Monday, August 20, 2007

Arctic carbon bodes ill

Climate Ark, via LA Times: Any lingering doubts about how ill-prepared we are to face up to the reality of climate change should have been laid to rest this month when two Russian minisubmarines dove two miles under the Arctic ice to plant a Russian flag made of titanium on the seabed. The government of Vladimir V. Putin claims that the seabed under the North Pole, known as the Lomonosov Ridge, is an extension of Russia's continental shelf and therefore Russian territory that will be open for oil exploration.

Russia is not alone in making such a claim. Geologists think that 25 percent of Earth's undiscovered oil and gas may be embedded in the rock under the Arctic Ocean. No wonder Norway, Canada and Denmark (through its possession of Greenland) are all using the continental-shelf argument to claim the Arctic seabed as an extension of their own sovereign territories.

…What makes this development so depressing is that the interest in prospecting the Arctic seabed, and subsoil, is only now becoming possible because climate change is melting away Arctic ice.

…But there is an even more dangerous aspect to the unfolding drama in the Arctic. While governments and oil giants are hoping the melting ice will allow them access to the world's last treasure trove of oil and gas, climatologists are deeply worried about something else buried under the ice that, if unearthed, could wreak havoc on the biosphere, with dire consequences for human life.

…Now the permafrost is thawing on land and along the seabeds. If it occurs in the presence of oxygen on land, the decomposing of organic matter leads to the production of carbon dioxide. If the permafrost thaws along lake shelves, in the absence of oxygen, the decomposing matter releases methane. Methane is the most potent of the greenhouse gases, with a greenhouse effect 23 times that of carbon dioxide…The release of methane could create an uncontrollable feedback effect, dramatically warming the atmosphere, which would in turn warm the land, lakes and seabed, further melting the permafrost and releasing more methane….

Scientists particularly are concerned that the thawing permafrost is also creating shadow lakes across the Siberian sub-Arctic landscape. The lake waters have a higher ambient temperature than the surrounding permafrost.

As a result, the permafrost near the lakes thaws more quickly, forcing the ground surfaces to collapse into the lakes. The stored organic carbon then decomposes into the lake bottoms. Methane from that decomposition bubbles to the surface and escapes into the atmosphere. Scientists calculate that thousands of tons of methane will be released from Arctic lakes as the permafrost thaws…

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