Describing the relationship between a weather event and climate change
Describing the relationship between a weather event and climate change -- a science usually termed event attribution -- involves quantifying the extent to which human influence has affected the frequency or the strength of an observed event. First, I will describe how this topic has emerged and developed over the last 20 years, and provide some background on climate science.
Then I will show how event attribution can be implemented through the application of non-stationary statistics to simulations performed by climate models over the 1850-2100 period -- those models underlying the IPCC assessment reports. As many such physical models are being used, we develop a technique for providing a multi-model synthesis, in which model uncertainty is treated consistently with other analysis.
Lastly, I describe how model estimates can be combined with historical observations to provide a single diagnosis accounting for all sources of information.
The method will be presented for the Normal distribution, with application to the 2003 European Heat Wave, and for Generalized Extreme Value Distribution (GEV), with application to the July 2019 French Heat Wave.