Understanding extremes in a warming climate: On acknowledging uncertainty, embracing complexity, and asking societally relevant questions*

Human-caused global warming is now an observable physical reality—but the most important consequences of climate change do not come from the incremental increase in global mean temperature itself. Instead, many human and natural systems are facing increased frequency of historically unprecedented extreme weather events. Indeed, there is now strong evidence that the frequency and/or intensity of certain types of extremes—particularly those most directly related to changes in atmospheric temperature and moisture—are already increasing in a statistically robust manner. Despite this, the complex spatiotemporal dynamics surrounding far-from-mean state conditions in the Earth system, combined with the noisy statistical signal inherent to infrequently occurring extreme events within a still-short observational record, continue to complicate research efforts and often lead to confusion in community and public interpretation of results. In this talk, I will explore recent advances in the burgeoning sub-field of extreme event attribution—and offer thoughts on how embracing “Earth system complexity” and focusing on societally-relevant physical science questions can help move the field forward in the climate change era.