day'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.
While some studies have shown changes in lightning associated with seasonal or year-to-year variations in temperature, there have been no reliable analyses to indicate what the future may hold. Romps and graduate student Jacob Seeley hypothesized that two atmospheric properties -- precipitation and cloud buoyancy -- together might be a predictor of lightning, and looked at observations during 2011 to see if there was a correlation.
"Lightning is caused by charge separation within clouds, and to maximize charge separation, you have to loft more water vapor and heavy ice particles into the atmosphere," he said. "We already know that the faster the updrafts, the more lightning, and the more precipitation, the more lightning."
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