INTERNATIONAL COURT OF JUSTICE
OBLIGATIONS OF STATES IN RESPECT
OF CLIMATE CHANGE
(REQUEST FOR ADVISORY OPINION)
Written Comments of the Republic of Mauritius
15 August 2024
TABLE OF CONTENTS
I. INTRODUCTION ........................................................................................5
II. QUESTION A: THE OBLIGATIONS OF STATES ................................9
A. The best available science and the obligation to take it into account......9
B. Paris Agreement as a strengthened response .........................................19
C. Due diligence .........................................................................................22
1. Temperature goal..............................................................................26
2. Ambition and progression.................................................................28
3. Nationally Determined Contributions (NDCs) .................................29
4. Environmental Impact Assessment ...................................................31
D. Phasing out fossil fuels ..........................................................................32
E. CBDRRC and Equity ............................................................................35
F. Finance. .................................................................................................41
G. Adaptation .............................................................................................43
H. Human Rights ........................................................................................45
I. Customary international law .................................................................49
1. Prevention .........................................................................................52
2. Cooperation ......................................................................................54
3. Precaution.........................................................................................55
III. QUESTION B: LEGAL CONSEQUENCES ...........................................57
A. Responsibility and damage ....................................................................57
1. Attribution .........................................................................................61
2. Breach ...............................................................................................62
3. Significant harm................................................................................68
4. Temporal aspects ..............................................................................70
5. Causation ..........................................................................................72
6. Compensation ...................................................................................74
B. Maritime Boundaries and Entitlements .................................................75
IV. CONCLUSIONS .........................................................................................78
5
I. INTRODUCTION
1. The Republic of Mauritius (“Mauritius”) submits these Written Comments
on the Written Statements filed by other participants in the matter of the
request for an Advisory Opinion on the Obligations of States in respect of
Climate Change, pursuant to the Order of the Court dated 30 May 2024.
2. The urgent and catastrophic risk posed by climate change is underscored by
the unprecedented participation in these proceedings. Written Statements
have been filed by 83 States and territories, representing approximately 6
billion people, about 75% of the world’s population. Written statements have
also been filed by 12 international organisations whose membership
encompasses all 193 UN Member States.
3. Mauritius notes that no participant has disputed the Court’s jurisdiction, and
there is near-universal acceptance that there are no compelling reasons for the
Court to decline to exercise its discretionary power to render the Advisory
Opinion sought by the UN General Assembly (“UNGA”).
4. Mauritius further notes that on 21 May 2024 the International Tribunal for
the Law of the Sea (“ITLOS” or “the Tribunal”) issued a unanimous
Advisory Opinion on Climate Change and International Law (“ITLOS
Advisory Opinion”).1 The Tribunal addresses many of the issues before the
Court in these proceedings, albeit specifically under the framework of the
United Nations Convention on the Law of the Sea (“UNCLOS”). Mauritius
1 Request for an Advisory Opinion submitted by the Commission of Small Island States on Climate
Change and International Law (Request for an Advisory Opinion submitted to the Tribunal),
ITLOS, Advisory Opinion of 21 May 2024 (hereinafter “ITLOS Advisory Opinion”), available
at: https://www.itlos.org/en/main/cases/list-of-cases/request-for-an-advisory-opinion-submittedby-
the-commission-of-small-island-states-on-climate-change-and-international-law-request-foradvisory-
opinion-submitted-to-the-tribunal/ (last accessed 10 August 2024).
6
considers that the ITLOS Advisory Opinion, and the manner in which the
Tribunal reached its determinations, provides an “authoritative statement of
international law on the questions with which it deal[t].”2 Accordingly,
having regard to the principle of comity between international courts and
tribunals, Mauritius invites the Court to have due regard to the ITLOS
Advisory Opinion and, as appropriate, to respect and build on ITLOS’
determinations (as addressed in more detail below).
5. The great majority of participants in these proceedings acknowledge that the
obligations of States in respect of climate change are firmly rooted in climate
science. The science informs the causes and consequences of climate change,
as well as what is needed to avert the most catastrophic of these
consequences. In seeking to assist the Court in its task of rendering an
Advisory Opinion that is based on the best available climate science,
Mauritius has obtained an independent expert report from Dr James E.
Hansen, a leader in the scientific community on matters of climate change for
more than four decades.3 Dr Hansen is an Adjunct Professor at Columbia
University’s Earth Institute, from where he directs a program in Climate
Science, Awareness and Solutions. Dr Hansen has been heavily involved in
matters of climate science for more than four decades, advising many
governments and the Intergovernmental Panel on Climate Change (“IPCC”).
2 Dispute concerning delimitation of the maritime boundary between Mauritius and Maldives in
the Indian Ocean (Mauritius/Maldives), ITLOS, Preliminary Objections, Judgment of 28 January
2021, para. 202.
3 Expert Report of Dr James E. Hansen in Support of the Republic of Mauritius (9 August 2024),
(hereinafter “Report of Dr James E. Hansen”), Annex 1.
7
6. In these Written Comments, Mauritius will address the following nine issues
with respect to the first question – the obligations of States under international
law – in response to the Written Statements filed by other participants:
a. the obligation to take into account the best available science;
b. the Paris Agreement, which emphasises the urgent need to close the gap
between what is required and what has been achieved so far;
c. the obligation of due diligence, in particular having regard to:
i. the 1.5°C temperature goal;
ii. the requirement for the “highest possible ambition” and
“progression” (Article 4(3) of the Paris Agreement);
iii. Nationally Determined Contributions (“NDCs”); and
iv. environmental impact assessment;
d. the obligation to make urgent and deep reductions in greenhouse gas
(“GHG”) emissions, including the immediate need to transition away
from fossil fuels;
e. the obligation to give effect to principles of equity and common but
differentiated responsibility and respective capabilities (“CBDRRC”);
f. the obligation to make available accessible, fair and transparent climate
finance for developing countries;
g. the obligation to address adaptation, particularly for developing States
and those most vulnerable to the impacts of climate change, including
Small Island Developing States (“SIDS”);
8
h. the obligations on States to protect human rights, based on the principle
of systemic integration; and
i. the role of customary international law obligations to supplement (and
not being superseded by) multilateral treaties in the field of climate
protection, including the duties of:
i. prevention;
ii. cooperation; and
iii. precaution.
7. As to the second question – on legal consequences – Mauritius addresses the
applicability of the general principles of State responsibility with respect to
breaches of climate related obligations, in particular:
a. the methodology by which to attribute climate change and its
consequences to the emissions, acts and omissions of individual States;
b. the emissions, acts and omissions of States, both individual and
collectively, that may give rise to breaches of international climate
obligations;
c. the significant harm which has already been caused by climate change,
and the impending risk of even more catastrophic damage;
d. historic emissions and the temporal aspects of State responsibility;
e. the applicable principles in relation to causation; and
f. the obligation to make reparation, including compensation for loss and
damage resulting from GHG emissions.
9
8. Finally, Mauritius addresses the potential impact of sea level rise on maritime
boundaries and entitlements, a matter which ITLOS did not address but which
is of fundamental importance for so many States, particularly SIDS.
II. QUESTION A: THE OBLIGATIONS OF STATES
A. THE BEST AVAILABLE SCIENCE AND THE OBLIGATION TO TAKE IT INTO
ACCOUNT
9. Virtually all States and organisations participating in these proceedings
(including Mauritius) have emphasised the need to be guided by the science
relating to climate change and, in particular, the scientific findings and
recommendations of the IPCC. Mauritius agrees with the large number of
participants who have emphasised the way in which international legal
obligations are rooted in this science.
10. ITLOS relied extensively on the best available scientific knowledge as
forming the bedrock of its legal determinations in its Advisory Opinion.
ITLOS affirmed that “the science undoubtedly plays a crucial role” in
determining what is required of States under UNCLOS.4 Throughout its
Advisory Opinion, ITLOS took account of scientific evidence of a “high risk”
that outcomes will be even worse if the 1.5℃ target is not met.5 In the
identification of the best available scientific knowledge, ITLOS relied
primarily on the reports of the IPCC.6 The Tribunal observed that:
4 ITLOS Advisory Opinion, para. 212.
5 Ibid., paras. 209, 241, 243, 399-400 & 441.
6 Ibid., paras. 49-66. See also: Written Statement of the Republic of Mauritius submitted to the
International Court of Justice in the request for an Advisory Opinion on the Obligations of States
10
“…most of the participants in the proceedings referred to reports
of the IPCC, recognizing them as authoritative assessments of the
scientific knowledge on climate change, and that none of the
participants challenged the authoritative value of these reports.”7
11. Mauritius notes that the same is true of these proceedings, and invites the
Court to so recognise.
12. One important implication of this nexus between climate science and the law
is that the interpretation of relevant legal obligations must be considered in
the light of the specific, measurable and timebound risks identified by climate
science. In that way, the science also informs an understanding of what it
means to breach those obligations, and what the legal consequences of such
breaches may be. Such an approach gives full weight to the authoritative
scientific knowledge of the IPCC.
13. Mauritius does not agree with the small number of participants who invite the
Court to answer the UNGA’s questions in a legal vacuum, without regard to
the science and effects of climate change. In fulfilling its judicial mandate,
the Court must engage with the relevant facts. In these proceedings, those
facts include, as a central element, the best available climate science, and in
particular, the reports of the IPCC.8
14. Mauritius agrees with the great majority of participants who have underlined
the importance of key principles of the 1994 UN Framework Convention on
Climate Change (“UNFCCC”) and the Paris Agreement, including principles
of equity and CBDRRC. The dynamic nature of the climate treaty regime is
in respect of Climate Change dated 22 March 2024 (hereinafter “Mauritius Written Statement”),
paras. 45-53 & 104-105.
7 ITLOS Advisory Opinion, para. 51.
8 Mauritius Written Statement, paras. 15 & 39-85.
11
based on the need to ensure that those most responsible, and most able to do
so, take the lead in reducing GHG emissions, and that those most vulnerable
to the impacts of climate change, are enabled to increase their resilience and
reduce vulnerability.
15. Like other participants, Mauritius has pointed to the need for urgent and
immediate action to address climate change, as confirmed by the best
available science presented by the IPCC.9 The following key elements are
emphasised by many participants:
a. In light of the scientific evidence that the impacts of climate change
will be much lower at a temperature increase of 1.5°C, Parties have
recognised the need to limit the temperature increase to 1.5°C
(although it is widely recognised that damage will still be caused with
a rise of 1.5°C).10 Therefore, the effective temperature goal under
Article 2(1)(a) of the Paris Agreement, as informed by the best
available science, is to limit the global average temperature rise to
1.5°C (as opposed to 2°C). This is the minimum goal necessary to
prevent the most dangerous anthropogenic interference with the climate
system pursuant to Article 2 of the UNFCCC which provides the
overall objective for the international climate regime.11
9 Mauritius Written Statement, paras. 83-85.
10 See e.g. the Sharm el-Sheikh Implementation Plan, adopted at the 27th UNFCCC Conference of
the Parties on 20 November 2022 (hereinafter “Sharm el-Sheik Implementation Plan”), at para.
4, available at: https://unfccc.int/documents/624444 (last accessed 10 August 2024). See further:
Mauritius Written Statement, para. 101.
11 Participants supporting 1.5°C as the minimum temperature goal in their Written Statements
include: Bangladesh (paras. 135-139), Chile (para. 89), Colombia (para. 3.34), Grenada (para. 35),
Kenya (para. 5.41), Liechtenstein (para. 73), Madagascar (paras 25 & 42), Mexico (para. 50),
Micronesia (para. 35), Namibia (paras. 46 & 81), Seychelles (para. 91), Sierra Leone (para. 3.129),
Singapore (para. 3.30), Spain (para. 7), St Lucia (para. 53), Timor-Leste (para. 100), Tonga (para.
12
b. Importantly, many participants have highlighted the high risk of
catastrophic irreversible harm if the 1.5°C temperature goal is
exceeded. The scale of the difference between limiting the rise to 1.5°C
as opposed to 2°C is starkly demonstrated by the IPCC. To take just
one example of what is at stake:
“Limiting warming to 1.5°C, instead of 2°C, could result in
around 420 million fewer people being frequently exposed
to extreme heatwaves, and about 65 million fewer people
exposed being to exceptional heatwaves, assuming constant
vulnerability (medium confidence).”12
Parties to the UNFCCC and the Paris Agreement have expressed
serious concerns about the very real risk of crossing tipping points.13
Many participating States and organisations have highlighted this risk,
addressed below at paragraphs 16-22, 36, 105 and 129.14
c. The ability to meet the temperature goal is constrained by the
cumulative amount of GHG emissions in the atmosphere, generally
referred to as the “carbon budget”. The IPCC and UNEP have indicated
that the size of the available carbon budget is rapidly diminishing, and
this has direct implications for the depth and scale of GHG reductions
141), Tuvalu (para. 111), Vanuatu (paras. 400-405), Vietnam (para. 19), the African Union (para.
101), the IUCN (paras. 34 & 111-113) and COSIS (paras. 106-114).
12 IPCC, “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” (2018), available at: https://www.ipcc.ch/sr15/ (last
accessed 10 August 2024) (hereinafter “SR1.5”), Chapter 3, pp.177-178. As to the IPCC’s use of
“confidence” and “probability” assessments, see: Mauritius Written Statement para. 51.
13 See e.g. Sharm el-Sheik Implementation Plan, para. 5.
14 See e.g. the Written Statements of: Bahamas (para. 71), Barbados (paras. 90-91), Kenya (para.
3.17), Pakistan (para. 5(c)), Solomon Islands (paras. 47-51), Micronesia (paras. 32-35), Vanuatu
(para. 405), COSIS (para. 176) and the African Union (para. 97(a)).
13
(pathways) required in order to meet the temperature goal.15 At the 28th
Conference of the Parties (“COP”), Parties expressed their concern
that:
“…the carbon budget consistent with achieving the Paris
Agreement temperature goal is now small and being rapidly
depleted…”16
The IPCC has noted that all global modelled pathways to limit warming
to 1.5°C, or even 2°C, require “rapid and deep, and in most cases,
immediate [GHG] emissions reductions in all sectors this decade.”17
d. Together with many other participants, Mauritius has highlighted the
importance of the emissions gap and the production gap in showing
how much more needs to be done in order to meet the international
climate goals (see further paragraphs 49, 121(c-d), 124 & 127 below).18
These gaps are addressed annually in reports published by UNEP. The
most recent Emissions Gap Report titled ‘Broken Record’ confirms
that: “[t]he world is witnessing a disturbing acceleration in the number,
speed and scale of broken climate records”, and that these are
accompanied by devastating extreme events.19 The 2023 UNEP
Production Gap Report (“UNEP PGR”) underscores that: “[c]ontinued
15 Mauritius Written Statement, paras. 74-76.
16 UNFCCC, First Global Stocktake (13 December 2023), para. 25, available at:
https://unfccc.int/sites/default/files/resource/cma2023_L17_adv.pdf (last accessed 10 August
2024) (hereinafter “First Global Stocktake”).
17 IPCC, “Synthesis Report of the Sixth Assessment Report” (2023), Summary for Policymakers,
B.6, available at: https://www.ipcc.ch/report/sixth-assessment-report-cycle/ (last accessed 10
August 2024) (hereinafter “AR6 SYR”). See also: Mauritius Written Statement, para. 76.
18 Mauritius Written Statement, paras. 77-82.
19 UNEP, Emissions Gap Report (2023), “Broken Record”, p. 1, available at:
https://wedocs.unep.org/bitstream/handle/20.500.11822/43922/EGR2023.pdf?sequence=3&isAllo
wed=y (last accessed 10 August 2024). See also: Mauritius Written Statement, para. 78.
14
production and use of coal, oil, and gas are not compatible with a safe
and liveable future.”20 UNEP’s analysis, which draws directly on the
science presented by the IPCC, provides the clearest indication of the
catastrophe facing life on this planet if current policies on fossil fuel
production are maintained. As the IPCC confirmed in its Sixth
Assessment Report (“AR6”), there is a rapidly closing window within
which States can act on the basis of the science to prevent further
catastrophic harm. This provides the context for identifying and
interpreting the legal obligations to be considered by the Court.21
e. Although much is known about the risks posed by differing levels of
temperature rise, there remains uncertainty as to whether certain
temperature rises could in turn trigger even higher temperature rises
because of what are commonly referred to as “feedback loops”. The
IPCC has noted that warming above 4°C could occur if climate
sensitivity or carbon cycle feedbacks are higher than the best estimate
(high confidence).22 In such circumstances, the precautionary principle,
to which many participants have referred, is clearly relevant (see
paragraphs 105-107 below).
20 UNEP, Production Gap Report (2023), “Phasing down or phasing up?”, p. 8 (hereinafter
“UNEP PGR”), available at:
https://productiongap.org/wp-content/uploads/2023/11/PGR2023_ExecSum_web.pdf (last
accessed 10 August 2024). See also: Mauritius Written Statement, para. 81.
21 Mauritius notes that ITLOS has confirmed that assessments of the IPCC relating to climaterelated
risks and climate change mitigation deserve particular consideration (ITLOS Advisory
Opinion, para. 208).
22 IPCC, Working Group III, “Mitigation of Climate Change”, Sixth Assessment Report
(hereinafter “AR6”), Summary for Policymakers (hereinafter “SPM”), C.1.3, available at:
https://www.ipcc.ch/report/ar6/wg3/downloads/report/IPCC_AR6_WGIII_SummaryForPolicyma
kers.pdf (last accessed 10 August 2024).
15
f. Notwithstanding the consensus as to the science and almost universal
adherence to the international climate goals, the world is not on track
to prevent dangerous climate change. This central fact is an essential
element for the interpretation of legal obligations. Concern as to this
key issue has been expressed with increasing desperation by the
international scientific community, as well as vulnerable States.
16. All of these indications from the best available science confirm the urgency
of taking action if catastrophic climate change, entailing irreversible harm, is
to be averted. Those who acknowledge the importance of the science but do
not refer to these specific elements tend to argue for a more gradualist
approach, one that does not take into account the situation of grave urgency.
In light of the rapidly diminishing carbon budget, the existence of wide
emissions and production gaps, and the risks posed by the crossing of tipping
points and feedback loops, States’ actions must, as a matter of international
law, be informed by the quantified emission pathways and scenarios
presented by the IPCC as those necessary to achieve the temperature goal.23
17. A further key area of focus in the IPCC’s AR6 is the fact that climate change
impacts and risks are becoming increasingly complex and more difficult to
manage. The IPCC has noted that:
“Multiple climate hazards will occur simultaneously, and
multiple climatic and non-climatic risks will interact, resulting in
compounding overall risk and risks cascading across sectors and
23 See ITLOS Advisory Opinion para. 222: “…the temperature goal and the timeline for emission
pathways set out in the Paris Agreement inform the content of necessary measures to be taken
under article 194, paragraph 1, of the Convention.”
16
regions. Some responses to climate change result in new impacts
and risks. (high confidence)”24
18. The present and impending global consequences of climate change, as
determined by the IPCC, are summarised by Dr Hansen as follows:
“• Climate change has caused local species losses, increases in
disease, mass mortality events of plants and animals, resulting
in the first climate driven extinctions, ecosystem restructuring,
increases in areas burned by wildfire, and declines in key
ecosystem services.
• Widespread and severe loss and damage to human and natural
systems are being driven by human-induced climate changes
increasing the frequency and/or intensity and/or duration of
extreme weather events, including droughts, wildfires,
terrestrial and marine heatwaves, cyclones (high confidence),
and flood (low confidence). Extremes are surpassing the
resilience of some ecological and human systems.
• Extreme events and underlying vulnerabilities have intensified
the societal impacts of droughts and floods and have
negatively impacted agriculture, energy production and
increased the incidence of water-borne diseases. Economic
and societal impacts of water insecurity are more pronounced
in low-income countries than in the middle- and high-income
ones.
• Over 9 million climate-related deaths per year are projected by
the end of the century, under a high emissions scenario and
accounting for population growth, economic development,
and adaptation.
• In many regions, the frequency and/or severity of floods,
extreme storms, and droughts is projected to increase in
coming decades, especially under high-emissions scenarios,
raising future risk of displacement in the most exposed areas.
Under all global warming levels, some regions that are
presently densely populated will become unsafe or
uninhabitable.
24 IPCC, Working Group II, “Impacts, Adaptation and Vulnerability”, AR6, SPM, B.5, available
at: https://www.ipcc.ch/report/ar6/wg2/ (last accessed 10 August 2024).
17
• Approximately 3.3 to 3.6 billion people live in contexts that
are highly vulnerable to climate change. A high proportion of
species is vulnerable to climate change. Human and ecosystem
vulnerability are interdependent.” 25
19. The continuous re-evaluation of relevant scientific, technical and economic
considerations is recognised as necessary in the UNFCCC.26 Such reevaluation
is relevant to:
a. the recognition that the 1.5°C (minimum) temperature goal is consistent
with the overall purpose of the climate regime and required to prevent
dangerous climate change (Article 2 of the UNFCCC); and
b. the urgency with which GHG emission reductions are required and the
need to transition away from fossil fuels as rapidly as possible.
20. The science provides a clear basis for the level of urgency required, and the
legal framework is designed to meet this challenge by requiring a level of
progressive ambition on the part of States that corresponds to the scale of the
risk posed by climate change.27 In tacit recognition of this, those who seek to
sidestep these obligations ignore the urgency and the scale of risk, as
evidenced by the science (as can be seen in some of the Written Statements
submitted in these proceedings).
21. Notwithstanding the consensus as to the importance of the science in
addressing the legal questions put to the Court, there is a clear fault line
25 Expert Report of Dr James E. Hansen, p. 2, Annex 1.
26 UN Framework Convention on Climate Change (hereinafter “UNFCCC”), Preamble, para. 16:
(“Recognizing that steps required to understand and address climate change will be
environmentally, socially and economically most effective if they are based on relevant scientific,
technical and economic considerations and continually re-evaluated in the light of new findings in
these areas”).
27 Mauritius Written Statement, paras. 83-85.
18
running through the Written Statements. None of the participants in these
proceedings have taken a position of climate denial, seeking to disavow the
scientific evidence as to the existence of climate change. However, a small
number of participants have sought to sidestep the urgency which is an
integral feature of the scientific evidence presented by the IPCC. Against this,
many participants readily acknowledge, not only the science establishing the
existence of climate change and the key role played by GHG emissions, but
also, and crucially, the urgency of closing the current gaps and the scale of
potential harm if the 1.5°C temperature goal is not met.28
22. Mauritius submits that a failure to engage with the urgent need to alter the
status quo represents a failure to engage with the science, and it implies
(erroneously) that deferring deeper emission cuts and a swifter transition
away from fossil fuels is consistent with climate goals and obligations.
However, this form of climate deferral puts those very goals at grave risk. As
noted by Dr Hansen in his Expert Report
“The situation is urgent. More delay will elicit additional
warming, amplified risk for natural and human systems, and
increased likelihood of crossing tipping points in the global
system.”29
23. Climate deferral risks the overshooting of the temperature goal, the crossing
of irreversible planetary tipping points and the escalation of catastrophic
harm to a terrifying degree. According to the IPCC:
28 See e.g. the Written Statements of: Bahamas (para. 70), Colombia (paras. 2.4-2.13), Grenada
(para. 27), Kenya (paras. 3.14-3.17), Nauru (para. 11), New Zealand (para. 5), Peru (para. 63),
Romania (para. 39), St Vincent and the Grenadines (para. 51), Tuvalu (paras. 22-24 & 62),
Uruguay (paras. 24-25 & 33), Vanuatu (paras. 94-101) and the African Union (para. 7).
29 Report of Dr James E. Hansen, p. 3 (Annex 1).
19
“Without a strengthening of policies beyond those that are
implemented by the end of 2020, GHG emissions are projected
to rise beyond 2025, leading to a median global warming of 3.2
[2.2 to 3.5] °C by 2100 (medium confidence).”30
24. The world at 3.2°C is not one in which life as we know it today can be
sustained. This is confirmed by the IPCC:
“At global warming of 3°C, additional risks in many sectors and
regions reach high or very high levels, implying widespread
systemic impacts, irreversible change and many additional
adaptation limits… (high confidence)”31
25. Climate deferral flies in the face of the science, and therefore, as set out
below, it is not permitted by international law.
B. PARIS AGREEMENT AS A STRENGTHENED RESPONSE
26. As Mauritius and many others have pointed out, the Paris Agreement is
explicitly designed as a strengthened response to the threat of climate change,
in circumstances where the international community recognised that it was
not on track to avert that threat. Kenya has aptly described the Paris
Agreement as signalling “‘a tectonic shift’ in the international regulation of
climate change”.32 The fact that States, when adopting the Paris Agreement,
emphasised the urgent need to close the gap between what was required to
30 IPCC, Working Group III, “Mitigation of Climate Change”, AR6, SPM, C.1 (footnotes
omitted), available at:
https://www.ipcc.ch/report/ar6/wg3/downloads/report/IPCC_AR6_WGIII_SummaryForPolicyma
kers.pdf (last accessed 10 August 2024).
31 IPCC, AR6 SYR (Longer Report), p. 37, available at:
https://report.ipcc.ch/ar6syr/pdf/IPCC_AR6_SYR_LongerReport.pdf (last accessed 10 August
2024).
32 Written Statement of Kenya, para. 5.35.
20
prevent dangerous climate change, and what had been achieved thus far, is a
critical context for the interpretation of its provisions.33
27. As expressly stated in Article 2(1), the Paris Agreement is designed to
provide a more effective and ambitious response to the urgent threat posed
by dangerous climate change, while respecting and developing the core
principles of the UNFCCC.34 In this context, many participants have
highlighted the explicit requirements for Parties to demonstrate the ambition
and fairness of their NDCs as reflected in the decision by which the Paris
Agreement was adopted, as well as in the express provision for transparency
in Articles 4(13) and 13.35
28. The Paris Agreement strengthened response includes the following key
elements:
a. an express temperature goal (Article 2(1)(a));
b. a greater and explicit focus on adaptation and finance flows (Articles
2(1)(b) & (c), 7 and 9); and
33 UNFCCC, 21st Conference of the Parties, Adoption of the Paris Agreement (12 December
2015), FCCC/CP/2015/L.9/Rev.1, (hereinafter “COP21 Adoption of the Paris Agreement”),
Preamble, 9th Recital, available at: https://unfccc.int/resource/docs/2015/cop21/eng/l09r01.pdf
(last accessed 16 February 2024): “Emphasizing with serious concern the urgent need to address
the significant gap between the aggregate effect of Parties’ mitigation pledges in terms of global
annual emissions of greenhouse gases by 2020 and aggregate emission pathways consistent with
holding the increase in the global average temperature to well below 2°C above pre-industrial
levels and pursuing efforts to limit the temperature increase to 1.5°C above pre-industrial levels”.
34 Paris Agreement, Article 2(1): “This Agreement, in enhancing the implementation of the
Convention, including its objective, aims to strengthen the global response to the threat of climate
change, in the context of sustainable development and efforts to eradicate poverty…”. See also
Articles 3 and 4(3) of the Paris Agreement.
35 See e.g. the Written Statement of New Zealand, paras. 58-59.
21
c. a timetable for securing the peaking of emissions and what is
commonly referred to as “net zero” (Article 4(1), representing the deep
cuts in emissions that are required in order to meet the Article 2 goals
and those of the UNFCCC).
29. The momentum of this strengthened response is to be preserved through the
mechanism of the Global Stocktake (“GST”), the outcome of which:
“…shall inform Parties in updating and enhancing, in a nationally
determined manner, their actions and support in accordance with
the relevant provisions of [the Paris] Agreement, as well as in
enhancing international cooperation for climate action.”36
30. Many participants have referred to the outcome of the GST, adopted in 2023
at COP28 in Dubai, in which the Parties recognised: “the need for deep, rapid
and sustained reductions in [GHG] emissions in line with 1.5°C pathways.”37
This requires, inter alia, transitioning away from fossil fuels in energy
systems in a just, orderly and equitable manner “accelerating action in this
critical decade so as to achieve net zero by 2050 in keeping with the
science.”38 The Conference of the Parties has repeatedly referred to urgency
and expressed serious concern that:
“…2023 is set to be the warmest year on record and that impacts
from climate change are rapidly accelerating, and emphasize[d]
the need for urgent action and support to keep the 1.5°C goal
36 Paris Agreement, Article 14(3).
37 UNFCCC, First Global Stocktake (13 December 2023), available at:
https://unfccc.int/sites/default/files/resource/cma2023_L17_adv.pdf (last accessed 10 August
2024) (hereinafter “GST”). See e.g. the Written Statements of: Antigua and Barbuda (para. 284),
Grenada (para. 31), Latvia (para. 18), Indonesia (paras. 58-59), the Netherlands (para. 3.13), the
United Kingdom (para. 62) and the European Union (paras. 162-163).
38 GST, para. 28(d).
22
within reach and to address the climate crisis in this critical
decade”.39
31. Mauritius agrees with the many participants who have pointed to the dynamic
nature of the international climate regime and the elements which entail an
accelerated effort to meet an urgent threat.40 This dynamic element is
indicated in the express provision for ambition and progression, and the
requirement to act on the basis of the best available science (addressed in
paragraphs 9-25 above).41
C. DUE DILIGENCE
32. A great majority of participants in these proceedings have referred to the
obligation of due diligence in their submissions.42 The obligation of due
diligence in relation to climate change arises under relevant treaty regimes,
including the UNFCCC, the Paris Agreement and UNCLOS, as well as under
customary international law, principally through the duty of prevention. Due
39 Ibid., para. 5.
40 See e.g. the Written Statements of: Bahamas (para. 70), Colombia (paras. 2.4-2.13), Grenada
(para. 27), Kenya (paras. 3.14-3.17), Nauru (para. 11), New Zealand (para. 5), Peru (para. 63),
Romania (paras. 38-39), St Vincent and the Grenadines (para. 51), Tuvalu (paras. 22-24 & 62),
Uruguay (paras. 24-25 & 33), Vanuatu (paras. 94-101) and the African Union (para. 7).
41 Paris Agreement, Articles 3, 4, 7(5) and 14(1).
42 See e.g. the Written Statements of: Albania (paras. 71-82), Antigua and Barbuda (paras. 305-
337), Bangladesh (paras. 90-95), Belize (para. 35), Burkina Faso (para. 165), Cameroon (para. 13),
Chile (para. 89), China (para. 131), Colombia (paras. 3.13-3.30), Democratic Republic of the
Congo (paras. 134-165), Costa Rica (paras. 37-39), Denmark, Finland, Iceland, Norway &
Sweden (paras. 73-76), Ecuador (para. 3.23), Egypt (paras. 97-111), Ghana (para. 26), Grenada
(para. 41), Kenya (para. 5.9-5.13), Latvia (paras. 46 & 52-53), Marshall Islands (paras. 23 & 27),
Mexico (paras. 42-48), Nauru (paras. 28-33), the Netherlands (para. 3.66), the Philippines (para.
62-63), Romania (paras 75 & 90-104), Sierra Leone (para. 3.13-3.34), Seychelles (paras. 96, 101
& 124), Singapore (para. 3.2-3.20), Solomon Islands (paras. 153-160), South Africa (para. 77), Sri
Lanka (paras. 94-96), St Vincent and the Grenadines (para. 108), Switzerland (para. 47), Tonga
(paras. 146-154), Vanuatu (paras. 235 & 243), Vietnam (paras. 25 & 28), the African Union
(paras. 55, 90, 95-96 & 101), the European Union (paras. 81-87), OACPS (para. 96), and IUCN
(paras. 342-349).
23
diligence is central to the performance of specific obligations, including those
relating to environmental impact assessment (“EIA”), strategic
environmental assessment, and the scrutiny of decisions relating to finance
flows and adaptation.
33. In its Advisory Opinion, ITLOS stressed that:
“The content of an obligation of due diligence should be
determined objectively under the circumstances, taking into
account relevant factors. In many instances, an obligation of due
diligence can be highly demanding.” 43
34. Significantly, ITLOS rejected the argument of some States that due diligence
obligations are only ever obligations of conduct. Rather, the Tribunal
determined that due diligence obligations can be obligations of result where
the relevant legal obligation requires States to achieve a particular result.44
The Tribunal emphasised that due diligence is a “variable concept” which
evolves over time and depends to a significant degree on “scientific and
technological information, relevant international rules and standards, the risk
of harm and the urgency involved”.45 The work of the IPCC was relied upon
to reach the conclusion that the standard is a “stringent” one in light of the
urgency of achieving deep cuts to GHG emissions.46 The stringency of the
obligation in the context of transboundary pollution was found to be even
higher.47 ITLOS further stated that the implementation of the duty of due
diligence depends on States’ capabilities and resources, and those with
43 ITLOS Advisory Opinion, para. 257.
44 Ibid., para. 238.
45 Ibid., para. 239. See also: Mauritius Written Statement, paras. 83-85, 154(d) & 193-195.
46 ITLOS Advisory Opinion, para. 241.
47 ITLOS Advisory Opinion, para. 256: (“With respect to transboundary pollution affecting the
environment of other States, the standard of due diligence can be even more stringent”).
24
greater resources have a duty to do more than States with fewer resources.48
The reduction of GHG emissions was found to be a measure which was
necessary if States are to comply with their due diligence obligations.49
35. Mauritius submits that what is true in relation to the due diligence required
under UNCLOS is equally the case under UNFCCC and the Paris Agreement.
The factors relevant to the conduct of due diligence under the Paris
Agreement include:
a. the long-term temperature goal;
b. the express requirements for ambition and progression, which reflect
the urgent need to close the emissions and production gaps; and
c. the principle of equity.
36. These elements, in the light of the best available science, indicate that the
required standard of due diligence under the Paris Agreement is stringent.
Many States have recognised that the obligations of due diligence relevant to
climate change are informed by the evolving science.50 The science informs
the conduct of due diligence obligations under all branches of international
law relevant to climate change. The rate and scale of GHG emissions cuts
required to remain within the carbon budget and avoid overshoot are clearly
set out in the IPCC reports. Many participants have argued for an exacting
standard of due diligence, to avoid the grave risks of overshoot of targets and
48 Ibid., para. 241. See also: Mauritius Written Statement, paras. 118-121.
49 ITLOS Advisory Opinion, para. 243.
50 See e.g. the Written Statements of: Albania (paras. 72-82), Ecuador (paras. 3.23-3.24), Sierra
Leone (para. 3.14), Singapore (para. 3.8), Solomon Islands (para. 160), Switzerland (para. 42) and
Thailand (para. 14).
25
tipping points.51 In the context of due diligence, good faith requires that
investigations, assessments and actions must be informed by the best
available science and in full recognition of the urgency and scale of the risks
posed.
37. The principle of equity also informs the conduct of due diligence and requires
that developing countries are provided with the necessary support to conduct
effective due diligence. Equity and the principle of CBDRRC are addressed
in Mauritius’ Written Statement, and at paragraphs 59-73 below. 52
38. As many participants have indicated, the due diligence obligation means that
States are obliged by international law to regulate the conduct of private
actors – including the goods they manufacture and the services they provide
– who are subject to their jurisdiction and control, by putting in place laws,
policies and regulations, and to enforce them with the necessary vigilance.53
As noted by ITLOS: “[t]his obligation of due diligence is particularly relevant
in a situation in which the activities in question are mostly carried out by
private persons or entities.”54
51 See e.g. the Written Statements of: Seychelles (para. 96, “high standard of due diligence”),
Sierra Leone (para 3.41, by reference to the principle of “highest possible ambition”), IUCN (para.
39(i), “a significantly heightened level of due diligence”) and OACPS (para. 100, “stringent
standard”).
52 Mauritius Written Statement, paras. 118-121.
53 See e.g. the Written Statements of: Bahamas (paras. 191-197), Barbados (para. 163), Costa Rica
(para. 39), Dominican Republic (paras. 4.59 & 5.1), Ecuador (paras. 3.64-3.65, in the context of
the ‘polluter pays’ principle), Egypt (paras. 244-247), Kenya (para. 6.104), Namibia (paras. 132-
134), Solomon Islands (para. 200), the African Union (para. 208), and IUCN (para. 554).
54 ITLOS Advisory Opinion, para. 236.
26
39. Mauritius addressed the scope of this duty in its Written Statement,55 and in
the light of the submissions made by other participants, notes the following:
1. Temperature goal
40. As explained in paragraphs 15-28 above, in light of the best available science
it is clear that the international temperature goal is pivotal to the delivery of
all international climate goals, in particular the overall objective which is the
prevention of dangerous anthropogenic interference with the climate system
(Article 2 UNFCCC). As such, the 1.5°C temperature goal directly informs
the duty of due diligence.56 This has concrete and measurable implications
for compliance with the duty of due diligence: what is ‘due’ is to be assessed
in light of the science and the measurable steps required to meet the
temperature goal.57
41. Mauritius does not agree with those participants who have described the
temperature goal as aspirational or hortatory. Bearing in mind the scale of
additional and irreversible harm which will result if the 1.5°C goal is
overshot, and the measurable actions which have been identified as necessary
to give the best chance of meeting it, the 1.5°C temperature goal clearly
represents a viable and concrete standard framing the conduct of Parties to
the Paris Agreement.
42. Mauritius agrees with those who submit that the goal of reducing the global
average temperature as required by Article 2(1)(a) lies at the core of all
obligations of the Paris Agreement, with consequences under general
55 Mauritius Written Statement, paras. 189-199.
56 See also: ITLOS Advisory Opinion, para. 222.
57 As to the relationship between the 1.5°C goal and due diligence, see the Written Statements of
the Democratic Republic of the Congo (para. 208-210) and the African Union (para. 101).
27
international law and other specific legal regimes. It sets a binding goal and
quantifiable benchmark that all Member States are obliged to achieve
jointly.58 Mauritius submits that the temperature goal provides an objective
standard for measuring compliance with the good faith performance of
specific obligations under the Paris Agreement, including those contained in
Articles 4 and 9. In relation to Article 4 of the Paris Agreement, it is notable
that the very first words of sub-paragraph (1) refer directly to the long-term
temperature goal which thus frames the subsequent requirements as to the
peaking of emissions and the achievement of net zero, as well as the
associated obligations and requirements which follow in the subsequent text
of Article 4:
“In order to achieve the long-term temperature goal set out in
Article 2, Parties aim to reach global peaking of greenhouse gas
emissions as soon as possible, recognizing that peaking will take
longer for developing country Parties, and to undertake rapid
reductions thereafter in accordance with best available science,
so as to achieve a balance between anthropogenic emissions by
sources and removals by sinks of greenhouse gases in the second
half of this century, on the basis of equity, and in the context of
sustainable development and efforts to eradicate poverty.”59
43. Article 4(5) of the Paris Agreement provides for support to be provided to
developing countries, including financial support “for the implementation of
this Article” which again ties such support to the purpose of achieving the
long-term temperature goal. Finance related obligations in Article 9 are
considered in paragraphs 74-79 below, but it is important also to view those
obligations in the light of the long-term temperature goal and the need for
58 See e.g. the Written Statements of: Germany (para. 43), Ecuador (para. 3.77), Kenya (para.
5.36), Madagascar (paras. 25 & 42), Romania (para. 74), and IUCN (paras. 108-123).
59 Paris Agreement, Article 4(1) (emphasis added).
28
consistency with a low emissions pathway and climate resilient development
(Article 2(1)(c) of the Paris Agreement).
2. Ambition and progression
44. The express language of relevant treaties frames the conduct of due diligence.
Many participants have noted the references to ambition and progression in
Article 4(3) of the Paris Agreement.60 Mauritius considers that the language
relating to progression and ambition falls to be interpreted by reference to the
object and purpose of the Paris Agreement (Article 2), together with the
factual and scientific context of the current urgent threat. The requirements
of “highest possible ambition” and “progression” in Article 4(3) of the Paris
Agreement represent specific expressions of the general duty of good faith
reflected in Articles 26 and 31(1) of the Vienna Convention on the Law of
Treaties (“VCLoT”). These requirements are directly relevant to the
performance of specific obligations under the Paris Agreement, including the
conduct of due diligence. As some have noted, the language of Article 4(3)
of the Paris Agreement (“will”) is stronger than that used elsewhere (e.g.
“should” in Article 4(4)).
60 See e.g. the Written Statements of: Antigua and Barbuda (para. 358), Australia (para. 2.23),
Barbados (para. 207), China (paras. 47, 49, 54 & 56), Colombia (para. 3.41), Ecuador (para. 3.81),
Grenada (para. 31), Micronesia (para. 91), Marshall Islands (paras. 17 & 20), Samoa (para. 169),
Seychelles (paras. 72-77 & 150), St Lucia (para. 54), Tonga (para. 153), Vanuatu (paras. 319, 411,
414, 435, 441, 511 & 579), the African Union (paras. 104, 113, 132 & 205), the European Union
(paras. 144-154), and IUCN (paras. 37, 88, 93, 129, 132, 136-137, 140, 151, 303 & 370-376).
Article 4(3) of the Paris Agreement provides that: “Each Party’s successive [NDC] will represent a
progression beyond the Party’s then current [NDC] and reflect its highest possible ambition,
reflecting its common but differentiated responsibilities and respective capabilities, in the light of
different national circumstances.”
29
45. As many participants have also noted, the reference to CBDRRC in Article
4(3) of the Paris Agreement is a recognition that States should bear a fair
share of the mitigation burden, taking into account equitable considerations.
3. Nationally Determined Contributions (NDCs)
46. Most participants in these proceedings have considered the scope of States’
obligations relating to NDCs under the Paris Agreement, in particular relating
to mitigation of GHG emissions. Some have argued that elements of the
requirements relating to NDCs are non-binding, albeit that they must be
conducted in good faith.61 Mauritius submits that, while States enjoy a broad
degree of discretion as to the precise framing and content of their NDCs, that
discretion is not unlimited. Article 4(2) of the Paris Agreement mandates that:
“Each Party shall prepare, communicate and maintain successive
[NDCs] that it intends to achieve. Parties shall pursue domestic
mitigation measures, with the aim of achieving the objectives of
such contributions.”62
47. This necessarily entails a legal obligation to prepare, communicate and
maintain NDCs and to do so in good faith with the aim of achieving the
objectives therein. Good faith in this context is associated with acting on the
basis of the highest possible ambition and in the light of the best available
science, taking into account CBDRRC and obligations to provide support
(Article 9).
48. The exercise of discretion is framed by the principles laid down in the
UNFCCC and Paris Agreement, including precaution, prevention and
CBDRRC, together with ambition and progression. Mauritius agrees with
61 See e.g. the Written Statement of New Zealand, para. 54.
62 Paris Agreement, Article 4(2).
30
Ecuador and others that States’ NDCs must reflect their highest possible
ambition and be consistent with achieving the long-term temperature goal in
the light of the best available science.63 This has concrete implications given
that progress, or lack of it, towards achieving the temperature goal is
measurable at the global level and is accounted for in the mitigation pathways
identified by the IPCC.64 Taking into account the obligation of developed
States to take the lead in reducing emissions, and the principle of CBDRRC
more broadly (as discussed at paragraphs 59-73 below), the temperature goal
and global carbon budget have specific measurable implications for an
assessment as to whether NDCs are consistent with these requirements.
49. Mauritius submits that any regression of NDCs – such as a reduction in the
ambition of emission reduction targets – would breach the requirements of
Article 4(3) of the Paris Agreement. Furthermore, existing emission and
production gaps mean that regressive State action – for example to encourage
new fossil fuel production – whether expressly reflected in the NDC or (as is
more likely) simply left unaddressed, would undermine the achievement of
the temperature goal and is therefore inconsistent with the requirements of
Articles 3 and 4 of the Paris Agreement. Mauritius agrees with the many
participants who affirm that NDCs are informed by principles of equity and
CBDRRC, in relation to all obligations.65
63 Written Statement of Ecuador, para. 3.81.
64 The IPCC has stated that: “A substantial ‘emissions gap’ exists between global GHG emissions
in 2030 associated with the implementation of NDCs announced prior to COP26 and those
associated with modelled mitigation pathways that limit warming to 1.5°C (>50%) with no or
limited overshoot or limit warming to 2°C (>67%) assuming immediate action (high confidence)”
(footnote omitted). See: IPCC, AR6 SYR, SPM, A.4.3, available at:
https://www.ipcc.ch/report/ar6/syr/downloads/report/IPCC_AR6_SYR_FullVolume.pdf (last
accessed 10 August 2024).
65 See e.g. the Written Statement of Antigua and Barbuda (para. 276).
31
4. Environmental Impact Assessment
50. Having regard to the transparency obligations laid down in the Paris
Agreement,66 and the nature of information required, due diligence requires
States to assess all activities that may cause climate change, and to do so prior
to the authorisation of the activity. This also means that all potential
emissions, including those referred to as “scope 3 emissions”, must be
quantified and assessed as part of the cumulative impacts of relevant
projects.67
51. In this regard, ITLOS has determined that the provision for EIA under
UNCLOS (Article 206) encompasses:
“Any planned activity, either public or private, which may cause
substantial pollution to the marine environment or significant and
harmful changes thereto through anthropogenic GHG emissions,
including cumulative effects.”68
52. Mauritius submits that the requirement to assess cumulative effects applies
equally to obligations to conduct EIAs under the UNFCCC and Paris
Agreement and/or customary international law, particularly in light of the
importance of cumulative effects in the context of climate change.
66 Paris Agreement, Articles 4(8) & (13), 6(2), 7(5), 9(7), 11(1), 13 and 15(2).
67 Written Statement of Mauritius, para. 195. See also: Written Statement of Belize, paras. 37-63.
“Scope 3 emissions” encompass those not produced by the State/actor/project itself, but for which
the State/actor/project is indirectly responsible for in its wider value chain (including suppliers and
customers). See also the recent judgments of the UK and Norwegian Courts in relation to the need
to include scope 3 emissions in EIA: Greenpeace Nordic v The State of Norway (represented by
the Ministry of Petroleum and Energy), Case No 23-099330TVI-TOSL/05 and R (Finch on behalf
of the Weald Action Group) v Surrey County Council and others [2024] UKSC 20.
68 ITLOS Advisory Opinion, para. 367.
32
D. PHASING OUT FOSSIL FUELS
53. As to the urgent need to make deep reductions in GHG emissions in order to
meet the temperature goal, the science is clear: fossil fuels must be phased
out and States are obliged as a matter of general international law to transition
away from their use. In its Net Zero by 2050 Report, the IEA underlined that:
“Beyond projects already committed as of 2021, there are no new
oil and gas fields approved for development in our pathway, and
no new coal mines or mine extensions are required.”69
54. As noted by Dr Hansen, fossil fuel emissions increased by 0.9% in 2022 and
again by 1.1% in 2023.70 The safe level of atmospheric CO2 has already been
exceeded.71 According to the UNEP, “the world’s governments, still, in
aggregate, plan on increasing coal production out to 2030 and increasing oil
and gas production out to at least 2050.”72 Dr Hansen concludes that: “[t]hese
planned fossil fuel production increases are incompatible with an
international commitment to prevent dangerous climate change.”73
55. The urgent need to transition away from fossil fuels has been acknowledged
with increasing clarity by Parties to the Paris Agreement, including in the
GST.74 In addition to “accelerating action in this critical decade, so as to
69 IEA, “Net Zero by 2050: A Road map for the Global Energy Sector” (2021), available at:
https://www.iea.org/reports/net-zero-by-2050 (last accessed 10 August 2024), p.13.
70 Report of Dr James E. Hansen, p. 1, Annex 1.
71 Ibid., p. 2.
72 UNEP PGR, p. vii.
73 Report of Dr James E. Hansen, p. 3, Annex 1.
74 GST, para 5: “Expresses serious concern that 2023 is set to be the warmest year on record and
that impacts from climate change are rapidly accelerating and emphasizes the need for urgent
action and support to keep the 1.5 °C goal within reach and to address the climate crisis in this
critical decade.” See also paras. 15-17.
33
achieve net zero by 2050 in keeping with the science”, the GST also calls for
“[a]ccelerating efforts towards the phase-down of unabated coal power” and
the “[p]hasing out of inefficient fossil fuel subsidies that do not address
energy poverty or just transitions, as soon as possible.”75
56. The conclusions of the GST also note that “transitional fuels can play a role
in facilitating the energy transition while ensuring energy security”.76 Any
transition must ensure that States remain within the existing global carbon
budget. Effective implementation of the Paris Agreement in good faith means
that the phasing out of fossil fuels cannot be deferred in such a way as to
threaten achievement of the temperature goal and related goals. The
obligation of good faith requires the application of treaties in a manner that
does not frustrate their object and purpose.77 In this context, as many
participants have highlighted, States’ obligations to reduce GHG emissions
under Article 4 of the Paris Agreement must contribute to the collective
achievement of the temperature goal. Mauritius adds, however, that Parties
must also ensure that other actions, including the channelling of finance
flows, do not negate the efforts made by Parties in limiting their national
GHG emissions.78 Finance is addressed below at paragraphs 74-79.
57. In light of Articles 4(9) and 14(3) of the Paris Agreement, Parties are required
to ensure that their NDCs are informed by the outcome of the GST.
Furthermore, Parties have agreed that in their 2025 NDCs, they must provide
information on how the GST outcome has informed the preparation of their
75 GST, para. 28. See also Mauritius Written Statement, para. 127.
76 GST, para. 29.
77 See the Written Statement of New Zealand, para. 51.
78 Article 2(1)(c) of the Paris Agreement.
34
updated NDCs.79 In 2025, all Parties must communicate an NDC that
contains a country-specific breakdown of the global efforts on renewable
energy, transitioning away from fossil fuels, protecting nature, oceans and
biodiversity, and more. It follows that the conclusions of the GST relating to
fossil fuels must be taken into account by Parties.
58. Most participants in these proceedings have acknowledged the need to
transition away from fossil fuels.80 This general and explicit acknowledgment
must be reflected in the analysis of relevant legal obligations, taking fully into
account the scale and urgency of the threat posed by continued GHG
emissions to international climate goals. As explained in Mauritius’ Written
Statement, the following obligations are directly relevant to the phasing out
of fossil fuels:
a. the need to phase out fossil fuels on the basis of the science presented
by the IPCC and UNEP as regards the scale of reductions required and
the timescale for implementing those reductions, having regard to the
rapidly diminishing carbon budget;
b. the obligation to ensure that finance flows are consistent with low
emission pathways, recognising that, as indicated by UNEP and the
79 UNFCCC, Decision 4/CMA.1, “Further guidance in relation to the mitigation section of
decision 1/CP.21” (19 March 2019), UN Doc FCCC/PA/CMA/2018/3/Add.1, Annex I, para 4(c),
available at: https://unfccc.int/sites/default/files/resource/4-CMA.1_English.pdf (last accessed 10
August 2024).
80 See e.g. the Written Statements of: Albania (para. 78), Antigua and Barbuda (paras. 117 & 481-
482), Australia (para. 2.53), Bahamas (para. 184), Bangladesh (para. 10), Colombia (paras. 2.38)
& 4.10), Costa Rica (paras. 102 & 110), Democratic Republic of the Congo (paras. 211-212),
Dominican Republic (para. 4.62), Egypt (para. 137), Kenya (paras. 6.120-6.124), Ecuador (para.
3.30), Solomon Islands (para. 18), St Vincent and the Grenadines (para. 51), Tuvalu (paras. 7, 68
& 105), United Arab Emirates (para. 61), United States of America (para. 3.39), Vanuatu (para.
511), European Union (para. 162), Melanesian Spearhead Group (para. 315), the African Union
(paras. 107-108), COSIS (paras. 56-62), OACPS (para. 119) and IUCN (Appendix II, paras. 17-
18).
35
IEA, investment in new fossil fuel production is inconsistent with
meeting the Paris temperature goal; and
c. taking the above obligations into account, States, in particular
developed States and major emitters, should refrain from issuing new
licences for fossil fuel production.
E. CBDRRC AND EQUITY
59. Many participants have pointed out that unequal contributions to GHG
emissions and climate change, as well as unequal and unsustainable patterns
of consumption, are an important part of the context for considering legal
obligations, both under the Paris Agreement itself and under customary
international law.81
60. The principle of CBDRRC reflects an acceptance, in accordance with the
principle of equity, that the States which have historically benefited from
fossil fuel based development have a responsibility to support other States in
making a rapid transition away from fossil fuels. As explained in Mauritius’
Written Statement, the carbon budget is finite, diminishing and must be
shared equitably.82 As Thailand states, the best possible efforts of a
developing State and a developed State are not the same and this means that
the standard of due diligence should exhibit a degree of flexibility for States
81 See e.g. the Written Statements of: Brazil (para. 81), Ecuador (para. 1.9), New Zealand (para.
28(a)), Solomon Islands (para. 66) and Vanuatu (paras. 169-170). Some States have referred to
luxury emissions as compared to survival emissions to reflect this inequality, see e.g. the Written
Statements of China (paras. 30 & 60) and India (para. 37).
82 Mauritius Written Statement, paras. 74-82 & 118-121.
36
to use the “best practicable means at their disposal and in accordance with
their capabilities”.83
61. The IPCC has stated that: “[e]quity remains a central element in the UN
climate regime, notwithstanding shifts in differentiation between States over
time and challenges in assessing fair shares.”84 As many participants have
highlighted, the inclusion of the text “in the light of national circumstances”
in the Paris Agreement introduces a dynamic element as to the requirements
imposed on Parties.85 However, it is important to note that this language does
not undercut the provisions of the UNFCCC and Paris Agreement that impose
specific obligations on developed States.
62. The Paris Agreement recognises “the intrinsic relationship that climate
change actions, responses and impacts have with equitable access to
sustainable development and eradication of poverty”.86 The Agreement
expressly refers to sustainable development and the need to eradicate poverty
as the context for its goals and obligations.87 The IPCC has confirmed that
exceeding the temperature goal will increase the number of people living in
83 Written Statement of Thailand, para. 20 (by reference to Article 194 of UNCLOS).
84 IPCC, AR6 SYR, SPM, C.5.1, available at:
https://www.ipcc.ch/report/ar6/syr/downloads/report/IPCC_AR6_SYR_SPM.pdf (last accessed 11
August 2024).
85 See e.g. the Written Statements of: China (para. 64), the Netherlands (para. 3.6), New Zealand
(para. 47), the European Union (paras. 68, 83, 144, 146, 166, 198-210 & 362) and IUCN (para.
133). Article 4(3) of the Paris Agreement provides that: “Each Party’s successive nationally
determined contribution will represent a progression beyond the Party’s then current nationally
determined contribution and reflect its highest possible ambition, reflecting its common but
differentiated responsibilities and respective capabilities, in the light of different national
circumstances.”
86 Paris Agreement, Preamble, 8th recital.
87 Ibid., Articles 2(1), 4(1) & 6(8).
37
poverty and undermine achievement of the Sustainable Development Goals.88
Preventing dangerous climate change and achieving sustainable development
are therefore not competing goals, as some have argued. In fact, the opposite
is the case. The IPCC has concluded with high confidence that:
“Accelerated and equitable action in mitigating and adapting to
climate change impacts is critical to sustainable development.
Mitigation and adaptation actions have more synergies than
trade-offs with Sustainable Development Goals…”.89
63. It follows that climate goals and development goals are necessarily mutually
supportive and interdependent.
64. In 2018, the IPCC stated that:
“At approximately 1.5°C of global warming (2030), climate
change is expected to be a poverty multiplier that makes poor
people poorer and increases the poverty head count […]. Poor
people might be heavily affected by climate change even when
impacts on the rest of population are limited.”90
65. The eradication of poverty will be jeopardised if the 1.5°C temperature goal
is exceeded. That is why the Paris Agreement meshes the eradication of
88 IPCC, “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” (2018) (hereinafter “SR1.5”), chapter 5,
“Sustainable Development, Poverty Eradication and Reducing Inequalities”, available at:
https://www.ipcc.ch/sr15/ (last accessed 11 August 2024).
89 IPCC, AR6 SYR, SPM, C.4.
90 IPCC, SR 1.5, chapter 3, “Impacts of 1.5°C global warming on natural and human systems”,
3.4.10.1, p. 244, available at:
https://www.ipcc.ch/site/assets/uploads/sites/2/2022/06/SR15_Chapter_3_LR.pdf (last accessed
11 August 2024).
38
poverty and sustainable development with the science-based climate goals.
As the IPCC has also confirmed with high confidence that:
“Adaptation and mitigation actions that prioritise equity, social
justice, climate justice, rights-based approaches, and inclusivity,
lead to more sustainable outcomes, reduce trade-offs, support
transformative change and advance climate resilient
development.”91
66. The CBDRRC principle requires that, in pursuit of their common aims under
Article 2 of the UNFCCC and Paris Agreement, States cooperate and
contribute to the shared effort in accordance with their differentiated
responsibility and respective capabilities. In complying with their obligations
under the Paris Agreement, States are under a duty to allocate the burden of
GHG reductions equitably while ensuring that the carbon budget is not
exceeded. This has implications for the allocation of support, compensation,
technology transfer and potentially for other areas including contributions to
the Loss and Damage Fund, debt relief and the terms of trade.92
67. Mauritius notes that in the context of NDCs, Article 4(5) of the Paris
Agreement provides that:
“Support shall be provided to developing country Parties for the
implementation of this Article, in accordance with Articles 9, 10
and 11, recognizing that enhanced support for developing country
Parties will allow for higher ambition in their actions.”93
91 IPCC, AR6 SYR, SPM, C.5.2.
92 See: African Leaders Nairobi Declaration on Climate Change and Call to Action (2023), para.
52, available at:
https://www.afdb.org/sites/default/files/2023/09/08/the_african_leaders_nairobi_declaration_on_c
limate_change-rev-eng.pdf (last accessed 11 August 2024). See also the Written Statements of
Barbados (paras. 295 & 322) and Kenya (para. 6.123).
93 Paris Agreement, Article 4(5).
39
68. An assessment of a State’s implementation of its obligations must take into
account its resources and the extent to which it has received financial and
technical support, whilst also recognising that each State has an obligation to
act on the basis of its highest possible ambition.
69. Mauritius notes ITLOS’ finding that, under UNCLOS, States with greater
capabilities and sufficient resources are required to do more than States “not
so well placed”.94 Nonetheless, even the latter are required to do whatever
they can in accordance with their capabilities and available resources to
prevent, reduce and control marine pollution from anthropogenic GHG
emissions.95
70. Some argue that the Paris Agreement aims to secure for developing country
Parties an equitable share of the “remaining carbon budget”.96 Mauritius
notes that, while science dictates the size of the remaining carbon budget, the
principles of equity and CBDRRC cannot expand that budget. Equity and
CBDRRC operate to address the iniquities that arise from historic disparities
in the share of the budget taken up by States. These principles require
developed States to take the lead in cutting emissions, while also providing
support for developing States, in particular the most vulnerable, to ensure a
just transition and climate resilience. Some States have pointed to a “fair
shares” approach under which those States which have already used their
“fair share” of emissions space should also discharge their “fair share” of the
94 ITLOS Advisory Opinion, para. 241.
95 Ibid.
96 See e.g. the Written Statement of United Arab Emirates, para. 149.
40
effort to address climate change by taking radical and swift action to curb
emissions.97
71. Mauritius submits that equity, as an integral part of the legal framework,
requires a fair allocation of effort within the timeframes and scale of action
indicated by the science.98 The principle of equity requires that States
urgently review the extent to which rising emissions reinforce or perpetuate
inequality and unsustainable consumption patterns.
72. The principles of equity and CBDRRC are not merely aspirational. They have
real world measurable implications for the implementation of the
international climate regime, including in the context of customary
international law and other treaty regimes. These two principles inform the
following obligations:
a. The obligation of developed States to take the lead in mitigation
(Article 4(4) of the Paris Agreement): both the UNFCCC and Paris
Agreement recognise that enhanced support for developing country
Parties will allow for higher ambition in their actions (Article 4(5) of
the Paris Agreement). Further, Article 4(7) of the UNFCCC provides
that:
“The extent to which developing country Parties will
effectively implement their commitments under the
97 See e.g. the Written Statements of: Egypt (para. 64), Solomon Islands (paras. 98 & 244) and
Vanuatu (paras. 415, 440-441 & 520).
98 In the context of the continuing increase in global GHG emissions over 2010-2019, the IPCC’s
AR6 refers to: “unequal historical and ongoing contributions arising from unsustainable energy
use, land use and land-use change, lifestyles and patterns of consumption and production across
regions, between and within countries, and between individuals…”. See: IPCC, AR6 SYR, Longer
Report, at 2.1, p.6, available at:
https://report.ipcc.ch/ar6syr/pdf/IPCC_AR6_SYR_LongerReport.pdf (last accessed 11 August
2024).
41
Convention will depend on the effective implementation by
developed country Parties of their commitments under the
Convention related to financial resources and transfer of
technology and will take fully into account that economic
and social development and poverty eradication are the first
and overriding priorities of the developing country
Parties.”99
b. The obligation of developed States to provide financial and technical
assistance to developing States, in particular the most vulnerable and
SIDS, in order to meet their development goals whilst also contributing
to their shared goal of preventing dangerous climate change (Articles
9, 10 and 11 of the Paris Agreement).
c. The obligation of developed States to support developing States in
increasing their resilience and reducing vulnerability in the context of
adaptation, particularly given that they include the States most
vulnerable to the impacts of climate change even though they have
contributed the least to the problem (Articles 7(6) and 9(1) of the Paris
Agreement).
73. Closely associated with the implications of the principles of equity and
CBDRRC are the obligations relating to finance flows (see below).
F. FINANCE
74. Mauritius joins the participants, including Mexico and many others, who
stress the importance of accessible, fair, and transparent climate finance for
developing countries.100
99 UNFCCC, Article 4(7).
100 See e.g. the Written Statements of: Antigua and Barbuda (para. 505), China (para. 54, 66 &
73), Egypt (paras. 148, 165, 169-189 & 212-227), Mexico (para. 35), Micronesia (paras. 67-68),
42
75. Parties to the Paris Agreement recognised the importance of redirecting
finance flows by including this as one of the three key goals enshrined in
Article 2(1). Article 2(1)(c) of the Paris Agreement reflects the need to
redirect finance flows away from high emitting energy sources and into
renewables.
76. Mauritius recalls that Parties have agreed that they should phase out
“inefficient fossil fuel subsidies that do not address energy poverty or just
transitions, as soon as possible.”101 Mauritius agrees with the many
participants who have identified this as a key obligation in light of the
evidence as to the extent to which finance continues to be directed into fossil
fuels in such a way as to undermine progress towards the 1.5°C temperature
goal. Mauritius notes that the UNEP PGR indicates that, of the 20 countries
profiled: 17 continue to promote, subsidise, support, and plan on the
expansion of fossil fuel production.102 This conduct is not consistent with
achievement of the goal laid down in Article 2(1)(c) of the Paris
Agreement.103
77. Notwithstanding Articles 2(1)(c) and 9 of the Paris Agreement, and repeated
pledges of financial support, including at the adoption of the Agreement
itself, there remains a significant and longstanding finance gap, as many
participants have emphasised. In the 2023 Nairobi Declaration on Climate
Change and Call to Action, African Heads of State and Government called
New Zealand (para. 63), Solomon Islands (paras. 65 & 109-113), St Lucia (para. 59), Timor-Leste
(paras. 168-175), Tonga (paras. 199 & 204-206), Uruguay (paras. 125-132) and the African Union
(paras. 142-163).
101 GST, para 28(d).
102 UNEP PGR, available at: https://productiongap.org/wpcontent/
uploads/2023/11/PGR2023_web_rev.pdf (last accessed 11 August 2024).
103 Ibid., p. 5.
43
on States to honour the commitment to provide $100 billion in annual climate
finance, as promised at the 2009 Copenhagen Conference.104
78. Express provision is made to address the situation of SIDS and other
vulnerable States, including in Article 4(9) of the UNFCCC and Article 9(4)
of the Paris Agreement.105
79. In addition to specific treaty-based obligations, the general duty of
cooperation is also relevant in this context, as Barbados and others have
argued:
“…States responsible for the acceleration of climate change have
a duty to finance adaption and mitigation efforts of small island
States. The obligation to cooperate, in context, also implies an
obligation to finance adaption and mitigation efforts of small
island States.”106
G. ADAPTATION
80. Many participants, including Mauritius, have included detailed analysis of
the way in which climate change will adversely impact their people,
environments, and cultural and economic lives. The Paris Agreement called
for urgent measures of adaptation, particularly for developing States and
those most vulnerable to the impacts of climate change. A key aspect of the
strengthened response was the adoption of a new global goal on adaptation in
Article 2(1)(b) and specific provision in Article 7. Recurrent themes in the
Written Statements include the dire implications for fragile ecosystems,
104 Nairobi Declaration on Climate Change and Call to Action (2023), available at:
https://www.afdb.org/sites/default/files/2023/09/08/the_african_leaders_nairobi_declaration_on_c
limate_change-rev-eng.pdf (last accessed 11 August 2024).
105 See: Mauritius Written Statement, para. 112.
106 Written Statement of Barbados, para. 216.
44
including coral reefs, the undermining of food security, the erosion of coastal
territory, the threat posed to communities and workers by extreme events, and
the displacement of people. All of these impacts are evidenced in the reports
of the IPCC and the Court has before it a detailed and deeply disturbing
picture of the current and future situation presented by affected States
themselves.107
81. The obligations relating to finance (addressed in paragraphs 74-79 above) are
of critical importance in relation to the current adaptation gap as indicated in
the title of UNEP’s 2023 Adaptation Gap Report: “Underfinanced.
Underprepared. Inadequate investment and planning on climate adaptation”
(“UNEP AGR”).108 The Foreword to the UNEP AGR refers to a new finance
gap which:
“…results from growing needs coupled with adaptation finance
flows to developing countries declining 15 per cent in 2021 to
around US$21 billion. Considering that the finance needed to
implement domestic adaptation plans in developing countries is
currently estimated at US$387 billion per year until 2030 – most
of which will require international support to deliver – this is a
hugely worrying deceleration.”109
107 To take just one example: “Given the sensitivity of corals to heat stress, even short periods of
overshoot (i.e., decades) are expected to be extremely damaging to coral reefs. Losing 70-90% of
today’s coral reefs, however, will remove resources and increase poverty levels across the world’s
tropical coastlines, highlighting the key issue of equity for the millions of people that depend on
these valuable ecosystems”. See: IPCC, SR 1.5, chapter 3, “Impacts of 1.5°C global warming on
natural and human systems”, p. 230, available at:
https://www.ipcc.ch/site/assets/uploads/sites/2/2022/06/SR15_Chapter_3_LR.pdf (last accessed
11 August 2024).
108 UNEP, “The Adaptation Gap Report 2023: Underfinanced. Underprepared. Inadequate
investment and planning on climate adaptation”, available at:
https://www.unep.org/resources/adaptation-gap-report-2023 (last accessed 11 August 2024). The
adaptation finance gap is defined as the difference between the estimated costs of meeting a given
adaptation target and the amount of finance available for adaptation (see pp. xv & 31).
109 Ibid., p. xi.
45
82. The UNEP AGR identifies the implementation of Article 2(1)(c) of the Paris
Agreement as one of the ways of addressing the finance gap: “[a]lthough a
global goal, its implementation offers developing countries the potential to
help to close the adaptation gap…”.110
83. Parties to the Paris Agreement have recognised the importance of support for,
and international cooperation on, adaptation efforts and the importance of
taking into account the needs of developing country Parties, especially those
that are particularly vulnerable to the adverse effects of climate change
(Article 7(6)). It also provides for: “[c]ontinuous and enhanced international
support” to be provided to developing country Parties for the implementation
of Articles 7(7), (9)-(10) and (11).111 It is abundantly clear, however, that
current levels of support are not adequate to support those States most
vulnerable to climate change and that developed States are not meeting their
obligations of cooperation and support.
H. HUMAN RIGHTS
84. Most participants (including Mauritius) have recognised that human rights
obligations inform and strengthen States’ obligation to protect the climate
110 Ibid., p. 57.
111 Paris Agreement, Article 7(13).
46
system, including the right to self-determination,112 the right to life,113 the
right to health,114 the rights to food and water,115 the right to a clean, healthy
112 See e.g. the Written Statements of: Albania (para. 96), Antigua and Barbuda (para. 195),
Bahamas (paras. 154-156), Bangladesh (paras. 120-122), Burkina Faso (paras. 201 & 208-210),
Cook Islands (paras. 342-354), Costa Rica (para. 72), Dominican Republic (paras. 4.43 & 5.1),
Kenya (paras. 5.66-5.68), Liechtenstein (paras. 27-31), Madagascar (paras. 59-60), Micronesia
(para. 82), Nauru (para. 40), Philippines (para. 106), Sierra Leone (paras. 3.88-3.92), Singapore
(para. 3.81), Solomon Islands (para. 172), St Vincent and the Grenadines (para. 109), Timor-Leste
(paras. 333-345), Tuvalu (paras. 75-96), Vanuatu (para. 302), the European Union (paras. 237-
238), COSIS (paras. 74-78), OACPS (paras. 64-67), Melanesian Spearhead Group (paras. 233-
237) and the African Union (para. 198).
113 See e.g. the Written Statements of: Albania (para. 96), Antigua and Barbuda (para. 190),
Australia (para. 3.61), Bahamas (paras. 145-146), Bangladesh (para. 108), Burkina Faso (paras.
195-219), Democratic Republic of the Congo (paras. 145-157), Denmark, Finland, Iceland,
Norway and Sweden (paras. 78-79), Egypt (para. 211), Kenya (para. 5.54), Ecuador (para. 3.109),
Indonesia (para. 36), Liechtenstein (para. 36), Marshall Islands (paras. 47-48), Namibia (paras.
111-112), the Netherlands (paras. 3.75 & 4.24), Philippines (para. 106), Portugal (para. 74), Sierra
Leone (para. 3.62), Singapore (para. 3.77), Seychelles (para. 145), Solomon Islands (para. 165),
Sri Lanka (para. 89), Switzerland (para. 59), Uruguay (para. 113), Vanuatu (para. 346), the
European Union (para. 233), Melanesian Spearhead Group (para. 265), IUCN (para. 499) and the
African Union (para. 188).
114 See e.g. the Written Statements of: Antigua and Barbuda (para. 193), Australia (para. 3.61),
Bangladesh (para. 109), Burkina Faso (paras. 195-219), Republic of Korea (para. 29), Madagascar
(para. 61), Namibia (para. 107), Philippines (para. 196), Portugal (para. 75), Sierra Leone (para.
3.69), Seychelles (para. 145), Solomon Islands (para. 198), Switzerland (para. 59), Vanuatu (para.
375), European Union (para. 234), and the African Union (paras. 210-211).
115 See e.g. the Written Statements of: Albania (para. 96), Antigua and Barbuda (paras. 191-194),
Bahamas (paras. 150-153), Barbados (para. 201), Bangladesh (para. 108), Egypt (para. 227),
Kenya (paras. 5.58 & 5.62), Liechtenstein (para. 42), Namibia (para. 89), Philippines (para. 106),
Portugal (para. 75), Seychelles (para. 145), Sierra Leone (para. 3.80), Singapore (paras. 3.78-
3.79), Switzerland (para. 59), Tonga (para. 262), Vanuatu (paras. 367-369) and the African Union
(para. 188).
47
and sustainable environment,116 and the overarching principles of equality
and non-discrimination.117
85. Participants (including Mauritius) have further recognised that insofar as the
climate science forms the bedrock of the 1.5℃ temperature goal, this target
also has a bearing on the content of all climate related obligations, including
international human rights obligations. The scientific evidence demonstrates
that a failure to reach the agreed target will have severe effects on human
rights.118
86. In accordance with the approach adopted by the majority of participants,
Mauritius invites the Court to confirm that international human rights
obligations must be integrated into climate change obligations.119 The link
with human rights obligations has been recognised by Parties to the Paris
Agreement and UNFCCC,120 the UN Secretary General,121 and the UN
116 See e.g. the Written Statements of: Albania (para. 96), Antigua and Barbuda (paras. 182-185),
Argentina (para. 38), Bangladesh (para. 110), Barbados (paras. 160-162), Bolivia (para. 17),
Colombia (paras. 2.60-2.66), Democratic Republic of the Congo (paras. 145-157), Dominican
Republic (paras. 4.43 & 5.1), Costa Rica (paras. 82-83), Ecuador (paras. 3.106-3.108), El Salvador
(para. 42), India (para. 79), Iran (para. 139), Kenya (para. 5.73), Liechtenstein (para. 45),
Madagascar (para. 61), Marshall Islands (paras. 85-86), Mexico (paras. 95-103), Micronesia (para.
78), Namibia (para. 121), the Netherlands (paras. 3.33-3.34), Seychelles (paras. 143-44), Slovenia
(para.17), Solomon Islands (paras. 174-179), Spain (para. 15), Switzerland (para. 60), Tuvalu
(para. 100), Vanuatu (para. 389), the European Union (para. 258), Melanesian Spearhead Group
(para. 283) and the African Union (para. 192).
117 See e.g. the Written Statements of: Albania (para. 106), Chile (para. 68), Colombia (paras.
2.58-2.59), Egypt (paras. 229-243), Germany (paras. 114-116), Micronesia (paras. 81-87), Nepal
(para. 33), Thailand (paras. 27-28) and OACPS (para. 84).
118 Mauritius Written Statement, paras. 54-85. See also: Report of Dr James E. Hansen, Annex 1.
119 Mauritius Written Statement, paras. 155-165.
120 Paris Agreement, Preamble, 7th recital; UNFCCC, Report of the Conference of the Parties on its
16th session, held in Cancun from 29 November to 10 December 2010, Decision 1/CP.16, p. 4,
available at: https://unfccc.int/resource/docs/2010/cop16/eng/07a01.pdf (last accessed 11 August
2024).
121 UN Secretary-General, “The highest aspiration: a call to action for human rights”, remarks
made to the Human Rights Council on 24 February 2020, available at:
48
Human Rights Council.122 In light of the potential devastating consequences,
a failure to comply with the temperature goal and related obligations
contained in the UNFCCC and Paris Agreement may also entail a breach of
States’ international human rights obligations.
87. In its Advisory Opinion, ITLOS unambiguously placed the principle of
systemic integration at the heart of its analysis, determining that “UNFCCC
and the Paris Agreement, as the primary legal instruments addressing the
global problem of climate change, are relevant in interpreting and applying
the Convention…”.123 The Tribunal added that: “subject to article 293 of
[UNCLOS], the provisions of the Convention and external rules should, to
the extent possible be interpreted consistently.”124 Accordingly, ITLOS
proceeded to interpret States’ obligations under UNCLOS by reference to
several other treaties.
88. The Tribunal’s application of the principle of systemic integration has solid
foundations in international law.125 The principle of systemic integration has
long formed an important part of the rules concerning the interpretation of
treaties, encapsulated in Article 31(3)(c) of the VCLoT. As noted in
https://www.un.org/peacebuilding/sites/www.un.org.peacebuilding/files/documents/2020_sg_call_
to_action_for_hr_the_highest_aspiration.pdf (last accessed 11 August 2024).
122 UN Human Rights Council, resolution 53/6 (19 July 2023), available at:
https://www.ohchr.org/en/hr-bodies/hrc/regular-sessions/session53/res-dec-stat (last accessed 11
August 2024).
123 ITLOS Advisory Opinion, para. 222. See also: Mauritius Written Statement, para. 42.
124 ITLOS Advisory Opinion, para. 136.
125 Mauritius Written Statement, paras. 144-147.
49
Mauritius’ Written Statement, the International Law Commission (“ILC”)
has also endorsed the principle of systemic integration.126
89. ITLOS also stressed that the “coordination and harmonization” of different
international obligations touching on the same issue is vital in establishing a
unified and coherent approach to the obligations of States in relation to
climate change.127 Any other approach risks creating a situation whereby the
ultimate policy aims of multilateral treaties (such as the UNFCCC and Paris
Agreement) are undermined due to uncertainty as to which treaty or
obligation takes precedence.
90. Accordingly, Mauritius considers that obligations contained in the UNFCCC
and Paris Agreement, as informed by the best available science, guide the
identification and application of international human rights obligations. By
the same token, international human rights law informs the legal content of
the climate change regime as well as the legal consequences that flow from a
failure to meet climate change obligations.
I. CUSTOMARY INTERNATIONAL LAW
91. Mauritius agrees with Switzerland, Belize and others, that customary
international law is supplemented – but not superseded – by international
treaties enacted in the field of climate protection and, to a certain extent,
human rights.128 Mauritius agrees with Switzerland that participation in the
UNFCCC and Paris Agreement is not necessarily sufficient to ensure
126 Fragmentation of International Law, Report of the Study Group of the ILC, 2006, p. 8;
Guideline 9 of the 2021 ILC Guidelines on the Protection of the Atmosphere. See also: Mauritius
Written Statement, paras. 147 & 163.
127 ITLOS Advisory Opinion, para. 130.
128 Written Statement of Switzerland, para. 13; Written Statement of Belize, para. 36.
50
compliance with customary law obligations and that a case-by-case
assessment is required of the measures taken in response to risks in order to
ascertain compliance with customary obligations.129
92. Some participants seek to persuade the Court that treaty obligations under the
international climate regime exhaust the obligations placed on States in
relation to climate change, effectively superseding the customary
international duty of prevention.130 Mauritius does not share this view. This
is for the following reasons:
a. There is no indication in the language of the UNFCCC or the Paris
Agreement that these treaties are intended to displace other relevant
international obligations, whether under treaties such as UNCLOS or
under customary international law.
b. In the context of an urgent and existential threat to the lives of many
millions of people, to the very existence of a number of States, as well
as to entire ecosystems and species, it is difficult to see a basis for any
treaty to displace the existence of a general obligation under
international law on each and every State to prevent such catastrophic
harm.
93. If implementation of the UNFCCC and Paris Agreement serve to avert the
threat posed by climate change, the customary duty of prevention may not
need to be invoked. But if it does not, then the need for reliance on customary
international law becomes evident. In circumstances where the current treaty
129 Written Statement of Switzerland, para. 70.
130 See e.g. the Written Statements of: New Zealand (para. 105), the Russian Federation (pp. 8-9,
arguing the principle of prevention is subsidiary to the climate treaty regime), the United States of
America (generally) and the United Arab Emirates (in relation to prevention).
51
regime has not yet succeeded in putting the world on track to protect the
climate system from GHG emissions, and the window for doing so is rapidly
closing, the customary duty of prevention remains relevant and applicable.
94. Mauritius considers that this issue cannot be resolved through recourse to the
rule on lex specialis. In this context, ITLOS confirmed that UNCLOS and the
Paris Agreement are separate agreements with separate sets of obligations
and that the Paris Agreement is not lex specialis to UNCLOS.131
95. No State would become party to a climate treaty, the full performance of
which would nevertheless fail to prevent its own disappearance and, at the
same time, abandon the protection of customary international law. Rather, the
correct approach is one of systemic integration through which the various
treaty obligations and customary rules are interpreted in a harmonious and
mutually reinforcing manner (see paragraph 88 above).
96. This is particularly the case when the principal treaty in question, the Paris
Agreement, is stated to be a strengthened response to the threat of climate
change. The Paris Agreement must thus be interpreted and applied in a
manner that is strictly consistent with respect for international obligations in
other branches of international law. It cannot be interpreted as diminishing or
excluding those obligations. The real issue dividing States, in Mauritius’
view, is the degree to which the Paris Agreement imposes obligations which
are capable of preventing the harm threatened by climate change (as opposed
to whether such obligations are imposed at all).
131 ITLOS Advisory Opinion, para. 224.
52
1. Prevention
97. A small minority of participants argue that the customary duty of prevention
does not apply to climate change. Mauritius agrees with the majority of
participants, who take the view that the well-established customary obligation
of prevention, which requires States to take measures to avoid harming the
environment of other States and the environment beyond national
jurisdiction, applies to harm caused to the global climate system.132
98. Mauritius also agrees with those who argue that the principle of prevention
requires, as a minimum, that States adopt and effectively implement all the
necessary measures at their disposal to reduce GHG emissions. This
obligation applies to all sectors of the economy, but particularly those
contributing the most to GHG emission. What is “necessary” is informed by
the best available science, including as to the scale and timing of emission
reductions needed to align with the temperature goal.
99. This approach is consistent with that adopted by ITLOS in its Advisory
Opinion. The Tribunal determined that “necessary measures” taken under
Article 194(1) of UNCLOS must be determined objectively, noting that many
participants in the ITLOS proceedings had emphasised the importance of
objectively determining such measures, indicating that “the science is
132 See e.g. the Written Statements of: Albania (para. 65), Antigua and Barbuda (paras. 300-304),
Bahamas (para. 92), Bangladesh (para. 88), Belize (para. 31), Brazil (para. 70), Burkina Faso
(para. 175), Costa Rica (para. 44), Dominican Republic (paras. 4.31 & 5.1), Ecuador (para. 3.25),
Egypt (para. 88), Ghana (para. 23), Grenada (para. 38), Indonesia (para. 60), Kenya (para. 5.8),
Republic of Korea (paras. 33-37), Latvia (paras. 58-60), Madagascar (para. 34), Marshall Islands
(paras. 22-27), Mexico (paras. 40-47), Micronesia (para. 62), Nauru (para. 26), Nepal (para. 26),
the Netherlands (para. 3.65), Palau (para. 14), Pakistan (para. 29), Philippines (para. 55), Romania
(para. 98), Samoa (paras. 100-130), Seychelles (para. 100), Sierra Leone (para. 3.10), Singapore
(para. 3.1), Solomon Islands (paras. 146-152), South Africa (para. 74), St Lucia (paras. 66-68), Sri
Lanka (para. 95), Switzerland (para. 36), Thailand (para. 9), Uruguay (para. 88), Vanuatu (para.
265), OACPS (para. 101), IUCN (para. 307), the European Union (para. 317).
53
particularly relevant in this regard”, together with relevant international rules,
standards and factors such as available means and capabilities of the State
concerned.133
100. Further, Mauritius agrees that an objective approach to the determination of
what is necessary or effective is also relevant to interpreting obligations under
the Paris Agreement. What is required to meet obligations under the Paris
Agreement must be based on the best available science, taking into account
the precise nature, scale and urgency of the threat posed by climate change.
This is also the approach adopted by ITLOS:
“…in the determination of necessary measures to prevent, reduce
and control marine pollution from anthropogenic GHG
emissions, the science undoubtedly plays a crucial role, as it is
key to understanding the causes, effects and dynamics of such
pollution and thus to providing the effective response. However,
this does not mean that the science alone should determine the
content of necessary measures. In the Tribunal’s view, as
indicated above, there are other relevant factors that should be
considered and weighed together with the best available
science.”134
101. In the context of legal obligations relating to climate change more broadly,
the science is unequivocal that GHG emissions have caused, and will
continue to cause, significant harm to the environment and that this will have
devastating associated social and economic impacts. In its Advisory Opinion,
ITLOS confirmed that anthropogenic GHG emissions into the atmosphere
constitute pollution of the marine environment within the meaning of article
1(1)(4) of UNCLOS.135 This authoritatively confirms that GHG emissions are
133 ITLOS Advisory Opinion, paras. 206-207.
134 Ibid., para. 212.
135 Ibid., para. 179.
54
pollutants and thus fall within the general rules on transboundary pollution.
The Court is invited to confirm this conclusion.
102. The fact that climate change results from cumulative and collective emissions
does not mean that the duty of prevention does not apply to the climate
system.136 Each State has a duty to prevent harm to the climate system. The
greater the threat of transboundary harm to the natural environment of another
State or areas beyond national jurisdiction, the greater the degree to which
States are required to anticipate, prevent, and/or mitigate that harm. This is
relevant to individual obligations of prevention as well as to cooperation (see
paragraph 104 below).
103. Both the causes of climate change, and the actions required to address it, are
well understood and are now subject to greater specificity through the
international climate regime. However, the harmful impact of GHG
emissions on the climate system was understood and acknowledged at a
governmental level from at least the 1960s, at a time when the duty of
prevention was also clearly established under international law.137 The
temporal implications for State responsibility are addressed at paragraphs
135-138 below.
2. Cooperation
104. Most participants have acknowledged that the duty to cooperate is a legal
duty under customary international law but also that any failure of States to
agree cooperative measures does not limit the application of other relevant
136 c.f. Written Statement of New Zealand, para. 102.
137 Mauritius Written Statement, para. 189.
55
obligations.138 As Micronesia points out, a State cannot be excused under
international law from taking all appropriate measures to prevent harm
merely because that State is unable to agree on a cooperative approach to that
matter with one or more other relevant States.139 The duty to cooperate cannot
be used as justification for taking inadequate measures that represent the least
common denominator. In its Advisory Opinion, ITLOS affirmed that the duty
of cooperation under UNCLOS must be conducted “meaningfully and in
good faith”.140 Mauritius considers that this is equally true of the duty of
cooperation under the international climate regime and customary
international law.
3. Precaution
105. Many States acknowledge the relevance of precaution to climate change, both
under the UNFCCC and the Paris Agreement, and under customary
international law.141 Mauritius agrees with India that precaution requires
States to constantly and continuously monitor their own activities, as well as
138 See e.g. the Written Statements of: Albania (para. 83), Argentina (para. 45), Bahamas (para.
109), Bangladesh (para. 127), Barbados (paras. 208-226), Brazil (para. 36), Burkina Faso (paras.
236-240), Colombia (para. 3.63-3.65), Democratic Republic of the Congo (paras. 136-144),
Ecuador (para. 3.53), Grenada (para. 43), Indonesia (para. 64), Kenya (para. 5.21), Republic of
Korea (para. 38), Latvia (para. 22), Marshall Islands (para. 31), Micronesia (para. 65), Mexico
(para. 74), the Netherlands (para. 3.13), Philippines (para. 71), Portugal (para. 128), Romania
(para. 38), Sierra Leone (para. 3.26), Singapore (para. 3.2), Solomon Islands (paras. 116-120),
South Africa (para. 95), Sri Lanka (para. 91), St Lucia (paras. 75-78), Timor-Leste (para. 179),
Tuvalu (para. 103), Uruguay (para. 122), Vanuatu (para. 313), Vietnam (paras. 33-35), IUCN,
paras. 439 & 446), COSIS (paras. 117-121), OACPS, paras. 91-95), and the African Union (paras.
125-129).
139 Written Statement of Micronesia, para. 66.
140 ITLOS Advisory Opinion, para. 321.
141 See e.g. the Written Statements of: Bangladesh (para. 94), Ecuador (paras. 3.43-3.49), Egypt
(paras. 109-110), Grenada (para. 42), India (paras. 12 & 21), Micronesia (para. 64), Mexico
(paras. 54-73), Namibia (paras. 62-73), Philippines (paras. 88 & 90), Sierra Leone (paras. 3.10-
3.25), Solomon Islands (paras. 139-145), St Vincent and the Grenadines (paras. 104-107),
Uruguay (paras. 103-109) and the African Union (paras. 97(c) & 121).
56
activities of non-State actors in their territory.142 Like Mexico and other
participants, Mauritius considers that:
a. the application of the precautionary principle is binding as a matter of
international law, and requires scientific evidence to be relied on where
it provides plausible indicators of risk, and
b. that it operates to shift the burden of proof to those claiming no or
limited environmental impact where there is scientific uncertainty.143
106. Precaution is relevant inter alia to the risk posed by the crossing of tipping
points and the impact of feedback loops, in so far as there remains any
uncertainty as to the scale of these risks.
107. Precaution is also relevant to the conduct of due diligence in relation to the
use of technologies aimed at capturing carbon emissions or otherwise
addressing their impact. So too is the precautionary principle relevant to
proposed geoengineering technologies which may pose risks to the
environment and undermine efforts to reduce emissions.144 Mauritius notes
that ITLOS, in its Advisory Opinion, determined that marine geoengineering
would be contrary to article 195 of UNCLOS if it had the consequence of
transforming one type of pollution into another, and referred to discussion of
the topic in other fora.145
142 Written Statement of India, para. 12.
143 Written Statement of Mexico, paras. 54-73.
144 As to the relevance of precaution in the context of the protection of the marine environment,
see: ITLOS Advisory Opinion, para. 213.
145 ITLOS Advisory Opinion paras. 231 & 242.
57
III. QUESTION B: LEGAL CONSEQUENCES
A. RESPONSIBILITY AND DAMAGE
108. Mauritius agrees with the many participants who refer to the ILC draft
Articles on Responsibility of States for Internationally Wrongful Acts
(“ARSIWA”) as setting out the framework for State responsibility for the
consequences of breach of climate related obligations.
109. Article 1 of ARSIWA provides that: “[e]very internationally wrongful act of
a State entails the international responsibility of that State.” This reflects a
rule of customary international law, one that Mauritius considers to be fully
applicable to each and every internationally wrongful act or omission that
relates to climate change. Notwithstanding specific aspects of climate change
as a global phenomenon resulting from the actions and omissions of more
than one State, the vast majority of participants agree that the general rules of
State responsibility apply to climate change.146 The fact that all States have
contributed to climate change in varying amounts does not detract from the
fact that some States have contributed more than others.
146 See e.g. the Written Statements of: Albania (para. 129), Antigua and Barbuda (paras. 532-533),
Bangladesh (para. 145), Brazil (para. 80), Burkina Faso (paras. 346-401), Chile (para. 104),
Colombia (para. 4.4), Democratic Republic of the Congo (paras. 255-271), Denmark, Finland,
Iceland, Norway and Sweden (para. 102), Dominican Republic (para. 4.57), Ecuador (para. 4.6),
Egypt (para. 288), El Salvador (para. 50), Grenada (para. 74), Kenya (paras. 2.13 & 6.88-6.89),
Republic of Korea (para. 45), India (para. 82), Latvia (para. 74), Marshall Islands (paras. 56-58),
Micronesia (paras. 121-128), Namibia (para. 131), the Netherlands (para. 5.4), Philippines (para.
115), Portugal (para. 115), Sierra Leone (para. 3.134), Singapore (para. 4.1), Solomon Islands
(paras. 234), Sri Lanka (para. 104), St Lucia (para. 86), St Vincent and the Grenadines (para. 128),
Timor-Leste (para. 355), Tonga (paras. 288-296), Tuvalu (paras. 121-124), Uruguay (paras. 155-
165), Vanuatu (para. 559), Vietnam (para. 44), OACPS (para. 143), Melanesian Spearhead Group
(para. 292), IUCN (para. 534) and the African Union (para. 253).
58
110. A small number of participants have referred to Article 55 of ARSIWA which
provides that its rules are not applicable “where and to the extent that the
conditions for the existence of an internationally wrongful act or the content
or implementation of the international responsibility of a State are governed
by special rules of international law.”147 However, Mauritius agrees with the
many other participants who point out that, in this context, there are no such
special rules.148 The provisions of the Paris Agreement (Articles 8 and 15)
cited by those who argue that Article 55 disapplies the general rules under
ARSIWA do not constitute special rules on State responsibility. This is
because:
a. Article 8 of the Paris Agreement establishes a mechanism for
addressing loss and damage but does not address State responsibility
for significant harm. Mauritius concurs with those participants who
take the view that paragraph 52 of decision 1/CP/21 (on the adoption
of the Partis Agreement) does not prejudice existing rights and
responsibilities under international law.149 Many participants have
stressed that paragraph 52 does not exclude the application of liability
arising from other provisions of the Paris Agreement, nor does it
constitute renunciation of rights under the rules of State responsibility
147 See e.g. the Written Statements of: Sri Lanka (para. 105) and the European Union (paras. 350-
351).
148 See e.g. the Written Statements of: Chile (para. 105), Egypt (para. 288), Singapore (para. 4.1)
and IUCN (para. 598).
149 See e.g. the Written Statement of Chile (para. 109). See also: Mauritius Written Statement,
para. 123; COP21 Adoption of the Paris Agreement, para. 52 (“Decides that, in the
implementation of the Agreement, financial resources provided to developing country Parties
should enhance the implementation of their policies, strategies, regulations and action plans and
their climate change actions with respect to both mitigation and adaptation to contribute to the
achievement of the purpose of the Agreement as defined in its Article 2”).
59
for loss and damage associated with the adverse effects of climate
change.150
b. As to Article 15, that provision establishes a procedure: “to facilitate
implementation of and promote compliance with” the Paris Agreement,
but does not set out rules relating to responsibility for internationally
wrongful acts. Moreover, the dispute settlement provisions under both
Article 14 of the UNFCCC and Article 24 of the Paris Agreement are
similar to dispute settlement provisions under many multilateral
environmental treaties, none of which have been said to disapply the
rules under ARSIWA.
111. Further, the general rules on State responsibility are not displaced, as some
States appear to suggest, by provisions of the international climate regime
relating to adaptation, loss and damage and financial support. In the first
place, the mechanisms for support have largely not yet been met.151 Further,
these provisions and mechanisms, vitally important as they are, do not
address the particular responsibility of those States whose actions and
omissions may have undermined international goals and exacerbated the
problem of climate change. They simply do not concern the issue of actions
which may have imposed greater burdens on other States, both in terms of
the extra emission reductions that must be made, and in terms of the
catastrophic implications of overshooting the temperature goal, particularly
for the most vulnerable States.
150 See e.g. the Written Statements of: Barbados (para. 265), Kenya (para. 6.98) and the
Netherlands (para. 5.22).
151 Mauritius Written Statement, paras. 115-116.
60
112. Many States, including Mauritius, have pointed out that ARSIWA is drawn
broadly and capable of addressing potential responsibility for State acts or
omissions relevant to climate change. Mauritius considers that the best
available science, together with analysis as to the contribution of historic
GHG emissions, provides a basis for the application of the rules on State
responsibility in respect of climate change. As Dr Hansen explains:
“Mauritius emphasizes that the responsibility of States to take the
lead in combatting dangerous climate change is proportionate to
their contribution to the problem over time. That proposition
finds support in relevant science. In particular, CO2, CH4, N2O,
O3 and assorted CFCs do not condense and precipitate out, but
rather, once injected, remain in the atmosphere for decades or
centuries. Emissions from long ago have continuing effects.
Accordingly, the radiative forcing contribution of any State is
roughly proportional to the cumulative GHG emissions it has
enabled…”.152
113. The Court is not called upon in these proceedings to decide the liability of
any particular State. It can and should, however, provide clear advice on the
application of ARSIWA, so that States can be advised on their potential
responsibilities, including in relation to a failure to be guided by the science.
114. Some participants, while acknowledging the potential relevance of ARSIWA,
have urged caution, arguing that the issue of State responsibility for climate
change under ARSIWA needs to be addressed in a different and constructive
way. Some argue that climate change raises novel issues of attribution and
causation.153 However, in light of the widespread support for the application
of the principles laid down in ARSIWA, and the lack of any legal obstacle to
152 Expert Report of Dr James E. Hansen, p. 3 & Figure 1b, Annex 1 (footnotes omitted).
153 See e.g. the Written Statements of: Australia (para. 4.10), Indonesia (para. 74), the United
Kingdom (para. 126) and OPEC (para. 93).
61
their application, Mauritius invites the Court to confirm that ratification of
the Paris Agreement is without prejudice to, and does not constitute
renunciation of, a State’s rights with regard to the law of State responsibility.
1. Attribution
115. Some States argue that there is currently no single or agreed scientific
methodology with which to attribute climate change to the emissions of
individual States or to attribute extreme events caused by climate change to
the GHG emissions of any particular State.
116. Mauritius submits that this is not correct, as demonstrated by expert evidence
submitted to the Court and supported by the submissions of many other
participating States.154 As stated in the expert report of Corinne LeQuéré,
submitted by Vanuatu, such attribution is possible:
“The warming that occurred so far can be attributed to countries
based on their historical emissions of GHG. Using the emissions
of different GHG by country that are available annually since
1850, it is possible to estimate the contribution of each country to
observed global warming by considering the different lifetime of
specific GHG (CO2, methane and N2O), and accounting for the
influence of each of these GHG on global temperatures…”.155
117. The report identifies the top 10 contributors to global warming from historical
emissions of GHG in the period between 1851 and 2022, as well as other
States whose contribution to climate change has been significant.156 Such
154 See e.g. the Written Statements of Bangladesh (paras. 23-26) and Chile (paras. 96-98). See also
the Expert Report of Dr James E. Hansen, p. 3 & figure 1b, Annex 1.
155 Written Statement of Vanuatu, Expert Report of Corinne Le Quéré, para. 24 (p. 14).
156 Ibid., para. 25 (p. 15).
62
contributions have continuing effects, as Dr Hanson makes clear.157 It sets
out the principles and limits to country attribution as well as the methods and
data used.158 In this way, the science provides a basis for the attribution of
State responsibility with respect to significant harm to the climate system.
2. Breach
118. Future cases may well clarify the specific application of the rules on State
responsibility to individual State acts/omissions, but it is evident that the issue
of attribution does not, in principle, present an obstacle to establishing climate
related State responsibility under ARSIWA. Further, as Chile has pointed out,
while it is not possible to attribute specific climate change-induced events to
particular emissions, reasonable inferences can be accomplished by
quantifying States’ individual contributions to climate change.159
119. No participant has sought to argue that there are no international rules on
climate change in answer to Question (a). Mauritius considers that where
there are legal obligations, there is potential State responsibility for
internationally wrongful acts, unless a clear basis exists for disapplying the
general rules reflected in ARSIWA.
120. By way of example, the following obligations on States have broad support
among participants in these proceedings:
157 Expert Report of Dr James E. Hansen, p. 3, Annex 1.
158 Ibid., paras. 27-28 (pp. 16-17).
159 Written Statement of Chile, paras. 97-98.
63
a. the obligation of due diligence under both the climate regime,
customary international law and other areas, including the law of the
sea and human rights law;
b. the duty of cooperation;
c. obligations relating to transparency under the Paris Agreement and
customary international law;
d. obligations relating to finance flows;
e. obligations relating to the principles of prevention and precaution, as
well as the need to protect present and future generations; and
f. obligations on developed States to take the lead in cutting emissions
and to provide support to developing countries to address climate
change.
121. In relation to those and other obligations on which there is broad agreement,
and in the context of ever-increasing urgency in light of the rapidly
diminishing carbon budget, a number of elements are critical to establishing
whether or not, in a particular case, a breach of a relevant obligation has
occurred. These include:
a. Whether a State has met its obligation to base its actions on the best
available science in taking relevant decisions, including decisions as to:
(i) the licensing of fossil fuel production activities; (ii) the provision of
financial support for fossil fuel exploration; and (iii) production and the
64
regulation of the conduct of private entities engaged in those activities
(see paragraphs 9-25 above).160
a. Whether a State has in good faith/objectively sought to achieve the
1.5°C temperature goal which has become an international standard by
which to measure States’ actions and omissions. Mauritius notes that
ITLOS confirmed that the long term temperature goal under the Paris
Agreement “is consistent with the objective of the obligation under
article 194(1) of UNCLOS on the prevention, reduction and control of
marine pollution.”161 This is relevant, inter alia, to the preparation and
delivery of NDCs under the Paris Agreement (see paragraphs 46-49
above).
b. Whether, in the context of the urgent need to address the emissions gap,
a State has met its obligation to reduce GHG emissions, taking into
account the obligation on developed countries to take the lead,162 and
the recognised need to urgently transition away from fossil fuels in
energy systems and phase out inefficient fossil fuel subsidies (see
paragraphs 53-58 above).
c. Whether, in relation to adaptation, a State has respected the principle of
CBDRRC in the context of the provision of support to the most
vulnerable States, taking into account relevant human rights obligations
(see paragraph 59-73 above).163
160 Written Statement of Mauritius, paras. 104-105.
161 ITLOS Advisory Opinion, para. 200.
162 See Article 3(1) of the UNFCCC and Article 4(4) of the Paris Agreement. See further:
Mauritius Written Statement, paras. 106-107.
163 These include Article 2(1) of the International Covenant on Economic, Social and Cultural
Rights, which provides that: “Each State Party to the present Covenant undertakes to take steps,
65
d. Whether a State has made good faith efforts at cooperation, taking into
account that States which do not comply with their obligations to
reduce GHG emissions thereby impose a greater burden on all other
States to make even deeper GHG emissions cuts if dangerous climate
change is to be averted. In this regard, Mauritius agrees that a breach of
the duty of prevention can also be characterised as breach of duty of
cooperation (see paragraph 104 above).164
e. Whether a State has sought to undermine the global effort to prevent
climate change by deliberately misrepresenting the science or, in
specific cases, promoting disinformation as to the risks posed by
specific activities. States which do not regulate the conduct of private
entities in this regard may also be responsible for breaches of their
obligations, including those relating to transparency and reporting.
f. Whether a State has complied with its climate related obligations under
UNCLOS, having regard, inter alia, to harm caused to fragile marine
ecosystems, fisheries and coastlines by GHG emissions.
g. In relation to all of the above considerations, whether a State has
respected its obligations under international human rights law,
including the protection of the right to life, the right to health and the
right to a clean and healthy environment, as well as respect for the right
to self-determination (see paragraphs 84-90 above).
individually and through international assistance and co-operation, especially economic and
technical, to the maximum of its available resources, with a view to achieving progressively the
full realization of the rights recognized in the present Covenant by all appropriate means,
including particularly the adoption of legislative measures.”
164 See: Written Statement of the Netherlands, para. 3.72.
66
122. Decision-making in relation to financial support for activities likely to result
in high levels of GHG emissions may be attributed to the State. As some
participants have pointed out by reference to Article 6 of ARSIWA, when the
entity granting the subsidy in question is an organ of the State, the provision
of the subsidy is attributable to the State, irrespective of whether the conduct
is in the exercise of public authority or is of a commercial nature.
123. The question as to whether acts and omissions of States, individually and
collectively, are in breach of the standard of due diligence attached to
obligations in the Paris Agreement must be considered in light of the relevant
context for assessing the risk from any breach. Such context includes the
following:
a. The current rate of global GHG emissions far exceeds the rate at which
global average temperature increase could be limited to 1.5°C; and
b. States’ commitments to reduce GHG emissions in the near term,
including as expressed in NDCs submitted under the Paris Agreement,
are insufficient to limit warming to 1.5 °C.165
124. In this context, and taking into account the production gap identified in UNEP
reports, Mauritius considers that there is a prima facie case of such a breach,
taking into account the state of knowledge as to the risks posed by climate
change since at least the 1960s (see paragraph 135-138 below).
125. In relation to any State collusion in the misrepresentation of the science, or
as to the scale of risk posed by climate change, this would constitute, inter
alia, a breach of the obligation of good faith in that it would frustrate the
165 See e.g. the Written Statement of Bangladesh (paras. 26-43) and the Expert Report of Dr James
E. Hansen, Annex 1.
67
achievement of the object and purpose of the UNFCCC and Paris Agreement
by serving to delay action on emissions in the context of the diminishing
global carbon budget. Such action also runs counter to the principles of
transparency enshrined in the Paris Agreement and other treaties.166
126. Mauritius considers that the issue of whether an internationally wrongful act
has occurred must be appraised in the light of the specific facts and against
the framework of climate obligations considered under Question (a). If there
are obligations relating to GHG emissions, as the great majority, if not all,
participants accept, it follows that States could potentially breach, or will
breach, those obligations. All the more so in the context of the current
emissions and production gaps and the deep concern as to the risk of
overshooting the temperature goal. As Kenya and others have pointed out:
“Although the UNFCCC and the Paris Agreement represent
significant legal developments in the fight against climate
change, they have failed to protect the climate system from the
harmful effects of GHG emissions.”167
127. The implications of the production gap are addressed in the UNEP PGR, as
noted by the African Union:
“This disconnect between governments’ fossil fuel production
plans and their climate promises shows that, in the ongoing
process of responding globally to the climate emergency, a
State’s unilateral action may impermissibly defeat the
cooperative conduct to reduce GHG emissions, contributing
instead to increase the level of interference with the climate
system.”168
166 Paris Agreement, Articles 4(8) & (13), 6(2), 7(5), 9(7), 11(1), 13 and 15(2).
167 Written Statement of Kenya, para 5.40 (footnote omitted).
168 Written Statement of the African Union, para. 129.
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128. Mauritius notes that many participants consider that climate related
obligations constitute erga omnes obligations, including, but not limited to,
the impacts of climate change on the right to self-determination.169
3. Significant harm
129. As explained above, and in Mauritius’ Written Statement, there is no question
as to the significant harm already caused by climate change and the risk of
even more catastrophic damage if there is overshoot of the temperature
goal.170 The scale of harm is addressed in the reports of the IPCC and includes
the risk of a temperature rise to 3°C or 4°C, at which point life on large parts
of this planet may not be sustainable.
130. As Sierra Leone points out, nearly 70% of the deaths caused by climaterelated
disasters over the last five decades have been experienced in less
developed countries.171 Many participants have referred to impacts on food
security and health, as well as livelihoods and ecosystems, together with
increasing risks of largescale displacement of people. Mauritius shares the
view that, as it will not be possible for many SIDS to adapt to the
consequences of crossing tipping points, including in the near-term, it is
imperative to achieve the 1.5°C goal.
131. Some have argued that acting inconsistently with the 1.5°C temperature goal
is determinative of breach,172 while others have pointed out that significant
169 See e.g. the Written Statements of: Albania (para. 96), Bangladesh (para. 121), Barbados (para.
201), Kenya (para. 5.66), Liechtenstein (para. 28), Madagascar (para. 59), Sierra Leone (para. 3.99),
Solomon Islands (para. 171), Timor-Leste (para. 335), Vanuatu (para. 289), OACPS (para. 66),
Melanesian Spearhead Group (para. 234) and the European Union (para. 235).
170 Mauritius Written Statement, paras. 54-85.
171 Written Statement of Sierra Leone, para. 3.38.
172 See e.g. the Written Statement of IUCN, paras. 530-562.
69
harm can occur below 1.5°C, as indicated by the IPCC.173 This is a factual
issue to be determined by the scientific evidence, including as to cumulative
impacts of emissions.
132. The African Union and others have referred to the judgment in Certain
Activities (Costa Rica v Nicaragua), where the Court held that:
“…it is consistent with the principles of international law
governing the consequences of internationally wrongful acts […]
to hold that compensation is due for damage caused to the
environment, in and of itself, in addition to expenses incurred by
an injured State as a consequence of such damage.”174
133. In relation to responsibility towards States, including, in particular SIDS,
“which due to their geographical circumstances and level of development, are
injured or specially affected by or are particularly vulnerable to the adverse
effects of climate change”, the science as to the harm that is already being
suffered by those States is unequivocal.175 The evidence submitted by
participants is further indication of the impacts being experienced in many
States and by many peoples. These impacts clearly meet the threshold of
significant harm on any reasonable view.
134. Question (b)(ii) addresses the legal consequences with regard to “peoples and
individuals of the present and future generations affected by the adverse
173 See: Sharm el-Sheik Implementation Plan, para. 4, available at:
https://unfccc.int/documents/624444 (last accessed 12 August 2024); IPCC, SR 1.5, chapter 3,
“Impacts of 1.5°C global warming on natural and human systems”, available at:
https://www.ipcc.ch/site/assets/uploads/sites/2/2022/06/SR15_Chapter_3_LR.pdf (last accessed
12 August 2024); Mauritius Written Statement, para. 101.
174 Certain Activities Carried out by Nicaragua in the Border Area (Costa Rica v Nicaragua),
Compensation, Judgment, ICJ Reports 2018, p. 15, para. 41. See e.g. the Written Statements of
Barbados (para. 259), Chile (para. 114), Kenya (para. 2.10), Sierra Leone (para. 3.142),
Switzerland (para. 75) and the African Union (para. 290).
175 UN General Assembly resolution 77/276 of 29 March 2023, Question (b)(i).
70
effects of climate change”.176 Human rights obligations in respect of those
affected by, or at risk from, climate change have been addressed at paragraphs
155-187 of Mauritius’ Written Statement and above at paragraphs 84-90. As
many participants have highlighted, the protection of future generations is an
established principle under international law, informing climate related
obligations.177 Mauritius submits that the interest of those expressly referred
to in Question (b) is also relevant to claims for State responsibility, including
where climate impacts deprive populations of the basic conditions for life
and/or where entire territories may disappear due to sea level rise, thus
injuring the future generations deprived of their primary territorial rights.
4. Temporal aspects
135. Mauritius notes the differing views expressed by participants as to the
temporal point from which States were under a legal obligation, under
customary international law, to prevent significant harm from climate change,
the breach of which could result in liability. Some States have argued that,
taking into account the development of the science and governmental
acknowledgment of the risks, such duties first arose in the 1980s,178 and a few
others have suggested the 1990s.179 Others, including Vanuatu, argue that the
176 Ibid., Question (b)(ii).
177 See e.g. the Written Statements of: Bahamas (paras. 177-180), Bangladesh (para. 124), Burkina
Faso (paras. 82-83), Cameroon (paras. 19-27), Costa Rica (para. 56), Ecuador (paras. 3.56-3.57),
Kenya (para. 5.26), Republic of Korea (paras. 41-46), Peru (para. 83), Nepal (para. 36),
Philippines (paras. 83-84), Sierra Leone (para. 3.44), St Vincent and the Grenadines (paras. 123-
126), Timor-Leste (paras. 199-210), Vanuatu (paras. 480-482), Vietnam (para. 22), IUCN (paras.
388-389), the European Union (paras. 177 & 184) and the African Union (para. 166). Mauritius
further notes that the 11th recital of the Paris Agreement’s Preamble refers to intergenerational
equity as a matter which Parties should consider when taking action to address climate change.
178 See e.g. the Written Statements of the Netherlands (para. 5.6), Switzerland (para. 35) and the
United States of America (paras. 2.3-2.4, 2.11, 2.19 & 6.2).
179 See e.g. the Written Statements of: Germany (para. 40) and the Russian Federation (p. 16).
71
relevant responsibility dates back to the 1950s or 1960s on the basis that a
number of governments were aware of the risks posed by GHGs to the climate
system.180 As Professor Oreskes states in her expert report submitted by
Vanuatu:
“…at least from the 1960s, the United States and other States with
high cumulative emissions of greenhouse gases (GHGs),
including France and the UK, were aware that (i) the release of
[GHGs] into the Earth’s atmosphere had the potential to alter the
climate system, and (ii) that such interference, if unmitigated,
could have catastrophic effects for humans and the
environment”.181
136. A number of participants argue that historic emissions predate any legal
obligations. This, however, is not reconcilable with the established facts,
including, as recognised by Dr Hansen, that long ago emission have
continuing effects today.182 Notwithstanding the evolution of the science
following the establishment of the IPCC, and the adoption of the UNFCCC
in 1992, evidence that the risks were understood decades earlier is clear.
Furthermore, the legal duty of prevention was clearly in existence by the
1960s.183 In any event, these are matters of evidence to be tested on the facts,
taking into account the state of knowledge as to the risk and the availability
of pursuing renewable alternatives sources of energy.
137. Article 13 of ARSIWA provides that: “[a]n act of a State does not constitute
a breach of an international obligation unless the State is bound by the
180 See e.g. the Written Statements of: Egypt (paras. 304-306), Kiribati (paras. 184-186), Vanuatu
(paras. 73 & 177-192), OACPS (paras. 22-23) and the Melanesia Spearhead Group (para. 298).
181 Written Statement of Vanuatu, Expert Report of Professor Oreskes, para. 39.
182 Expert Report of Dr James E. Hansen, p. 3, Annex 1.
183 Mauritius Written Statement, para 189.
72
obligation in question at the time the act occurs.” In Mauritius’ submission,
the obligation to prevent harm caused by GHG emissions exists:
a. from the time at which States were aware that these emissions posed a
risk to the climate system which needed to be addressed; or
b. in relation to the continuing effects of GHG emissions after such time,
even if the emissions originally occurred when they were lawful.184
138. Mauritius notes that Article 14(2) of ARSIWA provides that the breach of an
international obligation by an act of State having a continuing character
extends over the entire period during which the act continues and remains not
in conformity with the international obligation. Article 15(1) of ARSIWA
provides that a breach occurring through a series of actions or omissions
defined in the aggregate as wrongful occurs when the act or omission which
taken with the other acts or omissions, is sufficient to constitute the wrongful
act. Article 15(2) of ARSIWA provides that in such a case the breach extends
over the entire period starting with the first of the actions or omissions of the
series.185
5. Causation
139. Mauritius agrees with those who have stated that the fact that no one State is
responsible for the total extent of global climate change does not call into
question the basic causality between GHG emissions and climate change, as
184 The principle of continuing effect is well-established in international law, see e.g. Cyprus v
Turkey, ECHR Application No. 25781/94, Judgment of 10 May 2001; Velásquez Rodríguez v
Honduras, IACHR Judgment of 29 July 1988. See also the Written Statements of Egypt (para.
323, in the context of prevention) and India (para. 88).
185 Mauritius Written Statement, para. 210(b).
73
established by the science.186 Article 47(1) of ARSIWA confirms that where
several States are responsible for the same internationally wrongful act, the
responsibility of each State may be invoked in relation to that act. Risks are
foreseeable risks when they take the form of a “high probability of causing
significant transboundary harm”.187 In this case, the evidence before the
Court shows that science established the risks posed by GHGs from the early
1960s, with specific understanding evolving in the 1980s and following the
establishment of the IPCC in 1988.
140. As to the responsibility of individual States, Mauritius agrees with those who
point to the historic and disproportionate contribution from developed States
and major emitters.188 The related issue of breach is determined according to
whether a specific obligation has in fact been breached.
141. Mauritius also agrees with those who take the view that causation is
established if a State was aware of the risk of harm posed by GHG emissions
and did not take preventive measures with the due diligence required. This is
not a situation where the ‘but for’ test for causation is appropriate because
individual contributions to global harm are measurable. In accordance with
the principle of CBDRRC, a State with higher levels of responsibility for
climate (and/or higher capabilities with respect to mitigation) has a
heightened level of due diligence compared to a State with less responsibility
and/or fewer capabilities, particularly SIDS. As Ecuador has stated: “each
186 See e.g. the Written Statements of: Chile (para. 99) and Switzerland (paras. 77-78).
187 ILC Draft Articles on Prevention of Transboundary Harm from Hazardous Activities (2001),
Article 2(a), available at:
https://legal.un.org/ilc/texts/instruments/english/commentaries/9_7_2001.pdf (last accessed 11
August 2024).
188 See e.g. the Written Statements of: Brazil (para. 81), Ecuador (para. 1.9), New Zealand (para.
28(a)), Solomon Islands (para. 66) and Vanuatu (paras. 169-170).
74
State is independently responsible, even if the wrongful act is the result of the
combined acts or omissions of more than one State.”189
6. Compensation
142. Mauritius agrees with Kenya and others who have pointed out that
compensation for loss and damage resulting from GHG emissions is a critical
component of reparations in respect of internationally wrongful acts relating
to climate change.190 This is because the impacts of climate change make it
largely impossible to return to the status quo ante.
143. Barbados and others take the position that States must pay compensation for
loss and damage on a strict liability basis:
“…both when their acts that caused damage are not otherwise
wrongful under international law and also when those acts are
otherwise wrongful under international law”.191
144. Mauritius submits that in the case of catastrophic harm, State acts which
increase the risk of such harm should be subject to strict liability, taking into
account the best available science.
145. In considering arguments in support of the application of the rules on State
responsibility for climate change, it is important to also consider the
alternative. In circumstances where there is, and has been, a failure to reduce
GHG emissions and transition away from fossil fuels within a timescale
which is likely to meet the 1.5°C temperature goal, it is unthinkable that no
189 Written Statement of Ecuador, para. 4.20 (footnote omitted).
190 Written Statement of Kenya, paras. 6.99-6.101.
191 Written Statement of Barbados, para. 228.
75
State can be held responsible for even the most abject failure to comply with
its obligations, including the failure to regulate private entities.
146. In fact, there is nothing in the rules on State responsibility which precludes
States injured by climate change, in particular SIDS and other vulnerable
States, from seeking reparations from States responsible for causing serious
harm to the climate system, including compensation for damage to the
environment itself. Such claims fall to be determined by reference to the
evidence as to individual State conduct in each case.
B. MARITIME BOUNDARIES AND ENTITLEMENTS
147. Many participants have stressed the importance of preserving States’
maritime entitlements and ensuring that these are not adversely impacted by
sea level rise caused by climate change.192 This is a matter of particular
significance to Mauritius, and many other SIDS and low-lying States.
148. In its Written Statement, Mauritius provided evidence of the sea level rise it
has already experienced, and the extreme vulnerability of large parts of
Mauritius to projected sea level rise in the future.193 The IPCC has found that
global mean sea level increased by 0.2 metres between 1901 and 2018, and
that the rate of sea level rise is increasing rapidly. The IPCC estimates that
192 See e.g. the Written Statements of: Bahamas (paras. 217-226), Burkina Faso (para. 345), Costa
Rica (paras. 125 & 127), Dominican Republic (para. 4.40), El Salvador (paras. 55-58), Kenya
(para. 5.68), Kiribati (paras. 188-191, 198 & 206(3)(f)), Liechtenstein (paras. 76-78), Marshall
Islands (paras. 101-105), Micronesia (paras. 114-117), Nauru (paras. 12 & 44), the Netherlands
(para. 5.38, in the context of population displacement), New Zealand (para. 13), Korea (para. 8),
Sierra Leone (para. 3.91), Solomon Islands (paras. 208-213), Tonga (paras. 90, 92 & 149), Tuvalu
(para. 1.13), Vanuatu (paras. 8, 487, 558, 643 & 644), Melanesian Spearhead Group (para. 326),
Parties to the Nauru Agreement Office (para. 22), Pacific Islands Forum (paras. 14-16), Forum
Fisheries Agency (paras. 38-40), AOSIS (para. 7), the African Union (para. 162), OACPS (para.
194) and COSIS (paras. 71-72 & 196).
193 Mauritius Written Statement, paras. 25-29.
76
global sea level rise could be as much as 0.29 metres by 2050 and 1.01 metres
by 2100.194 Sea level rise of this magnitude poses an existential threat to vast
swathes of Mauritius, as well as other SIDS and low-lying States.
149. It is inevitable that sea level rise will affect maritime features, the location of
basepoints, the drawing of baselines, the delimitation of maritime boundaries,
and entitlements up to and beyond 200 nautical miles. This can arise in at
least three contexts.
a. The first is where a maritime boundary has already been delimited. The
Arbitral Tribunal in the Bay of Bengal Maritime Boundary Arbitration
resisted the suggestion that its equidistance line could be affected by
climate change.195 Mauritius considers that the same reasoning applies
with equal force to maritime boundaries established by agreement. An
overwhelming majority of affected States have expressed support for
the position that their baselines and maritime entitlements must not be
affected by rising sea-levels.196 The ILC and the International Law
194 AR6 SYR, B.3.1.
195 Bay of Bengal Maritime Boundary Arbitration between Bangladesh and India, Award, 7 July
2014, paras. 217 & 213-220.
196 See e.g. the Taputapuātea Declaration on Climate Change signed by the leaders of French
Polynesia, Niue, Cook Islands, Samoa, Tokelau, Tonga and Tuvalu, available at:
https://www.samoagovt.ws/wp-content/uploads/2015/07/The-Polynesian-P.A.C.T.pdf (last
accessed 10 August 2024); The Delap Commitment on Securing Our Common Wealth of Oceans,
available at:
https://www.pnatuna.com/sites/default/files/Delap%20Commitment_2nd%20PNA%20Leaders%2
0Summit.pdf (last accessed 10 August 2024); Declaration on Preserving Maritime Zones in the
Face of Climate Change-related Sea-Level Rise, available at:
https://www.forumsec.org/2021/08/11/declaration-on-preserving-maritime-zones-in-the-face-ofclimate-
change-related-sea-level-rise/ (last accessed 10 August 2024); Launch Of The Alliance Of
Small Island States Leaders’ Declaration, available at: https://www.aosis.org/launch-of-thealliance-
of-small-island-states-leaders-declaration/ (last accessed 10 August 2024).
77
Association have rejected the notion of ambulatory baselines in the
context of sea level rise.197
b. The second is where a State has deposited with the UN Secretary-
General material to describe the outer limits of its continental shelf up
to 200 nautical miles. Mauritius considers that such descriptions apply
“permanently” in accordance with Article 76(9) of UNCLOS, and will
not be affected by sea level rise.
c. The third is where a State has submitted material in support of a
continental shelf entitlement beyond 200 nautical miles to the
Commission on the Limits of the Continental Shelf (“CLCS”),
pursuant to Article 76(8) of UNCLOS. Mauritius considers that this
provision is clear in providing that the limits of the shelf established
pursuant to that process shall be final and binding, but it does not
expressly address the possible effects of sea level rise which may
intervene in the potentially lengthy period between material being
submitted and a CLCS recommendation being made.
150. The principle of stability and certitude lies at the heart of the international
legal order, and operates as a golden thread which runs through the practice
and decisions of international courts and tribunal. In the Temple of Preah
Vihear case, the Court confirmed that the requirements of stability and
197 International Law Commission, “Sea Level Rise in Relation to International Law: First Issues
Paper”, UN Doc A/CN.4/740 (28 February 2020), paras. 78 & 82-104; Report of the International
Law Association, “Committee on International Law and Sea Level Rise, Sydney Conference”
(2018), pp. 16-19, available at: https://www.ila-hq.org/en_GB/documents/conference-reportsydney-
2018cteeversion (last accessed 10 August 2024); ILA Resolution 5/2018, available at:
https://www.ila-hq.org/en_GB/documents/conference-resolution-sydney-2018-english-2 (last
accessed 10 August 2024).
78
finality would be undermined if settled boundaries could become subject to
continuous change.198
151. Mauritius invites the Court to authoritatively affirm that maritime boundaries
and entitlements – in all three contexts outlined in paragraph 149 above –
remain immune from the impacts of sea level rise caused by climate change.
IV. CONCLUSIONS
152. As long ago as 1996, in another Advisory Opinion, the Court stated that it:
“…recognizes that the environment is not an abstraction but
represents the living space, the quality of life and the very health
of human beings, including generations unborn. The existence of
the general obligation of States to ensure that activities within
their jurisdiction and control respect the environment of other
States or of areas beyond national control is now part of the
corpus of international law relating to the environment.”199
153. Mauritius invites the Court to do no more than take this significant statement
and apply it to the issue of climate change, an environmental issue that is not
an abstraction.
154. Mauritius reiterates the conclusions set out at paragraphs 218-222 of its
Written Statement of 22 March 2024, in the light of its further Written
Comments herein.
198 Case Concerning the Temple of Preah Vihear (Cambodia v Thailand), Merits, Judgment, ICJ
Reports 1962 p. 6, para. 34.
199 Legality of the Threat or Use of Nuclear Weapons, Advisory Opinion, ICJ Reports 1996, p. 22,
para. 29.
79
H.E. Jagdish Dharamchand Koonjul, G.C.S.K., G.O.S.K.
Ambassador and Permanent Representative of the Republic of Mauritius to the
United Nations
15 August 2024
Written Comments of the Republic of Mauritius
Annex 1: Expert Report of Dr James E. Hansen (9 August 2024)
Page 1 of 5
Expert Report of Dr. James E. Hansen in Support of the Republic of Mauritius
August 9, 2024
I have been asked to provide this Expert Report in support of the written submissions made by the Republic of Mauritius in the ICJ Advisory Opinion on the Obligations of States in respect of Climate Change. As will be clear from my c.v. (attached below), I have been involved in these issues for more than four decades, including as an adviser to governments and the Intergovernmental Panel on Climate Change (IPCC).
The position adopted by Mauritius is that States have an overarching obligation under international law “to effect deep, rapid and sustained reductions of GHG emissions, including urgently reducing and phasing out the use of fossil fuels.” From a scientific perspective, I fully support the arguments of Mauritius. To that end, I here summarize what we understand about the recent and continuing causes and consequences of dangerous climate change, and what we need to do to avert it. To keep this submission brief, I reference several key studies in endnotes.
I conclude with an observation about the vital need for the Court to give an Advisory Opinion that is based squarely on the science, and that can contribute to actions by States and others to avoid catastrophic climate change.
Greenhouse Gas (GHG) Concentrations and Earth’s Energy Imbalance
More than three decades have passed since States committed “to achieve… stabilization of [GHG] concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system.”1 That stablization has not been achieved.
Most significantly, humanity continues to heat up the planet by releasing massive quantities of greenhouse gases (GHGs). Indeed, CO2 and methane (CH4) emissions arising predominantely from fossil fuel production, distribution, and utilization, continue at record high levels. In particular, fossil fuel CO2 emissions increased by 0.9% during 2022, and again by 1.1% in 2023, to reach 36.8 Gt.2 Trends in the atmospheric concentration of CO2 and also CH4, N2O, and SF6, are also in the upward direction, which is decidedly dangerous for present and future generations.3
Increasing GHG concentrations in turn strongly influence top-of-the-atmosphere radiative imbalance – known as Earth’s Energy Imbalance (EEI). The IPCC acknowleges EEI to be “an important metric of the rate of global climate change,”4 although surprisingly the term does not appear in the Paris Agreement (2015) or the recent Global Stocktake report.5 In my view, and that of colleagues, EEI is “the most critical number defining the prospects for continued global warming and climate change.”6
Earth’s Energy Imbalance has increased markedly in recent decades. Indeed, we have found a total heat gain of 358±37 ZJ over the period 1971–2018. Moreover, “[o]ur results show that EEI is not only continuing, but also increasing. Over the period 1971–2018 average EEI amounts to 0.47±0.1 W m−2, but it amounted to 0.87±0.12 W m−2 during 2010–2018.”7 If we are to stabilize climate at an ambient temperature conducive to human and natural systems then, at minimum, EEI must be reduced to approximately zero.8 That requires a reduction in the atmospheric CO2 concentration from the current 425ppm to 350ppm, the level passed during 1988.9 Annex 1
Page 2 of 5
Global Warming and Urgency
The 1992 UNFCCC failed to define precisely what it meant by “dangerous anthropogenic interference with the climate system” and so, in a series of studies, international colleagues and I have set out to determine what is a reasonably “safe” level of CO2 and the implications, with respect to Earth’s critical systems, of a multi-decade overshoot of that atmospheric concentration. I incorporate the findings and conclusions of those studies here by reference.10
In brief, the safe level of atmospheric CO2 has already been exceeded, as denoted above. We reside now in a period of consequences where the failure to decarbonize will with certainty inflict additional harm on communities and states.
In late 2021, the IPCC comprehensively reviewed some of those present and impending consequences, including that:
•
Climate change has caused local species losses, increases in disease, mass mortality events of plants and animals, resulting in the first climate driven extinctions, ecosystem restructuring, increases in areas burned by wildfire, and declines in key ecosystem services.
•
Widespread and severe loss and damage to human and natural systems are being driven by human-induced climate changes increasing the frequency and/or intensity and/or duration of extreme weather events, including droughts, wildfires, terrestrial and marine heatwaves, cyclones (high confidence), and flood (low confidence). Extremes are surpassing the resilience of some ecological and human systems.
•
Extreme events and underlying vulnerabilities have intensified the societal impacts of droughts and floods and have negatively impacted agriculture, energy production and increased the incidence of water-borne diseases. Economic and societal impacts of water insecurity are more pronounced in low-income countries than in the middle- and high-income ones.
•
Over 9 million climate-related deaths per year are projected by the end of the century, under a high emissions scenario and accounting for population growth, economic development, and adaptation.
•
In many regions, the frequency and/or severity of floods, extreme storms, and droughts is projected to increase in coming decades, especially under high-emissions scenarios, raising future risk of displacement in the most exposed areas. Under all global warming levels, some regions that are presently densely populated will become unsafe or uninhabitable.
•
Approximately 3.3 to 3.6 billion people live in contexts that are highly vulnerable to climate change. A high proportion of species is vulnerable to climate change. Human and ecosystem vulnerability are interdependent.
The harm inflicted on humanity and nature is global. That point is critical here, wherein Mauritius and others have invited the Court to consider the comparative inability of least developed nations, including Small Island Developing States, to adapt to and survive unabated climate change. I wish to add that hundreds of millions of persons (at a minimum) in developed nations also retain little capacity to protect themselves from worsening climate impacts including, as I write, wildfire and associated smoke.11 If it impels concerted
Annex 1
Page 3 of 5
international action to phase out fossil fuel emissions, this Court’s Advisory Opinion will protect communities everywhere.
The situation is urgent. More delay will elicit additional warming, amplified risk for natural and human systems,12 and increased likelihood of crossing tipping points in the global system.13 The IPCC observes, regarding abrupt changes, that “even a return to pre-threshold surface temperatures or to atmospheric carbon dioxide concentrations does not guarantee that the tipping elements return to their pre-threshold state.”14 I agree. In addition, following our study employing climate modeling, paleoclimate analyses, and modern observations, my international colleagues and I have determined that if fossil fuel emissions continue to climb, a shutdown of the North Atlantic Overturning Circulation is likely within the next several decades, which would make a multi-meter sea level rise over the next 50-150 year period practically unavoidable.15 Attendant increases in climate extremes, associated economic disruption, and consequential social dislocation may render the planet ungovernable.16
And yet, as a recent report from the UN Environment Programme, et al., establishes, “governments are in aggregate planning to increase oil and gas production out to at least 2050” and coal production through 2030.17 These planned fossil fuel production increases are incompatible with an international commitment to prevent dangerous climate change.
Responsibility
In its written submissions, Mauritius emphasizes that the responsibility of States to take the lead in combatting dangerous climate change is proportionate to their contribution to the problem over time. That proposition finds support in relevant science. In particular, CO2, CH4, N2O, O3 and assorted CFCs do not condense and precipitate out, but rather, once injected, remain in the atmosphere for decades or centuries.18 Emissions from long ago have continuing effects. Accordingly, the radiative forcing contribution of any State is roughly proportional to the cumulative GHG emissions it has enabled (Figure 1b).19 Thus, while China’s current emissions may be highest, the heaviest burden at present falls on the United States, my own country – to decarbonize, to innovate and share technology, and to assist other States to adapt to the considerable additional warming that is already in the pipeline.20
Fig. 1: Source Climate Science, Awareness and Solutions.21
Annex 1
Page 4 of 5
Conclusion
The major carbon polluting nations – along with the multi-national corporations over which they can and should exercise control – retain the capacity to dial-back the CO2 control knob,22 yet in defiance of the common interest they continue along a fatal path.23 An Advisory Opinion from the Court that is based on the relevant science and that spells out its necessary implications should inform the content and application of the law.
1 United Nations Framework Convention on Climate Change (1992, UNFCCC).
2 Carbon Budget Project data available here.
3 See NOAA Global Monitoring Laboratory, Trends in CO2, CH4, N2O, SF6 at https://gml.noaa.gov/ccgg/trends/.
4 Forster, P. et al., 2021: The Earth’s Energy Budget, Climate Feedbacks, and Climate Sensitivity, Section 7.2, In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change at www.ipcc.ch/report/ar6/wg1/chapter/chapter-7/
5 Report of the Conference of the Parties serving as the meeting of the Parties to the Paris Agreement on its fifth session, held in the United Arab Emirates from 30 November to 13 December 2023 Decision 1/CMA.5: Outcome of the first global stocktake. Dec. 13, 2023. https://unfccc.int/topics/global-stocktake
6 von Schuckmann, K., Hansen, J. et al., Heat stored in the Earth system: where does the energy go?, Earth Syst. Sci. Data, 12, 2013–2041, https://doi.org/10.5194/essd-12-2013-2020, 2020.
7 Ibid.
8 Ibid.
9 Op cit nte 3, data at https://gml.noaa.gov/ccgg/trends/data.html. See also, Hansen, J et al, Target atmospheric CO2: Where should humanity aim? (2008) Open Atmos. Sci. J., 2, 217-231, doi:10.2174/1874282300802010217.
10 They are Hansen, J. et al., Target atmospheric CO2: Where should humanity aim? Open Atmos. Sci. J., 2, 217-231 (2008); Hansen, J., et al., Earth's energy imbalance and implications, Atmos. Chem. Phys., 11, 13421-13449 (2011); Hansen, J. et al., Assessing "Dangerous Climate Change": Required Reduction of Carbon Emissions to Protect Young People, Future Generations and Nature. PLOS ONE, 8, e81468 (2013); Hansen, J., P. Kharecha, and M. Sato, Climate forcing growth rates: Doubling down on our Faustian bargain, Environ. Res. Lett., 8 (2013); Hansen, J., et al., Ice Melt, Sea Level Rise and Superstorms: Evidence from Paleoclimate Data, Climate Modeling, and Modern Observations that 2 C Global Warming is Highly Dangerous. (Ice Melt.) Atmos. Chem. & Phys. Discussions (2016); Hansen, J., et al., Young people's burden: requirement of negative CO2 emissions, Earth Syst. Dynam., 8, 577-616 (2017); von Schuckmann, J. Hansen et al., 2020: Heat stored in the Earth system: where does the energy go?, Earth System Science Data 12, 2013-2041 (2020); Hansen, J.E., et al., Global warming in the pipeline (Pipeline), Oxford Open Climate Change, 3, 1 (2023).
11 Claire Moses, Fires Have Burned 4.5 Million Acres This Year, Blanketing Much of North America in Smoke, New York Times (Aug. 3, 2024).
12 Climate-related risks for natural and human systems “are higher for global warming of 1.5°C than at present” and far higher still than at 2°C.” V. Masson-Delmotte, et al., IPCC, 2018: Summary for Policymakers (SPM) 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, Section A.3.
13 The IPCC foresees potential for abrupt climate shifts in the following critical global systems: monsoons, tropical forests, boreal forest, permafrost, Arctic sea ice, global sea-level rise, AMOC, Southern MOC, ocean acidification, and ocean deoxygenation. IPCC 6th Assessment Report, The Physical Science Basis, Table 4.10.
14 AR WG 1 Technical Report at 106.
15 Op. cit. nte 10, Ice Melt at 3799.
16 Ibid.
17 UNEP et al., Production Gap Report 2023. Annex 1
Page 5 of 5
18 Lacis, A.A., J.E. Hansen et al., The role of long-lived greenhouse gases as principal LW control knob that governs the global surface temperature for past and future climate change, Tellus B, 65 (2013).
19 See also, Jones, M.W., Peters, G.P., Gasser, T. et al. National contributions to climate change due to historical emissions of carbon dioxide, methane, and nitrous oxide since 1850, Nature Sci Data 10, 155 (2023).
20 Op. cit. nte. 10, Pipeline.
21 See https://www1.columbia.edu/~mhs119/CO2Emissions/Emis_moreFigs/
22 Op. cit. nte. 17.
23 My own nation, for instance, has yet even to impose a rising price on carbon, though in recent years US production of both oil and natural gas for export to the global market has climbed markedly. Annex 1
James E. Hansen
Columbia University Earth Institute, Climate Science, Awareness and Solutions
Interchurch Building, 475 Riverside Drive, Room 401-O, New York, NY 10115 [email protected]
1-paragraph bio/introduction:
Dr. James Hansen, formerly Director of the NASA Goddard Institute for Space Studies, is an Adjunct Professor at Columbia University’s Earth Institute, where he directs a program in Climate Science, Awareness and Solutions. Dr. Hansen is best known for his testimony on climate change in the 1980s that helped raise awareness of global warming. He is a member of the U.S. National Academy of Sciences and has received numerous awards including the Sophie and Blue Planet Prizes. Dr. Hansen is recognized for speaking truth to power and for outlining actions needed to protect the future of young people and all species on the planet.
1-long-paragraph bio:
Dr. James Hansen, formerly Director of the NASA Goddard Institute for Space Studies, is an Adjunct Professor at Columbia University’s Earth Institute, where he directs a program in Climate Science, Awareness and Solutions. He was trained in physics and astronomy in the space science program of Dr. James Van Allen at the University of Iowa. His early research on the clouds of Venus helped identify their composition as sulfuric acid. Since the late 1970s, he has focused his research on Earth's climate, especially human-made climate change. Dr. Hansen is best known for his testimony on climate change to congressional committees in the 1980s that helped raise broad awareness of the global warming issue. He was elected to the National Academy of Sciences in 1995 and was designated by Time Magazine in 2006 as one of the 100 most influential people on Earth. He has received numerous awards including the Carl-Gustaf Rossby and Roger Revelle Research Medals, the Sophie Prize and the Blue Planet Prize. Dr. Hansen is recognized for speaking truth to power, for identifying ineffectual policies as greenwash, and for outlining actions that the public must take to protect the future of young people and other life on our planet.
3-paragraph bio:
Dr. James Hansen, formerly Director of the NASA Goddard Institute for Space Studies, is an Adjunct Professor at Columbia University’s Earth Institute, where he directs a program in Climate Science, Awareness and Solutions. He was trained in physics and astronomy in the space science program of Dr. James Van Allen at the University of Iowa, receiving a bachelor’s degree with highest distinction in physics and mathematics, master’s degree in astronomy, and Ph. D. in physics in 1967. Dr. Hansen was a visiting student, at the Institute of Astrophysics, University of Kyoto and Dept. of Astronomy, Tokyo University, Japan from 1965-1966. He received his Ph.D. in physics from the University of Iowa in 1967. Except for 1969, when he was an NSF post-doctoral scientist at Leiden Observatory under Prof. H.C. van de Hulst, he has spent his post-doctoral career at NASA GISS.
In his early research Dr. Hansen used telescopic observations of Venus to extract detailed information on the physical properties of the cloud and haze particles that veil Venus. Since the mid-1970s, Dr. Hansen has focused on studies and computer simulations of the Earth's climate, for the purpose of understanding the human impact on global climate. He is best known for his testimony on climate change to Congress in the 1980s that helped raise broad awareness of the global warming issue. In recent years Dr. Hansen has drawn attention to the danger of passing climate tipping points, producing irreversible climate impacts that would yield a different planet from the one on which civilization developed. Dr. Hansen disputes the contention, of fossil fuel interests and governments that support them, that it is an almost god-given fact that all fossil fuels must be burned with their combustion products discharged into the atmosphere. Instead Dr. Hansen has outlined steps that are needed to stabilize climate, with a cleaner atmosphere and ocean, and he emphasizes the need for the public to influence government and industry policies.
Dr. Hansen was elected to the National Academy of Sciences in 1995 and, in 2001, received the Heinz Award for environment and the American Geophysical Union's Roger Revelle Medal. Dr. Hansen received the World Wildlife Federation’s Conservation Medal from the Duke of Edinburgh in 2006 and was designated by Time Magazine as one of the world’s 100 most influential people in 2006. In 2007 Dr. Hansen won the Dan David Prize in the field of Quest for Energy, the Leo Szilard Award of the American Physical Society for Use of Physics for the Benefit of Society, and the American Association for the Advancement of Science Award for Scientific Freedom and Responsibility. In 2008, he won the Common Wealth Award for Distinguished Service in Science and was also awarded both the Ohio State University’s Bownocker Medal and the Desert Research Institute’s Nevada Medal. In 2009, Dr. Hansen received the American Meteorological Society’s Carl-Gustaf Rossby Annex 1
Research Medal. In 2010 he received the Sophie Prize and the Blue Planet Prize.
Additional Information:
Http://www.columbia.edu/~jeh1/
http://www.columbia.edu/~mhs119/
Photos: http://www.mediafire.com/folder/8ecel33ccmg8l/Hansen_Photos
Education:
BA with highest distinction (Physics and Mathematics), University of Iowa, 1963
MS (Astronomy), University of Iowa, 1965
Visiting student, Inst. of Astrophysics, University of Kyoto & Dept. of Astronomy, Tokyo University, Japan, 1965-1966
Ph.D. (Physics), University of Iowa, 1967
Research Interests:
Analysis of the causes and consequences of global climate change using the Earth’s paleoclimate history, ongoing global observations, and interpretive tools including climate models. Connecting the dots all the way from climate observations
to the policies that are needed to stabilize climate and preserve our planet for young people and other species.
Professional Employment:
1967-1969 NAS-NRC Resident Research Associate: Goddard Institute for Space Studies (GISS), NY
1969 NSF Postdoctoral Fellow: Leiden Observatory, Netherlands
1969-1972 Research Associate: Columbia University, NY
1972-1981 Staff Member/Space Scientist: Goddard Institute for Space Studies (GISS), Manager of GISS Planetary and Climate Programs
1978-1985 Adjunct Associate Professor: Department of Geological Sciences, Columbia University
1981-2013 Director: NASA Goddard Institute for Space Studies
1985-2013 Adjunct Professor: Earth and Environmental Sciences, Columbia University
2013-present Director: Program on Climate Science, Awareness and Solutions, Columbia University
Project Experience:
1971-1974 Co-Principal Investigator AEROPOL Project (airborne terrestrial infrared polarimeter)
1972-1985 Co-Investigator, Voyager Photopolarimeter Experiment
1974-1994 Principal Investigator (1974-8) and subsequently Co-Investigator, Pioneer Venus Orbiter Cloud-Photopolarimeter Experiment
1977-2000 Principal Investigator, Galileo (Jupiter Orbiter) Photopolarimeter Radiometer Experiment
Teaching Experience:
Atmospheric Radiation (graduate level): New York Univ., Dept. of Meteorology & Oceanography
Intro. to Planetary Atmospheres & Climate Change: Columbia Univ., Dept. of Geological Sciences
Awards:
1977 Goddard Special Achievement Award (Pioneer Venus)
1978 NASA Group Achievement Award (Voyager, Photopolarimeter)
1984 NASA Exceptional Service Medal (Radiative Transfer)
1989 National Wildlife Federation Conservation Achievement Award
1990 NASA Presidential Rank Award of Meritorious Executive
1991 University of Iowa Alumni Achievement Award
1992 American Geophysical Union Fellow
1993 NASA Group Achievement Award (Galileo, Polarimeter/Radiometer)
1996 Elected to National Academy of Sciences
1996 GSFC William Nordberg Achievement Medal
1996 Editors’ Citation for Excellence in Refereeing for Geophysical Research Letters
1997 NASA Presidential Rank Award of Meritorious Executive
2000 University of Iowa Alumni Fellow
2000 GISS Best Scientific Publication (peer vote): “Global warming – alternative scenario”
2001 John Heinz Environment Award
2001 Roger Revelle Medal, American Geophysical Union Annex 1
2004 GISS Best Scientific Publication (peer vote): ‘Soot Climate Forcing’
2005 GISS Best Scientific Publication (peer vote): ‘Earth’s Energy Imbalance’
2006 Duke of Edinburgh Conservation Medal, World Wildlife Fund (WWF)
2006 GISS Best Scientific Publication (peer vote): ‘Global Temperature Change’
2006 Time Magazine designation as one of World's 100 Most Influential People.
2007 Laureate, Dan David Prize for Outstanding Achievements & Impacts in Quest for Energy
2007 Leo Szilard Award, American Physical Society for Outstanding Promotion & Use of Physics for the Benefit of Society
2007 Haagen-Smit Clean Air Award
2008 American Association for the Advancement of Science Award for Scientific Freedom and Responsibility
2008 Nevada Medal, Desert Research Institute
2008 Common Wealth Award for Distinguished Service in Science
2008 Bownocker Medal, Ohio State University
2008 Rachel Carson Award for Integrity in Science, Center for Science in the Public Interest
2009 Carl-Gustaf Rossby Research Medal, American Meteorological Society
2009 Peter Berle Environmental Integrity Award
2010 Sophie Prize for Environmental and Sustainable Development
2010 Blue Planet Prize, Asahi Glass Foundation – shared with Robert Watson
2011 American Association of Physics Teachers Klopsteg Memorial Award for communicating physics to the general public
2011 Edinburgh Medal from City of Edinburgh, Edinburgh Science Festival
2012 Steve Schneider Climate Science Communications Award
2012 Foreign Policy designation as one of its Top 100 Global Thinkers
2013 Ridenhour Courage Prize
2013 NASA Distinguished Service Medal
2014 Center for International Environmental Law’s Frederick R. Anderson Award for Outstanding Contributions to Addressing Climate Change
2014 Walker Prize, Museum of Science, Boston
2017 2017 AAG Honorary Geographer, American Association of Geographers
2017 BBVA Foundation Frontiers of Knowledge Award in Climate Change, Spain – shared with Suki Manabe
2018 Tang Prize in Sustainable Development – shared with Veerabhadran Ramanathan
Publications:
Hansen, J.E., M. Sato, L. Simons, L.S. Nazarenko, I. Sangha, P. Kharecha, J.C. Zachos, K. von Schuckmann, N.G. Loeb, M.B. Osman, Q. Jin, G. Tselioudis, E. Jeong, A. Lacis, R. Ruedy, G. Russell, J. Cao, J. Li, 2023: Global warming in the pipeline, Oxford Open Climate Change, 3, 1, kgad008, https://doi.org/10.1093/oxfclm/kgad008
Li, J., B.E. Carlson, Y.L. Yung et al., 2022: Scattering and absorbing aerosols in the climate system. Nat Rev Earth Environ 3, 363–379, https://doi.org/10.1038/s43017-022-00296-7
von Schuckmann, K., L. Cheng, M.D. Palmer, J. Hansen et al., 2020: Heat stored in the Earth system: where does the energy go?, Earth System Science Data, 12, 2013-2041, doi:10.5195/essd-12-2013-2020.
Beerling, D.J., E.P. Kantzas, M.R. Lomas, P. Wade, R.M. Eufrasio, P. Renforth, B. Sarkar, M.G. Andrews, R.H. James, C.R. Pearce, J. Mercure, H. Pollitt, P.B. Holden, N.R. Edwards, M. Khanna, L. Koh, S. Quegan, N.F. Pidgeon, I.A. Janssens, J. Hansen, S.A. Banwart, 2020: Potential for large-scale CO2 removal via enhanced rock weathering with croplands. Nature, 583, 242-248, https://doi.org/10.1038/s41586-020-2448-9.
Rye, C.D., J. Marshall, M. Kelley, G. Russell, L. Nazarenko, Y. Kostov, G.A. Schmidt, J. Hansen, 2020: Antarctic Glacial Melt as a Driver of Recent Southern Ocean Climate Trends. Geophysical Research Letters, 47, e2019GL086892. https://doi.org/10.1029/2019GL086892
Miller, D.H., J.E. Hansen, 2019: Why Fee and Dividend Will Reduce Emissions Faster Than Other Carbon Pricing Policy Options, Response to the Request for Information from the United States House of Representatives Select Committee on the Climate Crisis.
Lenssen, N.J.L., G.A. Schmidt, J.E. Hansen, M.J. Menne, A. Persin, R. Ruedy, and D. Zyss, 2019: Improvements in the GISTEMP uncertainty model, J. Geophys. Res. Atmos., 124, no. 12, 6307-6326, 10.1029/2018JD029522.
Hansen, J., P. Kharecha, 2018: Cost of carbon capture: Can young people bear the burden? Joule, 2, 1405-1407.
Beerling, D.J., J.R. Leake, S.P. Long, J.D. Scholes, J. Ton, P.N. Nelson, M. Bird, E. Kantzas, L.L. Taylor, B. Sarkar, M. Kelland, E. DeLucia, I. Kantola, C. Muller, G.H. Rau and J. Hansen, 2018: Farming with crops and rocks to address Annex 1
global climate, food and soil security, Nature Plants, 4, 138-147.
Hansen, J., M. Sato, P. Kharecha, K. von Schuckmann, D.J. Beerling, J. Cao, S. Marcott, V. Masson-Delmotte, M.J. Prather, E.J. Rohling, J. Shakun, P. Smith, A. Lacis, G. Russell, and R. Ruedy, 2017: Young people's burden: requirement of negativeCO2 emissions. Earth Syst. Dynam., 8, 577-616, doi:10.5194/esd-8-577-2017.
Cao, J, A. Cohen, J. Hansen, R. Lester, P. Peterson and H. Xu , 2016: China-U.S. cooperation to advance nuclear power. Science, 353, 547-548. doi: 10.1126/science.aaf7131. Get a PDF from Scholarly Publications page
Hansen, J., M. Sato, P. Kharecha, K. von Schuckmann, D.J. Beerling, J. Cao, S. Marcott, V. Masson-Delmotte, M.J. Prather, E.J. Rohling, J. Shakun, P. Smith, 2016: Young people's burden: requirement of negative CO2 emissions. Earth Syst. Dynam. Discuss., doi:10.5194/esd-2016-42, Published 4 October 2016.
Taylor, L.L., J. Quirk, R.M.S. Thorley, P.A. Kharecha, J. Hansen, A. Ridgwell, M.R. Lomas, S.A. Banwart, D.J. Beerling, 2016: Enhanced weathering strategies for stabilizing climate and averting ocean acidification. Nature Climate Change, 6, 402-406. doi:10.1038/NCLIMATE2882.
Hansen, J., M. Sato, P. Hearty, R. Ruedy, et al., 2016: Ice melt, sea level rise and superstorms: evidence from paleoclimate data, climate modeling, and modern observations that 2°C global warming could be dangerous Atmos. Chem. Phys., 16, 3761-3812. doi:10.5194/acp-16-3761-2016.
Hansen, J. & M. Sato, 2016: Regional Climate Change and National Responsibilities Environ. Res. Lett. 11 0340 09 (9 pp.), doi:10.1088/1748-9326/11/3/034009.
Von Schuckmann, K., Palmer, M.D., Trenberth, K.E., Cazenave, A., Chambers, D., Champollion, N. Hansen, J., Josey, S.A., Loeb, N., Mathieu, P.P., Meyssignac, B., and Wild, M., 2016: An imperative to monitor Earth’s energy imbalance, Nature Clim. Change, 6, 138-144. doi:10.1038/nclimate2876.
Hansen, J., Sato, M., Hearty, P., Ruedy, R., Kelley, M., Masson-Delmotte, V., Russell, G., Tselioudis, G., Cao, J., Rignot, E., Velicogna, I., Kandiano, E., von Schuckmann, K., Kharecha, P., Legrande, A. N., Bauer, M., and Lo, K.-W.: Ice melt, sea level rise and superstorms: evidence from paleoclimate data, climate modeling, and modern observations that 2 °C global warming is highly dangerous, Atmos. Chem. Phys. Discuss., 15, 20059-20179, doi:10.5194/acpd-15-20059-2015, 2015.
Hansen, J., 2015: Environment and Development Challenges: The Imperative of a Carbon Fee and Dividend. The Oxford Handbook of the Macroeconomics of Global Warming, Eds. Lucas Bernard and Willi Semmler, Chapter 26, doi:10.1093/oxfordhb/9780199856978.013.0026.
Nazarenko, L., G.A. Schmidt, R.L. Miller, N. Tausnev, M. Kelley, R. Ruedy, G.L. Russell, I. Aleinov, M. Bauer, S. Bauer, R. Bleck, V. Canuto, Y. Cheng, T.L. Clune, A.D. Del Genio, G. Faluvegi, J.E. Hansen, R.J. Healy, N.Y. Kiang, D. Koch, A.A. Lacis, A.N. LeGrande, J. Lerner, K.K. Lo, S. Menon, V. Oinas, J.P. Perlwitz, M.J. Puma, D. Rind, A. Romanou, M. Sato, D.T. Shindell, S. Sun, K. Tsigaridis, N. Unger, A. Voulgarakis, M.-S. Yao, and J. Zhang, 2015: Future climate change under RCP emission scenarios with GISS ModelE2. J. Adv. Model. Earth Syst., 6, 441-477, no. 1, doi:10.1002/2013MS000266.
Hansen, J. 2014: The Energy to Fight Injustice. Chemistry World.
Miller, R.L., G.A. Schmidt, L.S. Nazarenko, N. Tausnev, S.E. Bauer, A.D. Del Genio, M. Kelley, K.K. Lo, R. Ruedy, D.T. Shindell, I. Aleinov, M. Bauer, R. Bleck, V. Canuto, Y.-H. Chen, Y. Cheng, T.L. Clune, G. Faluvegi, J.E. Hansen, R.J. Healy, N.Y. Kiang, D. Koch, A.A. Lacis, A.N. LeGrande, J. Lerner, S. Menon, V. Oinas, C. Pérez García-Pando, J.P. Perlwitz, M.J. Puma, D. Rind, A. Romanou, G.L. Russell, M. Sato, S. Sun, K. Tsigaridis, N. Unger, A. Voulgarakis, M. S. Yao, and J. Zhang, 2014: CMIP5 historical simulations (1850-2012) with GISS ModelE2. J. Adv. Model. Earth Syst., 6, no. 2, 441-477, doi:10.1002/2013MS000266.
Schmidt, G.A., M. Kelley, L. Nazarenko, R. Ruedy, G.L. Russell, I. Aleinov, M. Bauer, S.E. Bauer, M.K. Bhat, R. Bleck, V. Canuto, Y.-H. Chen, Y. Cheng, T.L. Clune, A. Del Genio, R. de Fainchtein, G. Faluvegi, J.E. Hansen, R.J. Healy, N.Y. Kiang, D. Koch, A.A. Lacis, A.N. LeGrande, J. Lerner, K.K. Lo, E.E. Matthews, S. Menon, R.L. Miller, V. Oinas, A.O. Oloso, J.P. Perlwitz, M.J. Puma, W.M. Putman, D. Rind, A. Romanou, M. Sato, D.T. Shindell, S. Sun, R.A. Syed, N. Tausnev, K. Tsigaridis, N. Unger, A. Voulgarakis, M.-S. Yao, and J. Zhang, 2014: Configuration and assessment of the GISS ModelE2 contributions to the CMIP5 archive. J. Adv. Model. Earth Syst., 6, 141-184, doi:10.1002/2013MS000265.
Hansen, J., M. Sato, and R. Ruedy, 2013: Reply to Rhines and Huybers: Changes in the frequency of extreme summer heat. Proc. Natl. Acad. Sci., 110, E547-E548, doi:10.1073/pnas.1220916110.
Hansen, J., P. Kharecha, M. Sato, V. Masson-Delmotte, F. Ackerman, D. Beerling, P.J. Hearty, O. Hoegh-Guldberg, S.-L.Hsu, C. Parmesan, J. Rockstrom, E.J. Rohling, J. Sachs, P. Smith, K. Steffen, L. Van Susteren, K. von Schuckmann, and J.C. Zachos, 2013: Assessing "dangerous climate change": Required reduction of carbon emissions to protect young people, future generations and nature. PLOS ONE, 8, e81648.
Hansen, J., M. Sato, and R. Ruedy, 2013: Reply to Stone et al.: Human-made role in local temperature extremes. Proc. Natl. Acad. Sci., 110, E1544, doi:10.1073/pnas.1301494110. Annex 1
Kharecha, P., and J.E. Hansen, 2013: Response to comment by Rabilloud on “Prevented mortality and greenhouse gas emissions from historical and projected nuclear power”. Environ. Sci. Technol., 47, 13900-13901, doi:10.1021/es404806w.
Kharecha, P.A., and J.E. Hansen, 2013: Response to comment on “Prevented mortality and greenhouse gas emissions from historical and projected nuclear power”. Environ. Sci. Technol., 47, 6718-6719, doi:10.1021/es402211m.
Hansen, J., M. Sato, G. Russell, and P. Kharecha, 2013: Climate sensitivity, sea level, and atmospheric carbon dioxide, Phil. Trans. Roy. Soc. A, 371, 20120294, http://dx.doi.org/10.1098/rsta.2012.0294.
Kharecha, P.A., and J.E. Hansen, 2013: Prevented mortality and greenhouse gas emissions from historical and projected nuclear power. Environ. Sci. Technol., 47, 4889-4895, doi:10.1021/es3051197
Hansen, J., P. P. Kharecha, and M. Sato, 2013: Climate forcing growth rates: Doubling down on our Faustian bargain. Environ. Res. Lett., 8, 011006, doi:10.1088/1748-9326/8/1/011006.
Lacis, A.A., J.E. Hansen, G.L. Russell, V. Oinas, and J. Jonas, 2013: The role of long-lived greenhouse gases as principal LW control knob that governs the global surface temperature for past and future climate change. Tellus B, 65, 19734, doi:10.3402/tellusb.v65i0.19734
Previdi, M., B.G. Liepert, D. Peteet, J. Hansen, D.J. Beerling, A.J. Broccoli, S. Frolking, J.N. Galloway, M. Heimann, C. Le Quéré, S. Levitus, and V. Ramaswamy, 2013: Climate sensitivity in the Anthropocene. Q. J. R. Meteorol. Soc., 139, 1121-1131, doi:10.1002/qj.2165.
Rohling, E.J., A. Sluijs, H.A. Dijkstra, P. Köhler, R.S.W. van de Wal, A.S. von der Heydt, D.J. Beerling, A. Berger, P.K. Bijl, M. Crucifix, R. DeConto, S.S. Drijfhout, A. Fedorov, G.L. Foster, A. Ganopolski, J. Hansen, B. Hönisch, H. Hooghiemstra, M. Huber, P. Huybers, R. Knutti, D.W. Lea, L.J. Lourens, D. Lunt, V. Masson-Demotte, M. Medina-Elizalde, B. Otto-Bliesner, M. Pagani, H. Pälike, H. Renssen, D.L. Royer, M. Siddall, P. Valdes, J.C. Zachos, and R.E. Zeebe, 2012: Making sense of palaeoclimate sensitivity. Nature, 491, 683-691, doi:10.1038/nature11574.
Hansen, J., M. Sato, and R. Ruedy, 2012: Perception of climate change. Proc. Natl. Acad. Sci., 109, 14726-14727, E2415- E2423, doi:10.1073/pnas.1205276109.
Hansen, J.E., and M. Sato, 2012: Paleoclimate implications for human-made climate change. In Climate Change:Inferences from Paleoclimate and Regional Aspects. A. Berger, F. Mesinger, and D. Šijački, Eds. Springer, pp. 21- 48, doi:10.1007/978-3-7091-0973-1_2.
Hansen, J., M. Sato, P. Kharecha, and K. von Schuckmann, 2011: Earth's energy imbalance and implications. Atmos. Chem. Phys., 11, 13421-13449, doi:10.5194/acp-11-13421-2011.
Kharecha, P.A., C.F. Kutscher, J.E. Hansen, and E. Mazria, 2010: Options for near-term phaseout of CO2 emissions from coal use in the United States. Environ. Sci. Technol., 44, 4050-4062, doi:10.1021/es903884a.
Hansen, J., R. Ruedy, M. Sato, and K. Lo, 2010: Global surface temperature change. Rev. Geophys., 48, RG4004, doi:10.1029/2010RG000345.
Masson-Delmotte, V., B. Stenni, K. Pol, P. Braconnot, O. Cattani, S. Falourd, M. Kageyama, J. Jouzel, A. Landais, B. Minster, J.M. Barnola, J. Chappellaz, G. Krinner, S. Johnsen, R. Röthlisberger, J. Hansen, U. Mikolajewicz, and B. Otto-Bliesner, 2010: EPICA Dome C record of glacial and interglacial intensities. Quat. Sci. Rev., 29, 113-128, doi:10.1016/j.quascirev.2009.09.030.
Rockström, J., W. Steffen, K. Noone, Å. Persson, F.S. Chapin, III, E. Lambin, T.M. Lenton, M. Scheffer, C. Folke, H. Schellnhuber, B. Nykvist, C.A. De Wit, T. Hughes, S. van der Leeuw, H. Rodhe, S. Sörlin, P.K. Snyder, R. Costanza, U. Svedin, M. Falkenmark, L. Karlberg, R.W. Corell, V.J. Fabry, J. Hansen, B. Walker, D. Liverman, K. Richardson, P. Crutzen, and J. Foley, 2009: Planetary boundaries: Exploring the safe operating space for humanity. Ecol. Soc., 14 (2), 32.
Rockström, J., W. Steffen, K. Noone, Å. Persson, F.S. Chapin, III, E.F. Lambin, T.M. Lenton, M. Scheffer, C. Folke, H.J. Schellnhuber, B. Nykvist, C.A. de Wit, T. Hughes, S. van der Leeuw, H. Rodhe, S. Sörlin, P.K. Snyder, R. Costanza, U. Svedin, M. Falkenmark, L. Karlberg, R.W. Corell, V.J. Fabry, J. Hansen, B. Walker, D. Liverman, K. Richardson, P. Crutzen, and J.A. Foley, 2009: A safe operating space for humanity. Nature, 461, 472-475, doi:10.1038/461472a.
Xu, B., J. Cao, J. Hansen, T. Yao, D.J. Joswia, N. Wang, G. Wu, M. Wang, H. Zhao, W. Yang, X. Liu, and J. He, 2009: Black soot and the survival of Tibetan glaciers. Proc. Natl. Acad. Sci., 106 , 22114-22118, doi:10.1073/pnas.0910444106.
Hansen, J., Mki. Sato, P. Kharecha, D. Beerling, R. Berner, V. Masson-Delmotte, M. Pagani, M. Raymo, D.L. Royer, and J.C. Zachos, 2008: Target atmospheric CO2: Where should humanity aim? Open Atmos. Sci. J., 2, 217-231, doi:10.2174/1874282300802010217.
Kharecha, P.A., and J.E. Hansen, 2008: Implications of "peak oil" for atmospheric CO2 and climate. Global Biogeochem. Cycles, 22, GB3012, doi:10.1029/2007GB003142.
Hansen, J., 2008: Tipping Point: Perspective of a Climatologist. In The State of the Wild: A Global Portrait of Wildlife, Wild Lands, and Oceans. E. Fearn, Ed. Wildlife Conservation Society/Island Press, pp. 6-15.
Hansen, J.E., 2007: Scientific reticence and sea level rise. Environ. Res. Lett., 2, 024002, doi:10.1088/1748-9326/2/2/024002. Annex 1
Hansen, J., Mki. Sato, R. Ruedy, and 44 co-authors, 2007: Climate simulations for 1880-2003 with GISS modelE. Clim. Dynam., 29, 661-696, doi:10.1007/s00382-007-0255-8.
Hansen, J., 2007: Climate catastrophe. New Scientist, 195, no. 2614 (July 28), 30-34.
Hansen, J., 2007: Why we can't wait: A 5-step plan for solving the global crisis. Nation, 284, no. 18 (May 7), 13-14.
Hansen, J., Mki. Sato, P. Kharecha, G. Russell, D.W. Lea, and M. Siddall, 2007: Climate change and trace gases. Phil. Trans. Royal. Soc. A, 365, 1925-1954, doi:10.1098/rsta.2007.2052.
Hansen, J., Mki. Sato, R. Ruedy, and 44 co-authors, 2007: Dangerous human-made interference with climate: A GISS modelE study. Atmos. Chem. Phys., 7, 2287-2312.
Hansen, J.E., 2007: Scientific reticence and sea level rise. Environ. Res. Lett., 2, 024002, doi:10.1088/17489326/2/2/024002.
Nazarenko, L., N. Tausnev, and J. Hansen, 2007: The North Atlantic thermohaline circulation simulated by the GISS climate model during 1970-99. Atmos.-Ocean, 45, 81-92, doi:10.3137/ao.450202.
Mishchenko, M.I., B. Cairns, G. Kopp, C.F. Schueler, B.A. Fafaul, J.E. Hansen, R.J. Hooker, T. Itchkawich, H.B. Maring, and L.D. Travis, 2007: Precise and accurate monitoring of terrestrial aerosols and total solar irradiance: Introducing the Glory mission. Bull. Amer. Meteorol. Soc., 88, 677-691, doi:10.1175/BAMS-88-5-677.
Novakov, T., S. Menon, T.W. Kirchstetter, D. Koch, and J.E. Hansen, 2007: Reply to comment by R. L. Tanner and D. J.Eatough on "Aerosol organic carbon to black carbon ratios: Analysis of published data and implications for climate forcing". J. Geophys. Res., 112, D02203, doi:10.1029/2006JD007941.
Rahmstorf, S., A. Cazenave, J.A. Church, J.E. Hansen, R.F. Keeling, D.E. Parker, and R.C.J. Somerville, 2007: Recent climate observations compared to projections. Science, 316, 709, doi:10.1126/science.1136843.
Hansen, J., 2006: The threat to the planet. New York Rev. Books, 53, no. 12 (July 13, 2006), 12-16.
Hansen, J., Mki. Sato, R. Ruedy, K. Lo, D.W. Lea, and M. Medina-Elizade, 2006: Global temperature change. Proc. Natl. Acad. Sci., 103, 14288-14293, doi:10.1073/pnas.0606291103.
Nazarenko, L., N. Tausnev, and J. Hansen, 2006: Sea-ice and North Atlantic climate response to CO2-induced warming and cooling conditions. J. Glaciol., 52, 433-439.
Santer, B.D., T.M.L. Wigley, P.J. Gleckler, C. Bonfils, M.F. Wehner, K. AchutaRao, T.P. Barnett, J.S. Boyle, W. Brüggemann, M. Fiorino, N. Gillett, J.E. Hansen, P.D. Jones, S.A. Klein, G.A. Meehl, S.C.B. Raper, R.W. Reynolds, K.E. Taylor, and W.M. Washington, 2006: Forced and unforced ocean temperature changes in Atlantic and Pacific tropical cyclogenesis regions. Proc. Natl. Acad. Sci., 103, 13905-13910, doi:10.1073/pnas.0602861103.
Schmidt, G.A., R. Ruedy, J.E. Hansen, I. Aleinov, N. Bell, M. Bauer, S. Bauer, B. Cairns, V. Canuto, Y. Cheng, A. Del Genio, G. Faluvegi, A.D. Friend, T.M. Hall, Y. Hu, M. Kelley, N.Y. Kiang, D. Koch, A.A. Lacis, J. Lerner, K.K. Lo, R.L. Miller, L. Nazarenko, V. Oinas, Ja. Perlwitz, Ju. Perlwitz, D. Rind, A. Romanou, G.L. Russell, Mki. Sato, D.T. Shindell, P.H. Stone, S. Sun, N. Tausnev, D. Thresher, and M.-S. Yao, 2006: Present day atmospheric simulations using GISS ModelE: Comparison to in-situ, satellite and reanalysis data. J. Climate, 19, 153-192, doi:10.1175/JCLI3612.1.
Shindell, D., G. Faluvegi, A. Lacis, J. Hansen, R. Ruedy, and E. Aguilar, 2006: Role of tropospheric ozone increases in 20th century climate change. J. Geophys. Res., 111, D08302, doi:10.1029/2005JD006348.
Shindell, D.T., G. Faluvegi, R.L. Miller, G.A. Schmidt, J.E. Hansen, and S. Sun, 2006: Solar and anthropogenic forcing of tropical hydrology. Geophys. Res. Lett., 33, L24706, doi:10.1029/2006GL027468, 2006.
Hansen, J., L. Nazarenko, R. Ruedy, Mki. Sato, and 11 co-authors, 2005: Earth's energy imbalance: Confirmation and implications. Science, 308, 1431-1435, doi:10.1126/science.1110252.
Hansen, J., Mki. Sato, R. Ruedy, L. Nazarenko, A. Lacis, G.A. Schmidt, G. Russell, and 38 co-authors, 2005: Efficacy of climate forcings. J. Geophys. Res., 110, D18104, doi:10.1029/2005JD005776.
Hansen, J.E., 2005: A slippery slope: How much global warming constitutes "dangerous anthropogenic interference"? An editorial essay. Climatic Change, 68, 269-279, doi:10.1007/s10584-005-4135-0.
Koch, D., and J. Hansen, 2005: Distant origins of Arctic black carbon: A Goddard Institute for Space Studies ModelE experiment. J. Geophys. Res., 110, D04204, doi:10.1029/2004JD005296.
Novakov, T., S. Menon, T.W. Kirchstetter, D. Koch, and J.E. Hansen, 2005: Aerosol organic carbon to black carbon ratios: Analysis of published data and implications for climate forcing. J. Geophys. Res., 110, D21205, doi:10.1029/2005JD005977.
Santer, B.D., T.M.L. Wigley, C. Mears, F.J. Wentz, S.A. Klein, D.J. Seidel, K.E. Taylor, P.W. Thorne, M.F. Wehner, P.J. Gleckler, J.S. Boyle, W.D. Collins, K.W. Dixon, C. Doutriaux, M. Free, Q. Fu, J.E. Hansen, and 8 co-authors, 2005: Amplification of surface temperature trends and variability in the tropical atmosphere. Science, 309, 1551-1556, doi:10.1126/science.1114867.
Hansen, J., 2004: Defusing the global warming time bomb. Sci. Amer., 290, no. 3, 68-77.
Hansen, J., T. Bond, B. Cairns, H. Gaeggler, B. Liepert, T. Novakov, and B. Schichtel, 2004: Carbonaceous aerosols in the industrial era. Eos Trans. Amer. Geophys. Union, 85, no. 25, 241, 245.
Hansen, J., and L. Nazarenko, 2004: Soot climate forcing via snow and ice albedos. Proc. Natl. Acad. Sci., 101, 423-428,
Annex 1
doi:10.1073/pnas.2237157100.
Hansen, J., and Mki. Sato, 2004: Greenhouse gas growth rates. Proc. Natl. Acad. Sci., 101, 16109-16114, doi:10.1073/pnas.0406982101.
Mishchenko, M.I., B. Cairns, J.E. Hansen, L.D. Travis, R. Burg, Y.J. Kaufman, J.V. Martins, and E.P. Shettle, 2004: Monitoring of aerosol forcing of climate from space: Analysis of measurement requirements. J. Quant. Spectrosc. Radiat. Transfer, 88, 149-161, doi:10.1016/j.jqsrt.2004.03.030.
Novakov, T., and J.E. Hansen, 2004: Black carbon emissions in the United Kingdom during the past four decades: An empirical analysis. Atmos. Environ., 38, 4155-4163, doi:10.1016/j.atmosenv.2004.04.031.
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Novakov, T., V. Ramanathan, J.E. Hansen, T.W. Kirchstetter, Mki. Sato, J.E. Sinton, and J.A. Satahye, 2003: Large historical changes of fossil-fuel black carbon aerosols. Geophys. Res. Lett., 30, no. 6, 1324, doi:10.1029/2002GL016345
Santer, B.D., R. Sausen, T.M.L. Wigley, J.S. Boyle, K. AchutaRao, C. Doutriaux, J.E. Hansen, G.A. Meehl, E. Roeckner, R. Ruedy, G. Schmidt, and K.E. Taylor, 2003: Behavior of tropopause height and atmospheric temperature in models, reanalyses, and observations: Decadal changes. J. Geophys. Res., 108, no. D1, 4002, doi:10.1029/2002JD002258.
Sato, Mki., J. Hansen, D. Koch, A. Lacis, R. Ruedy, O. Dubovik, B. Holben, M. Chin, and T. Novakov, 2003: Global atmospheric black carbon inferred from AERONET. Proc. Natl. Acad. Sci., 100, 6319-6324, doi:10.1073/pnas.0731897100.
Sun, S., and J.E. Hansen, 2003: Climate simulations for 1951-2050 with a coupled atmosphere-ocean model. J. Climate, 16, 2807-2826, doi:10.1175/1520-0442(2003)016<2807:CSFWAC>2.0.CO;2.
Carmichael, G.R., D.G. Streets, G. Calori, M. Amann, M.Z. Jacobson, J. Hansen, and H. Ueda, 2002: Changing trends in sulfur emissions in Asia: Implications for acid deposition. Environ. Sci. Tech, 36, 4707-4713, doi:10.1021/es011509c.
Hansen, J., R. Ruedy, Mki. Sato, and K. Lo, 2002: Global warming continues. Science, 295, 275, doi:10.1126/science.295.5553.275c.
Hansen, J., Mki. Sato, L. Nazarenko, R. Ruedy, A. Lacis, D. Koch, I. Tegen, T. Hall,and 20 co-authors, 2002: Climate forcings in Goddard Institute for Space Studies SI2000 simulations. J. Geophys. Res., 107, no. D18, 4347, doi:10.1029/2001JD001143.
Hansen, J.E. (Ed.), 2002: Air Pollution as a Climate Forcing: A Workshop. NASA Goddard Institute for Space Studies.
Hansen, J.E., 2002: A brighter future. Climatic Change, 52, 435-440, doi:10.1023/A:1014226429221
Menon, S., J.E. Hansen, L. Nazarenko, and Y. Luo, 2002: Climate effects of black carbon aerosols in China and India. Science,297, 2250-2253, doi:10.1126/science.1075159.
Robinson, W.A., R. Ruedy, and J.E. Hansen, 2002: General circulation model simulations of recent cooling in the east –central United States. J. Geophys. Res., 107, no. D24, 4748, doi:10.1029/2001JD001577.
Hansen, J.E., R. Ruedy, Mki. Sato, M. Imhoff, W. Lawrence, D. Easterling, T. Peterson, and T. Karl, 2001: A closer look at United States and global surface temperature change. J. Geophys. Res., 106, 23947-23963, doi:10.1029/2001JD000354.
Hansen, J.E., and Mki. Sato, 2001: Trends of measured climate forcing agents. Proc. Natl. Acad. Sci., 98, 14778-14783, doi:10.1073/pnas.261553698.
Nazarenko, L., J. Hansen, N. Tausnev, and R. Ruedy, 2001: Response of the Northern Hemisphere sea ice to greenhouse forcing in a global climate model. Ann. Glaciol., 33, 513-520.
Oinas, V., A.A. Lacis, D. Rind, D.T. Shindell, and J.E. Hansen, 2001: Radiative cooling by stratospheric water vapor: Big differences in GCM results. Geophys. Res. Lett., 28, 2791-2794, doi:10.1029/2001GL013137.
Santer, B.D., T.M.L. Wigley, C. Doutriaux, J.S. Boyle, J.E. Hansen, P.D. Jones, G.A. Meehl, E. Roeckner, S. Sengupta, and K.E. Taylor, 2001: Accounting for the effects of volcanoes and ENSO in comparisons of modeled and observed temperature trends. J. Geophys. Res., 106, 28033-28059, doi:10.1029/2000JD000189.
Streets, D.G., K. Jiang, X. Hu, J.E. Sinton, X.-Q. Zhang, D. Xu, M.Z. Jacobson, and J.E. Hansen, 2001: Recent reductions in China's greenhouse gas emissions. Science, 294, 1835-1837, doi:10.1126/science.1065226.
Hansen, J., R. Ruedy, A. Lacis, Mki. Sato, L. Nazarenko, N. Tausnev, I. Tegen, and D. Koch, 2000: Climate modeling in the global warming debate. In General Circulation Model Development. D. Randall, Ed. Academic Press, pp. 127-164.
Hansen, J., Mki. Sato, R. Ruedy, A. Lacis, and V. Oinas, 2000: Global warming in the twenty-first century: An alternative scenario. Proc. Natl. Acad. Sci., 97, 9875-9880, doi:10.1073/pnas.170278997.
Hansen, J.E., 2000: The Sun's role in long-term climate change. Space Sci. Rev., 94, 349-356, doi:10.1023/A:1026748129347.
Lacis, A.A., B.E. Carlson, and J.E. Hansen, 2000: Retrieval of atmospheric NO2, O3, aerosol optical depth, effective radius and variance information from SAGE II multi-spectral extinction measurements. Appl. Math. Comput., 116, 133-151, doi:10.1016/S0096-3003(99)00200-3.
Hansen, J., R. Ruedy, J. Glascoe, and Mki. Sato, 1999: GISS analysis of surface temperature change. J. Geophys. Res., 104, 30997-31022, doi:10.1029/1999JD900835.
Hansen, J., Mki. Sato, J. Glascoe, and R. Ruedy, 1998: A common sense climate index: Is climate changing noticeably? Proc. Annex 1
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Hansen, J., Mki. Sato, A. Lacis, R. Ruedy, I. Tegen, and E. Matthews, 1998: Perspective: Climate forcings in the industrial era. Proc. Natl. Acad. Sci., 95, 12753-12758.
Hansen, J.E., 1998: Book review of Sir John Houghton's Global Warming: The Complete Briefing. J. Atmos. Chem., 30, 409-412.
Hansen, J.E., Mki. Sato, R. Ruedy, A. Lacis, and J. Glascoe, 1998: Global climate data and models: A reconciliation. Science, 281, 930-932, doi:10.1126/science.281.5379.930.
Matthews, E., and J. Hansen (Eds.), 1998: Land Surface Modeling: A Mini-Workshop. NASA Goddard Institute for Space Studies.
Hansen, J., C. Harris, C. Borenstein, B. Curran, and M. Fox, 1997: Research education. J. Geophys. Res., 102, 25677-25678, doi:10.1029/97JD02172.
Hansen, J., R. Ruedy, A. Lacis, G. Russell, Mki. Sato, J. Lerner, D. Rind, and P. Stone, 1997: Wonderland climate model. J. Geophys. Res., 102, 6823-6830, doi:10.1029/96JD03435.
Hansen, J., Mki. Sato, A. Lacis, and R. Ruedy, 1997: The missing climate forcing. Phil. Trans. Royal Soc. London B, 352, 231-240.
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Wilder, R. Willson, and J. Zawodny, 1997: Forcings and chaos in interannual to decadal climate change. J. Geophys. Res., 102, 25679-25720, doi:10.1029/97JD01495.
Hansen, J., 1996: Climatic change: understanding global warming, pp. 173-190, in One World: The Health and Survival of the Human Species in the 21st Century, Ed. R. Lanza, Health Press, Santa Fe, NM, 325 pp.
Hansen, J., R. Ruedy, Mki. Sato, and R. Reynolds, 1996: Global surface air temperature in 1995: Return to pre-Pinatubo level. Geophys. Res. Lett., 23, 1665-1668, doi:10.1029/96GL01040.
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Hansen, J., W. Rossow, B. Carlson, A. Lacis, L. Travis, A. Del Genio, I. Fung, B. Cairns, M. Mishchenko, and Mki. Sato, 1995: Low-cost long-term monitoring of global climate forcings and feedbacks. Climatic Change, 31, 247-271, doi:10.1007/BF01095149.
Hansen, J., Mki. Sato, and R. Ruedy, 1995: Long-term changes of the diurnal temperature cycle: Implications about mechanisms of global climate change. Atmos. Res., 37, 175-209, doi:10.1016/0169-8095(94)00077-Q.
Hansen, J., H. Wilson, Mki. Sato, R. Ruedy, K. Shah, and E. Hansen, 1995: Satellite and surface temperature data at odds? Climatic Change, 30, 103-117, doi:10.1007/BF01093228.
Hansen, J., 1993: Climate forcings and feedbacks. In Long-Term Monitoring of Global Climate Forcings and Feedbacks, NASA CP-3234. J. Hansen, W. Rossow, and I. Fung, Eds. National Aeronautics and Space Administration, pp. 6-12.
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Hansen, J., A. Lacis, R. Ruedy, Mki. Sato, and H. Wilson, 1993: How sensitive is the world's climate? Natl. Geog. Soc. Res. Exploration, 9, 142-158.
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Hansen, J., and H. Wilson, 1993: Commentary on the significance of global temperature records. Climatic Change, 25, 185-191, doi:10.1007/BF01661206.
Pollack, J.B., D. Rind, A. Lacis, J.E. Hansen, Mki. Sato, and R. Ruedy, 1993: GCM simulations of volcanic aerosol forcing. Part I: Climate changes induced by steady-state perturbations. J. Climate, 6, 1719-1742, doi:10.1175/1520-0442(1993)006<1719:GSOVAF>2.0.CO;2.
Sato, Mki., J.E. Hansen, M.P. McCormick, and J.B. Pollack, 1993: Stratospheric aerosol optical depths, 1850 -1990. J. Geophys. Res., 98, 22987-22994, doi:10.1029/93JD02553.
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Hansen, J., A. Lacis, R. Ruedy, and Mki. Sato, 1992: Potential climate impact of Mount Pinatubo eruption. Geophys. Res. Lett., 19, 215-218, doi:10.1029/91GL02788.
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Hansen, J.E., and A. Lacis, 1991: Sun and water in the greenhouse: Reply to comments. Nature, 349, 467, doi:10.1038/349467c0.
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Hansen, J., A. Lacis, and M. Prather, 1989: Greenhouse effect of chlorofluorocarbons and other trace gases. J. Geophys. Res., 94, 16417-16421.
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Hansen, J., and S. Lebedeff, 1988: Global surface air temperatures: Update through 1987. Geophys. Res. Lett., 15, 323-326, doi:10.1029/88GL02067.
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Hansen, J.E., 1985: Geophysics: Global sea level trends. Nature, 313, 349-350.
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Hansen, J., G. Russell, A. Lacis, I. Fung, D Rind, and P. Stone, 1985: Climate response times: Dependence on climate sensitivity and ocean mixing. Science, 229, 857-859, doi:10.1126/science.229.4716.857.
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Hansen, J., D. Johnson, A. Lacis, S. Lebedeff, P. Lee, D. Rind, and G. Russell, 1983: Climatic effects of atmospheric carbon Annex 1
dioxide. Science, 220, 874-875, doi:10.1126/science.220.4599.874-a.
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Gornitz, V., S. Lebedeff, and J. Hansen, 1982: Global sea level trend in the past century. Science, 215, 1611-1614, doi:10.1126/science.215.4540.1611.
Hansen, J., D. Johnson, A. Lacis, S. Lebedeff, P. Lee, D. Rind, and G. Russell, 1981: Climate impact of increasing atmospheric carbon dioxide. Science, 213, 957-966, doi:10.1126/science.213.4511.957.
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Hansen, J., 1980: Book review of Theory of Planetary Atmospheres by J.W. Chamberlain. Icarus, 41, 175-176.
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Travis, L.D., D.L. Coffeen, J.E. Hansen, K. Kawabata, A.A. Lacis, W.A. Lane, S.A. Limaye, and P.H. Stone, 1979: Orbiter cloud photopolarimeter investigation. Science, 203, 781-785, doi:10.1126/science.203.4382.781.
Hansen, J.E., W.-C. Wang, and A.A. Lacis, 1978: Mount Agung eruption provides test of a global climatic perturbation. Science, 199, 1065-1068, doi:10.1126/science.199.4333.1065.
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Schubert, G., C.C. Counselman, III, J. Hansen, S.S. Limaye, G. Pettengill, A. Seiff, I.I. Shapiro, V.E. Suomi, F. Taylor, L. Travis, R. Woo, and R.E. Young, 1977: Dynamics, winds, circulation and turbulence in the atmosphere of Venus. Space Sci. Rev., 20, 357-387, doi:10.1007/BF02186459.
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Kawabata, K., and J.E. Hansen, 1975: Interpretation of the variation of polarization over the disk of Venus. J. Atmos. Sci., 32, 1133-1139, doi:10.1175/1520-0469(1975)032<1133:IOTVOP>2.0.CO;2
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Hansen, J.E., and J.W. Hovenier, 1974: Interpretation of the polarization of Venus. J. Atmos. Sci., 31, 1137-1160, doi:10.1175/1520-0469(1974)031<1137:IOTPOV>2.0.CO;2.
Hansen, J.E., and J.W. Hovenier, 1974b: Nature Venus Clouds as Derived from Their Polarzation in Exploration of the planetary system; Proceedings of the Symposium, Torun, Poland, September 5-8, 1973. (A75-21276 08-91) Dordrecht, D. Reidel Publishing Co., 1974, p. 197-200. Research supported by the Nederlandse Organisatie voor Zuiver-Wetenschappelijk Onderzoek; Bibliographic Code: 1974IAUS...65..197H
Hansen, J.E., and L.D. Travis, 1974: Light scattering in planetary atmospheres. Space Sci. Rev., 16, 527-610, doi:10.1007/BF00168069.
Lacis, A.A., and J.E. Hansen, 1974: A parameterization for the absorption of solar radiation in the Earth's atmosphere. J. Annex 1
Atmos. Sci., 31, 118-133, doi:10.1175/1520-0469(1974)031<0118:APFTAO>2.0.CO;2.
Lacis, A.A., and J.E. Hansen, 1974: Atmosphere of Venus: Implications of Venera 8 sunlight measurements. Science, 184, 979-983, doi:10.1126/science.184.4140.979.
Somerville, R.C.J., P.H. Stone, M. Halem, J.E. Hansen, J.S. Hogan, L.M. Druyan, G. Russell, A.A. Lacis, W.J. Quirk, and J. Tenenbaum, 1974: The GISS model of the global atmosphere. J. Atmos. Sci., 31, 84-117, doi:10.1175/1520- 0469(1974)031<0084:TGMOTG>2.0.CO;2.
Coffeen, D., and J.E. Hansen, 1973: Airborne infrared polarimetry. In International Symposium on Remote Sensing of Environment, 8th, Ann Arbor, Mich., October 2-6, 1972, Proceedings. 1. (A73-39829 20-13) Ann Arbor, Mich., Environmental Research Institute of Michigan, 1973, 515-522. NASA-supported research.
Whitehill, L.P., and J.E. Hansen, 1973: On the interpretation of the "inverse phase effect" for CO2 equivalent widths on Venus. Icarus, 20, 146-152, doi:10.1016/0019-1035(73)90047-X.
Hansen, J.E., and D. Coffeen, 1972: Polarization of near-infrared sunlight reflected by terrestrial clouds. Conference on Atmospheric Radiation, Fort Collins, Colo., August 7-9, 1972, Preprints. (A73-10351 01-13) Boston, American Meteorological Society, 1972, p. 55-60.
Hansen, J.E., 1971: Multiple scattering of polarized light in planetary atmospheres. Part I. The doubling method. J. Atmos. Sci., 28, 120-125, doi:10.1175/1520-0469(1971)028<0120:MSOPLI>2.0.CO;2.
Hansen, J.E., 1971: Multiple scattering of polarized light in planetary atmospheres. Part II. Sunlight reflected by terrestrial water clouds. J. Astmos. Sci., 28, 1400-1426, doi:10.1175/1520 0469(1971)028<1400:MSOPLI>2.0.CO;2.
Hansen, J.E., 1971: Circular polarization of sunlight reflected by clouds. J. Atmos. Sci., 28, 1515-1516, doi:10.1175/1520-0469(1971)028<1515:CPOSRB>2.0.CO;2.
Hansen, J.E., and A. Arking, 1971: Clouds of Venus: Evidence for their nature. Science, 171, 669-672, doi:10.1126/science.171.3972.669.
Hansen, J.E., and J.W. Hovenier, 1971: The doubling method applied to multiple scattering of polarized light. J. Quant. Spectrosc. Radiat. Transfer, 11, 809-812, doi:10.1016/0022-4073(71)90057-4.
Liou, K.-N., and J.E Hansen, 1971: Intensity and polarization for single scattering by polydisperse spheres: A comparison of ray optics and Mie theory. J. Atmos. Sci., 28, 995-1004, doi:10.1175/1520-0469(1971)028<0995:IAPFSS>2.0.CO;2.
Hansen, J.E., and J.B. Pollack, 1970: Near-infrared light scattering by terrestrial clouds. J. Atmos. Sci., 27, 265-281, doi:10.1175/1520-0469(1970)027<0265:NILSBT>2.0.CO;2.
Hansen, J.E., 1969: Absorption-line formation in a scattering planetary atmosphere: A test of Van de Hulst's similarity relations. Astrophys. J., 158, 337-349.
Hansen, J.E., 1969: Exact and approximate solutions for multiple scattering by cloud and hazy planetary atmospheres. J. Atmos. Sci., 26, 478-487, doi:10.1175/1520-0469(1969)026<0478:EAASFM>2.0.CO;2.
Hansen, J.E., 1969: Radiative transfer by doubling very thin layers. Astrophys. J., 155, 565-573, doi:10.1086/149892.
Hansen, J.E., and H. Cheyney, 1969: Theoretical spectral scattering of ice clouds in the near infrared. J. Geophys. Res., 74, 3337-3346.
Hansen, J.E., and H. Cheyney, 1968: Near infrared reflectivity of Venus and ice clouds. J. Atmos. Sci., 25, 629-633, doi:10.1175/1520-0469(1968)025<0629:NIROVA>2.0.CO;2.
Hansen, J.E., and H. Cheyney, 1968: Comments on the paper by D.G. Rea and B.T. O'Leary, "On the composition of the Venus clouds". J. Geophys. Res., 73, 6136-6137, doi:10.1029/JB073i018p06136.
Hansen, J.E., and S. Matsushima, 1967: The atmosphere and surface temperature of Venus: A dust insulation model. Astrophys. J., 150, 1139-1157.
Hansen, J.E., and S. Matsushima, 1966: Light illuminance and color in the Earth's shadow. J. Geophys. Rev., 71, 1073-1081, doi:10.1029/JZ071i004p01073.
Matsushima, S., J.R. Zink, and J.E. Hansen, 1966: Atmospheric extinction by dust particles as determined from three -color photometry of the lunar eclipse of 19 December 1964. Astron. J., 71, 103-110. Annex 1
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