A new study by researchers from the Massachusetts Institute of Technology and the Swiss Federal Institute of Technology in Zurich shows that the most extreme rain events in most regions of the world will increase in intensity by 3% to 15%, depending on region, for every degree Celsius that the planet warms.
If global average temperatures rise by 4 degrees Celsius over the next hundred years, as many climate models predict given relatively high carbon dioxide emissions, much of North America and Europe would experience increases in the intensity of extreme rainfall of roughly 25%, MIT News reported.
Some places such as parts of the Asian monsoon region would experience greater increases, while there will be smaller increases in the Mediterranean, South Africa and Australia.
There are a few regions projected to experience a decrease in extreme rainfall as the world warms, mostly located over subtropical oceans that lie just outside the tropical, equatorial belt.
The study, published on May 15 in Nature Climate Change, finds that the varied changes in extreme precipitation from region to region can be explained by different changes in the strength of local wind patterns.
As a region warms due to human-induced emissions of carbon dioxide, winds loft that warm, moisture-laden air up through the atmosphere, where it condenses and rains back down to the surface.
But changes in strength of the local winds also influence the intensity of a region’s most extreme rainstorms.
Paul O’Gorman, a co-author on the paper and associate professor of atmospheric science in MIT’s Department of Earth, Atmospheric and Planetary Sciences, says being able to predict the severity of the strongest rain events, on a region-by-region basis, "could help local planners prepare for potentially more devastating storms".
