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INTERNATIONAL COURT OF JUSTICE
ADVISORY PROCEEDINGS
OBLIGATIONS OF STATES IN RESPECT OF CLIMATE CHANGE
Oral Proceedings of 2 – 13 December 2024
REPUBLIC OF COSTA RICA
Questions put by Judges Cleveland, Tladi, Aurescu and Charlesworth at the end of the
public sitting of 13 December.
19 December 2024
Costa Rica refers to the following question put 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?”
I. Introduction
1. The right to a clean, healthy and sustainable environment exists in general international
law and is a human right. The analysis the Court followed in the Separation of Chagos
advisory opinion with regard to Resolution 1514 (XV) in order to determine its
normative character as containing rights and obligations is equally applicable to
Resolution 76/300 declaring the right to a clean, healthy and sustainable environment a
human right. The terms employed by the Court in that advisory opinion can also be
applied verbatim here: “although Resolution [76/300] is formally a recommendation, it
has a declaratory character with regard to [the right to a clean, healthy and sustainable
environment] as a customary norm, in view of its content and the conditions of its
adoption. The resolution was adopted by [161 votes in favour, no votes against and 8
abstentions]. None of the States participating in the vote contested the existence of [this
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right ]”.1 The wording employed by resolution 76/300 clearly refers to a right, not to a
mere aspiration.2 Like Resolution 1514 (XV) for decolonization, Resolution 76/300
“represents a defining moment in the consolidation of State practice”3
2. A manifestation of the existence of this right can already be found in the 1972
Stockholm Declaration of the United Nations Conference on the Human Environment,
which in its Principle 1 states: “Man has 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, and he bears a solemn responsibility to protect and improve the
environment for present and future generations.”4
3. The fact that several regional instruments have included the right to a clean, healthy and
sustainable environment, and that 161 States have explicitly incorporated in their
Constitutions or legislations this right, prove that it is not only widely recognized as
such, but it is concretely already being applied at the domestic and regional level,
enabling citizens and the societies as a whole to effectively participate in the
implementation and discussion to enhance its application.
II. Legal Content of the Right
4. The right to a clean, healthy and sustainable environment is both an individual and a
collective human right. It has acquired the status of a customary international human
right and consequently States are obliged to make concrete efforts to enforce it.
5. Like the right of peoples to self-determination, finally incorporated as common Article
1 of the two UN 1966 human rights Covenants, the right to a healthy, clean, and
sustainable environment is the premise for the exercise of most of the other human
rights. Its realization is an essential precondition for the effective guarantee, enjoyment,
1 Legal Consequences of the Separation of the Chagos Archipelago from Mauritius in 1965, Advisory Opinion,
I.C.J. Reports 2019, p. 132, para. 152.
2 Ibid., para.153.
3 Ibid., para. 150
4 A/CONF.48/14/Rev.1
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and observance of those rights and for the promotion and strengthening of them, which
require a minimum environmental quality.5
6. The content of Article 2 of the UN Covenant of Economic, Social and Cultural Rights
is applicable to the right to a clean, healthy and sustainable environment. In particular,
its paragraph 1 can be mentioned concerning the manner through which the right must
be implemented. Mutatis mutandis, it means that all States undertake to take steps,
individually and through international assistance and co-operation, especially economic
and technical, to the maximum of their available resources, with a view to achieving
progressively the full realization of this right by all appropriate means, including
particularly the adoption of legislative measures.
7. As the Inter-American Court of Human Rights stated in its Advisory Opinion on The
Environment and Human Rights:
“This Court has recognized the existence of an undeniable relationship between the
protection of the environment and the realization of other human rights, in that
environmental degradation and the adverse effects of climate change affect the real
enjoyment of human rights.60 In addition, the preamble to the Additional Protocol
to the American Convention on Human Rights in the Area of Economic, Social and
Cultural Rights (hereinafter “Protocol of San Salvador”), emphasizes the close
relationship between the exercise of economic, social and cultural rights – which
include the right to a healthy environment – and of civil and political rights, and
indicates that the different categories of rights constitute an indivisible whole based
on the recognition of the dignity of the human being. They therefore require
permanent promotion and protection in order to ensure their full applicability;
moreover, the violation of some rights in order to ensure the exercise of others can
never be justified.”6
8. The right to a clean, healthy and sustainable environment includes substantive and
procedural rights, as depicted in the Report of the Special Rapporteur on the issue of
human rights obligations relating to the enjoyment of a safe, clean, healthy and
sustainable environment of the Human Rights Council of 30 December 2019. The
substantive elements include clean air, a safe and stable climate, access to safe water
and adequate sanitation, healthy and sustainably produced food, non-toxic environments
5 Cf. IACHR, Indigenous and Tribal Peoples’ Rights over their Ancestral Lands and Natural Resources – Norms
and jurisprudence of the inter-American human rights system, December 30, 2009, OEA/Ser.L/V/II. Doc. 56/09,
para. 190.
6 Inter-American Court of Human Rights, Advisory Opinion OC-23/17 of 15 November 2017, The Environment
and Human Rights, para. 47
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in which to live, work, study and play, and healthy biodiversity and ecosystems. The
procedural elements include access to information, the right to participate in decisionmaking,
and access to justice and effective remedies, including the secure exercise of
these rights free from reprisals and retaliation. Realizing the right to a healthy
environment also requires international cooperation, solidarity and equity in
environmental action, including resource mobilization, as well as recognition of
extraterritorial jurisdiction over human rights harms caused by environmental
degradation.7
9. Costa Rica also refers to its Written Statement, in particular paragraphs 83 and 84.
III. Its Relation with other human rights
10. While the right to health, food, water and life are crucially dependent on the right to a
clean, healthy and sustainable development, other rights are similarly concerned, such
as the rights of children codified in the United Nations Convention on the Rights of
Children and those of the future generations as well. As recently judicially recognized,
the protection of the right of protection of private and family life is impacted by climate
change.8
11. The increased frequency of cyclones and other extreme weather events as a result of
global warming caused by anthropogenic climate changes affects human rights at
different levels, including the conditions of life, housing, access to food, water,
education and sanitation, as well as culture in general. The rights of indigenous peoples,
including their heritage, are also affected. All relevant related rights are not only of
customary character but have also been incorporated into universal and regional human
rights instruments. Without any doubt, the right to a healthy, clean and sustainable
environment possesses a close relation to them in the sense that it constitutes a prerequisite
for their effective enjoyment.
7 Right to a Healthy Environment: Good Practices, UN Doc. A/HRC/43/53. See also United Nations Human
Rights Officer of the High Commissioner, United Nations Environment Programme and United Nations
Development Programme, What is the Right to a Healthy Environment? Information Note, 2023, p. 9
8 Case of Verein Klimaseniorinnen Schweiz and others v. Switzerland, ECtHR Application no. 53600/20, Judgment
of the Grand Chamber (9 April 2024), in particular para. 548.
Written reply of Costa Rica to the questions put by Judges Cleveland, Tladi, Aurescu and Charlesworth at the end of the hearing held on 13 December 2024