Legal Memorandum Advisory Opinion on Climate Change Delivered by the International Tribunal for the Law of the Sea: Relevance for the International Court of Justice Climate Advisory Proceedings

The memorandum examines the ITLOS advisory opinion, which establishes that anthropogenic greenhouse gas (GHG) emissions constitute marine pollution under UNCLOS. It highlights the 'stringent' due diligence required of States to protect the marine environment, the role of the best available science (IPCC), and the principle that the Paris Agreement does not supersede UNCLOS obligations. The document further discusses the necessity of environmental impact assessments that account for cumulative and socio-economic impacts, and cautions against the use of marine geoengineering if it transforms pollution types.

• The ITLOS Tribunal concluded that anthropogenic greenhouse gas (GHG) emissions into the atmosphere meet the three cumulative criteria of UNCLOS Article 1(1) (4) and therefore constitute "pollution of the marine environment".
• Under UNCLOS Article 192, States have a legal obligation to protect and preserve the marine environment from climate change and ocean acidification, which requires a "stringent" standard of due diligence due to the high risk of irreversible harm.
• The ITLOS AO establishes that the Paris Agreement and UNCLOS are separate agreements with distinct obligations; consequently, complying with the Paris Agreement alone is insufficient to fulfill a State's obligations under UNCLOS Article 194(1) to prevent, reduce, and control marine pollution.
• States must determine the necessary measures to combat marine pollution objectively, relying on the best available science, which the Tribunal identifies as the works of the Intergovernmental Panel on Climate Change (IPCC).
• The Tribunal clarified that the standard of due diligence is an obligation "to do the utmost" and must be more severe for riskier activities, noting that GHG emissions pose a high risk in terms of foreseeability and severity of harm.
• Environmental impact assessments (EIAs) for planned activities that may cause substantial marine pollution through GHG emissions must include cumulative impacts and may include socio-economic impacts.
• The ITLOS AO warns that marine geoengineering could violate UNCLOS Article 195 if it results in transforming one type of pollution into another, and may be subject to Article 196 regarding the use of technologies.

APA

ClientEarth (2024). Legal Memorandum Advisory Opinion on Climate Change Delivered by the International Tribunal for the Law of the Sea: Relevance for the International Court of Justice Climate Advisory Proceedings. https://www.clientearth.org/media/wfhekd0q/final_-legal-memorandum_-relevance-of-itlos-climate-ao-for-the-icj-ao-2.pdf

Chicago

ClientEarth. Legal Memorandum Advisory Opinion on Climate Change Delivered by the International Tribunal for the Law of the Sea: Relevance for the International Court of Justice Climate Advisory Proceedings. 2024. https://www.clientearth.org/media/wfhekd0q/final_-legal-memorandum_-relevance-of-itlos-climate-ao-for-the-icj-ao-2.pdf.

Wikipedia

{{cite report |author=ClientEarth |title=Legal Memorandum Advisory Opinion on Climate Change Delivered by the International Tribunal for the Law of the Sea: Relevance for the International Court of Justice Climate Advisory Proceedings |date=July 2024 |url=https://www.clientearth.org/media/wfhekd0q/final_-legal-memorandum_-relevance-of-itlos-climate-ao-for-the-icj-ao-2.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{clientearth2024legal, author = {{ClientEarth}}, title = {{Legal Memorandum Advisory Opinion on Climate Change Delivered by the International Tribunal for the Law of the Sea: Relevance for the International Court of Justice Climate Advisory Proceedings}}, institution = {ClientEarth}, year = {2024}, month = jul, url = {https://www.clientearth.org/media/wfhekd0q/final_-legal-memorandum_-relevance-of-itlos-climate-ao-for-the-icj-ao-2.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }