads/sites/3/2022/03/01_SROCC_
SPM_FINAL.pdf. 
8
heat content data.
Source: Updated from
von Schuckmann et al.,
2016 (see footnote 22).
OHC (ZJ) 
–100
–150
–200
–250
1960   1965    1970    1975   1980    1985    1990   1995    2000   2005    2010    2015   2020
Year
over the period 2006–2021 (1971–2021). For
comparison, the values for the upper 700 m
depth amount to 0.7 (0.4) ± 0.1 W m
100
-2
Satellite Altimetry
Average trend: 3.33 +/– 0.4 mm/yr
4.5 mm/yr
(Jan 2013—Jan 2022)
 over
the period 2006–2021 (1971–2021). Below
the 2 000 m depth, the ocean also warmed,
albeit at the lower rate
90
80
27
 of 0.07 ± 0.04 W m
-2
.
70
2.9 mm/yr
(Jan 2003—Dec 2012)
SEA LEVEL
Global mean sea level (GMSL) integrates
changes occurring in many components
of the climate system. On interannual to
multidecadal time scales, changes to GMSL
result from ocean warming via thermal
expansion of sea water, melting of land ice
and exchange of water with water bodies
on land. Measured since the early 1990s 
2.1 mm/yr
(Jan 1993—Dec 2002)
1993   1995    1997    1999    2001    2003    2005    2007    2009   2011    2013    2015    2017   2019    2021    2023
Year
by high-precision altimeter satellites, the 
GMSL rose by 2.1 mm per year between 1993
and 2002, and by 4.5 mm per year between
2013 and 2021, an increase by a factor of
two between the periods, mostly due to
the accelerated loss of ice mass from the
ice sheets.
28
 In 2021, GMSL reached a new
record high. Compared to previous El Niño
and La Niña years (for example, in 1997/1998,
2010/2011, 2015/2016), during which the GMSL
displayed temporary positive or negative
anomalies of several millimetres, 2021 was
marked by an increase of the GMSL that was
close to the long-term trend (Figure 5). 
Although sea level has risen almost everywhere
since
1993,
it
has
not
risen
equally

everywhere.
Regional
patterns
of
sea-level

change
are
dominated
by
local
changes
in

ocean
heat
content
and
salinity.
Several

regions
continue
to
be
affected
by a
rate
of

sea-level
rise
substantially
faster
than
the

global
mean
(see
Figure 6,
which
shows
the

difference
between
local
and
global
sea
level).

This
is
particularly
the
case
in
the
western

Tropical
Pacific,
the
South-west
Pacific,
the

North
Pacific,
the
South-west
Indian
Ocean

and
the
South
Atlantic.
In
other
regions,
local
27 
Update from Purkey, S. G.; Johnson, G. C. Warming of Global Abyssal and Deep Southern Ocean Waters between the
1990s and 2000s: Contributions to Global Heat and Sea Level Rise Budgets. Journal of Climate 2010, 23, 6336–6351.
https://doi.org/10.1175/2010JCLI3682.1. 
28 
WCRP Global Sea Level Budget Group. Global sea-level budget 1993–present. Earth System Science Data 2018, 10 (3),
1551–1590, https://doi.org/10.5194/essd-10-1551-2018.
Latitude
Sea level (mm)
60
50
40
30
20
10
0
Figure 5. Global mean
sea level evolution from
January 1993 to January
2022 (black curve)
based on high-precision
satellite altimetry. The
coloured straight lines
represent the average
linear trend over three
successive time spans
(January 1993 to
December 2002; January
2003 to December
2012; January 2013 to
January 2022). 
Source: AVISO altimetry
(https://www.aviso.
altimetry.fr).
10
60°N
, 
5
- 
Figure 6. Regional
trend patterns in sea
level after the global
mean trend has been
removed (mm/yr), from
1993 to 2020, based on
satellite altimetry. Note
that the actual sea level
has increased almost
everywhere. 
Source: Copernicus
Climate Change Service
(https://climate.
copernicus.eu).
30°N
r 
0°
0
30°S
–5
60°S
–10
0°                     60°E                  120°E                   180°                  120°W                   60°W                   0°
Longitude
mm/yr
9
(a)
(b)
(c)
(d)
sea level has risen more slowly than the
global mean, such as around Greenland and
south of Iceland, and in the Southern Ocean
around Antarctica. The patterns of trends in
sea level have only varied a little over the last
30 years of the altimetry era, and changes
from one year to another are small. 
MARINE HEATWAVES AND COLD SPELLS
Much of the ocean experienced at least
one “strong” MHW at some point in 2021 
(Figure  7). Due to the below-average
sea-surface temperatures associated with
the double-dip La Niña (see El Niño–Southern
Oscillation (ENSO)), MHWs were conspicuously
absent
in
the
eastern
Equatorial

Pacific
Ocean,
which
was
also
one
of
the

only
regions
of
the
global
ocean
to
see

broad
coverage
of
MCSs
(Figure 8).
The

Laptev
and
Beaufort
Seas
experienced
“se-
Analogous to heatwaves and cold spells on 
vere” and “extreme” MHWs from January 
land, marine heatwaves (MHW) and marine
cold spells (MCS) are prolonged periods of
extreme heat or cold that affect the ocean.
They can have a range of consequences for
marine life and dependent communities,
29
to April 2021. The ice-edge regions to
the east of Greenland (August), north of
Svalbard (October), and east of the Ross
Sea (December) experienced notable “extreme”
MHWs.
In
2021,
almost
all
MCSs

were
“moderate”,
except
in
areas
of
high

variability
such
as
the
poleward
extension

of
the
Gulf
Stream.

and MHWs have become more frequent over
the twentieth century. Satellite retrievals of
sea-surface temperature are used to monitor
MHWs
and
MCSs,
categorized
here
as

moderate,
strong,
severe
or
extreme
(for
MHWs in 2021 showed an average daily cov-
definitions, see Marine heatwave and marine 
erage of 13%, which is less than the record of 
cold spell data).
17% in 2016 and 16% in 2020. For the eighth 
29 
Smale, D. A.; Wernberg, T.; Oliver, E. C. J. et al. Marine heatwaves threaten global biodiversity and the provision of
ecosystem services. Nature Climate Change 2019, 9 (4), 306–312. https://www.nature.com/articles/s41558-019-0412-1. 
10
Daily MHW coverage for
ocean  (non-cumulative)
80%
60%
40%
20%
80%
60%
40%
20%
  2021-2   2021-4   2021-6     2021-8   2021-10  2021-12
  2021-2    2021-4   2021-6    2021-8   2021-10  2021-12
Day of the year
Top MHW category for
ocean (cumulative)
36
24
12
   2021-2   2021-4   2021-6     2021-8   2021-10  2021-12
Day of first occurrence
Average MHW days for
ocean (cumulative)
Day of the year
Category             I Moderate           II Strong          III Severe          IV Extreme    
Figure 7. (a) Global
map showing the
highest MHW category
(for definitions, see
Marine heatwave and
marine cold spell data)
experienced at each
pixel in 2021 (reference
period 1982–2011). Light
grey indicates that no
MHW occurred in a pixel
over the entire year. 
(b) Stacked bar plot
showing the percentage
of the surface of the
ocean experiencing an
MHW on any given day
of the year. 
(c) Stacked bar plot
showing the cumulative
percentage of the
surface of the ocean
that experienced an
MHW over the year.
Note: These values
are based on when in
the year a pixel first
experienced its highest
MHW category, so no
pixel is counted twice.
Horizontal lines in this
figure show the final
percentages for each
category of MHW. 
(d) Stacked bar plot
showing the cumulative
number of MHW days
averaged over the
surface of the ocean.
Note: This average is
calculated by dividing
the cumulative sum
of MHW days per
pixel weighted by the 
• 
• 
• 
surface area of those 
pixels. Data are from
the National Oceanic
and Atmospheric
Administration Optimum
Interpolation Sea
Surface Temperature
(NOAA OISST). 
Source: Robert Schlegel.
Figure 8. As for Figure 7,
but showing MCSs
rather than MHWs.
Data are from the
National Oceanic
and Atmospheric
Administration Optimum
Interpolation Sea
Surface Temperature
(NOAA OISST). 
Source: Robert Schlegel.
(a)
• •
• 
(b)
(c)
(d)
Category             I Moderate           II Strong          III Severe          IV Extreme    
consecutive year, the most common category
of MHW in 2021 was “strong” (28%). Overall,
57% of the ocean surface experienced at least
one MHW during 2021 (Figure 7c) – less than
the record of 65% in 2016, and the lowest
annual coverage since 2012 (57%).
OCEAN ACIDIFICATION
The ocean absorbs around 23% of the annual
emissions
of
anthropogenic
CO2

into

the
atmosphere.
30,31
 While this slows the
rise of atmospheric concentration of CO2
,
32

CO2
 reacts with seawater and reduces the
pH of the ocean,
The average daily coverage of the global
ocean by MCSs in 2021 was 4% (Figure 8b)
– a lower value than the record high in 1982
(7%) and comparable to 2020 (4%). In total, 
33
 a process known as ocean
acidification (Figure 9). The current global rate
of ocean acidification exceeds, by at least an
order of magnitude, the rates inferred for the 
25% of the ocean surface experienced at 
Paleocene–Eocene thermal maximum (PETM), 
least one MCS during 2021 (Figure 8c), which
is comparable to 2020 (25%), but much less
than the 1985 record (63%).
which occurred around 56 million years ago
and was associated with large perturbations
of the global carbon cycle.
34
 The IPCC Sixth 
30 
Intergovernmental Panel on Climate Change (IPCC), 2019: Summary for Policymakers. In: IPCC Special Report on the
Ocean and Cryosphere in a Changing Climate, https://www.ipcc.ch/site/assets/uploads/sites/3/2022/03/01_SROCC_
SPM_FINAL.pdf.
31 
World Meteorological Organization (WMO). WMO Greenhouse Gas Bulletin (GHG Bulletin) - No.15: The State of
Greenhouse Gases in the Atmosphere Based on Global Observations through 2018. Geneva, 2019. 
32 
Le Quéré, C.; Andrew, R. M.; Friedlingstein, P. et al. Global carbon budget 2017. Earth System Science Data 2018, 10, 
405–448. https://doi.org/10.5194/essd-10-405-2018. 
33 
Intergovernmental Panel on Climate Change (IPCC), 2021: Climate Change 2021: The Physical Science Basis, https://
www.ipcc.ch/report/ar6/wg1/#FullReport.
34 
Intergovernmental Panel on Climate Change (IPCC), 2021: Climate Change 2021: The Physical Science Basis, Chapter 2,
section 2.3.3.5 Ocean pH, https://www.ipcc.ch/report/ar6/wg1/.
Daily MCS coverage for
ocean (non-cumulative)
80%
60%
80%
60%
40%
20%
40%
20%
  2021-2   2021-4   2021-6    2021-8   2021-10  2021-12
   2021-2   2021-4   2021-6    2021-8   2021-10  2021-12
Day of the year
T op MCS category for
ocean (cumulative)
10
7
3
   2021-2   2021-4   2021-6    2021-8   2021-10  2021-12
Day of first occurrence
Average MCS days for
ocean (cumulative)
Day of the year
• 
• 
• 
11
11
Figure 9. Global mean
ocean surface pH (blue)
covering the period
1985–2020. The shaded
area indicates the
estimated uncertainty
in each estimate. Data
from Copernicus Marine
Environment Monitoring
Service. 
Source: Met Office,
United Kingdom.
stations”) highlight the need for sustained,
repeated observation and measurement of
ocean acidification along the coastlines and in
the open ocean. While there are currently still
gaps in the global coverage, capacity building
efforts increase the capability of many nations
to measure, manage and report ocean acidification
data,
as
confirmed
by
the
growing

number
of
countries
participating
in
data

collection
towards
the
SDG
Indicator 14.3.1.
CMEMS
8.11
8.10
8.09
8.08
8.07
8.06
8.05
1985           1990          1995         2000           2005          2010          2015          2020
Year
Assessment Report concluded that “[t]here is
very high confidence that open ocean surface
pH is now the lowest it has been for at least
26 kyr and current rates of pH change are
unprecedented since at least that time”. As
the pH of the ocean decreases, its capacity
to absorb CO2
 from the atmosphere also
declines.
CRYOSPHERE
The cryosphere comprises the frozen parts
of the Earth. This includes sea ice, glaciers,
ice sheets, snow and permafrost.
Figure 10. Sea-ice
extent difference from
the 1981–2010 average 
35
in the Arctic (left) and 
SEA ICE
Arctic sea ice
Ocean acidification threatens organisms and
ecosystem services, and hence food security,
tourism and coastal protection. Local and
regional acidification is of great relevance to
marine organisms and biological processes.
However, there is high variability in coastal
areas due to a range of factors affecting CO2

levels. National data sets of ocean acidification
observations
submitted
towards
the

Sustainable
Development
Goal
(SDG) 14.3

and
the
associated
SDG
Indicator 14.3.1

(“Average
marine
acidity
(pH)
measured

at
agreed
suite
of
representative
sampling
The 2020/2021 Arctic winter saw anomalously
high sea-level pressure over the central Arctic
Ocean (see Arctic Oscillation (AO)). The resulting
anticyclonic
wind
pattern
drove
thicker

multi-year
ice
into
the
Beaufort
Sea.
36
 The
maximum Arctic sea-ice extent for the year
was reached
37
 on 21 March, at 14.8 million km
2
.
March 2021 was the ninth or tenth lowest
extent on record (1979–2021), depending on
the data source (Figure 10). For more details
on the data sets used, see Sea-ice data. 
35 
Middelburg, J. J.; Soetaert, K.; Hagens, M. Ocean Alkalinity, Buffering and Biogeochemical Processes. Reviews of 
Geophysics 2020, 58, e2019RG000681. https://doi.org/10.1029/2019RG000681. 
36 
Mallett, R. D. C.; Stroeve, J. C.; Cornish, S. B. et al. Record winter winds in 2020/21 drove exceptional Arctic sea ice
transport. Communications Earth & Environment 2021, 2, 149. https://doi.org/10.1038/s43247-021-00221-8. 
37 
https://nsidc.org/arcticseaicenews/2021/03/arctic-sea-ice-reaches-uneventful-maximum 
12
12
Antarctic (right) for the
months with maximum
ice cover (Arctic: March;
Antarctic: September)
and minimum ice cover
(Arctic: September;
Antarctic: February)
from 1979 to 2021. 
Source: Data from
EUMETSAT OSI
SAF v2p1 and National
Snow and Ice Data
Centre (NSIDC) v3
(Fetterer et al., 2017)
(see reference details in
Sea-ice data).
million km
2
pH
© Crown Copyright. Source: Met Oce
1
1
0
0
–1
NSIDC v3 (September)
NSIDC v3 (March)
OSI SAF v2p1 (September)
OSI SAF v2p1 (March)
–2
–3
1980
1990
2000
2010
2020
Year
million km
2
–1
–2
–3
NSIDC v3 (September)
NSIDC v3 (February)
OSI SAF v2p1 (September)
OSI SAF v2p1 (February)
1980
1990
2000
2010
2020
Year
Melt rates were close to the 1981–2010 average
early
in
the
melt
season.
However,

sea-ice
extent
decreased
very
rapidly
in

June
and
early
July
in
the
Laptev
Sea
and

east
Greenland
Sea
regions.
As a
result,

the
Arctic-wide
sea-ice
extent
reached
a

record
low
for
the
time
of
year
in
the
first

half
of
July.
The
monthly
July
average
was

the
second
to
fourth
lowest
on
record
(tied

with
2012
and
2019),
with
strong
regional

contrasts
38
Figure 11. Arctic
sea-ice concentration
anomalies for July 2021
(difference from the
1981–2010 average).
Red represents areas
with less ice than
normal, blue represents
more ice. 
Source: EUMETSAT OSI
SAF data with research
and development input
from the European
Space Agency Climate
Change Initiative
(ESA CCI).
 (Figure 11). More ice than normal
(1981–2010) was found in the Beaufort and
Chukchi Seas, but the Siberian and European
sectors (Laptev Sea and East Greenland Sea)
had much less sea ice than normal. One
exception was the eastern Kara Sea, where
some sea ice persisted for the whole season.
Conditions shifted rapidly after July, with a 
Concentration (%)
–10 0
0
10 0
sustained period of colder weather across the 
ice at the annual minima began to increase 
Arctic Ocean. This slowed the sea-ice melt
and August 2021 ended up with the tenth
lowest extent on record.
in magnitude in the early 1990s, reaching a
maximum of 3.68 million km
2
 in 2013, before
dropping sharply to 2.08 million km
2
 in 2017,
the lowest ice extent in the period 1979–2021.
Since then, the extents at the annual minima
have increased slowly. In February, most
Antarctic sea ice was found in the Weddell
Sea and therefore the sea-ice extents at
the annual minima largely reflect regional
changes in that area.
With the slowdown in melt in August, the
minimum September extent was greater
than in recent years but still well below the
1981–2010 average, representing the twelfth
lowest minimum ice extent in the 43-year
satellite record (Figure 10). The 2021 minimum
extent was observed
39
 on 16 September at
4.72 million km
2
, while the mean September
ice extent was 4.92 million km
2
Antarctic sea ice reached its maximum annual
extent of 18.80 million km
, well below
the 1981–2010 average.
2
Antarctic sea ice
 on 30 August 2021.
This was close to the average magnitude
in terms of extent, and the twenty-second
largest in the 43 years of data. However,
this was the second earliest maximum, with
only one other maximum having occurred in
August (that of 2016).
Sea-ice extent across the Southern Ocean
in 2021 was generally below the 1981–2010
mean, with below-average extents before the 
February minimum, slightly above-average 
After the middle of September, the sea-ice 
extents during most of the winter, an exceptionally
early
maximum
ice
extent
at
the
end

of
August,
and
the
establishment
of
extents

that
were
well
below
average
by
the
end
of

the
year.
extent for the whole Southern Ocean was persistently
below
average,
with
the
ice
extent
decreasing
to
6.77 million km
2
 (–1.82 million km
2
The minimum in the 2021 annual cycle occurred
on
19 February,
when
sea
ice
covered

2.60 million km
2
, the fifteenth lowest extent
in the record (1979–present). The extent of 

below average) on 24 December, the third
lowest for that day in the record. At that
time, ice extents were below average in all
sectors around the continent, but the lack
of ice in the Weddell, Bellingshausen and
Ross Seas had the greatest impact on the
Antarctic-wide anomaly. 
38 
Sea-ice cover for July 2021: https://climate.copernicus.eu/sea-ice-cover-july-2021
39 
https://nsidc.org/arcticseaicenews/2021/09/arctic-sea-ice-at-highest-minimum-since-2014 
13
GLACIERS
2015 to 2019. Examples include thinning of
1.52 m per year in New Zealand, 1.24 m per
year in Alaska, 1.11 m per year in Central
Europe, and 1.05 m per year in Western North
America (not including Alaska).
Glaciers are formed from snow that has
compacted to form ice, which can deform
and flow downhill to lower and warmer altitudes,
where
it
melts.
If
the
glacier
terminates

in a
lake
or
the
ocean,
ice
loss
also
occurs

through
melting,
where
ice
and
water
meet,

or
by
calving
of
the
glacier
front
to
form

icebergs.
Glaciers
are
sensitive
to
changes

in
temperature,
precipitation
and
sunlight,

as
well
as
other
factors,
such
as
changes
in

basal
lubrication,
warming
ocean
waters
or

the
loss
of
buttressing
ice
shelves.
The World Glacier Monitoring Service collates
and analyses global glacier mass balance
data, including a set of 42 reference glaciers
with long-term observations. For the glaciological
year
2020/2021,
preliminary
data

available
from
32 of
these
reference
glaciers

indicate
an
average
global
mass
balance
of

–0.77 m water
equivalent
(m w.e.
41
Over the period 2000–2019, global glaciers
and ice caps (excluding the Greenland and
Antarctic ice sheets) experienced
40
 an av-
 Figure 12).
This is a smaller mass loss than the average
for the last decade (–0.94 m w.e. from 2011
to 2020), but is larger than the average mass
loss for the period 1991–2020, –0.66 m w.e. 
erage mass loss of 267 ± 16 Gt per year. 
Figure 12. Global
glacier mass balance
1950–2021, from a
set of approximately
40 global reference
glaciers. 
(a) Average annual mass
balance for the set of
reference glaciers. 
(b) Cumulative mass
balance since 1950.
Units are m w.e. 
Source: Data are
provided by the World
Glacier Monitoring
Service, 
http://www.wgms.ch. 
Annual mass
balance (m w.e.)
Cumulative mass
balance (m w.e.)
Mass loss was higher, at 298 ± 24 Gt per
year, in the later part of the period from
2015–2019. Glaciers in several mid-latitude
regions thinned at more than double the
global average (0.52 ± 0.03 m per year) from 
Although the glaciological year 2020/2021
was characterized by a less negative glacier
mass balance than in recent years, there is a
clear trend towards an acceleration of mass
loss on multidecadal timescales (Figure 12).
On average, the reference glaciers have
thinned by 33.5 m (ice equivalent) since 1950,
with 76% of this thinning (25.5 m) occurring
since 1980.
(a)
Exceptional glacier mass loss in western
Canada
0
–0.5
Mass loss from North American glaciers
accelerated over the last two decades.
Glacier mass loss in Western North America
increased from 53 ± 13 Gt per year for the
period 2000–2004 to 100 ± 17 Gt per year for
2015–2019.
–1.0
1950 1960 
1970 1980 1990 2000 2010 2020
Year
(b)
42
 
0
An exceptionally warm, dry northern hem-
isphere summer in 2021 (see Heatwaves
and wildfires) exacerbated mass loss for
most glaciers in Alberta and southern British
Columbia in Canada, and the Pacific Northwest
of the United States of America. In the Coast
Mountains of British Columbia, Place and
Helm Glaciers lost more mass during the
period 2020–2021 than in any year since 
–10
–20
–30
1950 1960 
1970 1980 1990 2000 2010 2020
Year
40 
Hugonnet, R.; McNabb, R.; Berthier, E. et al. Accelerated global glacier mass loss in the early twenty-first century. 
Nature 2021, 592 (7856), 726–731. https://www.nature.com/articles/s41586-021-03436-z. 
41 
Metres water equivalent is the depth of water that would result if the lost ice were melted and spread across the surface
area of the glacier.
42 
Hugonnet, R.; McNabb, R.; Berthier, E. et al. Accelerated global glacier mass loss in the early twenty-first century.
Nature 2021, 592 (7856), 726–731. https://www.nature.com/articles/s41586-021-03436-z.
14
(a)
measurements began in 1965 (Figure 13a).
In the Canadian Rocky Mountains, mass loss
from Peyto Glacier was the second greatest
since 1965, after the strong El Niño year of
1998 (Figure 13b). Repeat LiDAR surveys
43
than usual, contributing to the extreme mass
loss. Kokanee Glacier, British Columbia, lost
5%–6% of its total volume in 2021, while
Columbia Icefield, the largest icefield in the
Rocky Mountains (210 km

indicate mass balances of –2.66, –3.30,
and –1.95 m w.e. on Place, Helm and Peyto
Glaciers, respectively. This represents roughly
twice the mean regional rate of thinning from 
2
), lost about 0.34 Gt
of ice (Figure 13c).
ICE SHEETS
Figure 13.Glacier mass
balance records from
(a) Place Glacier, British
Columbia, and 
(b) Peyto Glacier,
Alberta from 1965
to 2021. Data for
1965–2019 are from
the World Glacier
Monitoring Service.
Mass balance estimates
for 2021 are from
LiDAR surveys, with
firn-density corrections
based on Pelto et al.
(2019) (see Glacier mass
balance data). The blue
and yellow horizontal
bars indicate decadal
mean values for the
region from Hugonnet
et al. (2021) (see Glacier
mass balance data).
Data from 2021 indicate
the uncertainty (pink
bar), the mass balance
calculation using the
contemporaneous
LiDAR-derived glacier
area (red circles),
and the specific mass
balance calculated from
the Randolph Glacier
Inventory glacier areas/
outlines as used by
Hugonnet et al. (2021)
(black crosshairs). 
(c) LiDAR-derived
elevation change
on the Columbia
Icefield, Canadian
Rocky Mountains, for
the 2020/2021 mass
balance year.
Place Glacier, Coast Mountains, B.C.
(b)
Peyto Glacier, Rocky Mountains, Alberta
1.0
0.5
0.0
–0.5
–1.0
–1.5
–2.0
–2.5
–3.0
Glacier elevation change, 2020/2021: Columbia Icefield, Rocky Mountains, Canada
0
2 5.
5 km
2015 to 2019. 
Ice sheets are expanses of glacial ice that
cover an area larger than 50 000 km
Little snow remained on most of the mountain
glaciers in this region by mid-August 2021,
and many of these glaciers have lost their
firn zone, where multi-year snow undergoes
the transformation from snow to glacial ice.
Particulate deposition – including soot and
ash – from extensive regional wildfire activity
in summer 2021 meant that the surfaces
of the glaciers were unusually dark in July 
2
. In the
current climate, there are two ice sheets,
found on Greenland and Antarctica.
Greenland ice sheet
Changes in the total mass balance of the
Greenland ice sheet reflect the combined effects
of:
surface
mass
balance,
defined
as
the
and August and absorbed more sunlight 
difference between snowfall and meltwater 
43 
Pelto, B. M.; Menounos, B.; Marshall, S. J. Multi-year evaluation of airborne geodetic surveys to estimate seasonal
mass balance, Columbia and Rocky Mountains, Canada. The Cryosphere 2019, 13, 1709–1727. https://doi.org/10.5194/
tc-13-1709-2019.
Net mass balance (m w.e.)
Net mass balance (m w.e.)
0.5
0.0
–0.5
–1.0
–1.5
–2.0
1970     1980      1990      2000     2010      2020
1970     1980      1990      2000     2010      2020
Year 
Year 
(c)
yr 
Elevation 
–10
–8
–5
–3
0
change (m)
rt r, 
•
•
• 
1
• 
' 
' 
15
run-off from the ice sheet; the marine mass
balance, which is the sum of mass losses at
the periphery from the calving of icebergs and
the melting of glacier tongues on contact with
the ocean; and the basal mass balance, which
consists of basal melting due to geothermal
heat and frictional heat generated by sliding
at the base of the glacier and by deformation
of the ice.
the same period.
46
 GRACE satellite gravity
data processed by NASA
47
 give a total mass
balance of –126 Gt for this same period.
48
 The
estimated magnitude of mass loss differs
due to different methods and assumptions,
but there is agreement that the Greenland
ice sheet had a negative mass balance for
the twenty-fifth year in a row. 
For Greenland, an ensemble of regional climate
models
44
 gives an estimated total mass
balance
45
Over the period September 1986 to August
2021, climate modelling indicates that the
Greenland ice sheet lost a total of 5 511 Gt
of ice,
 of –166 Gt for the 2021 mass balance
year (1 September 2020 to 31 August 2021).
Estimates based on satellite observations and
the PROMICE surface weather station network
give a total mass balance of –85 Gt over 
49
 an average mass loss of 157 Gt per
year (Figure 14). Mass loss has accelerated
over the past two decades. Based on the
GRACE and GRACE-FO satellite gravity data,
50
44 
Based on the average of three regional climate and mass balance models. See Mankoff, K. D.; Fettweis, X.; Langen, P. L.
et al. Greenland ice sheet mass balance from 1840 through next week. Earth System Science Data 2021, 13, 5001–5025.
https://doi.org/10.5194/essd-13-5001-2021. 
45 
A negative mass balance indicates a loss of ice mass; a positive mass balance indicates a gain.
46 
Moon, T. A.; Tedesco, M.; Box, J. E. et al. Greenland Ice Sheet. In Arctic Report Card 2021; Moon, T. A.;
Druckenmiller, M. L.; Thoman, R. L., Eds.; National Oceanic and Atmospheric Administration, 2021. 
https://doi.org/10.25923/546g-ms61. 
47 
https://climate.nasa.gov/vital-signs/ice-sheets/. 
48 
Wiese, D.N.; Yuan, D.-N.; Boening, C. et al. 2019. JPL GRACE and GRACE-FO Mascon Ocean, Ice, and Hydrology Equivalent
Water Height RL06M CRI Filtered Version 2.0, Ver. 2.0, PO.DAAC, CA, USA. http://dx.doi.org/10.5067/TEMSC-3MJ62.
49 
Based on the average of three regional climate and mass balance models. See Mankoff, K. D.; Fettweis, X.; Langen, P. L.
et al. Greenland ice sheet mass balance from 1840 through next week. Earth System Science Data 2021, 13, 5001–5025.
https://doi.org/10.5194/essd-13-5001-2021.
50 
Wiese, D.N.; Yuan, D.-N.; Boening, C. et al. 2019. JPL GRACE and GRACE-FO Mascon Ocean, Ice, and Hydrology Equivalent
Water Height RL06M CRI Filtered Version 2.0, Ver. 2.0, PO.DAAC, CA, USA. http://dx.doi.org/10.5067/TEMSC-3MJ62. 
16

Greenland lost 5 151 Gt of ice from April 2002 
600
500
400
300
200
100
0
Mass balance (Gt/yr)
–100
–200
–300
–400
–500
–600
1985          1990            1995           2000           2005            2010           2015           2020
Year
Basal mass
balance
Marine mass
balance
Surface mass
balance
Total mass
balance
Figure 14. Components of
the total mass balance of the
Greenland ice sheet 1987–2021. 
Blue: surface mass
balance (SMB); 
green: marine mass balance
(MMB, also referred to as
discharge); 
orange/yellow: basal mass
balance (BMB), 
red: total mass balance (TMB),
the sum of SMB, MMB and BMB
(see footnote 44). 
Source: Mankoff, K. D.;
Solgaard, A.; Colgan. W. et al.
Greenland Ice Sheet solid ice
discharge from 1986 through
March 2020. 
Earth System Science Data
2020, 12 (2), 1367–1383.
https://doi.org/10.5194/
essd-12-1367-2020.
to November 2021, an average rate of mass
loss of 276 Gt per year (Figure 15). Greenland’s
mass balance in 2021 was close to the 35-year
normal, but mass loss was below the average
for the period 2002–2020 for which satellite
gravity data are available.
well above normal in late July and August
2021 (Figure 16).
51
Figure 15. GRACE and
GRACE-FO satellite
gravity data of Greenland
and Antarctic ice sheet
mass change from April
2002 to November 2021
(see footnote 48). The
Greenland ice sheet lost
mass at an average rate
of 276 Gt per year over
this period, while the
average rate of mass loss
in Antarctica was 152 Gt
per year. Combined, this
is equivalent to about
1.2 mm per year of global
sea-level rise.
(a)
Greenland Ice Sheet
(b)
Antarctic Ice Sheet
0
 The August event was
associated with a warm, humid air mass that
moved in from Baffin Bay and covered much
of south-western and central Greenland. On
14 August, rain was observed for several 
hours at Summit Station, the highest point 
For the summer 2021 melt season in
Greenland, melt extent was close to the longterm
average
through
the
early
summer,
but

temperatures
and
meltwater
run-off
were
on the Greenland ice sheet (3 216 m), and air
temperatures remained above freezing for
about nine hours.
52,53
 There is no previous
report of rainfall at Summit, and this is the 
51 
http://nsidc.org/greenland-today/2021/08/rain-at-the-summit-of-greenland/
52 
Moon, T. A.; Tedesco, M.; Box, J. E. et al. Greenland Ice Sheet. In Arctic Report Card 2021; Moon, T. A.;
Druckenmiller, M. L.; Thoman, R. L., Eds.; National Oceanic and Atmospheric Administration, 2021. 
https://doi.org/10.25923/546g-ms61.
53 
Mass change (Gt)
0
–1 000
–2 000
–3 000
–4 000
–5 000
2002 2004 2006 2008 2010 2012 2014 2016 2018 2020 2022
Year
http://nsidc.org/greenland-today/2021/08/rain-at-the-summit-of-greenland/
Mass change (Gt)
–1 000
–2 000
2002 2004 2006 2008 2010 2012 2014 2016 2018 2020 2022
Year
Figure 16. (a) Cumulative
melt days on the
Greenland ice sheet,
2021, indicating melt
impacts over most of the
ice sheet in summer 2021.
(b) Melt extent (%) over
the ice sheet through
the 2021 melt season on
Greenland, relative to
the median melt extent
from 1981 to 2010.
(c) Greenland meltwater
run-off through July–
August 2021 relative to
the recent extensive
melt seasons of 2012
and 2019, indicating
the record amount of
late-season ice sheet
melting associated with
the mid-August rainfall
event at Summit. 
Source: All images are
courtesy of the USA
National Snow and
Ice Data Center http://
nsidc.org/greenlandtoday/,
with
thanks
to

Ted
Scambos
and
the

Greenland
Ice
Sheet

Today
team.
Analysis

in
(a)
and
(b)
is
from

Thomas
Mote,
University

of
Georgia,
USA,
and

meltwater
run-off
in
(c)

is
estimated
from
the

regional
climate
model

MARv3.12,
courtesy

of
Xavier
Fettweis,

University
of
Liège,

Belgium.
17
–3 000
(a)
(b)
Greenland melt extent 2021
Greenland cumulative melt days
1 Jan. – 15 Oct. 2021
1981–2010 median
2021 melt percentage
Interquartile range
Meltwater runo (Gt)
Melt extent (%)
80
70
60
50
40
30
20
10
0
' 
• 
Apr.       May      Jun.      Jul.        Aug.      Sep.      Oct.
• 
 
 
 
 
 
 
15 Oct. 2021
(c)
Modelled meltwater run-o, July–August 2021
•
•
• 
1981–2010 maximum
1981–2010 average
2012    2019    2021
20
16
12
8
4
0
E • 
Number of
melt days
5 10 15 20 25 30 
5 10 15 20 
Jul. 
Aug.
latest date in the year that above-freezing
temperatures have been recorded at this
location. Melt events at Summit were also
observed in 1995, 2012 and 2019. Ice core
records indicate that prior to 1995, the last
time melting occurred at Summit was in the
late nineteenth century.
of the year were over the remnant Larsen B
and C ice shelves on the Antarctic Peninsula;
most other locations experienced near-normal
melt extent relative to the mean 1990–2020
conditions.
54
Antarctic ice sheet
Despite near-normal surface melting in
Antarctica in summer 2020/2021, GRACEFO
satellite
gravity
data
indicate
that
the

Antarctic
ice
sheet
continued
to
lose
mass

in
early
2021
(Figure 15),
associated
with

calving
and
marine
ice
sheet
melting
in
the

Amundsen
Sea
sector
of
West
Antarctica.

Antarctic
ice
sheet
mass
loss
since
2010
is

largely
driven
by
thinning
and
grounding-line

retreat
of
Thwaites
Glacier,
triggered
by
ocean

warming
in
this
sector
of
the
ice
sheet.
The Antarctic ice sheet experiences negligible
surface melt compared to Greenland, but
some melt typically occurs on the Antarctic
Peninsula between November and February,
as well as on some of the low-lying ice shelves
and in coastal zones. The summer 2020/2021
melt season in Antarctica was moderate and
was below the 1990–2020 average.
56
55
 The 

GRACE-FO data
57
 indicate that Antarctica 
northern Filchner Ice Shelf in the Weddell Sea 
lost a mass of 296 Gt from November 2020 
experienced a strong but brief melt event in
mid-December 2020. The summer melt season
in
Antarctica
concluded
in
mid-February

2021.
The
strongest
positive
melt
anomalies
to November 2021, which is roughly double
the average rate of ice loss in Antarctica from
2002 to 2021 (Figure 15).
Figure 17. May snowcover
extent
(SCE)

anomaly
in
the
northern

hemisphere
(NH)
for

the
period
1970–2021,

relative
to
the
1991–2020

average.

Source:
Rutgers

Northern
Hemisphere

Snow
Cover
Extent

product:
https://
snowcover.org.
Millions km
2
SNOW
5
Seasonal snow cover in the northern hemisphere
(NH)
has
been
experiencing a
longterm
decline
in
the
late
spring
and
summer,

along
with
evidence
of
relative
stability
or

increases
in
snow
extent
in
the
autumn.
4
3
2
58

Snow-cover extent (SCE) in 2021 was consistent
with
these
long-term
trends,
with a
May

NH
snow
cover
anomaly
of
–2 million km
1
0
2
,
the third lowest in the SCE record from
1970–2021 (Figure 17), based on analyses of
the Rutgers Northern Hemisphere (NH) Snow
Cover Extent (SCE) product.
–1
–2
59
 Reductions in
northern hemisphere spring snow extent are 
–3
consistent across data sets, and in 2021 this 
was driven by below-normal snow cover in 
54 
Meese, D. A.; Gow, A. J.; Grootes, P. et al. The Accumulation Record from the GISP2 Core as an Indicator of Climate
Change Throughout the Holocene. Science 1994, 266 (5191), 1680–1682. https://doi.org/10.1126/science.266.5191.1680. 
55 
http://nsidc.org/greenland-today/2021/04/the-antarctic-2020-to-2021-melt-season-in-review/ 
56 
Velicogna, I.; Mohajerani, Y.; Landerer, G. A. F. et al. Continuity of Ice Sheet Mass Loss in Greenland and Antarctica from
the GRACE and GRACE Follow-On Missions. Geophysical Research Letters 2020, 47 (8), e2020GL087291. https://doi.
org/10.1029/2020GL087291. See also Rignot, E.; Mouginot, J.; Scheuchl, B. et al. Four decades of Antarctic Ice Sheet
mass balance from 1979–2017. Proceedings of the National Academy of Sciences 2019, 116 (4) 1095–1103. https://doi.
org/10.1073/pnas.1812883116. 
57 
Wiese, D.N.; Yuan, D.-N.; Boening, C. et al. 2019. JPL GRACE and GRACE-FO Mascon Ocean, Ice, and Hydrology Equivalent
Water Height RL06M CRI Filtered Version 2.0, Ver. 2.0, PO.DAAC, CA, USA. http://dx.doi.org/10.5067/TEMSC-3MJ62.
58 
Intergovernmental Panel on Climate Change (IPCC), 2021: Summary for Policymakers. In: AR6 Climate Change 2021: The
Physical Science Basis, https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_SPM_final.pdf.
59 
https://snowcover.org 
18
1970
1972
1974
1976
1978
1980
1982
1984
1986
1988
1990
1992
1994
1996
1998
2000
2002
2004
2006
2008
2010
2012
2014
2016
2018
2020
2021
Year
Figure 18. Recent slope
instability associated
with permafrost thaw,
including active layer
detachment slides
and retrogressive
thaw slumps. In the
foreground, large
amounts of material
have pushed into the
river to form a debris
tongue. Foothills of the
Mackenzie Mountains
south of Norman Wells,
north-western Canada. 
Credit: Government of
Northwest Territories,
Canada.
! 
• 
~ 
Eurasian high latitudes. Eurasian Arctic snow
extent in May and June 2021 were the fifth
and third lowest on record for the period
1967–2021.
60
PERMAFROST
of permafrost temperatures (temperature
measured in boreholes) and active layer
thickness (the maximum thickness of the seasonally
thawed
layer
above
the
permafrost).

GTN-P
products
rely
mostly
on
research

projects
to
sustain
activities.
Long-term
data

series
from
national
and
regional
networks

operating
in
mountain
and
polar
areas
show

a
continuation
of
past
warming
trends up
to

2020,
which
is
the
most
recent
data
available.
Permafrost occurs beneath about one eighth
of Earth’s exposed land area. It is ground
that remains at or below 0 °C for at least two
consecutive years. Permafrost thaw can lead
to landscape instability and other impacts,
including the emission of greenhouse gases
from previously frozen organic material. As
permafrost temperature approaches 0 °C,
changes in temperature in the ice-rich ground 
STRATOSPHERIC OZONE
Following the success of the Montreal
Protocol, the use of halons and chlorofluor-
are stalled due to the phase change between 
ocarbons (CFCs) has been reported as discon-
ice and water. While temperature increase
may level off near 0 °C for several years
or decades due to the phase change, the
impacts of permafrost warming and thaw on
ground stability (including subsidence and
mass movements), hydrology, ecosystems
and infrastructure are often clearly visible
(Figure 18).
Since the 1990s, the Global Terrestrial Network 
tinued, although their levels in the atmosphere
continue to be monitored. Because of their
long lifetime, these compounds will remain
in the atmosphere for many decades. Even
if there were no new emissions, there is still
more than enough chlorine and bromine
present to cause the complete destruction
of ozone over Antarctica from August to
December. As a result, the formation of the
Antarctic ozone hole – an area of low ozone 
for Permafrost (GTN‐P) has compiled data sets 
concentration – continues to be an annual 
60 
Mudryk, L.; Chereque, A. E.; Derksen, C. et al. Terrestrial Snow Cover. In Arctic Report Card 2021; Moon, T. A.;
Druckenmiller, M. L.; Thoman, R. L., Eds.; National Oceanic and Atmospheric Administration, 2021. https://doi.
org/10.25923/16xy-9h55.
19
spring event, with the year-to-year variation in
its size and depth governed to a large degree
by meteorological conditions.
The 2021 Antarctic ozone hole developed
relatively early and continued growing,
resulting in a large and deep ozone hole. It
expanded to 24 million km
2
The 2021 hole was larger and deeper than 70%
of the ozone holes since 1979, and remained
as such until the closing of the hole in the
second half of December. It ranked as the
thirteenth largest ozone hole by area and the
sixth deepest ozone hole in terms of minimum
ozone. The unusually deep and large ozone
hole in 2021 was driven by a strong and
stable polar vortex and colder-than-average
conditions in 2021 in the stratosphere.
Figure 19. Left: Ozone
hole area (millions
of km
2
 on 24 September
and remained close to this value until
mid-October 2021. The development of the
hole, and its extent and severity, were close
to that for the 2020 and 2018 seasons. The
ozone hole reached its maximum area of
24.8 million km
2
 on 7 October 2021, similar
to the areas in 2020 and 2018, and close
to the highest values observed in earlier
years, such as 28.2 million km
DRIVERS OF SHORT-TERM
VARIABILITY
2
 in 2015 and
29.6 million km
2
 in 2006, according to an 
There are many different natural phenomena,
often referred to as climate patterns or climate 
analysis from the National Aeronautics and 
modes, that affect weather at timescales 
Space Administration (NASA) (Figure 19, left). 
ranging from days to several months. Surface
temperatures change relatively slowly over
the ocean, so recurring patterns in sea-surface
temperature can be used to understand and,
in some cases, predict the more rapidly
changing patterns of weather over land on
seasonal timescales. Similarly, albeit at a
faster rate, known pressure changes in the
atmosphere can help explain certain regional
weather patterns.
In terms of the total ozone column, NASA
reported a minimum ozone of 92 DU (Dobson
Units) on 7 October 2021, which was the lowest
value
for
the
2021
season
and
for
the
past

17 years
(Figure 19,
right).
After
September

2021,
the
concentration
of
stratospheric

ozone
was
persistently
reduced
to
near-zero

values
between
15 and
20 km
altitude
over

Antarctica.
Together
with
the
2020
season,

these
are
some
of
the
lowest
ozone
values

ever
measured
via
sondes
at
the
Antarctic

stations,
as
reported
by
the
National
Oceanic

and
Atmospheric
Administration
(NOAA).
In 2021, the El Niño–Southern Oscillation
(ENSO), the Indian Ocean Dipole (IOD), the
Arctic Oscillation (AO) and the Southern
Annular Mode (SAM) each contributed to 
20
). Right: Minimum
ozone, where the total
ozone column is less
than 220 Dobson Units.
The year 2021 is shown
in red. The most recent
years are shown for
comparison as indicated
by the legend. The
smooth, thick grey line is
the 1979–2020 average.
The blue shaded area
represents the 10th to
90th percentiles, and
the green shaded area
represents the 30th to
70th percentiles for the
period 1979–2020. The
thin black lines show the
maximum and minimum
values for each day in
the 1979–2020 period. 
Source: The plot was
generated at WMO
on the basis of data
downloaded from the
NASA Ozone Watch
(https://ozonewatch.
gsfc.nasa.gov/). The
NASA data are based on
satellite observations
from the OMI and TOMS
instruments.
Ozone hole area – Southern hemisphere
1979–2020
2017
2018
2019
2020
2021
30
25
Area (millions of km
2
)
20
15
10
5
0
Jul.           Aug.           Sept.          Oct.           Nov.           Dec.
Months
(a)
(b)
Minimum ozone – Southern hemisphere
300
250
Jul.           Aug.          Sept.          Oct.            Nov.          Dec.
Ozone (DU)
200
150
100
1979–2020
2017
2018
2019
2020
2021
Months
major weather and climate events in different
parts of the world, and are described in further
detail below.
EL NIÑO–SOUTHERN OSCILLATION
the Indian and Pacific Oceans) and lower than
normal in Patagonia at the beginning of the
year, which are typical patterns associated
with La Niña. Additionally, La Niña conditions
can contribute to above-average hurricane
activity in the North Atlantic, which experienced
21 named
tropical
cyclones
during

its
2021
hurricane
season
(the
1981–2010

average
for
the
entire
season
is
14).
La Niña
is

also
associated
with
warmer
and
drier
areas

across
the
southern
tier
of
the
United
States

of
America.
In
December,
most
states
in
this

region
reported
record
or
near-record
high

temperatures,
and
several
states
were
also

drier
than
average.
ENSO is one of the most important drivers of
year-to-year variability in weather patterns
worldwide. It is linked to hazards such as
heavy rains, floods and drought. El Niño, characterized
by
higher-than-average
sea-surface

temperatures
in
the
eastern
Tropical
Pacific

and a
weakening
of
the
trade
winds,
typically

has a
warming
influence
on
global
temperatures.
La Niña,
which
is
characterized
by

below-average
sea-surface
temperatures
in

the
central
and
eastern
Tropical
Pacific
and
INDIAN OCEAN DIPOLE
a strengthening of the trade winds, has the 
opposite effect.
The positive phase of the IOD is characterized
by below-average sea-surface temperatures in
the Eastern Indian Ocean and above-average
sea-surface temperatures in the west. The
negative phase has the opposite pattern. The
resulting change in the gradient of sea-surface
temperature across the ocean basin affects
the weather of the surrounding continents,
primarily in the southern hemisphere. Positive
IOD events are often associated with El Niño
and negative events with La Niña.
La Niña conditions emerged in mid-2020 and
peaked in the October–December period at
moderate strength, with average sea-surface
temperatures 1.3 °C below the 1991–2020
normal in the Niño 3.4 region (5°N–5°S,
120°W–170°W). La Niña weakened through
the first half of 2021, reaching an ENSOneutral
state
(temperatures
within
0.5 °C
of

normal)
in
May,
according
to
both
oceanic
and

atmospheric
indicators.
However,
sea-surface

temperatures
cooled
after
mid-year,
reaching

La Niña
thresholds
once
again
by
the
July–
September
period.
By
the
October–December

period,
average
sea-surface
temperatures

once
again
reached
moderate
strength,
at

1.0 °C
below
normal.
62
In addition to having a temporary cooling 
A negative IOD developed during July 2021
and returned to neutral, although on the
negative side, by the end of the year. This
marked the first negative IOD since 2016.
In combination with La Niña, this phase
contributed to wet conditions in much of
Australia in the late austral winter and spring.
South-west Western Australia reported its 
influence on Earth’s global temperature, 
highest July rainfall totals since 1996, as did 
La Niña is associated with drier-than-normal
conditions in East Africa. Kenya, Ethiopia
and Somalia experienced consecutive
below-average rainfall seasons in late 2020,
early 2021 and late 2021, which led to drought
in the region. In early 2021, precipitation
was higher than normal over the Maritime
Continent
many locations in South Australia. Australia
as a whole observed its tenth wettest spring
in its 122-year record, with the state of New
South Wales observing its fourth wettest.
November was the wettest November since
records began for both New South Wales
and Australia as a whole.
63
61
 (the climatologically important
region of islands and seas between mainland
South-east Asia and Australia and between 
 Conversely, the
negative IOD, again in combination with
La Niña, likely contributed to the extreme
dry conditions in Eastern Africa.
61 
Ramage, C. S. Role of a Tropical “Maritime Continent” in the Atmospheric Circulation. Monthly Weather Review 1968, 96 (6),
365–370. https://journals.ametsoc.org/view/journals/mwre/96/6/1520-0493_1968_096_0365_roatmc_2_0_co_2.xml. 
62 
http://www.bom.gov.au/climate/enso/history/ln-2010-12/IOD-what.shtml 
63 
http://www.bom.gov.au/climate/current/statements/scs75.pdf 
21
4
3
2
1
0
–1
–2
–3
–4
–5
1
2
3
4
5
6
7
8
0
9
0
0
0
1
0
2
0
3
0
4
0
5
0
0
6
0
0
7
1
0
8
1
0
9
1
0
0
1
0
1
1
0
1
0
/2
1
0
/2
1
0
/2
1
0
/2
1
0
/2
2
0
/2
2
0
/2
0
/2
0
/2
0
/2
0
/2
0
0
/2
1
0
/2
2
0
/2
3
/2
4
/2
5
/2
6
/2
7
0
/2
8
0
/2
9
0
/2
0
0
1
0
2
0
3
0
4
0
0
5
0
0
6
0
0
7
1
0
8
1
0
9
1
0
0
1
0
1
0
2
1
0
2
1
0
2
1
0
2
1
0
2
1
0
2
2
0
2
0
2
0
2
0
2
0
2
0
2
0
2
0
2
2
2
2
2
2
2
2
January
February
ARCTIC OSCILLATION
regions in Mongolia, China, Japan and the 
The AO is a large-scale atmospheric pattern
that
influences
weather
throughout
the

northern
hemisphere.
64
Republic of Korea reporting record high temperatures
for
this
time
of
year.
The
contrast

between
the
positive
AO
(winter
2019/2020)

and
the
negative
AO
(winter
2020/2021)
could

explain
some
of
the
differences
between

temperature
patterns
in
the
first
quarters
of

2020
and
2021.
The
negative
winter
phase

of
the
Arctic
Oscillation
has
also
been
linked

to
more
moderate
Arctic
sea-ice
loss
the

following
summer
 The positive phase is
characterized by lower-than-average air pressure
over
the
Arctic
and
higher-than-average

pressure
over
the
Northern
Pacific
and

Atlantic
Oceans.
The
jet
stream
runs
parallel

to
the
lines
of
latitude
and
farther
north
than

average,
locking up
cold
Arctic
air,
and
storms

can
be
shifted
northward
of
their
usual
paths.

The
mid-latitudes
of
North
America,
Europe,

Siberia
and
East
Asia
generally
see
fewer

cold
air
outbreaks
than
usual
during
the

positive
phase
of
the
AO. A
negative
AO
has

the
opposite
effect,
associated
with a
more

meandering
jet
stream
and
cold
air
spilling

south
into
the
mid-latitudes
where
the
jet

stream
dips
southward.
65
 (see Arctic sea ice).
SOUTHERN ANNULAR MODE
On the opposite side of the world, the SAM
(also referred to as the Antarctic Oscillation,
AAO) is a large-scale atmospheric pattern
that influences weather in the southern hemisphere.
It
is
measured
by
the
north–south

movement
of
the
westerly
wind
belt
that
The AO was negative during the northern 
circles Antarctica, dominating the middle to 
hemisphere 2020/2021 winter and, seasonally,
was the most negative on record since winter
2009/2010 (Figure 20). The jet stream swept
down over North America, contributing to
the coldest February for the continent since
1994. However, the same wavy jet stream also
contributed to extreme warmth in parts of
Northern and Eastern Asia in February 2021
as it surged northward over the area, with 
64 
Thompson, D. W. J.; Wallace, J. M. The Arctic Oscillation signature in the wintertime geopotential height and
temperature fields. Geophysical Research Letters 1998, 25 (9), 1297–1300.
65 
Rigor, I. G.; Wallace, J. M.; Colony, R. L. Response of Sea Ice to the Arctic Oscillation. Journal of Climate 2002, 15 (18),
2648–2663. https://doi.org/10.1175/1520-0442(2002)015<2648:ROSITT>2.0.CO;2. 
22
higher latitudes of the southern hemisphere.
The positive phase is characterized by the
belt of strong westerly winds contracting
towards Antarctica and is linked to the La Niña
phase of ENSO. During a positive SAM, warm
and moist westerly flow over the northern
Peninsula leads to foehn warming on the
eastern side and anomalous warmth. The
negative phase, in contrast, is characterized 
December
Monthly index values
Figure 20. Arctic
Oscillation monthly
index values for northern
hemisphere winter
months 2000/2021.
December is in blue,
January in orange and
February in grey. 
Source: National
Oceanic and
Atmospheric
Administration (NOAA)
Climate Prediction
Center.
In 
. 
I 
I 
I 
I 
- 
II - ■ L 
li 
I 
I 
• II I IL. - - I I 
·- 
I I 
II I 11 
II I 
l 
II 
II 
' 
■ 
II • 
I 
■ 
I 
I I 
■ 
■ 
■ 
■ 
by an expansion of the belt of strong westerly
winds towards the equator.
66
 Notably, the
SAM can have large impacts on Antarctic
surface temperatures, ocean circulation and
rainfall patterns in parts of Australia. 
The SAM was primarily positive or neutral
throughout 2021, and was strongly positive
both at the beginning of the year and near the
end of the year.
67
 This positive pattern likely
contributed to the record cold austral winter 
and April–September cold season at the South
Pole, as it created anomalous low wind speed
and wind directions predominantly from the
northeast at the pole and prevented warm air
masses from reaching the area. Conversely,
Esperanza Station, on the north-east Antarctic
Peninsula, experienced its warmest year
on record, with an average temperature
of −2.6 °C. On 18 December, the temperature
reached 14.6 °C, an all-time December high
for the station.
66 
http://www.bom.gov.au/climate/sam/ 
67 
http://www.nerc-bas.ac.uk/icd/gjma/sam.html 
23
High-impact events in 2021 
Although understanding broad-scale changes
in the climate is important, the acute impacts
of weather and climate are most often felt
during extreme meteorological events such
as heavy rain and snow, droughts, heatwaves,
cold waves and storms, including tropical
storms and cyclones. These can lead to or
exacerbate other high-impact events such as
flooding, landslides, wildfires and avalanches.
This section is based largely on input from
WMO Members. The wider socioeconomic
risks and impacts associated with these
events are described in Risks and impacts.
There were numerous major wildfires during
and after the heatwaves (including one which
largely destroyed the town of Lytton the
day after its record temperature). The Dixie
fire in northern California, which started
on 13 July, burned about 390 000 hectares
before being fully contained in October,
making it the largest single fire on record in
California. A rare winter wildfire caused major
property losses east of Boulder, Colorado on
30 December, with more than 1 000 homes
and other buildings destroyed or damaged.
The overall area burned during the season
in the United States was slightly below average,
72
HEATWAVES AND WILDFIRES
 but in Canada it was well above average,
with Ontario having its largest seasonal area
burned on record and British Columbia its
third largest. Prolonged smoke pollution 
Exceptional heatwaves affected Western North 
affected many parts of North America during 
America on several occasions during June and
July. By some measures, the most extreme was
in late June in the north-western United States
and western Canada. Lytton, in south-central
British Columbia, reached 49.6 °C on 29 June,
breaking the previous Canadian national record
by
4.6 °C,
with
temperatures
reaching
the

mid-40s
as
far
west
as
the
eastern
suburbs

of
Vancouver
and
the
interior
of
Vancouver

Island.
It
was
also
more
than 5 °C
higher
than

the
previous
highest
known
temperature
north

of
50°N.
Large
numbers
of
heat-related
deaths

occurred,
with
569 reported
in
British
Columbia

alone
between
20 June
and
29 July,
the summer, with Calgary reporting a record
512 hours of smoke or haze, compared with
the long-term average of 12.
68
 and
185 in Alberta,
69
 while in the United States
over a similar period, 154 heat-related deaths
were reported in Washington
70
 and at least 83
in Oregon.
71
 Many long-term stations broke
records by 4 °C to 6 °C, including Portland,
Oregon (46.7 °C). There were also multiple 
Extreme heat affected the broader
Mediterranean region on several occasions
during the second half of the northern
hemisphere summer. The most exceptional
heat was in the second week of August.
On 11 August, an agrometeorological station
near
Syracuse
in
Sicily,
Italy,
reached

48.8 °C,
a
provisional
European
record,
while

Kairouan
(Tunisia)
reached a
record
50.3 °C.

Montoro
(47.4 °C)
set a
national
record
for

Spain
on
14 August,
while
on
the
same
day

Madrid
(Barajas
Airport)
had
its
hottest
day

on
record
with
42.7 °C.
Earlier,
on
20 July,

Cizre
(49.1 °C)
set a
Turkish
national
record

and
Tbilisi
(Georgia)
had
its
hottest
day
on

record
(40.6 °C).
Major
wildfires
occurred
heatwaves in the south-western United States. 
across many parts of the region, with Algeria, 
Death Valley, California reached 54.4 °C on
9 July, equalling a similar 2020 value as the
highest recorded in the world since at least
the 1930s. It went on to be the hottest summer
on
record
averaged
over
the
continental

United States.
southern Turkey and Greece especially badly
affected. Over 40 deaths
73
 occurred in the
Algerian fires. France, Italy, North Macedonia,
Lebanon, Israel, Libya, Tunisia and Morocco
also experienced significant wildfires during
the period.
68 
https://www2.gov.bc.ca/gov/content/life-events/death/coroners-service/news-and-updates/heat-related 
69 
https://www.canada.ca/en/environment-climate-change/services/top-ten-weather-stories/2021.html 
70 
https://www.doh.wa.gov/Emergencies/BePreparedBeSafe/SevereWeatherandNaturalDisasters/HotWeatherSafety/
HeatWave2021#heading88455 
71 
Oregon Medical Examiner’s Office, quoted in media reports, https://flashalert.net/id/OSPOre/146352 
72 
https://www.nifc.gov/
73 
https://www.emdat.be/
24
June was exceptionally warm in many parts
of Eastern and Central Europe. National June
records were set for Estonia (34.6 °C) and
Belarus (37.1 °C), while locations which had
their hottest June day on record included
St. Petersburg (35.9 °C) and Moscow (34.8 °C),
both on 23 June, Yerevan (Armenia, 41.1 °C)
on the 24th, and Baku (Azerbaijan, 40.5 °C)
on the 26th. Tampere in Finland reported its
highest temperature on record (33.2 °C) on
22 June. Latvia had its hottest June and summer
on
record.
Further
afield,
Libya
also
saw

a
prolonged
heatwave
in
late
June.
Later
in

the
summer,
abnormal
warmth
also
reached

North-west
Europe;
31.3 °C
at
Castlederg
on

21 July
was a
record
for
Northern
Ireland.

Two
tropical
nights
were
observed
in
Ireland

in
July,
with
daily
minimum
temperatures
1949 respectively. Electricity transmission
was severely disrupted, with power outages
affecting
nearly
10 million
people
at
the

event’s
peak.
Frozen
pipes
were
another
major

cause
of
damage. A
total
of
226 deaths
were

reported
in
the
United
States
along
with
an

estimated
US$ 24 billion
in
economic
losses,

making
it
the
costliest
winter
storm
on
record

for
the
United
States.
75
 
The winter of 2020/2021 was a cold winter
in many parts of Northern Asia. The Russian
Federation had its coldest winter since
2009/2010. Below-average temperatures
affected much of Japan in late December
and early January, with heavy snowfalls on a
number of occasions. A number of locations
on the Sea of Japan coast of Honshu had their 
exceeding 20 °C in County Kerry.
heaviest 72-hour snowfall on record in early 
January. Much of China was also unusually
cold during this period, with Beijing reaching
−19.6 °C on 7 January, its lowest temperature
since 1966. 
For the third successive year, there were
major wildfires during the summer in Siberia,
particularly in the Sakha Republic around
Yakutsk. According to a report by the Federal
Forestry Agency of Russia, the number of fires
in Yakutia by the end of the summer was 2 295,
with an area of about 8.9 million hectares
burned since the beginning of the forest
fire season. 
A severe snowstorm hit many parts of Spain
from 7 to 10 January, followed by a week of
freezing air temperatures. A total of 53 cm of
snow fell at the central city location of Retiro
(Madrid), and heavy falls were also reported
in many other parts of Spain.
76
Fire activity in the Amazon region during the
August–September peak season was less than
in 2019 or 2020,
74
 but there was extensive
fire activity in other parts of Brazil, including
the Pantanal.
 Some locations,
including
Toledo
(−13.4 °C)
and
Teruel

(−21.0 °C),
had
their
lowest
temperatures

on
record
on
12 January
in
the
wake
of
the

storm.
There
were
major
disruptions
to
land

and
air
transport.
Later
in
the
winter,
in
the

second
week
of
February,
the
Netherlands

experienced
its
most
significant
snowstorm

since
2010,
with
heavy
snow
also
falling
in

Germany,
Poland
and
the
United
Kingdom;
COLD SPELLS AND SNOW
in the wake of the storm, Braemar recorded 
Abnormally cold conditions affected many
parts of the central United States and northern
Mexico in mid-February. The most severe
impacts were in Texas, which generally
experienced its lowest temperatures since
at least 1989, with temperatures in some
areas staying below freezing continuously
for 6 to 9 days. On 16 February, Oklahoma
City reached −25.6 °C and Dallas −18.9 °C,
their lowest temperatures since 1899 and 
−23.0 °C on 12 February, the lowest temperature
in
the
United
Kingdom
since
1995.

In
South-eastern
Europe,
Athens
had
its

heaviest
snow
since
2009
on
15 February.

Libya
experienced
unusual
snowfalls
between

15 and 21 February
and
again,
on
high
ground,

in
late
December.
An abnormal spring cold outbreak affected
many parts of Europe in early April. Record 
74 
https://queimadas.dgi.inpe.br/queimadas/portal-static/estatisticas_estados/ 
75 
https://www.ncdc.noaa.gov/billions/events/US/2021 
76 
http://www.aemet.es/en/conocermas/borrascas/2020-2021/estudios_e_impactos/filomena
25
low April temperatures in France included
−7.4 °C at Saint-Etienne on the 8th and −6.9 °C
at Beauvais on the 6th, while Belgrade
(Serbia) had its heaviest April snowfall on
record on the 7th. It was the coldest April in
Poland in the twenty-first century. At high
elevations, national records for April were
set for Switzerland (−26.3 °C at Jungfraujoch)
and Slovenia (−20.6  °C at Nova vas na
Blokah). This followed a very warm end to
March with France having its warmest March
day on record on the 31st. Frost damage
to agriculture was widespread and severe,
with losses to vineyards and other crops
in France alone exceeding US$ 4.6 billion.
The United Kingdom went on to have its
lowest monthly mean temperature for April
since 1922.
the Middle East, parts of Southern Africa,
parts of Southern South America and areas
in Central North America.
The onset of the West African Monsoon was
delayed. Later in the season, rainfall totals
were higher than normal, especially in the
western monsoon region. In total, the seasonal
rainfall
was
close
to
normal.
In
Southern

Africa,
in
an
area
centred
on
Zambia,
rainfall

amounts
during
the
wet
season
until
May

were
below
the
long-term
mean.
It
was
at
least

the
second
year
in a
row
with
below-normal

rainfall
for
Madagascar;
rainfall
totals
have

been
below
average
in
most
years
since
2011.

In
addition,
both
the
wet
seasons
(April
to
May

and
October
to
November)
were
drier
than

usual
in
the
Greater
Horn
of
Africa
region.
PRECIPITATION
Above average rainfall totals were observed
in Alaska and the north of Canada, and in
the south-eastern United States and parts
of the Caribbean. Between these two
wetter-than-average bands was a swath of
unusually dry conditions extending across
the width of the continent.
Compared to temperature, precipitation is
characterized by higher spatial and temporal
variability.
In
2021,
large
regions
with

above-normal
precipitation
totals,
relative
to

the
chosen
climatology
period
(1951–2000),

were
Eastern
Europe,
South-east
Asia,
the

Maritime
Continent,
areas
of
Northern
South

America
and
parts
of
South-eastern
North

America
(Figure 21).
Large
regions
with
a

rainfall
deficit
included
South-west
Asia
and
Unusually high precipitation amounts, relative
to the reference period, were recorded in
south-western and south-eastern Australia.
On the other hand, abnormally low precipitation
amounts
were
received
on
the
North

Island
of
New
Zealand.
90°N
Figure 21. Total
precipitation in 
45°N
2021, expressed as 
26
Latitude
0°
45°S
90°S
180˚                               90˚W                                    0˚                                  90˚E                                 180˚
Longitude
0.0             0.2             0.4             0.6             0.8             1.0
Quantile
a percentile of the
1951–2010 reference
period, for areas in the
driest 20% (brown) and
wettest 20% (green)
of years during the
reference period, with
darker shades of brown
and green indicating the
driest and wettest 10%,
respectively. 
Source: Global
Precipitation
Climatology Centre
(GPCC), Deutscher
Wetterdienst, Germany.
� 
k 
. 
v 
4 
• 
' 
Unusually low precipitation amounts fell
around the Mediterranean Sea, while unusually
high
totals
were
detected
around
the

Black
Sea
and
in
parts
of
Eastern
Europe.
in Australia.
79
FLOOD
 The week from 18 to 24 March
was the wettest on record averaged over
coastal New South Wales. The most severe
flooding was along the Hastings, Karuah and
Manning Rivers north of Sydney, but there
was also significant flooding in other areas,
including parts of western Sydney. There was
also flooding on many inland rivers, which
led to substantial recovery in water storages
severely depleted by the 2017–2019 drought.
At least US$ 2.1 billion in economic losses
were reported.
Extreme rainfall, which was enhanced by
the moisture influx ahead of Typhoon In-fa,
hit Henan province in central China from
17 to 21 July. The most severely affected area
was around the city of Zhengzhou (the capital
of Henan Province), which on 20 July received
201.9 mm of rainfall in one hour (a Chinese
national record) and 382 mm in 6 hours.
For the event as a whole, the area received 
Two flash flood events associated with localized
heavy
rainfall
occurred
in
Afghanistan

during
2021,
in
early
May
around
Herat
in
the

west,
and
on
28–29 July
centred
on
Nuristan

in
the
east.
There
was
significant
loss
of
life
720 mm, more than its annual average. The 
in both events, with 61 deaths reported in 
city experienced extreme flash flooding,
with many buildings, roads and subways
inundated. The flooding was associated with
380 deaths or missing persons, and economic
losses of US$ 17.7 billion were reported.
the May event and 113 in the July event.
80
77

Further late-season flooding occurred in
early October, focused on Shanxi and Hebei
provinces.
Flash flooding occurred on several occasions
around the Mediterranean and Black Sea
coasts. The most impactful event was on
the Black Sea coast of Turkey on 10 August,
where several towns experienced severe
damage and 77 deaths were reported. Rainfall
of 399.9 mm was recorded at Bozkurt in
24 hours. This event was associated with a
“Medicane” – a storm forming outside the
tropics that nevertheless has characteristics
of a tropical storm – in the Black Sea. Extreme
rainfall and flooding were also reported on
the Black Sea coast of the Russian Federation
from 12 to 14 August.
Western Europe experienced some of its most
severe flooding on record in mid-July. The
worst-affected area was western Germany
and eastern Belgium, where 100 to 150 mm
of rain fell over a wide area on 14–15 July
onto ground which was already unusually wet
after high recent rainfall. Hagen (Germany)
reported 241 mm of rainfall in 22 hours.
Numerous rivers experienced extreme flooding,
with
several
towns
inundated,
and
there

were
also
several
landslides.
France,
the
On 4 October, exceptional rainfall fell in coastal
regions of Liguria (north-west Italy), including
496.0 mm in 6 hours at Montenotte Inferiore 
Netherlands, Luxembourg and Switzerland 
and 740.6 mm in 12 hours at Rossiglione. 
also experienced significant flooding. The
number of deaths reported in Germany
was 183, and in Belgium it was 36, with
economic losses in Germany exceeding
US$ 20 billion.
78
Persistent heavy rainfall in mid-March resulted
in major flooding in eastern New South Wales 
Persistent above-average rainfall in the first
half of the year in parts of Northern South
America, particularly the northern Amazon
basin, led to significant and long-lived flooding
in
the
region.
The
Rio
Negro
at
Manaus

(Brazil)
reached
its
highest
level
on
record,

peaking
at
30.02 m
on
20 June.
81
 The most 
77 
RM 114.3 billion, from China’s national contribution
78 
National contribution, Germany
79 
http://www.bom.gov.au/climate/current/statements/scs74.pdf?20210621 
80 
https://reliefweb.int/disaster/fl-2021-000050-afg
81 
http://www.cprm.gov.br/sace/boletins/Amazonas/20211022_11-20211025%20-%20114229.pdf 
27
widespread flooding was reported in northern
Brazil, but Guyana, Bolivarian Republic of
Venezuela and Colombia were also affected.
and Sudan despite near-normal rainfall
in 2021. In Southern Africa, much of which
had been experiencing long-term drought,
rainfall during the 2020/2021 rainy season
was above average in some regions, including
northern South Africa and Zimbabwe, with
some flooding reported, but was near or
below average further north. 
The progress and withdrawal of the Indian
Monsoon was delayed, but overall Indian
monsoon rainfall was close to average, with
above-average rainfalls in the west offset
by below-average values in the north-east.
During the course of the season, 529 deaths in
India and 198 in Pakistan (as of 30 September)
were attributed to flooding, with further
deaths in Bangladesh and Nepal.
82
 There
was further flooding in eastern India and
Nepal during the north-east monsoon season
in October and November. In Eastern Asia,
eastern China (except for Henan) was generally
less
wet
during
the
monsoon
season
Western Canada was affected by severe
flooding in November. At numerous locations
in southern British Columbia 200 to 300 mm
of rain fell in 60 hours, causing floods and
landslides (in some cases exacerbated by
runoff from fire-affected areas). Transport
was severely disrupted, with most major
routes connecting Vancouver with the rest
of Canada closed for several weeks, and 
than in 2020, but August was extremely wet 
several communities were partly or wholly 
in Japan. Western Japan had its wettest
August on record,
83
inundated. Six deaths were reported, and
economic losses exceeded Can$ 2 billion.
Flooding also affected adjacent areas of the
north-western United States. Seattle and
Vancouver both had their wettest autumns
on record.
 with some locations
receiving more than 1400 mm of rain between
11 and 26 August. A tropical depression made
landfall in Malaysia on 16 December, leading
to severe flooding in Selangor and Kuala
Lumpur, with at least 52 deaths reported.
At Kuala Lumpur International Airport,
230 mm of rain was reported in 12 hours on
17–18 December.
84
DROUGHT
The rainy season in the African Sahel was
generally close to the average (1951–2000),
and less wet than in some recent years,
although there was still some significant
flooding reported, especially in Niger, Sudan
and South Sudan as well as Mali. Elsewhere
in Africa, Lake Tanganyika rose to more
than 3 m above its normal level in May,
Significant drought affected much of subtropical
South
America
for
the
second
successive
year.
Rainfall
was
well
below
average

over
much
of
central
and
southern
Brazil,
86
85

displacing lakeshore residents in Burundi, 

Paraguay, Uruguay and northern Argentina.
The drought led to significant agricultural
losses, exacerbated by a cold outbreak at the
end of July, in which maximum temperatures
were below 10 °C for five consecutive days 
while Lake Victoria rose to its highest level 
over higher parts of southern Brazil and which 
since satellite data began in 1992, surpassing
its peak from the previous year. High flows
in the Nile downstream of Lake Victoria,
along with substantial standing water still
remaining from floods in 2020, contributed to
continued flooding in parts of South Sudan 
contributed to damage in many of Brazil’s
coffee-growing regions. Low river levels
also reduced hydroelectricity production
87

and disrupted river transport. The Brazilian
government declared a situation of critical
scarcity of water resources in the Paraná 
82 
National contributions of India and Pakistan; EM-DAT has 120 deaths in Nepal over two incidents and 21 in Bangladesh
from one
83 
https://ds.data.jma.go.jp/tcc/tcc/news/press_20210924.pdf
84 
https://reliefweb.int/disaster/fl-2021-000209-mys
85 
https://reliefweb.int/disaster/fl-2021-000039-bdi 
86 
https://clima.inmet.gov.br/prec 
87 
http://www.ons.org.br/Paginas/Noticias/20210707-escassez-hidrica-2021.aspx 
28
hydrographic region, with numerous water
stores at or near their lowest levels in the
last 20 years.
88
precipitation – but drought continued away
from the west coast and extended farther
east through the south-central United States
as the year ended.
 The 24-month Standardized
Precipitation Index (SPI) over the region
reached its lowest level since the 1960s. The
Paraguay River at Asuncion fell to a record
low 0.75 m below the reference level on
6 October, 0.21 m below the previous record
set in 2020. In Chile, where long-term drought
has persisted for the last decade, 2021 was
another dry year, with most locations having
rainfall at least 30% below average. A number
of locations south of Santiago had their driest
year on record in 2021 with totals 40% to
50% below normal, including Concepción
(559.2 mm), Valdivia (949.0 mm) and Puerto
Montt (921.7 mm). 
Significant drought affected large areas
of
South-west
Asia
during
2021.

Well-below-average
precipitation
fell
during

the
2020/2021
cool
season
in
regions
including
most
of
the
Islamic
Republic
of
Iran,

Afghanistan,
Pakistan,
south-east
Turkey,
and

Turkmenistan.
Pakistan
had
its
third-driest

February
and
fifth-driest
January–March

on
record.
Mountain
snowpack
was
also

well
below
average,
with
snow
cover
extent

in
Islamic
Republic
of
Iran
about
half
the

long-term
average
for
most
of
January
and

February,
leading
to
reduced
streamflow
in
Widespread drought in Western North 
rivers depending on snowmelt, and reduced 
America, which had become established
during 2020, spread and intensified in 2021.
By September, extreme to exceptional drought
covered most of the United States over and
west of the Rocky Mountains, despite some
slight easing from July onwards in parts of the
inland south-west, due to an active summer
monsoon. Extreme to exceptional drought
also extended eastwards on both sides of the
United States–Canada border, affecting northern
border
states
as
far
east
as
Minnesota
and

the
Prairie
Provinces
of
Canada.
The
20 months

from
January
2020
to
August
2021
were
the

driest
on
record
for
the
south-western
United

States,
water availability for irrigation.
Drought developed during the course of the
year in the Greater Horn of Africa region, particularly
affecting
Somalia,
Kenya
and
parts
of

Ethiopia,
after
three
successive
below-average

rainy
seasons.
The
October–December
rainy

season
was
especially
poor,
despite
some

rains
in
Kenya
late
in
the
season.
A severe drought, which has persisted for at
least two years, continues to affect southern
Madagascar.
91
89
 with precipitation more than 10%
below the previous record. Forecast wheat
and canola crop production for Canada in 2021
was 35% to 40% below 2020 levels,
90
 Rainfall for the 12 months
from July 2020 to June 2021 was around 50%
below normal over the region. There were
significant food security issues in the area,
with 1.14 million people classified by the
World Food Programme as needing urgent
assistance as of August 2021.
 while in
the United States, the level of Lake Mead on
the Colorado River fell in July to 47 m below 
92
full supply level, the lowest level on record 
since the reservoir was fully commissioned.
The drought situation in California was eased
by heavy rain in late October and December –
Sacramento had its wettest day on record with
138 mm on 24 October, only days after ending
a record 211-day period with no measurable 
TROPICAL CYCLONES
Tropical cyclone activity around the globe
in 2021 was close to average (1981–2010). For
the second successive year, the North Atlantic 
88 
https://www.gov.br/ana/pt-br/assuntos/noticias-e-eventos/noticias/ana-declara-situacao-de-escassez-quantitativa-
dos-recursos-hidricos-da-regiao-hidrografica-do-parana 
89 
https://www.drought.gov/news/new-noaa-report-exceptional-southwest-drought-exacerbated-human-caused-warming 
90 
https://www150.statcan.gc.ca/n1/daily-quotidien/210914/dq210914b-eng.htm 
91 
https://reliefweb.int/sites/reliefweb.int/files/resources/cb7310en.pdf
92 
https://reliefweb.int/sites/reliefweb.int/files/resources/WFP%20Madagascar%20Country%20Brief%20-%20August%
202021.pdf 
29
had a very active season, with 21 named
storms, well above the 1981–2010 average
of 14. It was also an active season in the North
Indian Ocean, but activity in the western North
Pacific and eastern North Pacific was near to
or below average. The 2020/2021 southern
hemisphere season was also slightly below
average in both the Pacific and Indian Oceans. 
from flooding and associated landslides from
its precursor system in Timor-Leste, and the
Indonesian region of East Nusa Tenggara.
Kupang (Timor) received 700.4 mm of rainfall
in the four days from 2 to 5 April. A total of
226 deaths were associated with Seroja,
181 in Indonesia, 44 in Timor-Leste and one in
Australia.
95
 In January, Eloise contributed to
flooding in Southern Africa, with damage and
casualties reported in Mozambique, South
Africa, Zimbabwe, Eswatini and Madagascar,
while in the South Pacific, Ana and Niran
caused flooding and power outages in Fiji
and New Caledonia, respectively. 
The most significant hurricane of the North
Atlantic season was Ida. Ida made landfall as a
category 4 system in Louisiana (United States)
on 29 August with sustained one-minute
winds of 240 km per hour, equalling the
strongest landfall on record for the state,
with major wind damage and storm surge
inundation. The system then continued on
a north-east track over land with significant 
The most severe cyclone of the North Indian
Ocean season was Tauktae, which tracked
north off the west coast of India, with a peak 
flooding, especially in the New York City area. 
three-minute sustained wind speed
96
 of 
New York, which had already experienced
flooding from Hurricane Henri two weeks
earlier, had a record hourly rainfall of 80 mm,
with 24-hour totals exceeding 200 mm in
parts of the city. Before it developed into a
tropical cyclone, Ida’s precursor system also
caused significant flooding in Venezuela. In
total, 72 deaths were directly attributed to Ida
and 43 deaths were indirectly attributed to it
in the United States and Venezuela, with economic
losses
in
the
United
States
estimated

at
US$ 75 billion.
50–53 m per second, before making landfall
in Gujarat on 17 May at slightly below peak
intensity, equalling the strongest known
landfall in Gujarat. At least 144 deaths were
reported in India and 4 in Pakistan.
97
93
 Another significant landfall
during
the
season
was
Grace,
which
hit

Veracruz
(Mexico)
as a
category 3
hurricane,

having
earlier
resulted
in
impacts,
mostly

from
flooding,
in
Haiti
(where
it
hindered

post-earthquake
recovery),
the
Dominican

Republic,
Jamaica,
and
Trinidad
and
Tobago.
 Later in
the season, Cyclone Gulab crossed the eastern
coast of India from the Bay of Bengal in late
September; the remnant system crossed India
before emerging and re-intensifying in the
Arabian Sea, where it was renamed Shaheen.
Shaheen made landfall on 3 October on the
northern coast of Oman north-west of Muscat,
the first cyclone since 1890 to make landfall
in this area. Al Suwaiq recorded 294 mm rain
in 24 hours, about three times the region’s
annual average. A total of 39 deaths were
reported across India, Pakistan, Oman and the
Islamic Republic of Iran, mostly from flooding. 
In the southern hemisphere, 2021’s most 
The most significant tropical cyclone of the 
significant cyclone
94
 was Seroja in April. 
season in the western North Pacific was 
Seroja formed south of Indonesia and tracked
south-east towards Western Australia. It
made landfall near Kalbarri on 11 April as an
(Australian) category 3 cyclone, the strongest
landfall so far south in Western Australia
since 1956. Seroja’s most severe impacts were 
Typhoon Rai (Odette), which crossed the
central Philippines on 16 December, making
landfall at near peak intensity, with a minimum
central
pressure
of
915 hPa,
after
rapidly

intensifying
prior
to
landfall.
It
reintensified

on
18 December
after
entering
the
South
93 
https://www.ncdc.noaa.gov/billions/events/US/2021 
94 
Tropical Cyclone Yasa (December 2020) forms part of 2020/2021 seasonal statistics but was reported on in the 2020 State
of the Climate.
95 
https://reliefweb.int/disaster/tc-2021-000033-idn
96 
https://rsmcnewdelhi.imd.gov.in/uploads/report/26/26_e0cc1a_Preliminary%20Report%20on%20ESCS%20TAUKTAE19july.pdf
97 
From national contributions
30
China Sea, before weakening and dissipating
without
making
further
landfall.
Severe

damage
occurred
across
the
Philippines,
with

at
least
406 deaths
reported,
while
flooding

also
occurred
in
Viet Nam.
There
were
several

other
significant
landfalls,
most
notably
from

Typhoon
Chanthu
on
the
Batanes
Islands
(the

Philippines).
Chanthu
and
Typhoon
In-fa,
in

July,
also
both
contributed
to
flooding
and

disruptions
to
shipping
around
Shanghai,

while

Dianmu contributed to flooding in
Thailand in September after making landfall
in Viet Nam. 
Six deaths and US$ 1.8 billion in economic
losses were reported. During December 2021,
there were 193 confirmed tornado reports,
around eight times the 1991–2010 December
average of 24. This was double the previous
record of 97 from 2002. On 10 December
there was an historic outbreak across several
south-eastern and central states in which
93  people died and economic losses of
US$ 3.9 billion were reported. This was the
deadliest December tornado outbreak in the
United States, surpassing the Vicksburg,
Mississippi tornado of 5 December 1953,
which led to 38 deaths. Hailstorms in Texas
and Oklahoma on 27–28 April resulted in
US$ 3.3 billion in losses.
SEVERE STORMS
There were multiple severe thunderstorm 
outbreaks in Western and Central Europe
in the second half of June and in July.
An F4 tornado
ATTRIBUTION
98
 struck several villages in
southern Moravia on 24 June, with major
damage and six deaths reported. This was
the strongest tornado on record in the Czech
Republic. Tornadoes were also reported
during the month in Belgium, France and
Poland. Large hail (6–8 cm in diameter) was
reported in multiple countries, including the
Czech Republic, Slovakia, Switzerland and
Germany. In the Czech Republic alone, losses
were around US$ 700 million.
Attribution of individual extreme events
can often take several months because of
the need to complete peer review. But it
is becoming increasingly possible to carry
out near-real-time attribution assessments
that use peer-reviewed methods to reach
conclusions within just a few days of a
weather record being broken. Such “rapid
attribution” studies have been carried out
for the heatwave in Western North America
in June and July,
99,100,101
 the floods in Western
Europe in July
102
 and the British Columbia
floods in November.
In the United States, 1 376 tornadoes were
provisionally reported during 2021, above the
1991–2010 average. A significant outbreak hit
the south-east on 25 March, with the most severe
impacts
in
Alabama
and
western
Georgia.
103
 Studies of the Western
North America heatwave found that while
such a heatwave is rare in today’s climate, it
would have been virtually impossible without
climate change. 
98 
On both the Fujita scale and the Enhanced Fujita scale, a tornado that causes devastating damage is classified as
category 4 tornado (F4 and EF4 respectively). The scales differ in the wind speeds thought to be associated with
“devastating damage”, with lower wind speeds assumed in the enhanced system for the same level of damage.
99 
https://www.worldweatherattribution.org/western-north-american-extreme-heat-virtually-impossible-without-humancaused-climate-change/
100 
Philip, S. Y.; Kew, S. F.; van Oldenborgh, G. J. et al. Rapid Attribution Analysis of the Extraordinary Heatwave on the
Pacific Coast of the US and Canada June 2021. Earth System Dynamics Discussions, In review, 1–34. Preprint: 
https://doi.org/10.5194/esd-2021-90.
101 
Christidis N., 2021. Using CMIP6 Multi-model Ensembles for Near Real-time Attribution of Extreme Events;
Hadley Centre Technical Notes 107. United Kingdom Met Office Hadley Centre: Exeter, 2021. https://digital.nmla.
metoffice.gov.uk/IO_e2e76d02-d72e-49d6-8419-728fb313d075/; https://blog.metoffice.gov.uk/2021/06/29/
heatwave-record-for-pacific-north-west/
102 
https://www.worldweatherattribution.org/heavy-rainfall-which-led-to-severe-flooding-in-western-europe-mademore-likely-by-climate-change/
103 
Gillett, N.; Cannon, A.; Malinina, E. et al. Human Influence on the 2021 British Columbia Floods; SSRN Scholarly Paper ID
4025205; Social Science Research Network: Rochester, 2022. https://doi.org/10.2139/ssrn.4025205. 
31
For the Western Europe flooding, the rapid
attribution study found that the detection of
trends in extreme precipitation at the scale of
the event in question was challenging, and that
saturated soils and the local hydrology were
also factors in the event. However, significant
trends in extreme precipitation were found
across a wider area of Western Europe, and the
study concluded that over this broader region,
human-induced climate change had increased
the likelihood of an extreme precipitation event
comparable to that which occurred.
More generally, events such as these fit
into a broader pattern of change. The IPCC
assessed
104
 that hot extremes in the regions
of Western North America and North-western
North America have increased, and that there
is at least medium confidence in a human
contribution to this increase. Similarly, the
IPCC assessed that heavy precipitation has
increased in the region of Western and Central
Europe affected by flooding, but that there
is currently low confidence in the attribution
of this change to human influence.
104 
Intergovernmental Panel on Climate Change (IPCC), 2021: Summary for Policymakers. In: AR6 Climate Change 2021: The
Physical Science Basis, https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_SPM_final.pdf. 
32
Risks and impacts 
The risk of climate-related impacts depends
on
complex
interactions
between

climate-related
hazards
and
the
vulnerability,

exposure
and
adaptive
capacity
of
human

and
natural
systems.
Climate-related
events

pose
humanitarian
risks
to
society
through

impacts
on
health,
food
and
water
security

as
well
as
human
security,
human
mobility,

livelihoods,
economies,
infrastructure
and

biodiversity.
Climate
and
extreme
weather

events
also
affect
the
use
and
distribution

of
natural
resources
across
regions
and

within
countries,
and
have
large
negative

impacts
on
the
environment.
These
negative

environmental
effects
include
impacts
on
the

land
such
as
droughts,
wildfires
in
forest
and

peatland
areas,
land
degradation,
sand
and

dust
storms,
desertification,
flooding
and
FOOD SECURITY
GLOBAL FOOD SECURITY OUTLOOK
IN 2021
The compounded effects of conflict, extreme
weather events and economic shocks, further
exacerbated by the COVID-19 pandemic,
have led to a rise in hunger, undermining
decades of progress towards improving food
security (Figure 22). Worsening humanitarian
crises in 2021 have also caused the number of
countries at risk of famine to grow. Of the total
number of undernourished people in 2020,
more than half live in Asia (418 million) and a
third in Africa (282 million). Following a peak
in undernourishment in 2020 (768 million 
coastal erosion. At current levels of global 
people), projections indicated a decline in 
greenhouse gas emissions, the world remains
on course to exceed the agreed temperature
thresholds of either 1.5 °C or 2 °C above
pre-industrial levels, which would increase
the risks of pervasive climate change impacts
beyond what is already being seen.
global hunger to around 710 million in 2021
(9% of the world population).
105
 However, 
as of October 2021, the numbers in many
countries were already higher than in 2020.
This striking increase was mostly felt among
groups already suffering from food crises 
1 000
19
900
811.0
800
17
810.7
768.0
15
700
720.4
650.3
600
606.9 615.1
13
500
12.4%
400
11
9.9%
9
300
9.2%
8.3% 8.3%
200
8.4%
7
100
0
5
33
%
Millions
10.4%
Figure 22. The number of
undernourished people
in the world significantly
increased during the
COVID-19 pandemic,
from 650 million people
in 2019 to 768 million
people in 2020. Dotted
lines and empty circles
illustrate projected
values in the figure. 
Source: Food and
Agriculture Organization
of the United Nations
(FAO).
• 
6. 
• 
I 
I 
I
I 
I 
I 
I 
'. 
• • 
0 
I 
I 
·% 
• 
I 
• 
I 
.. 
2005    2006     2007    2008     2009     2010     2011     2012    2013     2014     2015    2016     2017     2018     2019     2020*
Year
Prevalence of undernourishment
(percentage, left axis)
Number of undernourished
(millions, right axis)
105 
Food and Agriculture Organization of the United Nations (FAO), 2021: The State of Food Security and Nutrition in the World
2021: Transforming Food Systems for Food Security, Improved Nutrition and Affordable Healthy Diets for All, https://docs.
wfp.org/api/documents/WFP-0000130141/download/?_ga=2.47516911.931354890.1634299853-763856357.1633873374. 
or worse (IPC/CH Phase 3 or above
106
); the
number of people in these groups rose
from 135 million in 2020 to 161 million by
September 2021, a 19% increase.
107
as regional impacts from severe storms,
cyclones and hurricanes, have significantly
affected livelihoods and the ability to recover
from recurrent weather shocks.
 Another
consequence of these shocks was growth in
the number of people facing starvation and a
total collapse of livelihoods (IPC/CH Phase 5);
a total of 584 000 people were in this group,
mostly in Ethiopia, South Sudan, Yemen and
Madagascar. The first quarter of 2021 also
saw the highest global consumer food prices
in the last six years, concentrated in Latin
America and the Caribbean.
Dry conditions across wide areas of South
America could further threaten crop yields
within this region. However, larger plantings
have largely compensated for crop productivity
losses
throughout
the
continent
(−3.6% in

2021
compared
to 2020).
109
108
 In the Caribbean,
Haiti has been triply hit – by earthquakes,
irregular rains and political instability –
contributing to agricultural damage and
significantly worsening food insecurity. 
 In West Africa,
prices of coarse grains increased, driving
food prices to record and near-record highs
in several countries. The price increases were
exacerbated by civil insecurity and torrential
rains. In North Africa, food inflation rates 
In West Africa, floods and dry spells have led
to crop damage and losses in localized areas 
remained at modest levels in 2021, buffered 
resulting in small production downturns 
by subsidies on many basic commodities
that prevented price increases.
in 2021, but the forecasted aggregate outputs
for the whole continent of Africa remained
above average (+2.9% in 2021 over 2020).
110
IMPACTS OF HYDRO-METEOROLOGICAL
HAZARDS ON FOOD PRODUCTION

The 2021 first season harvest in central and
southern areas of East Africa was negatively
affected by prolonged droughts, mostly in
Kenya where maize outputs were officially
estimated to be 42%–70% below average.
The 2020/2021 La Niña altered rainfall seasons,
disrupting
livelihoods
and
agricultural

campaigns
across
the
world.
Associated

extreme
weather,
water
and
climate
events

during
the
2021
rainfall
season
compounded
shocks
from
the
previous
year
or
years,

making
it
increasingly
difficult
to
quantify
impacts
resulting
from a
single
event.

Consecutive
droughts
across
large
parts
of

Africa,
Asia
and
Latin
America
associated
in

places
with
the
double-dip
La Niña,
as
well
111

In northern parts of East Africa, the scale of
seasonal flooding and its impact on crops
was lower than in 2020. In Southern Africa,
the second consecutive below-average
rainfall season in Madagascar has led to
a severe reduction in staple food production
and a
decline
in
livestock
herd
size.
In

addition,
weather-related
hazards,
pests

and
diseases
were
expected
to
result
in

sharp
harvest
declines,
with
yield
estimates
106 
The Integrated Food Security Phase Classification (IPC) is a common global scale for classifying the severity and
magnitude of food insecurity and malnutrition. https://www.ipcinfo.org/ipcinfo-website/resources/ipc-manual/en/. The
Cadre Harmonisé (CH) is a unifying tool for classifying the nature and severity of current and projected acute food and
nutrition insecurity.
107 
Global Network Against Food Crises, 2021: Global Report on Food Crises: Joint Analysis for Better Decisions. September
2021 Update, http://www.fightfoodcrises.net/fileadmin/user_upload/fightfoodcrises/doc/resources/FINAl_GRFC2021_
Sept_Update.pdf.
108 
Food and Agriculture Organization of the United Nations (FAO), 2021: The State of Food Security and Nutrition in the World
2021: Transforming Food Systems for Food Security, Improved Nutrition and Affordable Healthy Diets for All, https://docs.
wfp.org/api/documents/WFP-0000130141/download/?_ga=2.47516911.931354890.1634299853-763856357.1633873374.
109 
Food and Agriculture Organization of the United Nations (FAO), 2021: Crop Prospects and Food Situation: Quarterly Global
Report, https://www.fao.org/3/cb6901en/cb6901en.pdf.
110 
Food and Agriculture Organization of the United Nations (FAO), 2021: Crop Prospects and Food Situation: Quarterly Global
Report, https://www.fao.org/3/cb6901en/cb6901en.pdf.
111 
Food and Agriculture Organization of the United Nations (FAO), 2021: Crop Prospects and Food Situation: Quarterly Global
Report, https://www.fao.org/3/cb6901en/cb6901en.pdf.
34
50%–70% below the five-year average.
112
 In
Mozambique, Cyclone Eloise made landfall in
late January during the region’s lean season,
when vulnerabilities are at their highest,
affecting communities still recovering from
Cyclone Idai barely two years ago. According
to the Government of Mozambique, more
than 441 000 people were affected by the
cyclone, which displaced nearly 44 000
and destroyed more than 45 000 hectares
of cropland.
consideration of multi-hazard disaster risk
reduction measures, including early warning
systems and preparedness, and longer-term
sustainable development concerns, such as
land use and urban planning.
CLIMATE-RELATED HAZARDS WERE A
MAJOR DRIVER OF NEW DISPLACEMENT
113
Drought conditions in South-west Asia and
the Middle East reduced cereal production
to below-average levels, exacerbating the
impacts on agriculture and food security in
fragile contexts, mostly in Afghanistan and
the Syrian Arab Republic. While cereal pro-
Extreme weather, water and climate events
and conditions had major and diverse impacts
on
population
displacement
and
on

the
vulnerability
of
people
already
displaced

throughout
the
year.
From
Afghanistan
to

Central
America,
droughts,
flooding
and
other

extreme
events
hit
those
least
equipped
to

recover
and
adapt.
114
 As in previous years, 
duction decreased in the Middle East, wheat 
many of the largest-scale displacements 
production in Eastern Asia reached a record
high in 2021, with paddy rice outputs at high
levels due to suitable weather conditions. In
contrast, central China was hit by torrential
rains in mid-July 2021, leading to significant
loss of life and damage to property. This
sparked concerns over the nation’s food
supplies, as 1 million hectares of cropland –
mostly corn, soybeans and peanuts – were
affected, a third of which was wiped out by
heavy rains. 
in 2021 occurred in populous Asian countries.
Most disaster displacements in 2021 resulted
from tropical storms and floods in East Asia
and the Pacific, South Asia, the Americas and
Sub-Saharan Africa.
HUMANITARIAN IMPACTS AND
POPULATION DISPLACEMENT
Refugees, internally displaced people and
stateless people are often among those most
vulnerable to climate and weather-related 
Over the course of 2021, hazardous hydrometeorological
events
and
environmental

degradation
further
contributed
to
the

displacement
of
millions
more
people
in

exposed
and
vulnerable
situations.
This

includes
the
impact
of
rapid-onset
events

such
as
floods,
storms
and
wildfires,
as
well

as
slow-onset
processes
such
as
drought
and

desertification.
This
affects
people’s
safety

and
ability
to
meet
their
basic
needs
for

survival
such
as
food,
water,
resilient
housing

and
productive
land.
Over
the
first
half
of
the

year
in
Afghanistan,
for
example,
disasters

resulted
in
some
22 500 new
displacements,
hazards. Many vulnerable individuals who 
primarily linked to floods.
115
 In June, the 
are displaced end up settling in high-risk
areas, where they are exposed to climate
and weather hazards at a range of scales.
Hydrometeorological hazards and human
mobility may also intersect with social and
political tensions and conflict in complex
settings and, therefore, require the integrated 
Government declared a national drought,
with 80% of the country classified as being
in either severe or serious drought status,
on top of escalating conflict, food insecurity,
and health and socioeconomic impacts of
COVID-19, with humanitarian, development
and government actors foreseeing that 
112 
Famine Early Warning Systems Network (FEWSNET), 2021: Madagascar Food Security Alert, https://reliefweb.int/sites/
reliefweb.int/files/resources/Madagascar%20Food%20Security%20Alert%20-%20June%2010%2C%202021.pdf. 
113 
https://www.fao.org/mozambique/news/detail-events/en/c/1393190/ 
114 
https://www.unhcr.org/news/stories/2021/4/60806d124/data-reveals-impacts-climate-emergency-displacement.html 
115 
https://story.internal-displacement.org/2021-midyear-review/index.html 
35
agricultural families would very likely become
displaced.
116
was submerged by flood waters in November
2021, leaving 35 000 South Sudanese refugees
in need of urgent assistance.
 People forced to leave their
homes had to sell their assets and engage
in dangerous work to survive, while some
children were sent to work in other areas or in
neighbouring countries or were married off as
a way to reduce financial burdens.
122
117
 Displaced
people in the Syrian Arab Republic, a country
decimated by over a decade of conflict, also
faced flooding due to heavy rainfall, with
close to 142 000 internally displaced people
affected in mid-January 2021.
118
 In India, more
than 100 000 people were displaced between
November and December 2021.
119
High-income countries were also affected.
In the western parts of the United States
and Canada exceptional heatwaves, drought
and wildfires displaced thousands from their
homes. Wildfires also compounded risks related
to
other
hazards,
further
increasing
the
risk

of
displacement.
For
instance,
15 000 people

were
displaced
in
California
in
January
2021,

following
mandatory
pre-emptive
evacuation

orders
following
heavy
rains.
123
In line with established trends, 2021 saw the
overwhelming majority of new displacements
related to hazardous weather events take place 
PROTRACTED, PROLONGED AND
REPEATED DISPLACEMENT FUELLED BY 
within national borders. Most of these internal 
HYDROMETEOROLOGICAL HAZARDS 
displacements were triggered by tropical
cyclones, floods, earthquakes and volcanic
eruptions, especially in the East Asia and
Pacific region. The countries with the largest
numbers of displacements recorded as of
October 2021 were China (more than 1.4 million
displacements recorded in July), Viet Nam
(more than 664 000 recorded in September),
and the Philippines (more than 214 000 in July
and more than 386 000 in October).
Many displacement situations triggered by
hydrometeorological events have become
prolonged or protracted for people unable to
return to their former homes or without options
for integrating locally or settling elsewhere. At
the beginning of 2021, at least 7 million people
were living in internal displacement following
disasters
124
120
 
 related to natural hazard events
in previous years, according to the Internal
Displacement Monitoring Centre (IDMC). The
largest numbers of people in this situation
were in Afghanistan, India and Pakistan,
followed by Ethiopia, Sudan, Bangladesh,
Niger and Yemen.
In East Africa, floods and droughts resulted
in large-scale displacement, especially in
Somalia and Ethiopia. Many of the people
affected were already living in overcrowded
and insecure camps for internally displaced
people to which many newly flood-displaced
people also moved. Farmers whose crops
were devastated by desert locusts were
also forced to move in search of survival 
125
 
Due to continuing or growing risk in their
areas of origin (and return) or settlement,
people who have been displaced by hydrometeorological
events
may
also
be
subject
to
assistance.
121
 In Sudan, Alganaa refugee camp 
repeated and frequent displacement, leaving 
116 
https://prod.drc.ngo/about-us/for-the-media/press-releases/2021/7/drought-crisis-in-afghanistan-intensifies-risk-of-
displacement
117 
https://prod.drc.ngo/about-us/for-the-media/press-releases/2021/7/drought-crisis-in-afghanistan-intensifies-risk-of-
displacement
118 
https://reliefweb.int/disaster/fl-2021-000007-syr 
119 
https://www.internal-displacement.org/global-displacement-map 
120 
https://www.internal-displacement.org/global-displacement-map 
121 
https://www.unhcr.org/news/stories/2021/8/611a2bca4/displaced-somalis-refugees-struggle-recover-climate-change-
brings-new-threats.html 
122 
https://www.unhcr.org/news/stories/2021/11/619c9aea4/refugees-count-losses-floods-destroy-camp-sudan.html 
123 
https://story.internal-displacement.org/2021-midyear-review/index.html 
124 
https://www.internal-displacement.org/sites/default/files/publications/documents/grid2021_idmc.pdf 
125 
https://www.internal-displacement.org/global-displacement-map 
36
little time for recovery between one shock
and the next. In Indonesia, for example,
557 000 new disaster displacements were
recorded in the first half of the year, mostly
triggered by major rainy season floods.
Human activities, including deforestation, urbanization
and
land
degradation
have
reduced

the
capacity
of
some
regions
of
Indonesia

to
absorb
heavy
rainfall.
Between
October

and
November
2021,
well
before
the
peak
of

the
rainy
season,
heavy
rainfall
and
flooding

further
displaced
more
than
50 000,
double

the
figure
for
2020.
fourth biggest internal displacement crisis,
with over 4 million internally displaced people.
The
annual
rainy
season
brings
heavy

rainfall,
high
winds
and
flooding,
particularly

to
coastal
areas,
with
thousands
of
families

affected
by
flash
floods
in 2021.
Flooding

also
blocks
roads,
impeding
the
delivery
of

life-saving
assistance.
128
126
In Mozambique, multiple tropical storms and
floods, on top of recurrent disease outbreaks
and conflict, significantly increased the vulnerability
of
affected
people,
 Such situations highlight
the importance of disaster preparedness and
risk management, but also the importance of
supporting solutions to displacement that are
sustainable and supporting the resilience of
people who might otherwise see their living
conditions progressively eroded through
repeated disasters and displacement. 
129
 including
thousands of families still displaced since
Cyclones Idai and Kenneth in 2019. In January,
strong winds and floods from Tropical Storm
Chalane and then Cyclone Eloise damaged
or destroyed the shelters of over 8 700 of
these internally displaced families as well as
schools and hospitals.
130
 These events also
resulted in new displacement, with Cyclone
Eloise displacing more than 43 300 people.
131

Tens of thousands of people remain displaced
and held back from recovery.
HAZARDOUS EVENTS AND CHANGING
CLIMATIC CONDITIONS ALSO ADDED
TO THE MULTIPLE RISKS FACED IN
CONFLICT-AFFECTED COUNTRIES BY
INTERNALLY DISPLACED PEOPLE AND
REFUGEES
132
 The impacts
of compounding disasters, recurrent disease
outbreaks and conflicts have significantly
increased the vulnerability of people in the
region. This situation, and similar ones in
other regions, could be ameliorated through
greater effort to reduce climate-related vulnerability
and
risks
in
fragile
and
conflict-affected

contexts
and
to
strengthen
community-based

preparedness.
In Yemen, people’s vulnerabilities were
further exacerbated by hazard events, such
as floods and droughts, that have led to the
destruction of shelters and infrastructure,
restricted access to markets and basic services,
wrecked
livelihoods,
facilitated
the

spread
of
deadly
diseases
and
contributed

to
fatalities.
In
mid-April,
heavy
rain
and

flooding
hit
several
parts
of
the
country,

affecting
7 000 people,
75%
of
whom
were
in-
133
Nigeria also experienced drought and floods,
which affected agricultural activities, resulting
in loss of shelter and increased vulnerability
of people already displaced by conflict in
the north-east. The situation further deteri-
ternally displaced people living in precarious 
orated in the first half of 2021, with around 
conditions.
127
 This contributed to population
displacement in what was already the world’s 
294 000 new displacements reported between
January and June 2021.
134
126 
https://story.internal-displacement.org/10-internal-displacement-situations-to-watch-in-2022/index.html 
127 
https://reliefweb.int/sites/reliefweb.int/files/resources/Humanitarian%20Update_May%202021%20v4.pdf 
128 
https://reliefweb.int/report/yemen/climate-crisis-exacerbates-humanitarian-situation-yemen-enar 
129 
https://www.unhcr.org/news/briefing/2021/4/606c17bf4/unhcr-scales-response-thousands-flee-attacks-northernmozambique.html
130 
https://displacement.iom.int/reports/mozambique-%E2%80%93-flash-report-16-tropical-cyclone-eloise-january-
2021?close=true 
131 
https://reliefweb.int/report/afghanistan/internal-displacement-mid-year-10-situations-review 
132 
https://www.unhcr.org/news/stories/2020/3/5e6a6e50b/year-people-displaced-cyclone-idai-struggle-rebuild.html
133 
https://www.unhcr.org/news/stories/2020/3/5e6a6e50b/year-people-displaced-cyclone-idai-struggle-rebuild.html
134 
https://www.unhcr.org/news/stories/2020/3/5e6a6e50b/year-people-displaced-cyclone-idai-struggle-rebuild.html
37
In Bangladesh, monsoon rains led to massive
flooding and the displacement of millions
of people following Cyclone Yaas in May
and June 2021. Flooding in July 2021 in
the Rohingya refugee sites in Cox’s Bazar
damaged over 6 000 shelters and more than
25 000 refugees were forced to seek shelter in
communal facilities or with other families.
affect the 1.9 billion people living in mountain
areas or directly downstream from them.
138
135

Climate change may exacerbate water stress,
especially in areas of decreased precipitation
and where groundwater is already depleted,
affecting agricultural production, arable land,
and the more than 2 billion people who already
experience
water
stress.

Floods also heavily affected people living in
China, Nepal and the Philippines, where thousands
of
people
were
displaced
by
Typhoon

In-fa
in
July
2021.
Without
preparedness

measures
undertaken
in
the
camp
areas,

including
the
strengthening
of
shelters,
the

building
of
retaining
structures
on
hillsides

and
improved
drainage,
roads
and
bridges,

these
impacts
would
have
been
far
worse.
139
Climate change is also affecting climatesensitive
species.
There
is
evidence
that

temperature-sensitive
plants
are
flowering

and
starting
to
produce
leaves
earlier
in

spring
and
dropping
their
leaves
later
in

autumn.
140
 Also, there has been a clear shift
in the timing of marine and freshwater fish
spawning events and animal migrations
worldwide. Substantial changes in species’ 
abundance and distribution may in turn af-
fect the interactions between species.
141,142
CLIMATE IMPACTS ON ECOSYSTEMS
Ecosystems – including terrestrial, freshwater,
coastal
and
marine
ecosystems –
and

the
services
they
provide,
are
affected
by

the
changing
climate,
and
some
are
more

vulnerable
than
others.
136

Risks to ecosystems and individual species
from pests, pathogens and diseases are
changing. Climate change also exacerbates
other threats to biodiversity. The number of
species projected to become extinct increases
dramatically as global temperature rises – and
is 30% higher at 2 °C warming than at 1.5 °C
warming.
 In addition, some
ecosystems are degrading at an unprecedented
rate,
limiting
their
ability
to
support

human
well-being
and
harming
their
adaptive

capacity
to
build
resilience.
143
 
137
For example, mountain ecosystems – the
water towers of the world – are vulnerable and
can be profoundly affected by climate change
due to their low capacity to adapt. This may 
Meanwhile, large-scale changes have been
observed in marine ecosystems, including
declining ocean productivity, migration of
species to higher latitudes and altitudes,
and damage to coral reefs and mangroves.
Warming towards 1.5 °C will increase water
temperatures
and
change
the
ocean’s
135 
https://www.unhcr.org/news/stories/2021/7/6103c43c4/floods-bring-new-misery-rohingya-refugees-bangladeshcamps.html
136 
United Nations Environment Programme (UNEP), 2021: Adaptation Gap Report 2020, https://www.unep.org/resources/
adaptation-gap-report-2020.
137 
United Nations Environment Programme (UNEP), 2021: Making Peace with Nature: A Scientific Blueprint to Tackle the
Climate, Biodiversity and Pollution Emergencies, https://www.unep.org/resources/making-peace-nature.
138 
Immerzeel, W. W.; Lutz, A. F.; Andrade, M. et al. Importance and Vulnerability of the World’s Water Towers. Nature 2020,
577 (7790), 364–369. https://doi.org/10.1038/s41586-019-1822-y.
139 
United Nations Environment Programme (UNEP), 2021: Making Peace with Nature: A Scientific Blueprint to Tackle the
Climate, Biodiversity and Pollution Emergencies, https://www.unep.org/resources/making-peace-nature.
140 
Hemming, D.L.; Garforth, J.; Park, T. et al. Phenology of Primary Producers. In State of the Climate in 2020, supplement.
Bulletin of the American Meteorological Society 2021, 102 (8), S57–S60. https://doi.org/10.1175/BAMS-D-21-0098.1.
141 
Scheffers, B. R.; De Meester, L.; Bridge, T.C. et al. The Broad Footprint of Climate Change from Genes to Biomes to 
People. Science 2016, 354 (6313), aaf7671. https://doi.org/10.1126/science.aaf7671 .
142 
Thackeray, S. J.; Henrys, P. A.; Hemming, D. et al. Phenological Sensitivity to Climate across Taxa and Trophic Levels.
Nature 2016, 535 (7611), 241–245. https://doi.org/10.1038/nature18608.
143 
United Nations Environment Programme (UNEP), 2021: Making Peace with Nature: A Scientific Blueprint to Tackle the
Climate, Biodiversity and Pollution Emergencies, https://www.unep.org/resources/making-peace-nature.
38
chemistry (for example, acidification), resulting
in
new
ecosystems.
Species
that
are
less

able
to
relocate
are
projected
to
experience

high
rates
of
mortality
and
decline.
144
 Climate
change is also affecting the Greenland and
Antarctic ice sheets and increasing the chances
of
the
Arctic
Ocean
being
ice-free
in
the

summer,
further
disrupting
ocean
circulation

and
Arctic
ecosystems.
145
Rising temperatures heighten the risk of
irreversible loss of marine and coastal 
ecosystems, including seagrass meadows
and kelp forest. Coral reefs are especially
vulnerable to climate change. They are
projected to lose between 70% and 90%
of their former coverage area at 1.5 °C of
warming and over 99% at 2 °C. Between
20% and 90% of current coastal wetlands
are at risk of being lost by the end of this
century, depending on how fast sea levels
rise. This will further compromise food
provision, tourism and coastal protection,
among
other
ecosystem
services.
146 
144 
Intergovernmental Panel on Climate Change (IPCC), 2019: Summary for policymakers. In: Global Warming of 1.5°C:
An IPCC Special Report on the Impacts of Global Warming of 1.5°C above Pre-industrial Levels and Related Global
Greenhouse Gas Emission Pathways, in the Context of Strengthening the Global Response to the Threat of Climate 
Change, Sustainable Development, and Efforts to Eradicate Poverty, https://www.ipcc.ch/sr15/chapter/spm/.
145 
United Nations Environment Programme (UNEP), 2021: Making Peace with Nature: A Scientific Blueprint to Tackle the
Climate, Biodiversity and Pollution Emergencies, https://www.unep.org/resources/making-peace-nature.
146 
United Nations Environment Programme (UNEP), 2021: Making Peace with Nature: A Scientific Blueprint to Tackle the
Climate, Biodiversity and Pollution Emergencies, https://www.unep.org/resources/making-peace-nature.
39
Northern hemisphere summer extremes: 
the role of the quasi-stationary planetary
waves and the Arctic warming amplification 
José Álvaro Silva (WMO)
54.4 °C for the second year in a row (the
world’s highest recorded temperature in at
least the last 90 years). 
2021 NORTHERN HEMISPHERE
EXTREMES: BRIEF DESCRIPTION
On 14 and 15 July, exceptional severe floods
occurred in some countries in the Western
part of Europe. Parts of western Germany and
eastern Belgium were the most affected by the
long-lasting heavy precipitation. Just a few
days later, in the Chinese province of Henan,
more rain fell on Zhengzhou between 17 and
21 July than falls there in an average year,
and a one-hour rainfall total of 201.9 mm, on
20 July, was a new record for China.
In 2021, during the boreal summer, several
extreme weather and climate events occurred
in
the
mid-latitude
regions
of
the

northern
hemisphere
(NH).
Record
hot
days

and
heatwaves,
severe
droughts,
powerful

and
destructive
wildfires,
and
heavy
rain

events
led
to
vast
damage
and
high
death

tolls,
as
is
described
in
depth
in
the
section

on
High-impact
events
in
2021.
In August, the extreme heat was associated
with powerful and destructive wildfires that
affected some Mediterranean countries.
On 11 August, a station near Syracuse, in
Sicily, Italy, reached 48.8 °C, a provisional
European record. 
Hot summer conditions started early, and
several NH regions experienced extreme
heat in June, including North Africa, Eastern
Europe and the Middle East. The high temperatures
were
particularly
exceptional
in

the
north-western
United
States
and
western

Canada
in
late
June
(Figure 23).
Lytton,
in

British
Columbia,
recorded
49.6 °C
on
29 June,

which
was a
new
record
for
Canada.
On 9 July,

during
one
of
the
multiple
heatwaves
that

affected
the
south-western
United
States

during
the
summer,
the
Furnace
Creek
weather
station
(Death
Valley,
California),
reached
POTENTIAL CAUSES AND
MECHANISMS OF NORTHERN
HEMISPHERE SUMMER EXTREMES 
Figure 23. ERA5
reanalysis of maximum
air temperature (°C)
on 29 June 2021.
Source: Copernicus
Climate Change Service
and KNMI Climate
Explorer.
Latitude
Following the trend that has emerged in
recent decades, NH summer 2021 saw numerous
weather
and
climate
extremes.
But

what
might
be
the
causes
for
the
increase
in number and the intensification of the NH 
summer extremes?
60°N
The frequency of certain types of weather
and climate extremes is increasing due to
climate change,
30°N
1
 and some attribution studies
2,3,4,5,6,7,8
0°
 have shown that it has made many
single recent events more intense. Some of
these studies suggest that a wide diversity
of spatio-temporal scales and atmospheric
processes are involved in the evolution of 
30°S
60°S
extreme events, but it is usually the anom-
180˚               120˚W             60˚W                    0˚                  60˚E                120˚E                180˚
alous large-scale circulation patterns that
set the background for their occurrence, and
quasi-resonant circulation regimes play an
important role here.
Longitude
–50     –40      –30      –20     –10       10        20        30        40        50       °C 
40
40
THE QUASI-RESONANT
AMPLIFICATION 
5
2021-06-29 
L
There is growing evidence that physical
mechanisms involving atmospheric dynamics,
in
particular
planetary
wave
dynamics,

can
explain
the
characteristics
associated

with
persistent
disturbances
in
the
polar

jet
stream
and
NH
summer
extremes.
1
L
4
x
L
North Pole
L
9,10,11

The Rossby waves
12
 (Figure 24), particularly
the quasi-resonant amplification (QRA)
13
 of
these mid-latitude high-amplitude waves
(zonal wavenumber 6–8), is an important
mechanism driving the conditions associated
with extremes.
w
−30    −20     −10      0       10      20       30
Anomaly relative to 1981–2010 (hPa) 
14,15,16
 The jet stream plays
a major role in shaping weather patterns,
and when it becomes weaker and wavier, in
association with these slow-moving waves, 
studies mentioned in the report identify a variety
of processes and positive feedbacks contributing
to
these
phenomena.
25
 The first is related to 
the air motion from west to east is slowed, 
sea-ice loss (Figure 25), which causes a change 
leading to blocking situations in which
weather systems remain near-stationary
over a prolonged period which can last
several weeks.
17,18
of surface albedo (reflective ice is replaced
by the darker ocean), leading to more heat
absorption from solar radiation. This is known
as the sea-ice albedo feedback. Other important
atmospheric processes inducing AA are the
temperature (both Planck and lapse rate) and the
cloud and water vapour feedbacks.
ARCTIC WARMING AMPLIFICATION 
26
Figure 24. Left:
Schematic example of
a five planetary-wave
pattern. 
Source: NOAA/NWS. 
Right: Sea level pressure
anomaly for 29 June
2021 (difference from
1981–2010), associated
with a slow and
meandering jet stream.
Data from the ERA5
reanalysis product. 
Source: Copernicus
Climate Change Service.
 Increases
in the atmospheric and oceanic equator-to-pole
transport of heat and moisture have also been
identified as drivers of AA.
Over the past 50 years, temperatures in the
Arctic have increased at more than twice the
global rate,
19
 a prominent feature of climate
change known as Arctic amplification (AA).
20

The AA influences mid-latitude summer
circulation by weakening the storm tracks,
shifting the position of the jet stream and
amplifying the quasi-stationary waves. While
some uncertainties related to how these
dynamical changes affect regional weather
conditions remain,
21
 it is generally accepted
that in recent decades the occurrence of con-
In summary, research focusing on summer
circulation and climate change needs to be
further developed to fill important knowledge
gaps, but there is evidence to support the idea
that changes in mid-latitude summer circulation –
amplified
and
more
stationary
planetary

waves, a
weaker
and
wavier
jet
stream –
associated
with
Arctic
warming,
may
be
linked
to

increased
blocking
situations
thus
favouring
ditions favourable for QRA
22,23
 promoted the 
the occurrence of extreme events in the NH. 
occurrence of persistent extreme weather
events that might be linked to the amplified
Arctic warming, and thus that climate change
influence is carried through amplified arctic
warming.
24
 Nevertheless, it is argued that the
observations and climate-model simulations
do not support a clear cause–effect relation,
making it difficult to establish a definite link. 
The causes of AA are not yet fully under-
stood, but as highlighted in Chapter 4 of the 
Working Group I contribution to the IPCC Sixth
Assessment Report, the understanding of the
physical mechanisms driving AA has improved
in the last decade, and the results of several 
a
v
e
le
n
gth
L
2
90ºW
3
Figure 25. Sea-ice
concentration trends in
March and September,
1979–2020. 
Source: C3S, https://
climate.copernicus.
eu/climate-indicators/
sea-ice.
Sea-ice concentration trends during 1979–2020
March
September
180º
180º
ºW
ºW
1
35
1
35
ºE
1
35
1
35
ºE
41
% per decade
90ºE
0º
1981–2010 median ice edge
90ºE
ºE
45
45
ºW
90ºW
ºE
30
24
18
12
6
0
–6
–12
–18
–24
45
45
ºW
–30
0º
Credit: C3S/ECMWF.
41
REFERENCES
1. Intergovernmental Panel on Climate Change (IPCC), 2021: AR6 Climate Change 2021: The Physical
Science Basis, https://www.ipcc.ch/report/ar6/wg1/. 
2. Philip, S. Y.; Kew, S. F.; van Oldenborgh, G. J. et al. Rapid Attribution Analysis of the Extraordinary
Heatwave on the Pacific Coast of the US and Canada June 2021. Earth System Dynamics
Discussions, In review, 1–34. Preprint: https://doi.org/10.5194/esd-2021-90.
3. Kreienkamp, F.; Philip, S. Y.; Tradowsky, J. S. et al. Rapid Attribution of Heavy Rainfall Events
Leading to the Severe Flooding in Western Europe During July 2021. World Weather
Attribution, 2021. https://www.worldweatherattribution.org/wp-content/uploads/
Scientific-report-Western-Europe-floods-2021-attribution.pdf. 
4. van Oldenborgh, G. J.; van der Wiel, K.; Kew, S. et al. Pathways and Pitfalls in Extreme Event
Attribution. Climatic Change 2021, 166 (1), 13. https://doi.org/10.1007/s10584-021-03071-7. 
5. Herring, S. C.; Christidis, N.; Hoell, A. et al., Eds.; Explaining Extreme Events of 2017 from a
Climate Perspective. Bulletin of the American Meteorological Society 2019, 100 (1),
S1–S117. https://doi.org/10.1175/BAMS-ExplainingExtremeEvents2017.1. 
6. Lu, C.; Lott, F.; Sun Y. et al. Detectable Anthropogenic Influence on Changes in Summer
Precipitation in China. Journal of Climate 2020, 33 (13), 5357–5369. https://doi.
org/10.1175/JCLI-D -19 - 0285.1.
7. Kahraman, A.; Kendon, E. J.; Chan, S. C. et al. Quasi-stationary Intense Rainstorms Spread
across Europe under Climate Change. Geophysical Research Letters 2021, 48 (13),
e2020GL092361. https://doi.org/10.1029/2020GL092361.
8. Sun, Y.; Dong, S.; Zhang X. et al. Anthropogenic Influence on the Heaviest June Precipitation
in Southeastern China since 1961. In: Explaining Extremes of 2017 from a Climate
Perspective, supplement. Bulletin of the American Meteorological Society 2019, 100 (1),
S79–S84. https://doi.org/10.1175/BAMS-ExplainingExtremeEvents2017.1.
9. Mann, M. E.; Rahmstorf, S.; Kornhuber, K. et al. Projected Changes in Persistent Extreme Summer
Weather Events: The Role of Quasi-resonant Amplification. Sci . Advance 2018, 4 (10),
eaat3272. https://doi.org/10.1126/sciadv.aat3272.
10. Coumou, D.; Petoukhov, V.; Rahmstorf, S. et al. Quasi-resonant Circulation Regimes and
Hemispheric Synchronization of Extreme Weather in Boreal Summer. Proceedings of
the National Academy of Sciences 2014, 111 (34), 12331–12336. https://doi.org/10.1073/
pnas.1412797111. 
11. Petoukhov, V.; Petri, S.; Rahmstorf, S. et al. Role of Quasiresonant Planetary Wave Dynamics in
Recent Boreal Spring-to-autumn Extreme Events. Proceedings of the National Academy
of Sciences 2016, 113 (25), 6862–6867. https://doi.org/10.1073/pnas.1606300113.
12. A Rossby wave is a large horizontal atmospheric undulation associated with the polar jet stream
and separates cold polar air from warm tropical air. These planetary waves play an
important role in the poleward transports of energy and moisture.
13. The amplified Rossby waves associated with a meandering jet stream become slow and cause 
wave resonance known as quasi-resonant amplification (QRA).
14. Petoukhov, V.; Rahmstorf, S.; Petri, S. et al. Quasiresonant Amplification of Planetary Waves and
Recent Northern Hemisphere Weather Extremes. Proceedings of the National Academy
of Sciences 2013, 110 (14), 5336–5341. https://doi.org/10.1073/pnas.1222000110.
15. Kornhuber, K.; Petoukhov, V.; Petri, S. et al. Evidence for Wave Resonance as a Key Mechanism
for Generating High-amplitude Quasi-stationary Waves in Boreal Summer. Climate
Dynamics 2016, 49 (5), 1961–1979. https://doi.org/10.1007/s00382-016-3399-6.
16. Kornhuber, K.; Coumou, D.; Vogel, E. et al. Amplified Rossby Waves Enhance Risk of Concurrent
Heatwaves in Major Breadbasket Regions. Nature Climate Change 2020, 10 (1), 48–53.
https://doi.org/10.1038/s41558-019-0637-z.
17. Teng, H.; Branstator, G.; Wang, H. et al. Probability of US Heat Waves Affected by a Subseasonal 
Planetary Wave Pattern. Nature Geoscience 2013, 6 (12), 1056–1061. https://doi.
org/10.1038/ngeo1988.
18. Grams, C. M.; Binder, H.; Pfahl, S. et al. Atmospheric Processes Triggering the Central European
Floods in June 2013, Natural Hazards and Earth System Sciences 2014, 14 (7), 1691–1702.
https://doi.org/10.5194/nhess-14-1691-2014.
42
42
19. Intergovernmental Panel on Climate Change (IPCC), 2021: AR6 Climate Change 2021:
The Physical Science Basis, https://www.ipcc.ch/report/ar6/wg1/.
20. Francis, J. A.; Vavrus, S. J. Evidence Linking Arctic Amplification to Extreme Weather in
Mid-latitudes. Geophysical Research Letters 2012, 39 (6), L06801. 
https://doi.org/10.1029/2012GL051000.
21. Coumou, D.; Di Capua, G.; Vavrus, S. et al. The Influence of Arctic Amplification on Mid-latitude
Summer Circulation. Nature Communications 2018, 9 (1), 2959. https://doi.org/10.1038/
s41467-018-05256-8.
22. Petoukhov, V.; Rahmstorf, S.; Petri, S. et al. Quasiresonant Amplification of Planetary Waves and
Recent Northern Hemisphere Weather Extremes. Proceedings of the National Academy
of Sciences 2013, 110 (14), 5336–5341. https://doi.org/10.1073/pnas.1222000110.
23. Kornhuber, K.; Petoukhov, V.; Petri, S. et al. Evidence for Wave Resonance as a Key Mechanism
for Generating High-amplitude Quasi-stationary Waves in Boreal Summer. Climate
Dynamics 2016, 49 (5), 1961–1979. https://doi.org/10.1007/s00382-016-3399-6.
24. Mann, M.; Rahmstorf, S.; Kornhuber, K. et al. Influence of Anthropogenic Climate Change on
Planetary Wave Resonance and Extreme Weather Events. Scientific Reports 2017, 7 (1),
45242. https://doi.org/10.1038/srep45242.
25. Intergovernmental Panel on Climate Change (IPCC), 2021: AR6 Climate Change 2021: The 
Physical Science Basis, https://www.ipcc.ch/report/ar6/wg1/.
26. Previdi, M.; Smith, K. L.; Polvani, L. M. Arctic Amplification of Climate Change: A Review of
Underlying Mechanisms. Environmental Research Letters 2021, 16 (9), 093003. 
https://doi.org/10.1088/1748-9326/ac1c29.
43
43
Observational basis for climate monitoring
Climate monitoring is performed by a system
of observing systems covering the atmosphere,
the
ocean,
hydrology,
the
cryosphere

and
the
biosphere.
Each
of
these
areas
is

monitored
in
different
ways
by a
range
of

organizations.
Cutting
across
all
these
areas,

satellite
observations
provide
major
contributions
to
global
climate
monitoring.
status reports. GCOS also identifies what is
needed to improve the system in implementation
reports.
In 1992, the Global Climate Observing
System (GCOS) was established by WMO,
the Intergovernmental Oceanographic
Commission (IOC) of the United Nations
Educational, Scientific and Cultural
Organization (UNESCO), the United Nations
Environment Programme (UNEP) and the
International Science Council (ISC) to coordinate
and
facilitate
the
development
and
In addition to observations provided by the
GCOS-coordinated Global Surface Network
(GSN) and Global Upper-Air Network (GUAN),
National Meteorological and Hydrological
Services (NMHSs) of WMO Members provide a
more
comprehensive
and
widespread

network
of
observation,
acquired
primarily

for
operational
weather
prediction.
WMO’s

Global
Basic
Observing
Network
(GBON),
a

globally
designed
network
with
prescribed

capabilities
and
observing
schedules
and

for
which
international
data
exchange
is

mandatory,
will
provide
critically
needed

observations
for
numerical
weather
predic-
improvement of global climate observations.
tion and will help substantially strengthen 
GCOS has identified a set of Essential Climate
Variables (ECVs) that together provide the
information necessary to understand, model
and predict the trajectory of the climate as well
as plan mitigation and adaptation strategies
(Figure 26). The status of the observational
basis for these ECVs is published in regular 
climate monitoring.
In order to provide the necessary financial and
technical assistance for the implementation
and operation of GBON in the poorest and
most poorly observed areas of the globe,
WMO and the members of the Alliance for 
2016 Essential Climate Variables (ECVs)
Surface
Precipitation, surface
pressure, surface radiation
budget, surface wind
speed and direction,
surface temperature,
surface water vapour
Physical
Ocean surface heat flux,
sea ice, sea level, sea state,
sea-surface salinity,
sea-surface temperature
subsurface currents,
subsurface salinity,
subsurface temperature
Hydrology
Groundwater, lakes, river
discharge, soil moisture
Cryosphere
Glaciers, ice sheets and ice
shelves, permafrost, snow
Upper air
Earth radiation budget,
lightning, upper-air 
Figure 26. Essential Climate Variables (ECVs) identified by GCOS
44
Atmospheric
Biogeochemical
Biosphere
Above-ground biomass,
albedo, fire, fraction
of absorbed
photosynthetically active
radiation, land cover, land 
temperature, upper air
water vapor, upper-air
wind speed and direction
Inorganic carbon, nitrous
oxide, nutrients, ocean
colour, oxygen, transient
tracers
surface temperature, latent
and sensible heat fluxes,
leaf area index, soil carbon
Composition
Aerosol properties, carbon
dioxide, methane and
other greenhouse gases,
cloud properties, ozone,
aerosol and ozone
precursors
Oceanic
Biological/ecosystems
Marine habitat properties,
plankton
Terrestrial
Human use of natural
resources
Anthropogenic greenhouse
gas fluxes, anthropogenic
water use
44
Hydromet Development
a
 are establishing
a Systematic Observations Financing
Facility (SOFF).
and coordinated through WMO. A number
of specialized Global Terrestrial Networks
(GTNs), for example, on hydrology, permafrost,
glaciers,
land
use,
and
biomass,
also

report
to
GCOS.
Data
exchange
agreements

are
generally
less
developed
for
the
terrestrial

networks,
and
many
important
observations

are
not
made
available
to
international
users.
Complementing the observations of the physical
and
dynamic
properties
of
the
atmosphere,

WMO’s
Global
Atmospheric
Watch
(GAW)

coordinates
atmospheric
composition
measurements,
ensuring
that
reliable
and
accurate

data
are
obtained
from
measurements
made

by
WMO
Members,
research
institutions
and/
or
agencies
and
other
contributing
networks.
Ocean observations of ocean physics, biogeochemistry,
biology
and
ecosystems
are
coordinated
through
the
Global
Ocean
Observing

System
(GOOS).
The
GOOS
Observations

Coordination
Group
(OCG)
monitors
the
per-
The Committee on Earth Observation
Satellites/Coordination Group for Meteorological
Satellites
(CEOS/CGMS)
Joint
Working

Group
on
Climate
(WGClimate)
bases
the

development
of
satellite
observations
for

climate
on
the
ECV
requirements
established

by
GCOS.
It
has
produced
an
ECV
Inventory

that
includes
records
for
766 climate
data

records
for
33 ECVs
covering
72 separate
formance of these observations
b 
and produces 
ECV products, with more planned. Satellite 
an annual Ocean Observing System Report
Card. Ocean observations are generally made
widely available to international users.
In the terrestrial domain, there is a wider group
of observing networks. Hydrological observations
are
generally
operated
by
NMHSs
observations have some advantages – they
have near-global coverage – but optical
observations can be interrupted by clouds.
Used with ground-based observations, either
as complementary data sets, or for validation
and calibration, they form an invaluable part
of the global observing system.
Figure 27. Dust storm in the Sahara Desert on 18 February 2021. This event led to widespread poor air quality for several days
and followed another one, earlier in the month, that coated the snow in the Pyrenees and Alps and turned skies orange in some
parts of Europe, including France, Germany and Switzerland.
a 
https://public.wmo.int/en/our-mandate/how-we-do-it/partnerships/wmo-office-of-development-partnerships
b 
https://www.ocean-ops.org/
45
45
Can sub-seasonal-to-seasonal
predictions improve disaster risk
preparedness for the South-east
Asia region?  
A review of the 20–26 September 2021 case study
Estelle De Coning
1
, Thea Turkington
2
,
Frederic Vitart
3
, Andrew Robertson
4
, Ryan Kang
2
,
Wee Leng Tan
2
 
1 
WMO
2 
National Environment Agency, Singapore
3  
S2S Co-chair, European Centre for Medium Range
Weather Forecasts
4  
S2S Co-chair, International Research Institute for
Climate and Society
was forecasted for south-eastern Indonesia
three weeks before the case study week. This
evolved by the week before to a moderate
increase in chance for Sulawesi, Maluku
Islands and West Papua and expanded
to small increase in chance over parts of
Thailand, Lao People’s Democratic Republic,
Viet Nam, and southern Philippines, southern
Sumatra, eastern Borneo and Java. This
outlook was reported in the AHA Centre’s
weekly report
f
 to national disaster management
organizations
and
others,
supporting
the

preparations
for
Dianmu
South-east Asia (SEA) is in a prime location
to benefit from sub-seasonal-to-seasonal
(S2S) climate services, as a region with some
of the highest skill at the S2S timescale. The
Association of Southeast Asian Nations
(ASEAN) Specialised Meteorological Centre
(ASMC) and partners (UN ESCAP,
g
 and other hazards
along with subsequent weather forecasts,
an example in the region of steps towards a
seamless prediction approach.
a
 RIMES,
b

the AHA Centre
c
) are working to develop S2S
products in SEA for disaster risk reduction
under the S2S SEA Pilot Project, which is part
of the S2S Prediction Project real-time pilot initiative
undertaken
by
WMO,
the
World
Weather

Research
Programme
(WWRP)
and
the
World

Climate
Research
Programme
(WCRP).
The

project
aims
to
explore
the
usefulness
of
S2S

predictions
for
disaster
risk
reduction.
Between 20 and 26 September 2021, more than
50 000 people
d
 were affected by floods in the
Philippines, and Sulawesi and eastern Borneo
in Indonesia. During the same week, Tropical 
These results are typical of the findings of the
pilot project so far, where increased chance
of extreme rainfall for the Maritime Continent
is a good indicator three weeks beforehand
that one or more hazardous events may occur
in the general area. The indicator works less
well for mainland South-east Asia though,
where the outlooks often only predict an
increased chance one week before. Increased
probabilities of hazardous events signal an
increased probability of disaster as well.
While there may not always be an indication
of
impending
hazardous
events
at
the

sub-seasonal
timescale,
the
relatively
small

number
of
false
alarms
means
that
action
can
Cyclone Dianmu contributed to severe floods 
be taken at the sub-seasonal timescale, such 
in parts of Viet Nam, Cambodia and Thailand,
affecting more than 180 000 people.
e
 Based
on the S2S SEA Pilot Project’s predictions,
a small increased chance of extreme rainfall 
as targeted monitoring of the development
of the events and activating institutional
processes earlier so that preparedness and
response are more efficient. 
a 
United Nations Economic and Social Commission for Asia and the Pacific: https://www.unescap.org/
b 
Regional Integrated Multi-Hazard Early Warning System for Africa and Asia: https://www.rimes.int/ 
c 
ASEAN Coordinating Centre for Humanitarian Assistance on Disaster Management: https://ahacentre.org/
d 
https://adinet.ahacentre.org
e 
https://adinet.ahacentre.org
f 
https://ahacentre.org/wp-content/uploads/2021/09/DWeek_37_13-19Sep2021.pdf
g 
https://ahacentre.org/flash-update/flash-update-no-01-tropical-depression-21w-twentyone-viet-nam-23september-2021/
46
46
Data sets and methods
GREENHOUSE GAS DATA
Estimated concentrations from 1750 are used to represent pre-industrial conditions.
Calculations assume a pre-industrial mole fraction of 278 ppm for CO2
, 722 ppb for CH4

and 270 ppb for N2
O.
World Data Centre for Greenhouse Gases operated by Japan Meteorological Agency
https://gaw.kishou.go.jp/.
World Meteorological Organization (WMO). WMO Greenhouse Gas Bulletin – No . 17: The State of
Greenhouse Gases in the Atmosphere Based on Global Observations through 2020 . Geneva, 2021.
World Ozone and Ultraviolet Radiation Data Centre operated by Environment and Climate
Change Canada https://woudc.org/home.php. 
GLOBAL TEMPERATURE DATA
GLOBAL MEAN TEMPERATURE TIME SERIES
The method for calculating global mean temperature anomalies relative to an 1850–1900
baseline has been updated since the State of the Global Climate 2020 report. The method was
updated to take advantage of the assessment made by Working Group I, in its contribution
to the IPCC Sixth Assessment Report, of long-term change and its uncertainty. The new
method also makes use of a wider range of shorter data sets that are routinely updated to
provide an authoritative assessment of recent temperature changes.
In the 2020 report (and earlier reports), changes relative to the 1850–1900 baseline were
based on the HadCRUT4 data set which was the only data set that extended back to 1850.
Other data sets were offset to match the average of HadCRUT4 over the period 1880–1900
(NASA GISTEMP and NOAA GlobalTemp) or 1981–2010 (ERA5, JRA-55).
In 2021, the IPCC Sixth Assessment Report Working Group I assessed change from
1850–1900 to other periods based on an average of four data sets – HadCRUT5, Berkeley
Earth, NOAA–Interim and Kadow et al. (2020) – which all extend back to 1850. They assessed
uncertainty by considering the range from the four estimates, taken from the lower bound
of the uncertainty range of the coolest data set to the upper bound of the uncertainty range 
of the warmest. By making use of four data sets that extend back to 1850, Working Group I 
was able to make a more comprehensive estimate of uncertainty.
As two of the four IPCC data sets are not regularly updated, in the present report the
estimate made by the IPCC for the temperature change between 1850–1900 and 1981–2010
is combined with estimated changes between 1981–2010 and the current year from six data
sets to calculate anomalies for 2021 relative to 1850–1900. 
There is good, though not perfect, agreement between the six data sets on changes from
1981–2010 to the present, as this is a period with good observational coverage. The additional
modest uncertainty from the spread of the six data sets is combined with that of the IPCC’s 
estimate of the uncertainty in the change from 1850–1900 to 1981–2010.
47
More precisely, six data sets (cited below) were used in the calculation of global temperature.
Global mean temperature anomalies were calculated relative to an 1850–1900 baseline
using the following steps:
 1. The starting point was a time series of global annual mean temperatures for each data
set, as provided by the data providers. The anomalies were presented on different
baselines.
2. For each data set, anomalies were calculated relative to the 1981–2010 average by
subtracting the average for the period 1981–2010.
3. The amount 0.69 °C was added to each series, based on the estimated difference
between 1850–1900 and 1981–2010, calculated using the method from the IPCC
Sixth Assessment Report Working Group I (the number is provided in the caption
for Figure 1.12 in that report).
4. The mean and standard deviation of the six estimates were calculated.
5. The uncertainty in the IPCC estimate was combined with the standard deviation, 
assuming the two are independent and assuming the IPCC uncertainty range (0.54 °C
to 0.79 °C) is representative of a 90% confidence range (1.645 standard deviations).
The number quoted in this report for 2021 (1.11 ± 0.13 °C) was calculated in this way with
1.11 °C being the mean of the six estimates.
Annual temperature maps
The method for calculating the map of annual temperature anomalies has also been
updated. In the 2020 report, a map showing anomalies relative to 1981–2010 from a single
data set (ERA5) was used. While the map was based on a single data set, the accompanying
assessment was based on all available data sets. 
For the map of temperature anomalies for 2021, a median value of five of the data sets
was used – HadCRUT5, ERA5, NOAAGlobalTemp, Berkeley Earth and GISTEMP – regridded
to the spatial grid of the lowest resolution data sets (NOAAGlobalTemp and HadCRUT5
data sets), which are presented on a 5° latitude by 5° longitude grid. The median is used
in preference to the mean to minimize the effect of potential outliers. The half-range of
the data sets provides an indication of the uncertainty. The spread between the data sets
is largest at high latitudes and in Central Africa, both regions with sparse data coverage.
The following six data sets were used:
Berkeley Earth – Rohde, R. A.; Hausfather, Z. The Berkeley Earth Land/Ocean Temperature
Record. Earth System Science Data 2020, 12, 3469–3479. https://doi.org/10.5194/
essd-12-3469-2020.
ERA5 — Hersbach, H.; Bell, B.; Berrisford, P. et al. The ERA5 global reanalysis. Quarterly Journal of
the Royal Meteorological Society 2020, 146 (730), 1999–2049. https://doi.org/10.1002/
qj.3803.
GISTEMP v4 — GISTEMP Team, 2022: GISS Surface Temperature Analysis (GISTEMP), version 4 .
NASA Goddard Institute for Space Studies, https://data.giss.nasa.gov/gistemp/. 
Lenssen, N.;Schmidt, G.; Hansen, J. et al. Improvements in the GISTEMP Uncertainty 
Model. Journal of Geophysical Research: Atmospheres 2019, 124 (12): 6307–6326.
https://doi.org/10.1029/2018JD029522.
48
HadCRUT.5.0.1.0 — Morice, C. P.; Kennedy, J. J.; Rayner, N. A. et al. An Updated Assessment
of Near-Surface Temperature Change From 1850: The HadCRUT5 Data Set. Journal
of Geophysical Research: Atmospheres 2021, 126 (3), e2019JD032361. https://doi.
org/10.1029/2019JD032361. HadCRUT.5.0.1.0 data were obtained from http://www.
metoffice.gov.uk/hadobs/hadcrut5 on 24 October 2021 and are © British Crown
Copyright, Met Office 2021, provided under an Open Government License, http://www.
nationalarchives.gov.uk/doc/open-government-licence/version/3/.
 JRA-55 — Kobayashi, S.; Ota, Y.; Harada, Y. et al. The JRA-55 Reanalysis: General Specifications
and Basic Characteristics. Journal of the Meteorological Society of Japan . Ser. II 2015,
93 (1), 5–48. https://doi.org/10.2151/jmsj.2015-001, https://www.jstage.jst.go.jp/article/
jmsj/93/1/93_2015-001/_article.
Figure 28. 
(a) Near-surface air
temperature anomalies
for 2021 relative to the
1981–2010 average
for the median of five
data sets on a 5° grid.
(b) Range of the five
estimates; near surface
temperature anomalies
on the native resolution
grid of the dataset for
(c) HadCRUT5 
(5° resolution), 
(d) ERA5 (0.25°),
(e) Berkeley Earth (1°),
(f) GISTEMP (2°) and 
(g) NOAAGlobalTemp (5°).
NOAAGlobalTemp v5 — Zhang, H.-M., et al., NOAA Global Surface Temperature Dataset
(NOAAGlobalTemp), Version 5.0. NOAA National Centers for Environmental Information.
doi:10.7289/V5FN144H. Huang, B.; Menne, M. J.; Boyer, T. et al. Uncertainty Estimates
for Sea Surface Temperature and Land Surface Air Temperature in NOAAGlobalTemp
Version 5. Journal of Climate 2020, 33 (4), 1351–1379. https://journals.ametsoc.org/view/
journals/clim/33/4/jcli-d-19-0395.1.xml.
(a) Median 2021
(b) Range
90ºN
45ºN
0º
45ºS
90ºS
180º
90ºW
0º
90ºE
180º
Longitude
–10        –3        –1            0          1           3         10   °C
(c) HadCRUT5
(d) ERA5
(e) Berkeley Earth
(f) NASA GISTEMP
(g) NOAAGlobalTemp
49
Latitude
Latitude
90ºN
45ºN
0º
45ºS
90ºS
180º
90ºW
0º
90ºE
180º
Longitude
0.0          0.2          0.4          0.6           0.8         2.0   °C
90ºN
45ºN
0º
45ºS
90ºS
180º
90ºN
45ºN
0º
45ºS
90ºS
180º
90ºN
45ºN
90ºW
Latitude
0º
90ºE
180º
90ºW
0º
90ºE
180º
Longitude
Latitude
0º
45ºS
180º
90ºW
0º
90ºE
180º
Longitude
Latitude
90ºS
Longitude
90ºN
45ºN
0º
45ºS
90ºN
45ºN
0º
45ºS
90ºS
180º
90ºW
0º
90ºE
180º
180º
90ºW
0º
90ºE
180º
Longitude
Latitude
Latitude
90ºS
Longitude
–10       –3          –1          0           1           3         10   °C
OCEAN HEAT CONTENT DATA
Data used for estimates up to 2021:
Cheng, L.; Trenberth, K. E.; Fasullo, J. et al. Improved estimates of ocean heat content from 1960 to
2015, Science Advances 2017, 3 (3), e1601545. ht tps://doi.org/10.1126/sciadv.1601545.
Ishii, M.; Fukuda, Y.; Hirahara, S. et al. Accuracy of Global Upper Ocean Heat Content Estimation
Expected from Present Observational Data Sets. SOLA 2017, 13, 163–167. https://doi.
org/10.2151/sola.2017-030.
Lyman, J. M.; Johnson, G. C. Estimating Global Ocean Heat Content Changes in the Upper 1800 m
since 1950 and the Influence of Climatology Choice. Journal of Climate 2014, 27 (5),
1945–1957. https://doi.org/10.1175/JCLI-D-12-00752.1.
von Schuckmann, K.; Le Traon, P.-Y. How well can we derive Global Ocean Indicators from Argo
data? Ocean Science 2011, 7 (6), 783–791. https://doi.org/10.5194/os-7-783-2011.
In addition, data used up to 2020:
Desbruyères, D. G.; Purkey, S. G.; McDonagh, E. L. et al. Deep and abyssal ocean warming from 
35 years of repeat hydrography, Geophysical Research Letters 2016, 43 (19), 310–356. 
https://doi.org/10.1002/2016GL070413.
Gaillard, F.; Reynaud, T.; Thierry, V. et al. In Situ–Based Reanalysis of the Global Ocean Temperature
and Salinity with ISAS: Variability of the Heat Content and Steric Height, Journal of
Climate 2016, 29 (4), 1305–1323. https://doi.org/10.1175/JCLI-D-15-0028.1.
Hosoda, S.; Ohira, T.; Nakamura, T. A monthly mean dataset of global oceanic temperature
and salinity derived from Argo float observations. JAMSTEC Report of
Research and Development 2008, 8, 47–59. https://www.jstage.jst.go.jp/article/
jamstecr/8/0/8_0_47/_article.
Kuusela M.; Stein, M. L. Locally stationary spatio-temporal interpolation of Argo profiling float
data. Proceedings of the Royal Society A 2018, 474, 20180400. http://dx.doi.org/10.1098/
rspa.2018.0400.
Levitus, S.; Antonov, J. I.; Boyer, T. P. et al. World Ocean heat content and thermosteric sea level
change (0-2 000 m) 1955–2010. Geophysical Research Letters 2012, 39 (10), L10603.
https://doi.org/10.1029/2012GL051106.
Li, H.; Xu, F.; Zhou, W. et al. Development of a global gridded Argo data set with Barnes successive
corrections, Journal of Geophysical Research: Oceans 2017, 122 (2), 866–889, https://doi.
org/10.1002/2016JC012285.
Roemmich, D.; Gilson, J. The 2004–2008 mean and annual cycle of temperature, salinity, and steric
height in the global ocean from the Argo Program, Progress in Oceanography 2009, 82
(2), 81–100. https://doi.org/10.1016/j.pocean.2009.03.004.
von Schuckmann, K.; Le Traon, P. -Y.; Smith, N. et al., Eds. Copernicus Marine Service Ocean State
Report, Journal of Operational Oceanography 2018, 11, S1–S142. https://doi.org/10.1080/
1755876X.2018.1489208.
SEA LEVEL DATA
GMSL from CNES/Aviso+ https://www.aviso.altimetry.fr/en/data/products/ocean-indicators-products/mean-sea-level/data-acces.html#c12195
MARINE HEATWAVE AND MARINE COLD SPELL DATA
Marine heatwaves (MHWs) are categorized as moderate when the sea-surface temperature
(SST) is above the 90th percentile of the climatological distribution for five days or longer;
the subsequent categories are defined with respect to the difference between the SST
and the climatological distribution average: strong, severe or extreme, if that difference is, 
50
respectively, more than two, three or four times the difference between the 90th percentile
and the climatological distribution average (Hobday et al., 2018). Marine cold spell (MCS)
categories are analogous, but are categorized with reference to sea-surface temperatures
below the 10th percentile.
The baseline used for MHWs and MCSs is 1982–2011, which is shifted by one year from the
standard normal period of 1981–2010 because the first full year of the satellite SST series
on which it is based is 1982.
Hobday, A.J.; Oliver, E. C. J.; Sen Gupta, A. et al. Categorizing and naming marine heatwaves.
Oceanography 2018, 31 (2), 1–13. https://doi.org/10.5670/oceanog.2018.205.
NOAA OISST v2: Optimum Interpolation Sea Surface Temperature (OISST): Banzon, V.; Smith, T. M.;
Chin, T. M. et al. A long-term record of blended satellite and in situ sea-surface
temperature for climate monitoring, modeling and environmental studies. Earth System
Science Data 2016, 8 (1), 165–176. https://doi.org/10.5194/essd-8-165-2016.
GLACIER MASS BALANCE DATA
Glacier mass balance data for the global network of reference glaciers are available
from the World Glacier Monitoring Service (WGMS), https://www.wgms.ch. Data for the
2020–2021 mass balance year are preliminary, and are based on a subset of 32 (out of a total
of ~42) WGMS reference glaciers. The glacier mass balance data for western Canada are
based on multi-year, bi-annual (April and September) repeat LiDAR surveys conducted by
Brian Menounos at the University of Northern British Columbia, Canada, as described in
Pelto et al. (2019).
Pelto, B. M.; Menounos, B.; Marshall, S. J. Multi-year evaluation of airborne geodetic surveys
to estimate seasonal mass balance, Columbia and Rocky Mountains, Canada. The
Cryosphere 2019, 13 (6), 1709–1727. https://doi.org/10.5194/tc-13-1709-2019.
Hugonnet, R.; McNabb, R.; Berthier, E. et al. Accelerated global glacier mass loss in the
early twenty-first century. Nature 2021, 592, 726–731. https://doi.org/10.1038/
s41586-021-03436-z. 
GREENLAND AND ANTARCTIC ICE SHEET DATA
Greenland ice sheet mass balance data are reported from three sources. Modelled changes
in surface mass balance and total mass balance from 1985 to 2021 are based on the average 
of three regional climate and mass balance models, described in Mankoff et al. (2021). 
An alternative estimate of 2021 mass balance is given in the NOAA Arctic Report Card
(Moon et al., 2021), based on satellite observations of melt area and surface mass balance
models driven by the PROMICE surface weather station network. Satellite gravity data of
total ice sheet mass balance from the GRACE and GRACE-FO missions are available from
Wiese et al. (2019, updated to 2021). These data are available for both the Greenland and
Antarctic ice sheets.
Mankoff, K. D.; Fettweis, X.; Langen, P. L. et al. Greenland ice sheet mass balance from 1840 through
next week. Earth System Science Data 2021, 13 (10), 5001–5025. https://doi.org/10.5194/
essd-13-5001-2021.
Moon, T. A.; Tedesco, M.; Box, J. E. et al. Greenland Ice Sheet. In Arctic Report Card 2021; Moon, 
T. A.; Druckenmiller, M. L.; Thoman, R. L., Eds.; National Oceanic and Atmospheric
Administration, 2021. https://doi.org/10.25923/546g-ms61.
Wiese, D.N.; Yuan, D. -N; Boening, C. et al. 2019. JPL GRACE and GRACE-FO Mascon Ocean, Ice, and
Hydrology Equivalent Water Height RL06M CRI Filtered Version 2.0, Ver. 2.0, PO.DAAC,
CA, USA. http://dx.doi.org/10.5067/TEMSC-3MJ62.
51
SNOW DATA
Snow data and monthly anomaly time series charts are available at: https://climate.rutgers.
edu/snowcover/files/wmo/rutgers-nh-sce-anomalies-2020-21-data.xlsx 
SEA-ICE DATA
The sea ice section uses data from the EUMETSAT OSI SAF Sea Ice Index v2.1 (OSI-SAF,
based on Lavergne et al., 2019) and the NSIDC v3 Sea Ice Index (Fetterer et al., 2017).
Sea-ice concentrations are estimated from microwave radiances measured from satellites.
Sea-ice extent is calculated as the area of ocean grid cells where the sea-ice concentration
exceeds 15%. Although there are relatively large differences in the absolute extent between
data sets, they agree well on the year-to-year changes and the trends. In this report, NSIDC
data are reported for absolute extents (for example, “18.95 million km
2
”) for consistency
with earlier reports, while rankings are reported for both data sets.
EUMETSAT Ocean and Sea Ice Satellite Application Facility, Sea ice index 1979-onwards 
(v2.1, 2020), OSI-420, Data extracted from OSI SAF FTP server: 1979–2020, Northern and 
Southern Hemisphere. https://osi-saf.eumetsat.int/products/osi-420.
Fetterer, F.; Knowles, K.; Meier, W. N. et al. 2017, updated daily. Sea Ice Index, Version 3 . Boulder,
Colorado USA. National Snow and Ice Data Center (NSIDC). https://doi.org/10.7265/
N5K072F8.
Lavergne, T.; Sørensen, A. M.; Kern, S. et al. Version 2 of the EUMETSAT OSI SAF and ESA CCI
sea-ice concentration climate data records. The Cryosphere 2019, 13 (1), 49–78. 
https://doi.org/10.5194/tc-13-49-2019.
PERMAFROST DATA
Noetzli, J.; Christiansen, H. H.; Hrbáček, F. et al. Global Climate Permafrost Thermal State.
In State of the Climate in 2020; Dunn, R. J., Aldred, H., F., Gobron, N. Eds.; Bulletin of
the American Meteorological Society 2021, 102 (8); S42–S44. https://doi.org/10.1175/
BAMS-D-21-0098.1. 
Smith, S. L.; Romanovsky, V. E.; Isaksen, K. et al. Permafrost. In State of the Climate in 2020;
Druckenmiller, M. L., Moon, T., Thoman, R., Eds.; Bulletin of the American Meteorological
Society, 2021, 102 (8); S293–S297. ht tps://doi.org/10.1175/BAMS-D -21- 0086.1. 
PRECIPITATION DATA
These Global Precipitation Climatology Centre (GPCC) data sets were used in the analysis:
• First Guess Monthly, doi: 10.5676/DWD_GPCC/FG_M_100. 
• Monitoring Product (Version 2020), doi: 10.5676/DWD_GPCC/MP_M_V2020_100. 
• Full Data Monthly (Version 2020), doi: 10.5676/DWD_GPCC/FD_M_V2020_100. 
• First Guess Daily, doi: 10.5676/DWD_GPCC/FG_D_100. 
• Full Data Daily (Version 2020), doi: 10.5676/DWD_GPCC/FD_D_V2020_100. 
52
List of contributors
CONTRIBUTING MEMBERS AND TERRITORIES
Algeria, Andorra, Argentina, Armenia, Australia, Austria, Bahrain, Barbados, Belarus,
Belgium, Belize, Bosnia and Herzegovina, Botswana, British Caribbean Territories, Bulgaria,
Burkina Faso, Cameroon, Canada, Chile, China, Colombia, Croatia, Cyprus, Czech Republic,
Denmark, Egypt, Estonia, Finland, France, Gambia, Georgia, Germany, Greece, Grenada,
Guinea, Guinea-Bissau, Hong Kong, China; Hungary, India, Islamic Republic of Iran, Ireland,
Israel, Italy, Japan, Jordan, Kazakhstan, Kenya, Latvia, Liberia, Libya, Lithuania, Luxembourg,
Macao, China; Madagascar, Mali, Malta, Mauritius, Morocco, New Zealand, Niger, Nigeria,
North Macedonia, Norway, Pakistan, Peru, Philippines, Poland, Portugal, Republic of
Moldova, Romania, Russian Federation, Rwanda, Saint Vincent and the Grenadines, Saudi
Arabia, Senegal, Serbia, Slovakia, Slovenia, South Africa, Spain, Saint Kitts and Nevis,
Sudan, Sweden, Switzerland, Syrian Arab Republic, Thailand, Netherlands, Togo, Trinidad
and Tobago, Tunisia, Turkey, Ukraine, United Kingdom, United Republic of Tanzania, United
States of America, Uruguay, Uzbekistan, Zimbabwe
INSTITUTIONAL CONTRIBUTORS
ARC Centre of Excellence for Climate Extremes, University of Tasmania, Australia; Birmingham
Institute of Forest Research, Birmingham University, UK; British Antarctic Survey (BAS);
Bureau of Meteorology (BoM), Australia; Carbon Portal, Lund University, Sweden; Centre
National d’Études Spatiales, CNES, France; Mercator Ocean international, France; Observatoire
Midi-Pyrénées (OMP), France; IFREMER, France; University of Brest, France; Centre National
de la Recherche Scientifique, (CNRS), France; Institut de Recherche pour le Développement
(IRD), France; Laboratoire d’Océanographie Physique et Spatiale (LOPS), France; Laboratoire
d’Etudes en Géophysique et Océanographie Spatiales (LEGOS), France; Institut Universitaire
Européen de la Mer (IUEM), France; CELAD, France; Sorbonne Université, France; Laboratoire
d’Océanographie de Villefranche, France; Center for Ocean Mega-Science, Chinese Academy
of Sciences; Copernicus Climate Change Service (C3S); CSIRO Oceans and Atmosphere,
Australia; Danmarks Meteorologiske Institut (DMI); Global Precipitation Climatology Centre,
Deutscher Wetterdienst (GPCC, DWD); Environment and Climate Change Canada (ECCC); ETH
Zürich, Switzerland; European Centre for Medium Range Weather Forecasts (ECMWF); George
Washington University, USA; Hong Kong Observatory; Institute of Atmospheric
Physics, Chinese Academy of  Sciences (IAP, CAS); Japan Marine-Earth Science and
Technology (JAMSTEC); Joint Institute for Marine and Atmospheric Research,
University of Hawai’i (JIMAR), USA; Met Office Hadley Centre, UK; Department of
Atmosphere, Ocean and Earth System Modeling Research, Meteorological Research
Institute, Japan; National Environment Agency, Singapore (NEA); National
Oceanographic and Atmosphere Administration, National Centers for Environmental
Information (NOAA NCEI), USA; NOAA, Pacific Marine Environmental Laboratory (NOAA
PMEL), USA; National Oceanography Centre (NOC), UK; Natural Resources Canada;
Norwegian Meteorological Institute; Rutgers University, USA; Scripps Institution of
Oceanography, USA; Tokyo Climate Center, Japan Meteorological Agency (TCC, JMA);
Universidade Federal do Rio de Janeiro, Brazil; University of Exeter, UK; University of
Victoria, Canada; Woods Hole Oceanographic Institution, USA; World Climate Research
Programme (WCRP); World Data Centre for Greenhouse Gases (WDCGG)
53
UNITED NATIONS AGENCIES
United Nations Office for Disaster Risk Reduction (UNDRR), United Nations Environment
Programme (UNEP), Food and Agriculture Organization of the United Nations (FAO),
United Nations High Commissioner for Refugees (UNHCR), International Organization
for Migration (IOM), World Food Programme (WFP), Intergovernmental Oceanographic
Commission – United Nations (IOC-UNESCO)
INDIVIDUAL CONTRIBUTORS
Signe Aaboe (Norwegian Meteorological Institute), Jorge Alvar-Beltrán (FAO), Omar Baddour
(WMO publication coordinator), Jessica Blunden (NOAA NCEI), Tim Boyer (NOAA NCEI),
Anny Cazenave (LEGOS CNES and OMP), Lijing Cheng (IAP; Center for Ocean Mega-Science,
Chinese Academy of Sciences), Louis Clement (National Oceanography Centre), Kyle Clem
(University of Victoria), Estelle De Coning (WMO), Damien Desbruyères (IFREMER, CNRS,
IRD, Laboratoire d’Océanographie Physique et Spatiale), Maxx Dilley (WMO), Robert Dunn
(Met Office Hadley Centre), Simon Eggleston (WMO/GCOS), Thomas Estilow (Rutgers
University), Florence Geoffroy (UNHCR), Donata Giglio (University of Colorado), Nathan
Gillett (ECCC), John Gilson (Scripps Institution of Oceanography, University of California),
Loretta Hieber Girardet (UNDRR), Atsushi Goto (TCC, JMA), Yvan Gouzenes (LEGOS and
OMP), Stephan Gruber (Carleton University), Debbie Hemming (Met Office Hadley Centre,
Birmingham Institute of Forest Research), Ana Heureux (FAO), Shigeki Hosoda (JAMSTEC),
Matthias Huss (ETH Zürich), Kirsten Isensee (IOC UNESCO), Gregory C. Johnson (NOAA,
PMEL), Ryan Kang (NEA), Maarten Kappelle (UNEP), John Kennedy (lead author, Met Office
Hadley Centre), Valentina Khan (Hydrometeorological Research Center of the Russian
Federation), Rachel Killick (Met Office Hadley Centre), Brian A. King (NOC), Animesh Kumar
(UNDRR), Mikael Kuusela (Carnegie Mellon University), Gernot Laganda (WFP), Thomas
Lavergne (Norwegian Meteorological Institute), Yuehua Li (University of New South Wales),
Renata Libonati (Universidade Federal do Rio de Janeiro), Juerg Luterbacher (WMO),
John Lyman (NOAA, PMEL), Shawn Marshall (ECCC and University of Calgary), Jesse
Mason (WFP), Brian Menounos (University of Northern British Columbia), Audrey Minière
(Mercator Ocean international), Maeva Monier (CELAD/Mercator Ocean international), Colin
Morice (Met Office Hadley Centre), Lev Neretin (FAO), Stoyka Netcheva (WMO), Rodica
Nitu (WMO), Jeannette Noetzli, (Institute for Snow and Avalanche Research), Ben Pelto
(University of Northern British Columbia), Claire Ransom (WMO), Andrew Robertson (S2S
co-chair, IRI), David Robinson (Rutgers University), Dean Roemmich (Scripps Institution 
of Oceanography), Kanako Sato (JAMSTEC), Katsunari Sato (JMA), Yousuke Sawa (JMA, 
WDCGG), Robert W. Schlegel (Sorbonne Université, CNRS, Laboratoire d’Océanographie
de Villefranche), Katherina Schoo (IOC UNESCO), Karina von Schuckmann (Mercator Ocean
international), Rahul Sengupta (UNDRR), Fumi Sezaki (TCC, JMA), José Álvaro Silva (WMO),
Sharon Smith (Natural Resources Canada), Michael Sparrow (WCRP), Martin Stendel (DMI),
Peter Stott (Met Office Hadley Centre, University of Exeter), Dmitry Streletskiy (George
Washington University), Toshio Suga (JAMSTEC, Tohoku University), Tanguy Szekely
(OceanScope), Wee Leng Tan (NEA), Oksana Tarasova (WMO), Blair Trewin (BoM), Thea
Turkington (NEA, Singapore), John Turner (BAS), Freja Vamborg (ECMWF), Alex Vermeulen
(Carbon Portal, Lund University), Frederic Vitart (S2S co-chair, ECMWF), Ying Wang (UNEP),
Michelle Yonetani (UNHCR), Zhiwei Zhu (Nanjing University of Information Science and
Technology), Markus Ziese (DWD)
54
(@@ UNHCR �
The UN Refugee Agency 
Food and Agriculture Organization
of the United Nations 
environment
programme 
WFP 
nm 
@1OM 
UN MIGRATION
(UNDRR 
t eN 
¥8 world Food
d, i , Programme 
United Nations 
Educational. Scientific ad
Cultural Organization 
UN Office for Disaster Risk Reduction 
� 
For more information, please contact:
World Meteorological Organization
7 bis, avenue de la Paix – P.O. Box 2300 – CH 1211 Geneva 2 – Switzerland
Strategic Communications Office
Cabinet Office of the Secretary-General
Tel: +41 (0) 22 730 83 14 
Email: [email protected] 
public.wmo.int
JN 22229