Historic International Court of Justice Opinion Confirms States’ Climate Obligations

A Major Shift in How Climate Change Adaptation is Perceived

The Court was equally clear that “adaptation obligations under the Paris Agreement complement the mitigation obligations in preventing and reducing the harmful consequences of climate change.”

Simply put, the level and need for future adaptation depends on states’ mitigation ambition and emission reductions today.

The ICJ’s opinion found that states have legal obligations under the climate treaties, customary international law, and other applicable international law, to carry out climate adaptation planning and implement adaptation actions, in line with the best available science. It spelled out that the adverse effects of climate change may “significantly impair the enjoyment of certain human rights,” including the right to life; to a healthy environment; to health; to an adequate standard of living; to privacy, family and home; and to the rights of women, children and indigenous peoples.

In other words, the ICJ sees states’ failure to implement adequate and timely adaptation measures as a potential violation of their international human rights obligations.

This opinion represents a major shift in how adaptation is perceived under global policy frameworks. While it has often been treated as optional or secondary, this decision puts adaptation on equal legal footing with mitigation efforts to cut emissions.

In addition, the Court also considers adaptation measures as a part of states’ customary duty to prevent significant harm to the environment by acting with due diligence. Applying a due diligence lens to states’ adaptation obligations allows for an assessment of whether governments are making serious, genuine efforts taking timely, informed, and credible adaptation actions in meeting their obligations under applicable treaties and customary international law.

What all this means is that the advisory opinion raises the bar for governments.

Adaptation can no longer be treated as an option, but a legal obligation. It clarifies governments’ accountability for their (in)action on strengthening resilience and providing support for the most vulnerable countries in meeting the costs of adaptation.

It also empowers the most vulnerable and most affected communities to assert their right to demand concrete, timely adaptation planning and meaningful actions and support to cope with the real and growing impacts of climate change now backed by international law.