Causation Puzzles in International Climate Litigation

The multiplicity of causes of climate change makes it difficult to establish causal connections between individual States’ greenhouse gas emissions and harmful effects of climate change. Several States and companies have invoked this causation puzzle as a defence against claims that they would be responsible for harmful effects. However, in recent opinions and judgments, the International Tribunal for the Law of the Sea, the European Court of Human Rights, and national courts have shown that this causation puzzle does not necessarily preclude a determination of the responsibility of States contributing to climate change. This paper examines how courts have (partially) solved puzzles of cause-effect relations by relying on normative standards based on the imperative to prevent global risks of climate harm. It also articulates possible solutions to the main causation puzzle that courts have not yet cracked: allocating compensation for climate change harm.