Not only do we have to worry about rising sea levels or a polar vortex, now we have lightning to worry about. So says climate scientists.
“With warming, thunderstorms become more explosive,” said David Romps, a climate scientist at the University of California Berkeley.
How ‘explosive’ are we talking? Romps and his colleagues predict a 50% increase in lightning strikes in the U.S. this century as temperatures continue to warm.
The reason is simple. Water vapor. More heat, means more water vapor.
“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,” Romps says in a UC Berkeley press release.
Increases in lightning strikes presents several dangers. One, more people being struck by lightning. Current estimates put the number injuries caused by lightning strikes at nearly 300 in the U.S. Another 33 die on average every year.
Another danger would be wildfires. Often times, lightning strikes cause some of the worst wildfires. Dry areas, such as present-day California, would be at more risk for wildfires.
Romp, along with graduate student Jacob Seeley, came up with a useful way for predicting lightning strikes. The two looked at how much precipitation fell, and how explosive the atmosphere is (known as CAPE in meteorology).
“We hypothesized that the product of precipitation and CAPE would predict lightning,” Romps said.
By applying their hypothesis to several different data points including precipitation, measurements of CAPE and the number of lightning strikes in the U.S. – the two variables explain nearly 80% of the observed lightning strikes.
“We were blown away by how incredibly well that worked to predict lightning strikes,” he said.
The pair then took their two variables and applied it to 11 different climate models look at precipitation and CAPE over the next 85 years. On average, the 11 models predict an 11% increase in CAPE in the U.S. per degree Celsius increase in global temperatures by 2100.
For precipitation, the models predict little increase in precipitation nationwide over the same period. Factor the two and it gives about a 12% rise in lightning strikes per degree Celsius rise.
With temperatures predicted to rise 4 degrees Celsius, you get about a 50% increase in lightning strikes by 2100.