Fire Made Arctic Spew, Rather Than Absorb, Carbon
STEVE INSKEEP, host:
The North Slope of Alaska is not a place that sees a lot of wildfires. It's tundra up there: cold and wet and covered in moss, grass and low scrub. But in 2007, an extraordinary fire broke out at a place called Anaktuvuk. It burned for four months. It was the biggest fire in the region since records started in the 1950s. And now scientists say they've discovered something disturbing about that fire: how much carbon it released into the atmosphere.
NPR's Christopher Joyce reports on what may be a new trend in the Arctic.
CHRISTOPHER JOYCE: It's peak field season right now for scientists who study the Arctic, like Michelle Mack.�
Ms. MICHELLE MACK (Ecologist, University of Florida): I'm at Toolik Lake field station, in a trailer that's on a gravel pad that's in the middle of Arctic tundra.��
JOYCE: Mack is an ecologist from the University of Florida who prefers the desolate beauty of the North Slope of Alaska and the snowcapped Brooks Mountain Range.�She says what the Anaktuvuk fire did - burn through 400 square miles of tundra - amazed her.�
Ms. MACK: We've never seen anything like it in this area. What's surprising is that forests have huge trees, whereas tundra has six-inch tall, tiny little plants.�
JOYCE: Nonetheless, the fire sizzled for three months, then burst into a major conflagration before snowfall put it out.�So if there weren't any trees, what was there to burn?�
Ms. MACK: It's coming from the soil.�
JOYCE: Organic matter, dead plants, accumulated over decades.�And what set it off was dry weather, and then a lightning strike.�
Ms. MACK:�There's been a marked increase in lightning strike activity on the North Slope, particularly in the last 10 years.�
JOYCE: But Mack was really surprised when she calculated how much carbon that fire put up into the atmosphere.�It was two million tons.�Is that a lot? Well, think of it this way:�Every year, the Arctic tundra absorbs more carbon from the atmosphere than it releases. It's a net carbon sink. Because carbon warms the atmosphere, the Arctic is actually cooling the planet by taking up carbon.�But Mack says the Anaktuvuk fire reversed that equation.�
Ms. MACK:�One fire, that alone is enough to offset the whole uptake.�
JOYCE: That's right. The fire put out more carbon than the entire Arctic tundra absorbed in 2007. That includes Alaska, Canada, Greenland and Russia.��
Mack's findings are part of an increasingly feverish research effort going on in the Arctic.� Arctic sea ice has been melting, putting more moisture in the air and creating more thunderstorms.�
Geographer Eric Kasischke of the University of Maryland is also in Alaska this week, studying, among other things, why there have been so many more fires there recently.�Between the region's big forests and the carbon-rich tundra soil, he says there's a lot of carbon that's at risk of getting loose.�
Mr. ERIC KASISCHKE (Geographer, University of Maryland): So you might see, in a single fire event, 30 to 40 to 50 to 60 years of carbon released instantaneously. And so I think this is part of a larger story that you're seeing deeper burning fires across the landscape, and together, they're really going to change things pretty dramatically.�
Besides pumping more carbon into the atmosphere, the Arctic fires also melt the permafrost. That's the permanent layer of frozen soil and water underneath the surface.�When that disappears, so does a major source of moisture for the tundra.��
Mr. KASISCHKE: It does have cause for concern. We might be seeing really major changes in the way that these ecosystems function in high northern latitudes, and fire might be that trigger.
The research appears in the latest issue of the journal Nature.��
Christopher Joyce, NPR News.
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