The ICJAO has the historic opportunity to legally interrogate fossil fuel subsidies. Judge Cleveland’s question invites the Court to finally place fossil fuel production and its explicit and implicit financial support from States within the framework of international environmental, climate, and human rights law. How can States credibly claim to reduce emissions under the Paris Agreement, while continuing to fund the industry most responsible for those emissions?

Fossil fuel subsidies artificially lower the cost of extraction and use, and many have long argued they are a major driver of continued fossil fuel proliferation. Yet, these subsidies have largely escaped legal scrutiny—obscured by vague definitions, lack of transparency, and complex structures. Panama offered one of the most legally useful definitions: fossil fuel subsidies include any government action—financial or otherwise—that reduces the cost of fossil fuel production, increases returns to fossil fuel companies, or lowers prices for consumers, with cross-border effects. This makes subsidies both measurable and addressable under international law.

The Court received 65 written submissions from States and international organisations, and over 70% addressed this question directly, underscoring the centrality of fossil fuel subsidies to any meaningful legal interpretation of climate obligations. While views varied, a clear majority affirmed that States—particularly fossil fuel producers—are obligated to address subsidies to meet their legal commitments to reduce greenhouse gas emissions in some manner. Several submissions emphasised that fossil fuel production itself is inconsistent with the object and purpose of the Paris Agreement and the United Nations Framework Convention on Climate Change (UNFCCC), and that existing voluntary mechanisms (such as subsidy reforms in Nationally Determined Contributions) have largely failed to deliver meaningful progress.

The African Union’s submission added a critical equity and human rights dimension, noting that two-thirds of projected oil and gas expansion in Africa is led by foreign companies, most based in developed countries. Regulating extraterritorial corporate conduct, particularly where it causes climate harm or violates human rights, could be one of the Court’s most groundbreaking contributions. Not only is eliminating fossil fuel subsidies essential to achieving a just transition and avoiding catastrophic climate breakdown, but it also discontinues the financial incentives that have unjustifiably diverted investments away from renewable energy and the sustainable development of the Global South.

Meanwhile, high-emitting States like Canada, Kuwait, and the United States (among others) continue to cling to the notion of permanent sovereignty over natural resources—arguing that no binding international obligation exists to phase out fossil fuels. Again, this underscores the importance of why the ICJAO must clarify and codify such obligations, especially if the ICJ properly recognises that the regulating fossil fuels is at the crux of States’ obligations to reduce GHG emissions under the Paris Agreement. If current climate treaties are interpreted so narrowly that they fail to regulate the core driver of climate change, then new legal tools—like the Fossil Fuel Non-Proliferation Treaty—will become ever more essential. Without a legally binding agreement that outlines precisely how States must phase out fossil fuels, it is absurd to think it will spontaneously happen. Voluntary inclusion of fossil fuel subsidy reform in some States’ nationally determined contributions has only gone so far (nowhere) and largely failed to curb the production and consumption of fossil fuels. Another international advisory opinion that does not directly attack this problem will be a tripartite miscarriage of climate justice from which international law may not recover.

Regardless of whether the ICJ invokes treaty law, human rights law, or customary law, the conclusion should be the same: States cannot claim to fight climate change while subsidising its primary cause. At this stage in the climate crisis, fossil fuel subsidies are not just unsustainable, they are indefensible. The Court now has a rare opportunity to affirm this in law.