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Episodes of heavy rainfall have multiplied with climate change

Episodes of heavy rainfall have multiplied with climate change

By Caty Arévalo

Researchers have analyzed the records of extreme rainfall episodes in all regions of the planet between the years 1901 and 2010 and have detected that until 1980 natural variations perfectly explain the frequency of these events.

However, coinciding with a significant increase in the accumulation of greenhouse gases in the atmosphere in the early 1980s, events with heavy rains have been 12 percent more common between 1981 and 2010 than if there had been no climate change.

The most serious cases

Scientists cite the severity of some of these extreme events, such as the heavy rainfall in Pakistan in 2010, which caused floods, hundreds of deaths and caused a cholera epidemic in that country.

Another example is the floods that Texas suffered, also in 2010, due to the heavy rainfall accumulated in a short period of time.

“In all these events, the rain that fell in a single day broke a record with respect to local records -since 1901- and although each case of extreme rainfall is explained by a combination of different factors, we have observed a notable increase in the frequency of these disasters. natural ”, explains in a statement Jascha Lehmann, one of the lead authors of the study.

Higher incidence in 2010

Thus, although the average increase of those three decades was 12%, the scientists point out that the increase was considerably greater in the last years analyzed, these events becoming 26% more common than normal in 2010 .

In addition, while the number of episodes of intense rainfall soared in the rainiest areas of the planet, it fell considerably in the driest.

Thus, for example, extreme rainfall increased by 56% in Southeast Asian countries, while in the Mediterranean basin or in the Western United States they decreased by 27 and 21% respectively in both regions, where the risk increases. drought.


Atmosphere temperature

To analyze the relationship between the increase in heavy rainfall events and climate change, the authors have studied the coexistence curve between the amount of water that can accumulate in the atmosphere when its temperature increases, based on the Clausius-Clapeyron equation. .

The result shows that the increase in extreme rainfall coincides with the increase in temperature in the lower layer of the atmosphere due to climate change.

This study is the first to provide knowledge on the influence of climate change on the multiplication of heavy rain events.

EFE Green


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