Arctic tundra may produce rather than absorb CO2, accelerating warming

It’s not often that drama emerges from the Arctic tundra, but there seems to be genuine excitement around revelations from a 20-year study just completed and published in the journal Nature. Researchers have long assumed that Arctic tundra would be a carbon dioxide “sink,” absorbing CO2 and slowing — at least slightly — the global-warming trend. Well, turns out not so much: According to the study, warming might cause accelerated decomposition of the lower levels of the tundra, releasing far more CO2 than subsequent growth will absorb and establishing a “positive feedback” that accelerates warming — and, incidentally, could foul up Canada’s attempt to meet its Kyoto targets. In other news from chilly-but-not-as-chilly-as-they-used-to-be spots, scientists have found that the collapse of the Antarctic’s Larsen B ice shelf two years ago has drastically accelerated the collapse of surrounding glaciers into the sea — a grim harbinger of things to come in a region particularly hard-hit by global warming.