Tuesday, September 18, 2012

Higher temperatures to cause extreme rainfall in the tropics

Global warming and the resulting higher temperatures will likely account for extreme rainfall in the tropics. According to a latest MIT study every 1 degree Celsius rise in temperature in the tropics will result in 10 percent heavier rainfall extremes. This rainfall increase could have major impact on flooding in many populous regions in the tropics.

The researchers are convinced that rainfall extremes in tropical regions are more sensitive to global warming compared to other regions thought they are yet to understand the reasons why.

The basic principle of this increase in precipitation is well known. Greenhouse gases such as carbon dioxide enter the atmosphere, more greenhouse gases in the atmosphere means higher temperature, and this in turn leads to increases in the amount of water vapor in the atmosphere. More water vapor in the atmosphere means that there will be heavier rain because of the increased humidity, which fuels more intense storms.

The MIT scientists have used satellite observations of extreme rainfall between the latitudes of 30 degrees north and 30 degrees south, an area just above and below the Equator, and were looking at the several climate models, which are able to simulate the effects of both El Niño and global warming.

They have discovered one clear pattern, namely that models that showed a strong response in rainfall to El Niño also responded strongly to global warming.

The researchers issued warnings to policymakers saying that although the rainfall will increase in the wettest regions, the drier parts of the tropics will likely become even more drier, meaning that they should not only take into account more damaging flooding, but also less reliable rains from year to year.

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