Changes in atmospheric circulation patterns are associated with increased European heat-related mortality

Heat poses a critical risk to human health around the world. Recent work has investigated how anthropogenic climate change can modulate atmospheric circulation patterns, finding that circulation patterns increasing in frequency are associated with high temperatures in Europe. Here, we investigate the role of these changes in the dynamics of the atmosphere for European heat-related mortality. Specifically, we identify circulation patterns whose occurrence has become either more or less frequent over past decades. We couple this with an epidemiological framework, which uses an advanced regression model to compute associations between temperature and mortality. This association accounts for lags extending up to three weeks, and is fit for each subnational region within our dataset, which covers almost all of Europe. This allows us to calculate the heat-related mortality burden associated with circulation patterns that have changed in frequency. We find that dynamical changes have reinforced the thermodynamic warming trend, and are associated with increased heat-related mortality in northern and central continental Europe. Furthermore, dynamical changes appear to have played an important role for the extreme temperatures of the European summer of 2003, and the associated heat-related mortality. We thus highlight the importance of considering the role of changes in atmospheric circulation patterns when investigating the role of climate change for heat events and their impacts. Furthermore, we argue that heat action plans should consider the possibility of record-shattering heat events, where dynamical changes contributing to anomalously high temperatures could coincide with the peak of the seasonal temperature cycle, as seen in 2003.