A global scale assessment of the intensification of rainfall extremes

Intensification of precipitation extremes under a changing climate is expected to severely impact societies due to increased flooding, and its impacts on infrastructure, agriculture, and ecosystems. Extensive research in the last decades has identified multiple facets of precipitation changes, from super Clausius – Clapeyron scaling of precipitation extremes with temperature increase, to the change of the intensity and spatial extent of mesoscale convective systems.

In this study we attempt to compile state of the art data and simulations to understand the multiple facets of the changes in precipitation extremes across the world. To do that we combined data from thousands of weather stations globally, reanalysis datasets, and general circulation and convection permitting model simulations. Our results show that:

• Hourly precipitation extremes scale with temperature at a rate of ~7%/K globally, albeit very large spatial heterogeneities were found, linked to topography, large-scale weather dynamics and local features of atmospheric convection
• Precipitation extremes change beyond this thermodynamic basis, with increases in the heaviness of the tails of precipitation distribution at fine scales
• The spatial extent of convective systems is expected to increase
• Precipitation extremes with shorter spell duration that are distributed more uniformly throughout the year are expected