Intense rain after warm weather
2008-08-08 17:19
Washington - US and British researchers have confirmed the link between warmer climate and an increase in powerful rainstorms, according to a study released on Thursday that underscores one of the challenges of global warming.
The researchers even found that the increase of extreme rainfall was higher than what has been predicted in current computer models, according to the study published in the journal Science.
The scientists pointed out that one of the biggest concerns regarding climate change is that heavy rainstorms will become more common and intense in a warmer climate due to the higher moisture available for condensation.
The more powerful rains also increase the risk of flooding that could have substantial impacts on societies and economies, they said.
To understand the link between warmer climate, the researchers used naturally-driven changes associated with the El Nino weather system as a laboratory for testing their hypotheses.
Warmer atmosphere
El Nino is an occasional seasonal warming of the central and eastern Pacific Ocean that upsets normal weather patterns from the western seaboard of Latin America to East Africa, and potentially has a global impact on climate.
Studying satellite observations from the past 20 years, the experts found that heavy rain events increased during warm periods and decreased during cold times.
"A warmer atmosphere contains larger amounts of moisture which boosts the intensity of heavy downpours," said Brian Soden, associate professor at the University of Miami Rosenstiel School of Marine & Atmospheric Science.
"Comparing observations with results from computer models improves understanding of how rainfall responds to a warming world" said Richard Allan, of the University of Reading's Environmental Systems Science Centre.