Lightning strikes to increase as much as 50% by end of century, study forecasts
WASHINGTON — Lightning strikes in the United States will likely increase by nearly 50 percent by the end of the century as the world gets warmer and wetter, a new study claims.
While those conditions were known to promote thunderstorms in general, the recent work focused on lightning strikes themselves.
Researchers calculated just how much lightning flashes increase as air warms, clouds fill with more energy from water vapor and rainfall intensifies.
They concluded that for every degree Fahrenheit the world warms, lightning strikes will go up nearly 7 percent.
Because scientists forecast that the world may get about 7 degrees warmer by the end of the century, based on current carbon dioxide emission trends, that comes to a 50 percent increase in lightning strikes, said David Romps. He’s the atmospheric scientist at the University of California, Berkeley, who led the study.
“When you used to have two lightning strikes, now you’ll have three,” Romps said. “It’s a substantial increase.”
The researchers based their calculation on 2011 weather data from across the United States. They presented their results in a paper released Thursday by the journal Science.
Romps said the key is that warmer air holds more water vapor. Water vapor is fuel for thunderstorms, sparking more lightning. The energy that storms get from vapor is the biggest driver in the forecast of increasing lightning strikes, Romps said.
The study shows that at any given level of rainfall intensity, there will be more lightning.