Defining events and extremes in climate change impact attribution

Climate change has impacts on natural systems and populations, which can be analysed in attribution studies and attempted to be predicted in forward-looking analyses. Climate extremes in particular can be very impactful, be it in in terms of extreme individual climate hazards, extreme combinations of climate hazards, or less extreme climatic conditions combined with particular settings of exposure and vulnerability resulting in severe impacts. As the field of impact attribution is burgeoning, different perspectives on these complexities become apparent in different study designs, with implications for the research questions they address and the potential role they might play beyond science.

Here, we will give an overview over different climate change impact approaches, including how they each do (or don’t) consider climate extremes. Besides different attribution framings and impact modelling approaches, we will present a discussion of the climate data types typically used in impact attribution, and their implication for capturing impacts of extreme weather and climate. We will especially talk about extreme event attribution framings, and how ‘event’ can be defined in different ways from climate and impact standpoints, respectively. The differences will be illustrated using references to existing literature as well as works in progress, particularly from the field of agriculture-related impacts on food security and nutrition-related health.