Written reply of the International Union for Conservation of Nature to the questions put by Judges Cleveland and Aurescu at the end of the hearing held on 13 December 2024

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INTERNATIONAL COURT OF JUSTICE
OBLIGATIONS OF STATES IN RESPECT OF CLIMATE CHANGE
(REQUEST FOR ADVISORY OPINION)
RESPONSES TO QUESTIONS FROM JUDGES CLEVELAND AND
AURESCU
SUBMITTED BY THE INTERNATIONAL UNION FOR
CONSERVATION OF NATURE (IUCN)
PREPARED BY THE IUCN WORLD COMMISSION ON
ENVIRONMENTAL LAW (WCEL)
20 DECEMBER 2024
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1. RESPONSE TO THE QUESTION POSED BY JUDGE CLEVELAND:
“During these proceedings, a number of Participants have referred to the
production of fossil fuels in the context of climate change, including with
respect to subsidies. In your view, what are the specific obligations under
international law of States within whose jurisdiction fossil fuels are produced to
ensure protection of the climate system and other parts of the environment from
anthropogenic emissions of greenhouse gases, if any?”
2. RESPONSE TO THE QUESTION POSED BY JUDGE AURESCU:
“Some participants have argued, during the written and/or oral stages of the
proceedings, that there exists the right to a clean, healthy and sustainable
environment in international law. Could you please develop what is, in your
view, the legal content of this right and its relation with the other human rights
which you consider relevant for this advisory opinion?”
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RESPONSE TO THE QUESTION POSED BY JUDGE CLEVELAND
1. At the public hearings on 13 December 2013, Judge Cleveland posed the following
question:
“During these proceedings, a number of Participants have referred to the
production of fossil fuels in the context of climate change, including with
respect to subsidies. In your view, what are the specific obligations under
international law of States within whose jurisdiction fossil fuels are produced to
ensure protection of the climate system and other parts of the environment from
anthropogenic emissions of greenhouse gases, if any?”
I. Due diligence-based obligations
2. The following response is grounded in the key point made in the IUCN’s written
statement and comments, and reiterated at the public hearings, that every State has the
obligation under international law to do its utmost to limit global warming to 1.5°C, and
to limit any overshoot as much as possible, and to reverse it. This is an obligation of
stringent due diligence, and it varies according to States’ different responsibilities and
capabilities.1
3. IUCN submits that this stringent due diligence obligation, informed among others by the
standard of “highest possible ambition” in the Paris Agreement,2 gives rise to several
specific obligations in relation to fossil fuel production, taking into account States’
different responsibilities and capabilities.
4. First, as indicated in IUCN’s written statement, States’ due diligence obligations require
them “to take into account the extra-territorial consequences of their actions, including,
for example, consequences for the marine environment beyond their national jurisdiction
or the consequences of exported fossil fuels. For example, a State with significant fossil
fuel exports would find it difficult to argue that it is demonstrating the ‘highest possible
ambition’ in its climate policy, and that it is acting with due diligence, if emissions caused
by these exports were to remain entirely unaddressed.”3 Accordingly, States within
whose jurisdiction fossil fuels are produced must adopt measures to address greenhouse
gas (GHG) emissions embedded in fossil fuel exports. Such measures may include but
are not limited to monitoring, disclosing, and/or regulating such emissions.
5. Second, doing the utmost also means that States within whose jurisdiction fossil fuels are
produced at a minimum should consider GHG emissions from fossil fuel combustion in
1 IUCN’s Written Comments (15 August 2024), para. 37; CR 2024/54, Verbatim Record, Public sitting held on
Friday 13 December 2024, at 3 p.m., at the Peace Palace, President Salam presiding, on the Obligations of States
in respect of Climate Change (Request for advisory opinion submitted by the General Assembly of the United
Nations), 31, paras. 3-4; see also IUCN’s Written Statement (19 March 2024), paras. 39 (i), 305 (d), 353-354 and
378.
2 Paris Agreement (adopted 12 December 2015, entered into force 4 November 2016) 55 ILM 740, art 4.3.
3 IUCN’s Written Comments (15 August 2024), para. 37; CR 2024/54, Verbatim Record, Public sitting held on
Friday 13 December 2024, at 3 p.m., at the Peace Palace, President Salam presiding, on the Obligations of States
in respect of Climate Change (Request for advisory opinion submitted by the General Assembly of the United
Nations), 31, paras. 3-4; see also IUCN’s Written Statement, paras. 39 (i), 305 (d), 353-354 and 378.
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environmental impact assessments (EIAs) of fossil fuel projects, including when such
emissions take place in another jurisdiction. As we submitted in our written statement,
“States’ due diligence obligation to carry out EIAs, where activities may lead to
significant harm, does not cease to apply when it comes to the extraction and combustion
of fossil fuels, where it is reasonably foreseeable that the extracted fossil fuel will lead to
emissions of GHGs within or outside the territory of that State.”4 After fossil fuels have
been extracted, they will almost inevitably be burned, leading to additional GHG
emissions.5 Preventing significant environmental harm from such GHG emissions
therefore requires carrying out an EIA that considers cumulative emissions, including
emissions from fossil fuel combustion by end users in other jurisdictions.6 As the United
Kingdom Supreme Court held in its recent Finch judgment, the transboundary nature of
such effects should not exclude them from assessment:
“The fact that an environmental impact will occur or have its immediate source
at a location away from the project site is not a reason to exclude it from
assessment. There is no principle that, if environmental harm is exported, it may
be ignored.”7
6. This obligation to conduct an EIA that considers the cumulative effects of fossil fuelproducing
projects is further underpinned by the ITLOS Advisory Opinion on Climate
Change, in which the Tribunal held:
“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, shall be
subjected to an environmental impact assessment. Such assessment shall be
conducted by the State Party under whose jurisdiction or control the planned
activity will be undertaken with a view to mitigating and adapting to the adverse
effects of those emissions on the marine environment.”8 (emphasis added)
7. Third, as we submitted in our written statement, “States’ due diligence obligations to
consult and notify where activities may lead to significant harm also apply to the
extraction and combustion of fossil fuels, where it is reasonably foreseeable that the
extracted fossil fuel will lead to emissions of GHGs within or outside the territory of that
4 IUCN’s Written Statement (19 March 2024), para. 424.
5 R (on the application of Finch) v Surrey County Council [2024] UKSC 20 (“Finch”), paras. 79-80: “It is known
with certainty that the extraction of oil at the proposed well site in Surrey - which is the activity giving rise to the
requirement to carry out an EIA - would initiate a causal chain that would lead to the combustion of the oil and
release of greenhouse gases into the atmosphere. … [A] situation where X is both necessary and sufficient to bring
about Y is the strongest possible form of causal connection - much stronger than is required as a test of causation
for most legal purposes.”
6 Finch, para. 174; Oslo District Court, Greenpeace Nordic and Nature & Youth v. Energy Ministry (The North
Sea Fields Case), case no. 23-099330TVI-TOSL/05, 18 January 2024, p. 26.
7 Finch, para. 93.
8 Request for an Advisory Opinion submitted by the Commission of Small Island States on Climate Change and
International Law (Request for Advisory Opinion submitted to the Tribunal) (ITLOS, Advisory Opinion of 21
May 2024) (“ITLOS Advisory Opinion on Climate Change”), para. 367.
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State.”9 Given the global nature of the problem, such consultation and notification can
take place through multilateral forums.10
8. Fourth, due diligence requires States within whose jurisdiction fossil fuels are produced
to refrain from adopting legislative, administrative, or other measures that support the
new production of fossil fuels.11 Studies clearly point to the incompatibility of new fossil
fuel production and the goal to keep warming below 1.5°C. Notably, the International
Energy Agency (IEA) has found that no new fossil fuel extraction projects are
permissible in its scenario to stay below 1.5°C: “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.”12 Another assessment of
Intergovernmental Panel on Climate Change (IPCC) scenarios confirms the IEA finding
that keeping global warming below 1.5°C entails no new fossil fuel projects.13 Moreover,
the United Nations Environment Programme’s 2023 Emissions Gap Report found that
“committed emissions” from “[t]he coal, oil and gas extracted over the lifetime of
producing and under-construction mines and fields as at 2018 would emit more than
3.5 times the carbon budget available to limit warming to 1.5°C with 50 per cent
probability, and almost the size of the budget available for 2°C with 67 per cent
probability”.14 Supporting new fossil fuel production therefore is clearly not aligned with
the due diligence obligation to do the utmost to avoid the harmful effects of climate
change. This means among others that States, and in particular developed States, need to
refrain from subsidising new fossil fuel production, and from providing licenses for new
fossil fuel production.
9. Fifth, the stringent due diligent obligation also requires States to redirect public financial
flows within their control away from fossil fuels. Such public finance includes but is not
limited to government subsidies for fossil fuel production and consumption. Fossil fuel
subsidy estimates vary, but a conservative estimate by the Organisation for Economic
Co-operation and Development (OECD) puts them at US$ 1.4 trillion in 2023 for OECD
members and 48 other countries.15 In addition, relevant public financial flows also
include fossil fuel investments by state-owned enterprises and international public
finance in support of fossil fuels. The provision of financial support through each of these
channels is under the control of States, and therefore such activities are attributable to
States.16 Redirecting such financial support will reduce the likelihood of significant harm.
As the IPCC finds with regard to fossil fuel subsidies specifically, “removing fossil fuel
subsidies would reduce emissions, improve public revenue and macroeconomic
performance, and yield other environmental and sustainable development benefits”.
9 IUCN’s Written Statement (19 March 2024), para. 437.
10 As envisaged, for example, in the Agreement under the United Nations Convention on the Law of the Sea on
the Conservation and Sustainable Use of Marine Biological Diversity of Areas Beyond National Jurisdiction
(adopted 19 June 2023, not yet entered into force), UN Doc. A/CONF.232/2023/4 (BBNJ Agreement), art. 32.
11 See also Written Statement by Burkina Faso (2 April 2024), para. 182; Written Comments by Mauritius (15
August 2024).
12 International Energy Agency, Net Zero by 2050. A Roadmap for the Global Energy Sector (Summary for
Policymakers) (2021), p. 11.
13 F. Green et al., “No New Fossil Fuel Projects: The Norm We Need” (2024) 384 Science 954.
14 United Nations Environment Programme (UNEP), Emissions Gap Report 2023: Broken Record. Temperatures
Hit New Highs, yet World Fails to Cut Emissions (again) (2023), p. xxiii.
15 OECD, OECD Inventory of Support Measures for Fossil Fuels 2023 (2023), p. 2.
16 See also Written Statement by Vanuatu (21 March 2024), para. 144.
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Moreover, “fossil fuel subsidy removal is projected … to reduce global CO2 emissions
by 1–4%, and GHG emissions by up to 10% by 2030, varying across regions”.17
10. Redirecting public financial flows away from fossil fuels would also directly contribute
to achieving the goal of the Paris Agreement of “[m]aking finance flows consistent with
a pathway towards low greenhouse gas emissions and climate-resilient development”.18
This goal can be understood as being also applicable to public finance for fossil fuels,
particularly when read in conjunction with the subsequent call by Parties to the Paris
Agreement to “[p]has[e] out inefficient fossil fuel subsidies that do not address energy
poverty or just transitions, as soon as possible” contained in the outcome of the Global
Stocktake.19 This call furthermore suggests that subsidising fossil fuels is only possible
under certain, limited circumstances, i.e. to address energy poverty and for the purposes
of ensuring just transitions.
II. Duty to prepare and communicate NDCs that are informed by the outcome of
the Global Stocktake
11. Under the Paris Agreement, Parties have the obligation to prepare, communicate and
maintain successive Nationally Determined Contributions (NDCs), according to art. 4.2
and 4.9. As a legal duty, Parties shall be informed by the outcome of the Global Stocktake
(GST) when communicating their NDC.20 Article 14(3) of the Paris Agreement provides
that:
“The outcome of the global stocktake shall inform Parties in updating and
enhancing, in a nationally determined manner, their actions and support in
accordance with the relevant provisions of this Agreement, as well as in enhancing
international cooperation for climate action.” (emphasis added)
and Article 4(9) states that:
“Each Party shall communicate a nationally determined contribution every five
years in accordance with decision 1/CP21 and any relevant decisions of the
Conference of the Parties serving as the meeting of the Parties to this Agreement
and be informed by the outcomes of the global stocktake referred to in Article 14.”
(emphasis added)
12. The GST took place for the first time in 2023 and will take place every five years thereafter,
always two years before the next NDCs are due. This “staggering” of the procedures has
been carefully designed so as to enable Parties to be informed by the GST outcome in next
round of NDCs, which are due in 2025 and every 5 years thereafter.
13. The 2023 CMA Decision on the ‘Outcome of the First Global Stocktake’ called on Parties
to undertake global efforts, including in “[t]ransitioning away from fossil fuels in energy
17 IPCC, “Summary for Policymakers” in P.R. Shukla et al., Climate Change 2022: Mitigation of Climate Change.
Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate
Change (Cambridge University Press 2022), para. E.4.2.
18 Paris Agreement, art. 2.1(c).
19 Decision 1/CMA.5, Outcome of the First Global Stocktake, UN Doc. FCCC/PA/CMA/2023/16/Add.1 (15
March 2024), para. 28(h).
20 Paris Agreement, arts. 4(9) and 14(3).
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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.”21
14. The efforts outlined in the 2023 GST Decision are crucial for holding temperature increases
to 1.5°C. Parties are legally obliged to take them into account and be informed by them
when preparing their next NDC, which is to be communicated by 10 February 2025, at the
latest. Moreover, in their next NDC, each Party must provide information on how the GST
outcome informed the preparation of its NDC.22 This means that each Party, individually,
must carefully consider the 2023 GST Decision and communicate in 2025 an NDC that
contains a country-specific reflection of the global efforts, including on transitioning away
from fossil fuels.
15. Following the same reasoning, each Party should contain country-specific reflection of the
global efforts on “[p]hasing out inefficient fossil fuel subsidies that do not address energy
poverty or just transitions, as soon as possible”.23
III. Duty to cooperate
16. In addition to the specific obligations derived from States’ due diligence obligation, the
international law duty to cooperate requires States to cooperate on transitioning away from
fossil fuels. As IUCN posits in its written statement, “the obligation to cooperate to protect
the climate system and other parts of the environment from anthropogenic emissions of
greenhouse gases is an obligation erga omnes, applying among all States, both as (i) an
aspect of due diligence in the prevention of harm to the climate system and (ii) as a
freestanding duty founded on recognition of the climate system as a matter of common
concern”.24
17. The duty to cooperate, as the Court found in Pulp Mills,25 means that States should refrain
from undertaking activities that could undermine cooperation. In the context of fossil fuel
production, such activities include, inter alia, providing financial support for increasing
fossil fuel production and approving new fossil fuel projects,26 reinforcing the specific
obligations based on due diligence outlined above. Given the clear evidence that such
projects are incompatible with keeping global warming below 1.5°C,27 supporting new
fossil fuel projects would undermine simultaneous efforts to “transition away from fossil
fuels”, as Parties to the Paris Agreement have called for.28
IV. International human rights law
21 Decision 1/CMA.5, para. 28.
22 “Decision 4/CMA.1, Further Guidance in Relation to the Mitigation Section of Decision 1/CP.21, UN Doc.
FCCC/PA/CMA/2018/3/Add.1 (19 March 2019), Annex I, para. 4(c).
23 Decision 1/CMA.5, para. 28(h).
24 Written Statement (19 March 2024), para. 447.
25 Pulp Mills on the River Uruguay (Argentina v. Uruguay), Judgment [2010] ICJ Rep 14, para. 144.
26 See also Written Statement by the African Union (22 March 2024), para. 129; Written Statement by Vanuatu
(21 March 2024), para. 414.
27 See International Energy Agency, Net Zero by 2050 (2021); UNEP, The Production Gap: Phasing Down or
Phasing Up? Top Fossil Fuel Producers Plan even More Extraction Despite Climate Promises (2023), p. 2:
“Governments, in aggregate, still plan to produce more than double the amount of fossil fuels in 2030 than would
be consistent with limiting warming to 1.5°C.”
28 Decision 1/CMA.5, para. 28(d).
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18. States also have an obligation to effectively contribute to phasing out fossil fuels under
international human rights law. This general obligation was affirmed by a joint statement
in 2019 by five human rights bodies (the Committee on the Elimination of Discrimination
Against Women, the Committee on Economic, Social and Cultural Rights, the Committee
on the Protection of the Rights of All Migrant Workers and Members of their Families, the
Committee on the Rights of the Child, and the Committee on the Rights of Persons with
Disabilities). In this statement, the five bodies among others suggests that “States parties
should effectively contribute to phasing out fossils fuels”.29 Similarly, in its General
Comment No. 26, the Committee on the Rights of the Child furthermore recognised that
“delaying rapid phase out of fossil fuels will result in higher cumulative emissions and
thereby greater foreseeable harm to children’s rights”.30
19. As we have submitted in our written comments, “[i]nternational human rights treaties
impose positive obligations on States to take all necessary and appropriate measures
aligned with the 1.5°C threshold and corresponding timelines for emission pathways and
to protect relevant human rights in an inter-temporal manner”.31
20. Fossil fuel production, by driving climate change, contributes to violations of a wide array
of human rights, including the right to life, the right to health, the right to property,
children’s rights, and women’s rights. The contribution of fossil fuel production, and the
need to address fossil fuel production was acknowledged, for example, by the Committee
on Economic, Social and Cultural Rights in its consideration of the sixth periodic report by
Norway, in which the Committee recommended that “the State party reconsider its decision
to increase oil and natural gas exploitation and take its human rights obligations as a
primary consideration in its natural resource exploitation and export policies”.32
21. International human rights law also imposes a positive obligation upon States to provide
for a just transition away from fossil fuels. As noted by the United Nations Office of the
High Commissioner for Human Rights and the International Labour Organization, “[a] just
transition is intrinsically grounded in human rights standards and obligations, including the
rights to equality and non-discrimination, a clean, healthy and sustainable environment,
decent work, social security, access to information, public participation and access to
justice and remedies”.33 The need for a just transition was emphasised by the Committee
29 “Five UN Human Rights Treaty Bodies Issue a Joint Statement on Human Rights and Climate Change” (16
September 2019), para. 3, https://www.ohchr.org/en/statements/2019/09/five-un-human-rights-treaty-bodiesissue-
joint-statement-human-rights-and?LangID=E&NewsID=24998 (Joint Statement on Human Rights and
Climate Change).
30 Committee on the Rights of the Child, “General Comment No. 26 (2023) on Children’s Rights and the
Environment, with a Special Focus on Climate Change”, UN Doc. CRC/C/GC/26 (22 August 2023), para. 98(d).
31 IUCN’s Written Comments (15 August 2024), para. 39 (General Comment No. 26).
32 Committee on Economic, Social and Cultural Rights (CESCR), “Concluding Observations on the Sixth Periodic
Report of Norway”, UN Doc. E/C.12/NOR/CO/6 (2 April 2020), para. 11. See also Committee on the Elimination
of Discrimination against Women, “Concluding Observations on the Tenth Periodic Report of Norway”, UN Doc.
CEDAW/C/NOR/CO/10 (2 March 2023), para. 49(a), recommending the State to “[r]eview its climate change and
energy policies, in particular its policy on the extraction and export of oil and gas, as well as the activities of
related State-owned companies and private companies, taking into account the disproportionate negative impact
on women and girls both within and outside its territory, with a view to radically reducing greenhouse emissions
in line with the Paris Agreement on climate change”.
33 United Nations Office of the High Commissioner for Human Rights and the International Labour Organization,
Key Messages on a Just Transition and Human Rights, p. 1,
https://www.ohchr.org/sites/default/files/documents/issues/climatechange/information-materials/key-messageshr-
a-just-trans.pdf.
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on the Rights of the Child, which found that States should “[e]quitably phase out the use of
coal, oil and natural gas, ensure a fair and just transition of energy sources and invest in
renewable energy, energy storage and energy efficiency to address the climate crisis”.34
22. Under human rights law States also are under a duty to reform fossil fuel subsidies. As the
five aforementioned human rights bodies find, “States should also discontinue financial
incentives or investments in activities and infrastructure which are not consistent with low
greenhouse gas emissions pathways, whether undertaken by public or private actors as a
mitigation measure to prevent further damage and risk”.35 This statement is in line with the
duty of States to use their “maximum available resources” for the progressive realisation
of economic, social, and cultural rights.36 States providing public financial support for fossil
fuels are not dedicating the maximum available resources to combating climate change.
Importantly, human rights law also suggests that fossil fuel subsidy reform efforts should
address the impacts on poorer segments of society, including by providing for
compensation if necessary.37
23. Lastly, international human rights law provides for certain procedural rights, including on
access to information.38 This right is further elaborated in the context of environmental
protection through Principle 10 of the Rio Declaration, which provides that “[a]t the
national level, each individual shall have appropriate access to information concerning the
environment that is held by public authorities, including information on hazardous
materials and activities in their communities.39 In the context of climate change,
information about fossil fuel production and fossil fuel subsidies is of crucial importance
for individuals, as such information offers an indication on the extent to which States are
contributing to harm to the climate system. However, relevant information, including for
instance inventories of fossil fuel subsidies, fossil fuel production plans and projections,
including underlying economic and technological assumptions, emissions embedded in
fossil fuel exports, and plans for decommissioning fossil fuel infrastructure, is often
unavailable.40 For States, therefore, a corresponding duty is to disclose such information
about fossil fuel production and financial support for fossil fuels.
34 General Comment No. 26, para. 65(d).
35 Joint Statement on Human Rights and Climate Change, para. 3.
36 International Convention on Economic, Social and Cultural Rights (adopted 16 December 1996, entered into
force 3 January 1976) 993 UNTS 3, art. 2.
37 CESCR, “Draft General Comment on Economic, Social and Cultural Rights and the Environmental Dimension
of Sustainable Development”, para. 22 https://www.ohchr.org/en/calls-for-input/2025/cescr-calls-writtencontributions-
draft-general-comment-economic-social-and (“Fiscal policies should be sustainable and promote a
just and rapid energy transition through reduced dependence on fossil fuels and the adoption of compensation
policies, where necessary”).
38 UNGA, “Universal Declaration of Human Rights”, UN Doc. A/Res/217 (III) (10 December 1948), art. 19; and
International Covenant on Civil and Political Rights (adopted 16 December 1966, entered into force 23 March
1976) 999 UNTS 171 art. 19
39 “Declaration of the UN Conference on Environment and Development”, UN Doc. A/CONF.151/26 (Vol. I) (12
August 1992), Principle 10.
40 UNEP, The Production Gap: Governments’ Planned Fossil Fuel Production Remains Dangerously Out of Sync
with Paris Agreement Limits (2021), p. 56.
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RESPONSE TO THE QUESTION POSED BY JUDGE AURESCU
24. At the public hearings on 13 December 2013, Judge Aurecu posed the following question:
“Some participants have argued, during the written and/or oral stages of the
proceedings, that there exists the right to a clean, healthy and sustainable
environment in international law. Could you please develop what is, in your view,
the legal content of this right and its relation with the other human rights which you
consider relevant for this advisory opinion?”
I. Existence of the right
25. Human rights and environmental rights are deeply and inherently interconnected. The
conservation of natural resources can only be achieved if human rights are considered and
respected. In turn, for human rights to be realized, maintaining a healthy planet is essential.
Building on this recognition, the IUCN respectfully invites the Court to recognize that the
right to a clean, healthy and sustainable environment (henceforth: right to a healthy
environment) is a cornerstone of providing adequate human rights protection in the face of
overlapping environmental crises, including especially climate change.
26. This right has been recognized in a large number of international and regional instruments,
as well as by “national constitutions, laws and policies by a vast majority of States”.41 The
present section non-exhaustively notes some of the key international and regional legal
instruments in this regard.
27. First, the right to a healthy environment has been recognized repeatedly on the UN level.
Already in 1972, in the Stockholm Declaration, States recognized “the fundamental right
to freedom, equality and adequate conditions of life, in an environment of a quality that
permits a life of dignity and well-being”.42 The United Nations Declaration on the Rights
of Indigenous Peoples (UNDRIP)43 and the International Labor Organization’s Indigenous
and Tribal Peoples Convention (ILO Convention No. 169)44 provide further important
examples of the recognition of the relationship between human rights and environmental
rights. An important milestone in the international recognition of a separate, universal (i.e.
not group-specific) right to a healthy environment was the UN General Assembly
Declaration to that effect,45 which was accepted in 2022 by 161 votes in favour, no votes
against, and eight abstentions. This declaration built on the prior recognition of the right by
the Human Rights Council.46 In addition, the UN Committee on the Rights of the Child, in
its 2023 General Comment No. 26 on children’s rights and the environment, with a special
focus on climate change, recognized that “[c]hildren have the right to a clean, healthy and
41 Committee on the Rights of the Child, ‘General Comment No. 26 (2023) on children’s rights and the
environment, with a special focus on climate change’, UN Doc CRC/C/GC/26 (22 August 2023), para. 10.
42 Declaration of the United Nations Conference on the Human Environment, 16 June 1972.
43 UNGA, UN Declaration on the Rights of Indigenous Peoples, UN Doc A/RES/61/295, 2 October 2007.
44 International Labor Organization, Convention (No. 169) concerning Indigenous and Tribal Peoples in
Independent Countries of 27 June 1989, 1650 UNTS 383.
45 UNGA, ‘The Human Right to a Clean, Healthy and Sustainable Environment’, UN Doc A/RES/76/300 (1
August 2022).
46 Human Rights Council, ‘The Human Right to a Clean, Healthy and Sustainable Environment’, Res. 48/13 (8
October 2021). See also Human Rights Council, ‘The Human Right to a Clean, Healthy and Sustainable
Environment’, UN Doc A/HRC/RES/52/23 (13 April 2023).
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sustainable environment”, as a right that is implicit within the UNCRC and linked to
various rights therein.47 Other international instruments also contain references to
environmental rights, for example Article 29(1) of the UNDRIP, which states that
“Indigenous peoples have the right to the conservation and protection of the environment
and the productive capacity of their lands or territories and resources.”48 Notably, after the
UNGA’s recognition of the right to a healthy environment, successive UNFCCC COP
outcome documents have included a reference to this right in their preambles.49
28. These international recognitions of the right to a healthy environment complement
numerous regional instruments recognizing this same right. The African Charter on Human
and Peoples’ Rights,50 the San Salvador Protocol;51 the Arab Charter on Human Rights;52
the ASEAN Human Rights Declaration;53 and the Escazú Agreement54 all unequivocally
recognize the right to a healthy environment. In Europe, recognition of the right is less
explicit, but it exists, nonetheless. For example, the Aarhus Convention recognizes this
right,55 and although discussions about its recognition within the Council of Europe through
e.g. an additional protocol to the European Convention on Human Rights are still
ongoing,56 the Council of Europe’s European Committee of Social Rights has recognized
this right in its case-law.57
29. In addition, this right has been recognized in the vast majority of domestic legal systems.
In 2023, a joint study by the UNEP, OHCHR and UNDP showed that even prior to the
UNGA recognition of the right to a healthy environment, the right had already been
recognized “in more than eighty percent of UN Member States (156 out of 193 States)”
through either regional or domestic instruments, or both.58 IUCN respectfully emphasizes
the relevance of these developments as a form of State practice contributing to the
emergence of customary law.59 The IUCN notes that, as a result of this process of
recognition and codification, various States have argued that the right to a healthy
47 Committee on the Rights of the Child, ‘General Comment No. 26 (2023) on Children’s Rights and the
Environment, with a Special Focus on Climate Change’, UN Doc CRC/C/GC/26 (22 August 2023), para. 63.
48 UNGA, United Nations Declaration on the Rights of Indigenous Peoples, UN Doc A/RES/61/295 (2 October
2007), Art. 29(1).
49 See Conference of the Parties serving as the meeting of the Parties to the Paris Agreement, Decision 1/CMA.5,
FCCC/PA/CMA/2023/16/Add.1 (13 December 2023), preamble, 7th recital; Conference of the Parties serving as
the meeting of the Parties to the Paris Agreement, Decision 1/CP.28, FCCC/CP/2023/11/Add.1 (15 March 2024),
preamble, 4th recital, among others.
50 African Charter on Human and Peoples’ Rights, adopted 27 June 1981, entered into force on 21 October 1986,
1520 UNTS 217 at Art. 24.
51 Additional Protocol to the American Convention on Human Rights in the Area of Economic, Social and Cultural
Rights (San Salvador Protocol), adopted 17 November 1988, entered into force on 16 November 1999, at Article
11.
52 Arab Charter on Human Rights, adopted 22 May 2004, entered into force on 15 March 2008, at Article 38.
53 ASEAN Human Rights Declaration, adopted on 18 November 2012, at Article 28 (f).
54 Regional Agreement on Access to Information, Public Participation and Justice in Environmental Matters in
Latin America and the Caribbean (Escazú Agreement), adopted on 4 March 2018, entered into force on 22 April
2021, at Article 1.
55 Aarhus Convention, adopted 25 June 1998, entered into force 30 October 2001, 2161 UNTS 447.
56 See the report of the Council of Europe Steering Committee on Human Rights, CDDH(2024)R101 Addendum
2, 29 November 2024.
57 European Committee of Social Rights, Marangopoulos Foundation for Human Rights (MFHR) v. Greece,
complaint no. 30/2005, 6 December 2006, paras. 194-195 and 202.
58 UNEP, OHCHR and UNDP, “What is the Right to a Healthy Environment? Information Note”, 3 January 2023,
https://wedocs.unep.org/bitstream/handle/20.500.11822/41599/WRHE.pdf?sequence=1&isAllowed=y%20, 8.
59 As e.g. recognized by this Court (ICJ, Arrest Warrant of 11 April 2000 (Democratic Republic of the Congo v.
Belgium), Judgment, I.C.J. Reports 2002, p. 3, at para. 58).
12
environment has crystallized into a norm of customary international law.60 While not all
States agree with this position, with some contesting the bindingness of the right and the
existence of sufficiently universal State practice and opinio juris both within the present
proceedings61 and outside them,62 these discussions certainly underscore the importance
accorded to this right.
II. Content of the Right
30. It is commonly argued that there is no agreed content of the right to a healthy environment.
This finding is used to argue that the right has no content, or no binding content, at all.
However, this is a misunderstanding. A more accurate understanding would be to clarify
that various systems provide a common core level of protection of this right, but that some
provide further-reaching protections than others. For example, the African Charter on
Human and Peoples’ Rights63 recognizes “peoples” as holders of the right in question, and
the Inter-American System protects rights of nature under this right,64 whereas other
regional and international systems recognize only an individual-oriented right to a healthy
environment. Likewise, the adjectives used to describe the right can also vary, with
descriptions including a right to a healthy environment, a safe environment, a clean
environment, a favourable environment, a healthy environment, or an ecologically sound
environment. However, “despite the variety of denominations, the core content of the right
to a healthy environment is generally common to all these national, regional, or
international texts. The fundamental interconnection between the protection of the
environment and the effective preservation of human rights is at the centre of each of these
formulations.”65
31. In a 2023 study, the UNEP, OHCHR and UNDP synthesized the various international and
regional instruments concerning the right to a healthy environment in order to set out those
aspects of the right to a healthy environment that represent a common core of the various
systems’ protection.66 These were:
- Substantive rights,67 namely entitlements to clean air, a safe and stable climate, healthy
ecosystems and biodiversity, safe and sufficient water and adequate sanitation, healthy
and sustainable food and a non-toxic environment in which to live, work, study and
play; and
60 See, within these proceedings, the written submissions of Costa Rica (82), Ecuador (3.108), El Salvador (43),
Federated States of Micronesia (79), Namibia, and the Philippines (54). See also C. Rodríguez-Garavito, ‘A
Human Right to a Healthy Environment?: Moral, Legal, and Empirical Considerations’ in J H Knox and R Pejan
(eds), The Human Right to a Healthy Environment (CUP 2018) 160.
61 Written submissions of the United States of America, para. 4.39.
62 UNGA, Seventy-Sixth Session, 97th meeting, Press Release GA/12437 (28 July 2022) explanation by
representative of New Zealand <https://press.un.org/en/2022/ga12437.doc.htm>.
63 African Charter on Human and Peoples’ Rights, adopted 27 June 1981, entered into force on 21 October 1986,
1520 UNTS 217 at Art. 24.
64 For example, the IACtHR has noted that “States are obliged to protect nature not only because of its
usefulness or effects on human beings, but also because of its importance for other living organisms with whom
the planet is shared” (see IACtHR, La Oroya v. Peru, Judgment of 27 November 2023, Series C-511, para. 118).
65 IUCN News/Yann Aguila, ‘The Right to a Healthy Environment’ (29 October 2021),
https://iucn.org/news/world-commission-environmental-law/202110/right-a-healthy-environment.
66UNEP, OHCHR and UNDP, ‘What is the Right to a Healthy Environment? Information Note’ (3 January 2023),
https://wedocs.unep.org/bitstream/handle/20.500.11822/41599/WRHE.pdf?sequence=1&isAllowed=y%20.
67 On this, see also e.g. Human Rights Council, ‘Report of the Special Rapporteur on Human Rights and the
Environment – Right to a Healthy Environment: Good Practices’, UN Doc A/HRC/43/53 (30 December 2019).
13
- Procedural rights, namely rights of access to information, public participation and
access to justice, as well as the exercise of these rights free from reprisals or retaliation.
These are concretized especially in the Aarhus Convention and the Escazú Agreement,
which protect rights to information, access to justice and public participation in
environmental matters and support environmental human rights defenders.
32. In terms of substance, the right to a healthy environment covers a wide range of
environmental impacts – e.g. impacts on the climate, ecosystems, biodiversity, water, food
and the overall environment – because “[e]nvironmental degradation may cause irreparable
harm to human beings; thus, a healthy environment is a fundamental right for the existence
of humankind.”68 Although some systems provide further-reaching protection, there seems
to be agreement about the core content of the right on the international level in terms of the
elements set out above. In this regard, like the UNEP, OHCHR and UNDP, the UN Special
Rapporteur on the right to a healthy environment has recently synthesized the wide range
of legal and practical developments relating to this right and clarified the substantive
elements of the right, namely: a right to clean air; a right to a safe climate; a right to safe
and sufficient water; a right to healthy and sustainable food; a right to non-toxic
environments; and a right to healthy ecosystems and biodiversity.69 Likewise, in its 2023
La Oroya judgment, the Inter-American Court of Human Rights (IACtHR) recognized that
this right enshrined protections against both air and water pollution,70 linking it to the due
diligence obligation of States to use all available means to avoid significant environmental
harm.71 Here the IACtHR considered it “difficult to imagine international obligations of
greater significance than those that protect the environment against unlawful or arbitrary
conduct that causes serious, extensive, lasting and irreversible damage to the environment
in a scenario of climate crisis that threatens the survival of species”, arguing that “the
international protection of the environment requires the progressive recognition of the
prohibition of conducts of this type as a peremptory norm (jus cogens)”.72
33. In terms of procedural rights, IUCN particularly stresses the importance of protecting
environmental human rights defenders. These are individuals and communities who – by
claiming their right to a clean, healthy and sustainable environment, as recognized by the
UNGA – have put their lives at risk. The UN Declaration on Human Rights Defenders
adopted by the UNGA in its Resolution 53/144 is fundamental when protecting these
defenders, especially now, at a time when climate change impacts are more visible than
ever and communities are demanding rapid action.73 Similar protections can be found in
the Escazú Agreement, also known as the Regional Agreement on Access to Information,
Public Participation and Justice in Environmental Matters in Latin America and the
Caribbean of 2018.74 This instrument explicitly mentions environmental human rights
68 IACtHR, Advisory Opinion OC-23/17 of 15 November 2017, para. 59.
69 UNGA, ‘Report of the Special Rapporteur on the Human Right to a Clean, Healthy and Sustainable
Environment: Overview of the Implementation of the Human Right to a Clean, Healthy and Sustainable
Environment’, UN Doc A/79/270 (2 August 2024), paras. 50-70.
70 IACtHR, La Oroya v. Peru, Judgment of 27 November 2023, Series C-511, para. 125.
71 Ibid., para. 126.
72 Ibid., para. 129.
73 UNGA, Declaration on the Right and Responsibility of Individuals, Groups and Organs of Society to Promote
and Protect Universally Recognized Human Rights and Fundamental Freedoms, UN Doc A/RES/53/144 (8
March 1999).
74 Regional Agreement on Access to Information, Public Participation and Justice in Environmental Matters in
Latin America and the Caribbean (Escazú Agreement), adopted on 4 March 2018, entered into force on 22 April
2021.
14
defenders. The agreement focuses on the implementation of the rights of access to
environmental information, public participation and access to justice in environmental
matters linked to the protection of the rights of present and future generations to live in a
healthy environment. Furthermore, the UNGA’s 2023 Resolution 78/216 on providing a
safe and enabling environment for human rights defenders and ensuring their protection
noted that environmental human rights defenders are “among the human rights defenders
most exposed and at risk” of reprisals, repression and human rights violations.75 It called
for the protection of universally recognized human rights and noted the “positive, important
and legitimate role played by human rights defenders in the promotion and protection of
human rights as they relate to the enjoyment of a safe, clean, healthy and sustainable
environment” including how human rights relate to sustainable development and climate
change.76
34. Like other rights, the right to a healthy environment continues to evolve over time.77 For
example, in addition to the substantive and procedural elements noted here, it has been
suggested that the right to a healthy environment has an intertemporal element, in that it
enshrines the principle of intergenerational equity.78
35. These components of the right to a healthy environment overlap to some degree with other
human rights enshrined in various international and regional human rights treaties, such as
rights to life, food, health, water, education, private and family life, freedom from torture,
culture, non-discrimination, freedom of expression, access to information, access to justice
and a remedy, and fair trial. The relationship between these rights and the right to a healthy
environment is discussed below.
III. Relationship with other Human Rights
36. As the IUCN noted in its written submission to the Court in these proceedings, existing
human rights protections are increasingly being aligned, whether implicitly or explicitly,
with the human right to a healthy environment. It is clear that this right is indivisible from
the protection of other human rights. UN mandate holders, already in 2013, remarked on
the “remarkably coherent” views of different human rights bodies and other authorities on
the relationship between human rights law and the environment, which provide “strong
evidence of converging trends towards greater uniformity and certainty in the human rights
obligations relating to the environment.”79 Because climate change is a crisis of human
rights protection, States’ international obligations in this regard (e.g. States’ obligations to
protect the climate system and other parts of the environment) accordingly include due and
75 UNGA, ‘Implementing the Declaration on the Right and Responsibility of Individuals, Groups and Organs of
Society to Promote and Protect Universally Recognized Human Rights and Fundamental Freedoms through
providing a safe and enabling environment for human rights defenders and ensuring their protection’, UN Doc
A/RES/78/216 (19 December 2023).
76 Ibid.
77 UNGA, ‘Report of the Special Rapporteur on the Human Right to a Clean, Healthy and Sustainable
Environment: Overview of the Implementation of the Human Right to a Clean, Healthy and Sustainable
Environment’, UN Doc A/79/270 (2 August 2024), para. 6.
78 See IACtHR, La Oroya v. Peru, Judgment of 27 November 2023, Series C-511, para. 129. See also for example
by the 2024 Maastricht Principles on the Human Rights of Future Generations (principle 5(b)). See also Brian J.
Preston, “The Nature, Content and Realisation of the Right to a Clean, Healthy and Sustainable Environment”,
36(2) Journal of Environmental Law (2024), 159-186.
79 UN Human Rights Council ‘Mapping report of the Independent Expert on the issue of human rights obligations
relating to the enjoyment of a safe, clean, healthy and sustainable environment’ (30 December 2013) UN Doc
A/HRC/25/53, para 27. ICJ Dossier No 304.
15
coherent regard for the international human rights framework as a whole. This approach is
in line with this Court’s recognition 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.”80
37. IUCN respectfully submits that the right to a healthy environment applies in two ways.
First, it is an independent right, such as that guaranteed under the various instruments
discussed above. However, it is also an implicit part of those other rights, such as the rights
to life, personal integrity, property, non-discrimination, health, food, water, progressive
development, education, culture, and freedom from torture and inhuman and degrading
treatment, freedom of expression, access to information, access to justice and a remedy,
and fair trial. This is explained by the fact that these rights are impacted by environmental
destruction – for example, the right to life is endangered in clear and unmistakeable ways
by climate-aggravated floods, storms, heatwaves, droughts, and other impacts. And other
rights listed here – for example the right to freedom of expression – overlap with the
procedural aspects of the right to a healthy environment, for example by guaranteeing
access to information and protection of environmental human rights defenders.
38. The interdependence of the right to a healthy environment and other human rights has been
prominently recognized by the UNGA. In its Resolution recognizing the right to a healthy
environment, the UNGA clarified that “the right to a clean, healthy and sustainable
environment is related to other rights and existing international law”.81 The same resolution
also affirmed that “all human rights are universal, indivisible, interdependent and
interrelated”82 – and that the right to a healthy environment and the right to sustainable
development, in particular, are interlinked.83 Existing human rights, in other words, cannot
be adequately protected absent effective mitigation of greenhouse gas emissions and
adaptation action.
39. Various human rights courts and bodies have recognized this interdependence. To name a
few examples among many, the UN Committee on Economic, Social and Cultural Rights
(CESCR) has noted that “[c]limate change already affects, in particular, the rights to health,
food, water and sanitation; and it will do so at an increasing pace in the future.”84 The CRC
has likewise noted that the right to a healthy environment is “directly linked to” rights in
the UNCRC, in particular the rights to life, survival and development, to the highest
attainable standard of health, to an adequate standard of living, and to education, including
the development of respect for the natural environment (Article 29 UNCRC).85
Accordingly, it held that “[t]his right should be mainstreamed across all decisions and
measures concerning children”.86 Notably, with 196 States Parties, the Convention on the
80 Legality of the Threat or Use of Nuclear Weapons (Advisory Opinion) [1996] ICJ Rep 226, 242
81 UNGA, ‘The Human Right to a Clean, Healthy and Sustainable Environment’, UN Doc A/RES/76/300 (1
August 2022), preamble, 8th recital.
82 Ibid., preamble.
83 Ibid., 2. See also the statement from Special Rapporteur on the right to development, Surya Deva, that these
rights go “hand in hand” (Surya Deva, ‘Reinvigorating the Right to Development: A Vision for the Future’, UN
Doc A/HRC/54/27 (4 August 2023) at 65).
84 CESCR ‘Climate Change and the International Covenant on Economic, Social and Cultural Rights’, UN Doc
E/C.12/2018/1 (31 October 2018), para 4. ICJ Dossier No 298.
85 Committee on the Rights of the Child, ‘General Comment No. 26 (2023) on children’s rights and the
environment, with a special focus on climate change’, UN Doc CRC/C/GC/26 (22 August 2023), para. 63.
86 Committee on the Rights of the Child, ‘General Comment No. 26 (2023) on children’s rights and the
environment, with a special focus on climate change’, UN Doc CRC/C/GC/26 (22 August 2023), para. 67.
16
Rights of the Child enjoys near-universal ratification – more even than the Paris Agreement.
Although not explicitly mentioned in the question posed to the Court during the present
proceedings, this Convention accordingly represents a key instrument for defining State
obligations concerning climate change, and we respectfully submit that it should inform
the Court’s opinion.
40. The United Nations Declaration on the Rights of Indigenous Peoples (UNDRIP)87 and the
International Labor Organization Indigenous and Tribal Peoples Convention (ILO
Convention No. 169)88 provide further important examples of the recognition of the
relationship between human rights and environmental rights. According to the UNDRIP,
Indigenous peoples have the right to the full enjoyment of all human rights (Art. 1) and to
the conservation, restoration and protection of the total environment and the productive
capacity of their lands, territories and resources (Art. 28). Similarly, Article 15 of ILO
Convention No. 169 indicates the rights of Indigenous peoples in relation to the natural
resources within their lands and the need to protect them. These include the rights of people
to participate in the management and conservation of these resources. It is clearly
recognized that climate change impacts are limiting the ability of Indigenous peoples to
exercise their rights to life; health; food; water; culture; and housing. In other words,
without a healthy and sustainable environment, it is not possible for indigenous peoples to
achieve these rights. The already visible impacts of environmental degradation and climate
change undermine the application of human rights under the Universal Declaration of
Human Rights. Indigenous Peoples, including Indigenous women, children, and youth, are
among the most vulnerable people that are fighting against the effects of climate change –
and their rights, as clearly reiterated in existing UN conventions and declarations, must be
protected.
41. Likewise, the UN General Assembly Declaration on the Rights of Peasants and Other
People Working in Rural Areas (UNDROP)89 also recognizes environment-related human
rights. In particular, it recognizes the difficulties that Peasants and other people working in
rural areas face when it comes to making their voices heard, defending their human rights
and land tenure rights, and securing the sustainable use of the natural resources. Article
17(1) UNDROP indicates that Peasants have a right to land including the right to have
access to, sustainably use and manage the land and the water bodies, coastal seas, fisheries,
pastures and forests. Art. 18 establishes that “Peasants and other people working in rural
areas have the right to the conservation and protection of the environment and the
productive capacity of their lands, and of the resources that they use and manage” (para. 1)
and establishes that “States shall take appropriate measures to ensure that peasants and
other people working in rural areas enjoy, without discrimination, a safe, clean and healthy
environment” (para. 2). These rights are clearly linked to the rights to life, culture and a
clean and heathy environment.
42. The interdependence between the right to a clean and healthy environment and other human
rights is also particularly clear when looking at the situation of environmental human rights
defenders (as discussed above), whose rights to life, freedom from torture, freedom of
expression, peaceful assembly and association, participation in the conduct of public
affairs, and access to justice are all put at risk by restrictions on freedom of association or
87 UNGA, UN Declaration on the Rights of Indigenous Peoples, UN Doc A/RES/61/295, 2 October 2007.
88 International Labor Organization, Convention (No. 169) concerning Indigenous and Tribal Peoples in
Independent Countries of 27 June 1989, 1650 UNTS 383.
89 UNGA, UN Declaration on the Rights of Indigenous Peoples, UN Doc A/RES/61/295, 2 October 2007.
17
expression or the right to peaceful assembly, arbitrary arrests and detention, abuse of
criminal or civil proceedings or what the UNGA calls “deplorable acts of intimidation and
reprisal”.90
43. In short, environmental human rights exist both in the form of an independent human right,
i.e. a right to a healthy environment, and as an aspect of other human rights obligations, i.e.
universal rights and rights specific to particular groups, including Indigenous peoples and
Peasants. A passage from a 2018 report by the UN Special Rapporteur on human rights and
the environment, John H. Knox, describes this interaction well. Noting that other human
rights likewise apply to environmental issues, he noted that “[e]xplicit recognition of the
human right to a healthy environment thus turned out to be unnecessary for the application
of human rights norms to environmental issues.”91 However, this did not mean that the right
lacked added value: he noted evidence that “recognition of the right has proved to have real
advantages. It has raised the profile and importance of environmental protection and
provided a basis for the enactment of stronger environmental laws. When applied by the
judiciary, it has helped to provide a safety net to protect against gaps in statutory laws and
created opportunities for better access to justice. Courts in many countries are increasingly
applying the right (…).”92 In addition, he noted that explicit recognition of this right “raises
awareness that human rights norms require protection of the environment and highlights
that environmental protection is on the same level of importance as other human interests
that are fundamental to human dignity, equality and freedom. It also helps to ensure that
human rights norms relating to the environment continue to develop in a coherent and
integrated manner”.93
44. In short, aspects of the right to a healthy environment are guaranteed through other human
rights. However, recognizing this right explicitly has important advantages, because it
creates a coordinated framework of human rights protections. It not only consolidates the
environment-related standards discussed above, drawing much-needed attention to the
interdependence of human rights and the environment, but provides clear, comprehensive,
coordinated protections for addressing the specific risks that arise in the context of
environmental human rights impacts – including pollution, climate change, ecosystem loss
and impacts on environmental human rights defenders.
90 UNGA, ‘Implementing the Declaration on the Right and Responsibility of Individuals, Groups and Organs of
Society to Promote and Protect Universally Recognized Human Rights and Fundamental Freedoms through
providing a safe and enabling environment for human rights defenders and ensuring their protection’, UN Doc
A/RES/78/216, 19 December 2023.
91 Human Rights Council, ‘Report of the Special Rapporteur on the issue of human rights obligations relating to
the enjoyment of a safe, clean, healthy and sustainable environment’, UN Doc A/HRC/37/59 (24 January 2018),
para. 13.
92 Ibid.
93 Ibid., para. 16.