Ten Uses of Extreme Event Impact Attribution: An Economic Research Agenda

This paper describes what Extreme Event Impact Attribution (EEIA) is, what it can provide, and why it is becoming increasingly more policy relevant. The core idea of EEIA is simple: If anthropogenic climate change modifies the probability or intensity of an extreme weather event or a class of such events, and if these events caused measurable adverse impact, then some portion of the measured impacts can be attributed to climate change. In practice, this requires a clear attribution question, a counterfactual climate, an impact model or impact data, and transparent assumptions about what is held constant. The literature shows that EEIA is already useful for estimating national and global climate-attributable losses, projecting future costs, identifying inequities, measuring response costs, tracing indirect losses, valuing health and mortality impacts, informing the Fund for Responding to Loss and Damage, supporting liability claims, and communicating the costs of climate change. Data gaps, methodological differences, ethical disagreements, and limited research capacity mean that impact attribution is best understood as one component of a broader evidence base, but one which, if it develops further, can contribute a lot to our knowledge of climate change.