Map of US lightning strikes in 2011
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Lightning map helps storm forecast

A network of lightning detectors has helped researchers calculate how much each extra degree in temperature will increase the frequency of lightning strikes.

"For every two lightning strikes in 2000, there will be three lightning strikes in 2100," said Prof David Romps, from the University of California, Berkeley, who led the research.

As well as triggering more wild fires, he said, this would alter the chemistry of the atmosphere.

The researchers validated their new lightning-predicting model against a year of data from the US National Lightning Detector Network, which - as this animation shows - produces a signal every time lightning strikes in the US.

The data imaged here is from 2011; each red dot is a lightning strike, and the whole year's lightning is animated over 30 seconds .

Animation courtesy of Prof David M. Romps, UC Berkeley