Friday, July 31, 2009

Thaw Point

(The past few weeks we've been tracking temperatures in the 70s and 80s precariously close to the Arctic Circle. The Canadian Yukon has experienced 90s in recent days! Kind of cool, huh? Not really. Here's what makes the hairs on the back of your neck stand straight up. Unusually warm spells WAY north, unnaturally far north, may release prodigious amounts of methane, a GHG, greenhouse gas 25 times more potent than carbon dioxide. The more methane released, the warmer it gets, the warmer it gets, the more methane is released....and so on. This is an example of "positive feedback", a runaway cycle that worries climate experts. What keeps these guys (and gals) awake late at night? The notion that unusual warming unusually far north is leading us closer to a "tipping point", a point of no return. That's why this article, coming after a spell of record warmth across FAR northern Alaska and Canada, caught my eye).

The Arctic tundra is one of the world’s most extensive ecosystems, and the frozen soil known as permafrost, which underlies it, can be hundreds of metres deep. But as the world warms up in response to the millions of tonnes of carbon dioxide and other greenhouse gases being poured into the atmosphere each year, so does the permafrost. As the permafrost thaws, bacteria start chewing up the organic matter it contains. This releases yet more carbon dioxide, as well as methane, another greenhouse gas, which has 25 times the warming potential of CO2. Edward Schuur of the University of Florida in Gainesville, a doyen of the field, estimates that the world’s permafrost contains twice as much carbon as its atmosphere. If even a fraction of that were released as CO2 and methane, it would be bad news.

Nor is that all. Thawing permafrost also leaks nitrates and phosphates into the tundra, allowing novel plant species to get a foothold in what was, to start with, a fairly spartan habitat. It distorts the Earth’s surface, too, creating a landscape of domes and pits known as thermokarst because of its resemblance to the karstic terrain of limestone-rich parts of the world. This changes the tundra’s ecology. It also plays havoc with human structures, such as buildings, roads and pipelines, that sit on top of it. For all of these reasons, then, more research is needed into this icy realm. And that is the object of a project with the unsnappy name of Spatial and Temporal Influences of Thermokarst Failures on Surface Processes in Arctic Landscapes, which was kicked off by a group of scientists who gathered in late June at the Toolik Field Station in northern Alaska.

The complete Economist article is here.

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