As permafrost thaws in the Arctic, huge pockets of methane -- a potent greenhouse gas -- could be released into the atmosphere. Experts are only beginning to understand how disastrous that could be.
Four miles south of the Arctic Circle, the morning sky is streaked with apricot. Frozen rivers split the tundra of the Seward Peninsula, coiling into vast lakes. And on a silent, wind-whipped pond, a lone figure, sweating and panting, shovels snow off the ice.
The young woman with curly reddish hair stops, scribbles data, snaps a photo, grabs a heavy metal pick and stabs at white orbs in the thick black ice.
"Every time I see bubbles, I have the same feeling," says Katey Walter, a University of Alaska researcher. "They are amazing and beautiful."
Beautiful, yes. But ominous. When her pick breaks through the surface, the orbs burst with a low gurgle, spewing methane, a potent greenhouse gas that could accelerate the pace of climate change across the globe.
International experts are alarmed. "Methane release due to thawing permafrost in the Arctic is a global warming wild card," warned a report by the United Nations Environment Programme last year. Large amounts entering the atmosphere, it concluded, could lead to "abrupt changes in the climate that would likely be irreversible."
Methane (CH4) has at least 20 times the heat-trapping effect of an equivalent amount of carbon dioxide (CO2). As warmer air thaws Arctic soils, as much as 50 billion metric tons of methane could be released from beneath Siberian lakes alone, according to Walter's research. That would amount to 10 times the amount currently in the atmosphere.
At 32, Walter, an aquatic ecologist, is a rising star among the thousands of scientists who are struggling to map, measure and predict climate change. Parts of her doctoral dissertation on Siberian lakes were published in three prestigious journals in 2007: Science, Nature and Philosophical Transactions of the Royal Society.
According to one of her studies, methane emissions from Arctic lakes were a major contributor to a period of global warming more than 11,000 years ago.
"It happened on a large scale in the past, and it could happen on a large scale in the future," says Walter, who refers to potential methane emissions as "a time bomb."
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