Lightning may go up due to global warming

Lightning strikes are likely to increase by 50 percent thanks to global warming, new research estimates.

Studying predictions of precipitation and cloud buoyancy in 11 different climate models, researchers have concluded that their combined effect will generate more frequent electrical discharges to the ground.

"With warming, thunderstorms become more explosive," said David Romps, climate scientist at University of California, Berkeley.

"Lightning is caused by charge separation within clouds, and to maximize charge separation, you have to loft more water vapour and heavy ice particles into the atmosphere," Romps noted.

Global warming is leading to more water vapour into our atmosphere which is the fuel for explosive deep convection in the atmosphere, said Romps.

Precipitation, total amount of water falling on ground in the form of rain, snow is basically a measure of how convective the atmosphere is, Romps said.

It is convection that generates lightning.

The ascent speeds of those convective clouds are determined by a factor called CAPE - convective available potential energy.

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, noted the study.

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 stressed.

More lightning also would likely generate more nitrogen oxides in the atmosphere, which exert a strong control on atmospheric chemistry.

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, suggested Romps.

The study appeared in the journal Science.