Extreme Tropical Rainfall Seasons Due to Global Warming

Global warming is set to intensify extreme precipitation like cyclones and hurricanes in the tropical regions, reveals a new study.

Increase in global temperatures due to release of greenhouse gases like carbon on account of human activity has caused an increase in water vapor in the atmosphere. This, in turn, is triggering intense rainfall events as warmer conditions continue to prevail.

Researcher Paul O'Gorman, assistant professor from the Massachusetts Institute of Technology, studied the extreme rainfall pattern in the tropical regions just above and below the equator based on satellite observations.

He compared the data with that of the results obtained using various climate models over a period of 20 years. He found that the trend in rainfall varied each year and noticed a strong link between extreme rainfall and global warming, wherein the warmer years were getting more rainfall.

According to the researcher, changes in rainfall patterns is due to El Nino, a quasiperiodic (unpredictable) climate pattern that occurs across the tropical Pacific Ocean warming the surface. El Nino triggered local warming which in turn changed the rainfall pattern.

When O'Gorman checked the climate models, he found a link between El Nino and global warming. The models that showed simulation of extreme rainfall due to El Nino also responded the similar way when exposed to global warming.

He indicated that the change in rainfall pattern is not only due to temperature changes every year but also due to long-term climate change. The satellite observations also revealed extreme rainfall events in tropical regions during warmer periods.

Based on his observations, O'Gorman estimated that for every 1 degree Celsius rise in global temperature would cause about 10 percent increase in tropical rainfall.

"Unfortunately, the results of the study suggest a relatively high sensitivity of tropical extreme rainfall to global warming," O'Gorman said in a news release.

"But they also provide an estimate of what that sensitivity is, which should be of practical value for planning," he said.

The findings of the study are published online in the journal Nature Geoscience.