Research Highlights

Nature Reports Climate Change
Published online: 14 August 2008 | doi:10.1038/climate.2008.81

Models rained out

Anna Barnett

Science doi:10.1126/science.1160787 (2008)

STEVEGEER, ISTOCKPHOTO

Rising temperatures could make wet regions even wetter than currently predicted by climate models, finds a new study. For the first time, scientists have found direct observational evidence that the most intense of tropical downpours are more frequent during warm periods.

Richard Allan at the University of Reading and Brian Soden at the University of Miami used satellite observations and climate models to analyse the response of tropical rainfall to naturally driven El Niño events, which tend to raise temperatures, over the past 20 years. Heavy precipitation pelted tropical oceans more often when El Niño warmed the seas, a trend that was reproduced well by the models. But models were less adept at simulating the frequency of the heaviest rainfall events, which in warm years increased twice as much as predicted.

Among the most dangerous threats from global warming are flooding of rain-swollen rivers and lakes in the tropics. As the latest climate models fall short of reproducing observed precipitation patterns, say the authors, they may also underestimate the extent of future rainfall in these regions.