Model projections of the future climate revealed that climate change is expected to alter the large-scale pattern in mean precipitation, the seasonal rainfall characteristics, the frequency and intensity of extreme weather events, the risks of water scarcity and flood, as well as the amount of water discharge in many rivers of the world.

Based on previous formal detection and attribution analysis, we found that the slowly evolving increase in greenhouse gas emissions and the inhomogeneous spatial repartition of anthropogenic aerosols emissions have already influenced the observed changes in precipitation and aridity through two emerging mechanisms: a global warming-driven land aridification and intensification of the wet-dry rainfall patterns, and an aerosol-driven inter-hemispheric temperature contrast governing the position of the tropical rain belt position.

In this presentation, we will explore the other end of the hydrological spectrum and investigate the underlying causes of the recent observed changes in extreme rainfall events. We will focus on the changes in extremes derived from daily rainfall data, with an emphasis on the role of anthropogenic aerosols and climate sensitivity, and with an analysis evaluating the sensitivity of results to the choice of precipitation extreme indices and observational datasets. Our results will be also compared with those obtained with traditional and machine-learning methods.

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.