Torrential rains increasing in a warming world: Study

Overall, there were 12 per cent more downpours which broke local records from 1981 to 2010 than would be expected

Reuters July 08, 2015
A man tries to clear debris in a Rawalpindi street flooded with rain water. PHOTO: APP

OSLO: Torrential rains have become more frequent worldwide since 1980, with Southeast Asia getting the biggest increase in downpours, a scientific study said on Tuesday.

The report adds to evidence that rising man-made greenhouse gas emissions are stoking extremes from heatwaves to precipitation. Warmer air absorbs more moisture, which then can be dumped in downpours.

"We find a clear overall upward trend for these unprecedented hazards," lead author Jascha Lehmann of the Potsdam Institute for Climate Impact Research said in a statement.

Overall, there were 12 per cent more downpours which broke local records from 1981 to 2010 than would be expected in an unchanged climate, according to an analysis of rainfall statistics from thousands of weather stations since 1900. Southeast Asia had the biggest increase with 56 per cent, while Europe saw a 31 per cent rise.

The study said 2010 was the year with most records broken, from Texas to Pakistan. Flooding in Pakistan was the worst in its history, killing more than 2,000 people and affecting 18 million.

The findings may help guide investment in flood prevention, from reinforcing riverbanks to building storm drains in cities. Dim Coumou, one of the authors, said natural climate shifts could explain the frequency of downpours until about 1980.

"After that we clearly go out of that range and see many more record-breaking events," he told Reuters. "I would expect this to continue over coming decades - it depends of course on how much humanity will emit."

The UN panel of climate scientists concluded last year there had been "an increase in the number of heavy precipitation events in a number of regions" since about 1950 due to rising temperatures.

In April, a Swiss-led study said global warming was to blame for most extremely hot days and almost a fifth of heavy downpours. Officials from almost 200 countries will meet in Paris in late 2015 to try to work out a UN deal to curb greenhouse gas emissions.

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