Washington – As the world warms, the United States will face more severe thunderstorms with deadly lightning, damaging hail and the potential for tornadoes, a trailblazing study by NASA scientists suggests.
While other research has warned of broad weather changes on a large scale, such as more extreme hurricanes and droughts, the study predicts even smaller events such as thunderstorms will be more dangerous because of global warming.
The basic ingredients for whopper U.S. inland storms are likely to be more plentiful in a warmer, wetter world, said lead author Tony Del Genio, a NASA research scientist.
“The strongest thunderstorms, the strongest severe storms and tornadoes are likely to happen more often and be stronger,” Del Genio said Thursday from his office at the Goddard Institute for Space Studies in New York. The paper he co-wrote was published online this month in the journal Geophysical Research Letters.
Other scientists caution that this area of climate research is too difficult and new for this study to be definitive. But some upcoming studies also point in the same direction.
A unique combination of geography and weather patterns already makes the United States the world’s hottest spot for tornadoes and severe storms in spring and summer: the large land mass that warms on hot days, the contours of the atmosphere’s jet stream, the wind coming off the Rocky Mountains and warm moist air coming up from the Gulf of Mexico.
Del Genio’s computer model shows global warming will mean more strong updrafts, when the wind moves up and down instead of sideways.
“The consequences of stronger updrafts are more lightning and bigger hail,” he said.
The Southeast and Midwest lie in the path of most of the most dangerous of these storms.
However, the new study also forecasts danger for the Western U.S. It predicts lightning will increase about 6 percent as carbon dioxide – the chief global-warming gas – doubles.
Previous studies have shown that the West will get drier, making it a tinderbox for more wildfires. This study shows that there will be more matches in the form of lightning strikes to start those fires, Del Genio said.
