Can we attribute changes in risk to anthropogenic emissions?

Thursday, 18 December 2014: 5:30 PM
Dáithí A Stone, Lawrence Berkeley National Laboratory, Berkeley, CA, United States, Christian Huggel, University of Zurich, Zurich, Switzerland and Gerrit Hansen, Potsdam Institute for Climate Impact Research, Potsdam, Germany
Losses and damages associated with extreme weather events have been receiving attention lately within the context of anthropogenic climate change, whether in discussions in the public, international negotiations, or legal arenas. Investigations of the role of anthropogenic emissions in this loss and damage have so far taken two forms. On the one hand, so-called "event attribution" studies have examined the role of anthropogenic emissions in the occurrence of the extreme weather event, usually in terms of the chance of the event. On the other hand, a different line of research has been primarily concerned with how losses related to extreme weather events have varied over time, by examining trends in disaster databases. According to these latter studies, the increase in asset values and in exposure are the main drivers of the strong increase of economic losses over the past several decades in many areas.

Here we propose a better integration of these existing lines of research in detection and attribution of extreme weather events and disasters by applying a risk framework, where risk is considered a function of the probability of occurrence of an extreme weather event as well as the associated consequences of that event. Attribution of risk thus requires consideration of intensity of the physical event, exposure and value of assets, and vulnerability. Through analysis of trends in these contributors for select case study events, as well as comparative analysis of repeated events, we examine the feasibility of considering the role of anthropogenic emissions against other factors in contributing to long-term trends in risk.