Call Us Now

+91 9606900005 / 04

For Enquiry

Advisory Opinion of the International Tribunal for the Law of the Sea


International climate change litigation reached a significant milestone on May 21, 2024, when the International Tribunal for the Law of the Sea (ITLOS) issued an advisory opinion requested by the Commission of Small Island States on Climate Change and International Law (COSIS). This opinion addressed the specific obligations of Parties to the United Nations Convention on the Law of the Sea (UNCLOS) concerning climate change mitigation. COSIS, an association established in 2021, represents small island states.



  • Important International Institutions, agencies and fora – their Structure, Mandate
  • Effect of Policies & Politics of Countries on India’s Interests


  • Conservation, Environmental Pollution and Degradation, Environmental Impact Assessment
  • Climate Change

Mains Question:

The advisory opinion by the International Tribunal for the Law of the Sea addressing the specific obligations of Parties to the United Nations Convention on the Law of the Sea (UNCLOS) concerning climate change mitigation is a high point in international climate change litigation. Discuss. (15 Marks, 250 Words).

Significance of the ITLOS Advisory Opinion:

  • The ITLOS advisory opinion is particularly noteworthy given the upcoming advisory proceedings by the International Court of Justice (ICJ) on the “Obligations of States in respect of Climate Change.”
  • In a bold move, ITLOS accepted COSIS’s request to identify the obligations of states not party to the COSIS Agreement, particularly regarding obligations under Article 194(1) of UNCLOS.
  • The Tribunal clearly stated that Parties have specific obligations to take all necessary measures to prevent, reduce, and control marine pollution from anthropogenic greenhouse gas (GHG) emissions.
  • Furthermore, the opinion clarified that the release of carbon dioxide by humans, directly or indirectly, into the marine environment, qualifies as a substance or energy with potential harmful effects on the marine environment as defined in Article 1(1)(4) of UNCLOS.
  • The ITLOS clarification that carbon dioxide qualifies as a pollutant supports the scientific community’s stance that the surface ocean absorbs about a quarter of atmospheric CO2 emissions, increasingly causing seawater acidification. Unlike other greenhouse gases (GHGs), CO2 contributes significantly to this effect.
  • Additionally, the ocean absorbs over 90% of the excess heat from global warming, leading to higher ocean temperatures and rising sea levels.

Understanding its Legal Importance:

  • Understanding its legal importance, the principle of prevention or the no-harm rule, which governs state behavior in regulating shared natural resources to prevent significant transboundary harm, faces limitations in addressing the climate crisis.
  • These limitations include its bilateral framework and challenges related to attribution and standing in proving breaches of climate obligations.
  • The opinion supports the principle of collective action for climate change, highlighting its importance over bilateral considerations.
  • It emphasizes that necessary measures should be based on the best available science and adhere to relevant international rules and standards, such as the United Nations Framework Convention on Climate Change, the 2015 Paris Agreement, and the goal of limiting global temperature rise to 1.5°C rather than 2°C.
  • The opinion characterizes the obligation to take necessary measures as a due diligence obligation, but with a stringent standard due to the high risks of serious and irreversible harm to the marine environment from such emissions.

Associated Shortcomings:

  • However, the obligations under Article 194(1) to reduce anthropogenic GHG emissions are broad and general. This implies that not all pollution (GHGs) must be entirely prevented, nor do anthropogenic GHG emissions need to cease immediately or even eventually.
  • Measures that progressively reduce marine pollution by decreasing GHG emissions over time would be sufficient.
  • Yet, ITLOS’s identification of a general obligation emphasizes that states do not have unlimited discretion in addressing climate change.
  • The mere identification of a general obligation holds symbolic value and is insufficient. Environmental law expert Christina Voigt points out that while most states are already taking some action on climate change mitigation, the critical issue is not the existence of an obligation to mitigate climate change, but the specific content and standard of conduct required for this obligation.

The Netherlands Supreme Court’s decision:

  • An illustrative example is the Netherlands Supreme Court’s decision in Urgenda Foundation vs. The Netherlands, where the court ruled that to comply with a general mitigation obligation derived from the European Convention on Human Rights (ECHR) in light of the standard of due care, the Netherlands had to reduce GHG emissions to 25% below 1990 levels by 2020, exceeding the government’s insufficient pledge of 17%.
  • The court largely identified this target by relying on scientific estimates and the least-cost method of achieving the 2°C temperature goal outlined in the Paris Agreement.
  • However, the opinion did not concretely identify a methodology for assessing a state’s requisite level of mitigation action, unlike the Urgenda judgment.


The necessary measures, according to the opinion, are to be based on the means and capabilities available to states, implying that the principle of equity must be considered when determining the required level of mitigation action, if any. Although the advisory opinion lacks legal force, it still holds significant political influence as an authoritative judicial pronouncement.

June 2024