Versión en español aquí

Joint Statement

Historic CLimate Opinion: States Must protect oceans from greenhouse gas emissions

HAMBURG, Germany, May 21, 2024 — Today,  the International Tribunal for the Law of the Sea (ITLOS) issued its Advisory Opinion on the protection of the marine environment from pollution caused by climate change. The Opinion is a groundbreaking first in international law — clarifying the legal obligations of States to address climate change as a crisis at the intersection of two critical global commons: the ocean and the atmosphere. ITLOS clearly stated that greenhouse gas emissions pollute the marine environment and States must take all necessary measures to prevent, reduce, and control them.

The Opinion was requested by the Commission of Small Island States on Climate Change and International Law (COSIS) in December 2022, seeking to clarify State obligations under the United Nations Convention on the Law of the Sea (UNCLOS) to prevent, reduce, and control pollution to the marine environment resulting from climate change and to protect and preserve the marine environment from these harmful impacts.

Sea level rise and marine pollution are significant threats to small island States and the human rights of coastal and island communities, in particular artisanal fishing communities. The ocean plays a crucial role in mitigating climate impacts, and the Tribunal’s Opinion is a vital step in clarifying State obligations to limit the pollution of our oceans as well as to restore marine habitats and ecosystems, protecting the rights of women, older persons, Indigenous Peoples, young people - present and future generations from the threats of climate change. 

As the first Advisory Opinion on climate change issued by an international court, ITLOS’ Opinion has the potential to shape forthcoming opinions by the International Court of Justice (ICJ) and the Inter-American Court of Human Rights (IACtHR). While much has been clarified by ITLOS, more work remains to be done by the ICJ and the IACtHR, especially in drawing a strong nexus between human rights and climate change obligations. Nevertheless, together these advisory opinions will be crucial sources on international law, clarifying and interpreting States’ obligations in respect of the causes and consequences of climate change, for the environment and human rights. 

The Tribunal’s Opinion clarifies what concrete steps States have to take under the law of the sea, to protect our oceans from climate change. While the Court has referred to other relevant sources of international law, the UNFCCC and the Paris agreement in particular, in order to achieve a harmonious interpretation, it has also emphasized that State’s obligations under UNCLOS are more extensive than under the Paris agreement. Under UNCLOS, States have extensive transboundary obligations in regard to both existing and future or potential pollution and must adhere to a stringent standard of due diligence. This is a major win and the first step on the international legal sphere to achieving climate justice for present and future generations. 


Nikki Reisch, Director of the Climate & Energy Program at the Center for International Environmental Law (CIEL), said: 

“The Tribunal’s opinion leaves no doubt: States are duty-bound to protect the oceans from the drivers and impacts of climate change. To those that would hide behind the weaknesses of international climate treaties, this opinion makes clear that compliance with the Paris Agreement alone is not enough. Pledges and promises at annual climate conferences do not satisfy States’ legal duties to take all necessary measures to prevent, reduce, and control the greenhouse gas emissions polluting the marine environment, in line with climate science and the goal of limiting warming to 1.5°C. We know that doing so requires rapidly phasing out all fossil fuels. States that fail to comply face legal responsibility. Protecting the global commons of the oceans and atmosphere is a matter of life and death — not just for entire marine ecosystems and the coastal and island communities most directly dependent on them and at greatest risk from climate change, but for all of humanity and the planet as a whole.”

Isabela Keuschnigg, Legal Officer at Opportunity Green, said:

“In an incredible moment for climate justice, ITLOS has found that human-caused greenhouse gas emissions constitute pollution of the marine environment under UNCLOS, placing the ocean firmly on the climate change agenda. The Tribunal has made clear that States must take all necessary steps to protect our seas from climate change harms in light of the best available science and the 1.5-degree temperature goal. Crucially, this means that to the extent that States’ global efforts, such as those under the international climate regime, fall short, the law of the sea requires States to do more.”

Ana Lucía Maya-Aguirre, Director of Observatory for Marine and Coastal Governance, said: 

"The ITLOS has made a remarkable step in extending the corpus juris to clarify States obligations to address climate change and ensure the sustainable and equitable use of marine biodiversity. The tribunal has interpreted that anthropogenic greenhouse gas emissions constitute marine pollution in accordance with the UNCLOS, which is crucial to integrate the Law of the Sea with the International Climate Change Law, as we stated in our amicus brief to the tribunal. We hope this decision lays the groundwork for the Inter-American Court of Human Rights and the International Court of Justice to further strengthen the international environmental framework based on a human rights approach."

Samira Ben Ali, Steering Committee Member & Outreach and Engagement Coordinator at World’s Youth for Climate Justice, said: 

“This Advisory Opinion is an incredible step forward to achieve climate justice as it acknowledges that anthropogenic greenhouse gas emissions are a form of pollution. Moreover, the Tribunal notes that the best available science should inform the content of all necessary measures created to prevent, reduce and control said emissions. States must look beyond the Paris Agreement as the Tribunal does not consider it enough to reach the obligations set out by UNCLOS. With this advisory opinion, ITLOS is sending a strong message to the most vulnerable communities, including islanders and future generations, that States have an obligation to protect their human rights from the consequences of climate change. To present a united voice, the upcoming advisory opinions from the International Court of Justice and the Inter-American Court of Human Rights should also seek to make those obligations clear.”

Siosiua Alo Veikune, Campaigner at Pacific Islands Students Fighting Climate Change, said:

“The small island States have upheld their moral obligations of amplifying the voices and concerns of their frontline communities and the ITLOS has responded to these pleas. The ITLOS being the authority on the interpretation of the UNCLOS have delivered an advisory opinion that sheds light on the science behind the climate crisis and its negative impacts that are all too familiar to the people of the small islands States. All around the world, our oceans are weaved into aspects of culture and identity. At its core, this advisory opinion has called upon States to protect and preserve the marine environment not just as a duty, but a call to become safeguarders of our oceans from further harm, ensuring their vitality for generations to come.”

Text of the advisory opinion here


Media contacts

Background Organisations

World’s Youth for Climate Justice (WYCJ) is the global sister organization of the Pacific Islands Students Fighting Climate Change, and as such, one of the movements calling for the historic UN request for an advisory opinion on climate change and human rights from the International Court of Justice.

Opportunity Green is an NGO working to unlock the opportunities from tackling climate change using law, economics, and policy. We do this by amplifying diverse voices, forging ambitious collaborations and using legal innovation to motivate decision makers and achieve climate justice, with particular emphasis on the aviation and shipping industries.

The Center for International Environmental Law (CIEL) uses the power of law to protect the environment, promote human rights, and ensure a just and sustainable society. CIEL is dedicated to advocacy in the global public interest through legal counsel, policy research, analysis, education, training, and capacity building.

The Observatory for Marine and Coastal Governance is a civil society organization based in Colombia dedicated to building capacity of communities that inhabit coastal and island territories, research and ocean environmental education. Its areas of work are marine justice and climate action, sustainable marine artisanal fishing and peace building based on the protection of a healthy environment.

Pacific Islands Students Fighting Climate Change is a youth-led organisation with the primary campaign to seek climate justice at the International Court of Justice by requesting the court to respond to a legal question that will develop international law, integrate legal obligations around environmental treaties and basic human rights, and clarify state responsibility for climate harm.