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On the 21st of May 2024, the International Tribunal for the Law of the Sea (ITLOS) issued an advisory opinion that could be essential to the fight against climate change by recognizing the obligation of States to reduce their greenhouse gas emissions to protect the ocean. In fact, to fulfill their legal obligations to protect the marine environment, States could be obliged to implement mitigation actions that go beyond what is outlined by the Paris Climate Agreement. Furthermore, according to ITLOS, countries with the greatest historical responsibility for the climate crisis must step up and do more to address greenhouse gas pollution than states with a smaller footprint.
ITLOS was established in 1982 by the United Nations Convention on the Law of the Sea (UNCLOS) and is headquartered in Hamburg, Germany. It is an independent judicial body that can adjudicate on all disputes relating to maritime zone delimitation, navigation, conservation and management of marine biological resources, protection and preservation of the marine environment, and marine scientific research.
In December 2022, the Commission of Small Island States on Climate Change and International Law (COSIS) made a legal request to ITLOS to obtain an opinion defining the obligations under international law that States have to protect the marine environment from climate damage.
COSIS is a group of nine Caribbean and Pacific island nations, led by Antigua and Barbuda and Tuvalu, which are particularly vulnerable to climate damage and are frustrated by the insufficient results achieved in nearly 30 years of international climate negotiations under the United Nations Framework Convention on Climate Change (UNFCCC).
“The foundation of a new international law”
“ITLOS advice will inform our future legal and diplomatic work in putting an end to the inaction that has brought us to the brink of an irreversible disaster,” Gaston Browne, Prime Minister of Antigua and Barbuda, said in a COSIS press release commenting on the ITLOS advisory opinion. “ITLOS has taken a critical first step in recognising that what small island nations have been fighting for at the COP negotiations for decades is already part of international law,” Payam Akhavan, Professor of International Law at the University of Toronto and legal representative of COSIS, said in the same press release.
Marta Torre-Shaub, lawyer, research director at the Centre National Recherche Scientifique (CNRS, in France), and specialist in environmental law and climate change said, in a preliminary analysis on LinkedIn, that the ITLOS opinion “may already be regarded as the foundation of a new international law”. The expert explains that this is the first opinion to be expressed on the obligations of States under the United Nations Convention on the Law of the Sea (UNCLOS) to combat pollution caused by greenhouse gas emissions that cause or aggravate climate change.
According to Torre-Shaub and colleagues, several elements are noteworthy in the ITLOS opinion. First of all, the Court believes that it has jurisdiction to issue its opinion and considers that various instruments of international law are applicable, not just climate change treaties. Furthermore, ITLOS also underlined that the state of scientific knowledge is essential and presupposes guidance to regulate the behavior of private and public actors (including IPCC reports) and reiterated that greenhouse gas emissions are considered as pollutants under UNCLOS.
In addition, according to Torre-Shaub, at least 15 obligations for States arise from the ITLOS opinion, including that of rigorous "due diligence", which the Court defines very precisely. In particular, one of these obligations is the precautionary principle because the recognized risk is serious and irreversible. Furthermore, monitoring, control and evaluation obligations must be continuous and based on an ecosystem approach.
Protecting the ocean is protecting the climate
"The opinion of the Tribunal is particularly relevant for the implementation of the human right to a clean, healthy, and sustainable environment. In particular, the Tribunal emphasises the precautionary and ecosystem approaches in the context of states' obligations to conduct environmental and socio-economic assessments of any activity that may cause marine pollution linked to climate change." This was stated in a joint press release by Elisa Morgera, UN Special Rapporteur on climate change and human rights, Astrid Puentes, UN Special Rapporteur for the human right to a clean, healthy and sustainable environment, and Marcos A. Orellana, UN Special Rapporteur on toxics and human rights.
“We must protect the ocean because the ocean protects us is one of the mottos of the LetsBeNicetotheOcean initiative and the support from ITLOS can really make a difference. By absorbing around 90% of the excess heat we produce and 25% of the CO2 we put into the atmosphere, the ocean is a critical buffer against climate change, but we are rapidly destroying it,” said Remi Parmentier, Director of the Varda Group, which is coordinating the Let's Be Nice to the Ocean initiative ahead of the Third United Nations Ocean Conference in Nice, France, in June 2025, in an interview with Renewable Matter.
Through the involvement of civil society, the initiative aims to encourage governments to take measures that make ocean protection the norm rather than the exception. One of their proposals is that of the protection principle, i.e. a paradigm shift through which the burden of proof is not placed on those seeking conservation and sustainable management measures, but rather on those wishing to pursue extractive or polluting activities.
National and international courts are increasingly being asked to define the precise nature of States' obligations to prevent climate change. The number of court cases has more than doubled in five years globally, according to the Global Climate Litigation Report: 2023 Status Review published in July 2023 by the United Nations Environment Program (UNEP), rising from 884 in 2017 to 2,180 in 2022. In 2021, in Italy, there was the first lawsuit against the Italian State for climate non-compliance.
“The opinion of the Court is not binding, but expresses a very authoritative legal assessment that cannot be ignored,” Luca Saltalamacchia, a lawyer specialising in human rights and climate change, told Renewable Matter. As the impacts of the climate crisis grow, disproportionately affecting the most vulnerable, courts are likely to place greater weight on the findings of advisory opinions. The ITLOS advisory opinion could be essential in the fight against climate change.
Image: David Courbit, Unsplash