WHICHEVER way you look at it, events in the Arctic bode ill for the global climate. The ice is disappearing, melting permafrost threatens to belch methane, and now comes a warning that vast regions of tundra could singe. When that happens, it will start emitting carbon far faster then healthy tundra soaks it up.
Adrian Rocha of the Marine Biological Laboratory in Woods Hole, Massachusetts, and colleagues placed sensors across the 1000-square-kilometre fire scar left by a blaze in 2007 on the Brooks mountain range in northern Alaska. They found that in the following year the most severely burnt tundra emitted twice as much carbon as tundra normally stores away. The fire itself is estimated to have released 1.3 million tonnes of carbon dioxide. What鈥檚 more, the burnt region absorbed 71 per cent more solar radiation than normal, melting 5 to 10 centimetres of its permafrost layer.
In results to be presented at the annual meeting of the Ecological Society of America in Albuquerque, New Mexico, Rocha warns that such fires will become worse. Tundra only burns once certain thresholds are crossed. Drier conditions, more thunderstorms and warming in the Arctic over the coming century, he says, will make this more likely.
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