Based on physical considerations, extreme precipitation is expected to intensify in a warming world. Global climate models project a general intensification of annual extreme precipitation in most land regions of the globe throughout the twenty-first century.

CLEX researchers have investigated the robustness of this future intensification over land across different models, regions, and seasons in an ensemble of 27 CMIP5 models. They have also evaluated the role of model interdependencies in this ensemble.

Future annual extreme precipitation intensity increases in the majority of models and over the majority of land areas, from the driest to the wettest regions of each model.

Strong similarities in extreme precipitation changes are found between models that share atmospheric physics and, in particular, their treatment of convection. This leads to a reduction of an ensemble of 27 projections into around 14 projections.

Models show more similarities in dry compared to wet regions, in the dry season compared to the wet season and in the extra-tropics compared to the tropics.

For each model, the future increase in the wettest day of the season or year exceeds the range of changes that could be explained by natural variability in the majority of the land areas. This result is particularly robust across models in extra-tropical regions because of a similar future change and a similar representation of natural variability.