Rising temp = More storms and tornadoes

Severe storms and violent tornadoes may become more common as Earth's climate warms, according to a new climate model developed by NASA scientists.

Previous climate model studies have shown that heavy rainstorms will be more common in a warmer climate, but few global models have attempted to simulate the strength of updrafts in these storms.

The model developed at NASA's Goddard Institute for Space Studies by researchers Tony Del Genio, Mao-Sung Yao and Jeff Jonas is the first to successfully simulate the observed difference in strength between land and ocean storms.

It is the first to estimate how a storm's strength will change in a warming climate, including "severe thunderstorms" that also occur with significant wind shear and produce damaging winds at the ground, according to a news release posted on EurekAlert.

This information can be derived from the temperatures and humidity predicted by a climate computer model, according to the new study.

It predicts that in a warmer climate, stronger and more severe storms can be expected, but with fewer storms overall.

"Global computer models represent weather and climate over regions several hundred miles wide. The models do not directly simulate thunderstorms and lightning. Instead, they evaluate when conditions are conducive to the outbreak of storms of varying strengths," the release said.

The model, when applied to a hypothetical future climate with double the current carbon dioxide level and a surface that is an average of 5 degrees Fahrenheit warmer than the current climate, found that continents warm more than oceans and that the altitude at which lightning forms rises to a level where the storms are usually more vigorous.

These effects combine to cause more of the continental storms that form in the warmer climate to resemble the strongest storms we currently experience.

The study also pointed out that lightning produced by strong storms often ignites wildfires in dry areas.

Researchers have predicted that some regions would have less humid air in a warmer climate and be more prone to wildfires as a result. However, drier conditions produce fewer storms.

"These findings may seem to imply that fewer storms in the future will be good news for disastrous western US wildfires," Tony Del Genio, lead author of the study and a scientist at NASA's Goddard Institute for Space Studies, New York, said.