ITLOS Advisory Opinion: States' Obligations Under UNCLOS to Combat Climate Change Effects on Oceans

A unanimous advisory opinion on States' responsibility to safeguard the world's seas from the effects of climate change, including ocean warming, sea level rise, and ocean acidification, was released by the International Tribunal for the Law of the Sea (ITLOS). For the first time, under the terms of the 1982 United Nations Convention on the Law of the Sea, an international court or tribunal has examined States' duties to tackle climate change (UNCLOS). ITLOS determined that anthropogenic greenhouse gas (GHG) emissions absorbed by the seas are considered marine pollution because of their detrimental impacts on the marine ecosystem. States must comply with UNCLOS and other pertinent international legal commitments by taking all necessary steps to minimize their GHG emissions.

According to a ruling by the International Maritime Organisation (IMO), it is within its authority to provide an advisory opinion regarding the matter of maritime pollution resulting from emissions of greenhouse gases that humans generate. According to an IMO ruling, greenhouse gas emissions are substances or forms of energy that people release into the marine environment to cause harm, including warming and acidification of the ocean. According to UNCLOS, this is deemed "pollution," and governments are required to take all appropriate action to minimize and regulate maritime pollution. The need to objectively evaluate all pertinent elements, such as the most advanced scientific research, international regulations and standards, and available resources, was again underlined by the IMO. The IMO also said that although poor countries have more resources and ability than industrialized countries, they nevertheless have the same responsibility to safeguard the environment and must take more steps to cut emissions.

Climate change and its effects fall under the environmental purview of the United Nations Convention on the Law of the Sea (UNCLOS), according to the International Tribunal for the Law of the Sea (ITLOS). The advisory opinion stressed that to control GHG-emitting activities, states must implement environmental impact assessment (EIA) rules and do "rigorous" due diligence. Since an EIA is required for the due diligence duty to be deemed satisfied, the two are interwoven. The verdict may spur more measures to address the effects of climate change and functions as a wake-up call for large CO2-emitting governments to adhere to UNCLOS' environmental duties. States must evaluate all implications in light of the particular conditions at hand when determining necessity in a given scenario. This is a fact-intensive and circumstance-dependent process.