Assessing recent trends in globally co-occurring hot, dry and wet events under climate change

The spring-to-summer seasons in recent years were characterized by co-occurring hot, dry, and wet extremes around the globe, leading to questions about the contribution of human-induced global warming to the changing likelihoods of such extreme years.  Here we investigate recent trends in the fraction of global (and regional) land-area that is affected by hot days, wet days and dry months. Observed trends are put into context of Earth System Model (ESM) ensemble simulations accounting for present day and pre-industrial climate conditions in a detection and attribution setting. The analysis is applied to the global land area as well as to the regions defined in the sixth IPCC assessment report. Results show that on a global scale as well as on a regional level, observed trends of co-occurring hot, dry and wet events cannot be explained by internal climate variability, but are only captured by model simulations that account for anthropogenic changes in the composition of the atmosphere. Thus, the results show that recent global trends in spatially co-occuring hot and dry extremes are very likely linked to anthropogenic climate change.