Lightning strikes inside the Arctic circle may double this century, sparking widespread tundra fires and increasing the risk of setting off the carbon time bomb held within permafrost, new research showed Monday.

Lightning strikes over San Pietro mountain, close from Ajaccio, in the French Mediterranean Island of Corsica, on August 9, 2013. Photo: VCG

The permafrost of North America and Siberia contains enough carbon dioxide to roughly double all the carbon currently in Earth's atmosphere, and there are fears that it will melt significantly as temperatures rise. Researchers in the US analyzed NASA satellite data on lightning strikes in northern and Arctic regions stretching back more than 20 years.

They then modeled how the strike rate was likely to increase as temperatures rise, using a business-as-usual projection that sees no significant reduction in carbon pollution this century. They found that the frequency of lightning strikes could increase by roughly 100 percent compared with current levels.

"We projected how lightning in high-latitude boreal forests and Arctic tundra regions will change across North America and Eurasia," said Yang Chen, a researcher at the University of California, Irvine's Department of Earth System Science. 

"The size of the lightning response surprised us because expected changes at mid-latitudes are much smaller."