Lightning expected to increase by 50 percent with global warming

http://www.eurekalert.org/pub_releases/2014-11/uoc--let111214.php

PUBLIC RELEASE DATE: 13-Nov-2014

Contact: Robert Sanders
University of California - Berkeley
Lightning expected to increase by 50 percent with global warming
Atmosphere will become more explosive because of increased water vapor

Today's climate models predict a 50 percent increase in lightning strikes across the United States during this century as a result of warming temperatures associated with climate change.

Reporting in the Nov. 14 issue of the journal Science, University of California, Berkeley, climate scientist David Romps and his colleagues look at predictions of precipitation and cloud buoyancy in 11 different climate models and conclude that their combined effect will generate more frequent electrical discharges to the ground.

"With warming, thunderstorms become more explosive," said Romps, an assistant professor of earth and planetary science and a faculty scientist at Lawrence Berkeley National Laboratory. "This has to do with water vapor, which is the fuel for explosive deep convection in the atmosphere. Warming causes there to be more water vapor in the atmosphere, and if you have more fuel lying around, when you get ignition, it can go big time."

More lightning strikes mean more human injuries; estimates of people struck each year range from the hundreds to nearly a thousand, with scores of deaths. But another significant impact of increased lightning strikes would be more wildfires, since half of all fires - and often the hardest to fight - are ignited by lightning, Romps said. More lightning also would likely generate more nitrogen oxides in the atmosphere, which exert a strong control on atmospheric chemistry.

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Precipitation - the total amount of water hitting the ground in the form of rain, snow, hail or other forms - is basically a measure of how convective the atmosphere is, he said, and convection generates lightning.

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