Scientists studying variations in tropical heat and rainfall since the mid-1980s have found a strong link between warm periods and more extreme downpours.
The observed rise in the heaviest rains is about twice that produced by computer simulations used to assess human-caused global warming, said the researchers.
Other studies have already measured a rise in heavy rains in areas as varied as North America and India, and climatologists have long forecast more heavy rains in a world warmed by accumulating greenhouse gases.