Deep dive: the ITLOS Advisory Opinion on climate change and its impact on the maritime sector – Executive Summary

  • Market Insight 27 June 2024 27 June 2024
  • Environmental, Social and Governance (ESG)

States must protect oceans and marine biodiversity from GHG emissions

In May 2024, a landmark ITLOS legal opinion confirmed states’ legal obligations to protect oceans and marine biodiversity from human-induced climate change. In this article we explore the main findings and its implications for the maritime sector.


On 21 May 2024, the International Tribunal for the Law of the Sea (ITLOS or the Tribunal) delivered an advisory opinion (the Opinion), finding that states have a legal obligation to protect the world’s oceans and marine biodiversity from climate change in accordance with the United Nations Convention on the Law of the Sea (UNCLOS).

The Opinion clarifies states’ specific obligations under (but not limited to) Part XII of UNCLOS to:

(a) prevent, reduce, and control pollution of the marine environment caused by the effects of climate change, particularly ocean warming, sea level rise and ocean acidification, caused by human induced GHG emissions; and

(b) protect and preserve the marine environment from these impacts.

One of the most significant written submissions came from the International Maritime Organization (IMO), which set out that the specific obligations developed by the IMO itself are consistent with the UNCLOS framework on setting international rules and standards in the shipping sector, given the wide membership of the IMO and the uptake of existing instruments, such as MARPOL.

Although the Opinion is not legally binding, the 169 signatory states of UNCLOS will be expected to implement legislation and effective enforcement measures to ensure compliance with their obligations to prevent marine pollution caused by GHG emissions and protect and preserve marine ecosystems.

Commercial shipping may lead the way in testing decarbonisation solutions, as is already the case with green shipping corridor initiatives.

Key findings of the Opinion

  • Greenhouse gas (GHG) emissions are marine pollution under UNCLOS, as GHGs:
    • are  considered to be a substance or energy.
    • are being introduced by humans, directly or indirectly into the marine environment; and
    • have caused or are likely to result in deleterious effects to the marine environment.
  • States must take all necessary steps to prevent, control and reduce, anthropogenic GHG emissions, including not only ocean-based emissions from vessels, but also land- and air-based emissions. States are required to act with strict “due diligence”.
  • States’ obligations go beyond existing climate change commitments: compliance with the Paris Agreement alone may not be sufficient to discharge states’ obligations.
  • Developed countries must take the lead in emissions reduction measures and must provide assistance to developing nations.
  • States have a duty to prevent “transboundary harm”. The Tribunal clarified that UNCLOS imposes strict and specific obligations on states to adopt all measures to ensure that anthropogenic GHG emissions within their jurisdiction or control do not cause damage to other states and their environment, and that any marine pollution from such emissions does not spread beyond their national jurisdiction.
  • States are required to monitor the risks and effects of marine pollution, conduct environmental impact assessments for any activity which “may cause substantial pollution to the environment or significant and harmful changes thereto through anthropogenic GHG emissions”, and publish reports on the findings.
  • States are legally obliged to protect and preserve the marine environment, which includes restoring degraded habitats and ecosystems.
  • Finally, the Tribunal found that States are required to cooperate directly, continuously, meaningfully, and in good faith to meet these obligations.

For a comprehensive overview and a detailed analysis of the Tribunal’s Opinion, including insights on the potential implications for the marine industry, we invite you to read our full article. 

Read the full article here


Stay up to date with Clyde & Co

Sign up to receive email updates straight to your inbox!