Observed Trends in Extreme Precipitation and Convective Intensity Under Global Warming

Abstract Satellite observations and general circulation models have demonstrated that the atmospheric overturning circulation weakens in response to global warming. This is rooted in thermodynamic and energetic constraints on near-surface specific humidity and precipitation. While the response of the globally-averaged convective mass flux, specific humidity, and precipitation is well established, the response of extreme events is more uncertain. We show, using satellite observations from the SSM/I and SSMIS instruments, the trends in the distribution of precipitation and a proxy for convective intensity from 1987 to 2024. We find that heavy rainfall events in the tropics have increased in frequency by ~8.2%/decade, while moderate rainfall events have decreased in frequency by ~-1.7%/decade, leading to a modest increasing trend in the tropical mean rain rate. Meanwhile we find that the distribution of convective events has shifted from higher to lower intensities, except at the highest intensities where the trend is near-neutral. This implies that the increase of extreme precipitation is driven by an increase of available moisture rather than a strengthening of convective updrafts.