Growing prevalence of heat over cold extremes with overall milder extremes and multiple successive events

Abstract

Temperature extremes with altered characteristics are one of the most threatening impacts of global warming. How their characteristics have changed is uncertain, and varies by region. Here we analyse ERA5 reanalysis data for the period 1980 to 2018 to illuminate the spatio-temporal characteristics of single and multiple successive temperature extreme events at the global scale. We show that in the global average, the magnitude of heat extremes significantly increased while that of cold extremes decreased at a faster rate. As a result, the prevailing climate shifted from a prevalence of cold extremes to one of heat extremes, and the overall magnitude of extremes decreased. Globally, the magnitude of multiple successive temperature extreme events constituted about a quarter of all identified events. These trends were not globally uniform. The most noteworthy trends were observed in the Tropical and Polar zones; the Middle East and North Africa, including the Mediterranean region, were identified as hotspots of climate shifts.