Today's climate models spredicted a 50 percent increase in lightning strikes across the U.S. over the next century as a result of global warming.
Researchers looked at precipitation and cloud buoyancy predictions in 11 different climate models, and the data suggested more frequent electrical discharges will hit the ground in upcoming decades, the University of California - Berkeley reported.
"With warming, thunderstorms become more explosive," said David 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."
Nearly thousands of people are struck by lightning every year in the U.S., and an increase in strikes could drive up those numbers. The phenomenon could also lead to more wildfires and an increase of nitrogen oxides in the atmosphere, which would change the world's chemistry.
"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," Romps said. "We already know that the faster the updrafts, the more lightning, and the more precipitation, the more lightning."
The amount of precipitation in the environment, be it rain or snow, can indicate how convective the atmosphere is and how likely it is for lightning to occur. The ascent speeds of convection clouds are determined by a factor called CAPE, which is measured by balloon-borne instruments. The researchers found they could predict 77 percent of lighting strike variations by looking at these factors.
"We were blown away by how incredibly well that worked to predict lightning strikes," Romps said.
The team also looked at 11 different climate models, which on average predicted an increase of CAPE throughout the century of about 12 percent per degree, which would be about a 50 percent increase by 2100 if the predicted 4-degrees Celsius temperature increase occurs.
The findings were published Nov. 14 in the journal Science.
