'Unprecedented' warming exposes ancient vegetation

An excellent story by Margaret Munro, from Canada.com, via Canwest News Service: Large tracts of land and ancient vegetation that has not seen the light of day in 1,600 years have been liberated from ice caps on Baffin Island, confirming the unprecedented scale of climate change underway in Canada's North. The "current warming exceeds any sustained warm episode in at least the past 1,600 years," reports a U.S. research team that is dating the landscape reappearing as the island's ice disappears.

While scientists and Inuit have noted the recent Arctic heat wave is extraordinary, the emerging moss, plants and rocks shows just how extraordinary. It exceeds the medieval warm period between 1000 and 1200 AD when Norse settlers took up farming in Greenland and Inuit hunters fanned out across the Canadian north, the researchers say.

"It is very unambiguous," says lead author Gifford Miller, of the Institute of Arctic and Alpine Research at University of Colorado, noting how the moss, plants, lichens and rocks carry a chemical signature showing how long they have been under ice.

They reveal some of the ice caps formed initially about 350 AD and persisted through the medieval warm period until they melted away, many them in the last few years, says Miller. The vanishing ice caps will be featured on the cover of Geophysical Research Letters this month. "The fact that they are now melting like crazy is even more remarkable because it is occurring in the face of a long-term trend that should result in cooling," says Miller, explaining how less solar radiation has been hitting the Arctic in summer months for the last 3,000 years because of a natural cycle that affects orientation of the sun and Earth. "The modern warming really is unusual," he says. "From a millennial perceptive, it's unprecedented."

Paleoclimatologist John Smol at Queen's University in Kingston, Ont., agrees. The new study is "another important, solid piece of science showing that what is happening now is nothing within the realm of normal, as far as I can tell," says Smol, whose research on Arctic lake sediments also points to "remarkable" warming in recent decades…

Photo of the northern coast of Baffin Island by Ansgar Walk (Wikimedia Commons)