Co-producing legally compelling climate impact attribution for climate damages cases

As governments’ and corporations’ climate pledges continue to inadequately contribute to globally agreed objectives of limiting global warming, litigants have begun using ‘polluter pays’ actions to seek compensation for climate related losses and damages, and to incentivise mitigation. While attribution science can now robustly quantify how anthropogenic greenhouse gas (GHG) emissions alter the frequency, magnitude and impacts of climate extremes, courts have found current submissions insufficient to establish legal causation for losses and damages. The gap is not purely scientific or purely legal: for example, scientific inference is probabilistic and context dependent, whereas legal causation is jurisdiction specific and defined by evidentiary standards.

We recently launched a transdisciplinary project, EXACT (Extreme event impact attribution for climate litigation), to translate advances in climate impact attribution into evidence that is both scientifically rigorous and legally compelling. We aim to build an international network of attribution scientists, climate impact researchers, legal scholars, and litigators working in this area, with open dialogue about challenges in impact attribution. The ultimate aim is to codevelop and validate a case-based method that links emissions to hazards, to exposure and vulnerability pathways, and finally to quantified losses and damages using procedures compatible with legal standards of proof.

We will present preliminary outcomes from our first transdisciplinary workshop, including progress on a coproduction framework that aligns attribution metrics (e.g., risk ratios, counterfactual estimates) with legal thresholds as well as suggested criteria for selecting test cases and harmonising data across jurisdictions.

Our contribution aims to integrate geoscience into legal practice by providing a practical framework, shared language, and tools for co-producing compelling climate impact evidence. We invite participants to discuss and comment on these preliminary outcomes, especially impact attribution evidence from scientists and priority case applications, to refine the framework and ensure usability for courts, policymakers, and vulnerable communities.