By Scott Waldman
The trend could worsen significantly in the future if tree cover spreads northward
Climate change is driving up the number of forest fires ignited by lightning, and it's pushing them farther north, to the edges of the Arctic tundra, researchers say.
Lightning-caused fires have risen 2 to 5 percent a year for the last four decades, according to a paper published yesterday in the journal Nature Climate Change. And as thunderstorms intensify and become more frequent, fires are increasingly occurring in the boreal forests, and even on the permafrost tundra. Warmer temperatures encourage more thunderstorms, which in turn bring more lightning and greater fire risk.
The changes are part of a complex climate feedback loop that is only now becoming more clear to scientists, said Sander Veraverbeke of Vrije Universiteit Amsterdam, the study's lead author. A feedback loop is a series of interrelated phenomena that is worsened by climate change and continues to build upon itself with additional consequences. In the north, fires release more carbon dioxide and methane from the permafrost, he said.