Warmer climates lead to more extreme rainfall (8/12/2008)

Researchers have confirmed the link between a warmer climate and more intense tropical rainstorms after analyzing 20 years of satellite data.

Dr Richard Allan of the Environmental Systems Science Centre at the University of Reading and Dr Brian Soden from the University of Miami's Rosenstiel School of Marine & Atmospheric Science used naturally-driven changes in climate associated with El Niņo to investigate how precipitation responds to a warmer climate.

The research, published in the journal Science Express and funded by the Natural Environment Research Council, found that both satellite observations and models indicated an increase in heavy rainstorms in response to a warmer climate.

Climate models have long predicted that global warming will increase the intensity of extreme precipitation events, but this is the first time observational evidence has been used to confirm the link. The research showed that the observed amplification of rainfall extremes is found to be larger than previously predicted, suggesting that forecasted changes in rainfall extremes may have been underestimated.

Dr Allan said, "Comparing observations with results from computer models improves our understanding of how rainfall responds to a warming world. Differences can relate to deficiencies in the measurements, or the models used to predict future climatic change. This research is based on 20 years of satellite observations, and we found a distinct link between rainfall extremes and temperature. This means that heavy rain events are likely to increase during warm periods and decrease during cold periods.

"One of the most serious challenges that humanity will face in response to climate change is adapting to changes in extreme weather events. There is a major concern that heavy rainstorms will become more common and more intense in a warmer climate. Floods can completely devastate areas and people's livelihoods and so this knowledge could have massive implications on how we plan for our changing climate in the future."

Dr Soden, associate professor at the University of Miami Rosenstiel School of Marine & Atmospheric Science, said, "A surprising result is that the models appear to underestimate the increase in intensity of the heaviest rain events to warming. This suggests that model projections of future changes in rainfall extremes due to human-caused global warming may also be underestimated."

Note: This story has been adapted from a news release issued by NERC

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