Azara Blog: Arctic all-year-round ice could disappear by 2040

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Date published: 2006/12/12

The BBC says:

The Arctic may be close to a tipping point that sees all-year-round ice disappear very rapidly in the next few decades, US scientists have warned.

The latest data presented at the American Geophysical Union Fall Meeting suggests the ice is no longer showing a robust recovery from the summer melt.

Last month, the sea that was frozen covered an area that was two million sq km less than the historical average.

"That's an area the size of Alaska," said leading ice expert Mark Serreze.

"We're no longer recovering well in autumn anymore. The ice pack may now be starting to get preconditioned, perhaps to show very rapid losses in the near future," the University of Colorado researcher added.

The sea ice reached its minimum extent this year on 14 September, making 2006 the fourth lowest on record in 29 years of satellite record-keeping and just shy of the all time minimum of 2005.

Dr Serreze's concern was underlined by new computer modelling which concludes that the Arctic may be free of all summer ice by as early as 2040.

The new study, by a team of scientists from the National Center for Atmospheric Research (NCAR), the University of Washington, and McGill University, found that the ice system could be being weakened to such a degree by global warming that it soon accelerates its own decline.

"As the ice retreats, the ocean transports more heat to the Arctic and the open water absorbs more sunlight, further accelerating the rate of warming and leading to the loss of more ice," explained Dr Marika Holland.

"This is a positive feedback loop with dramatic implications for the entire Arctic region."

Eventually, she said, the system would be "kicked over the edge", probably not even by a dramatic event but by one year slightly warmer than normal. Very rapid retreat would then follow.

Locally, this would have major consequences for wildlife in the region, not least polar bears which traverse ice-floes in search of food.

Loss of summer ice would seriously compromise the lifestyles of the region's indigenous peoples, though it could also bring new trading opportunities as sea routes opened up.

On a global scale, the Earth would lose a major reflective surface and so absorb more solar energy, potentially accelerating climatic change across the world.

A (seemingly) inevitable consequence of global warming. Although the BBC article implies otherwise, this possibility of an accelerated decrease in Arctic ice is well known. Of course treat any computer modelling with a pinch of salt, especially predictions of dates when events driven by nonlinear dynamics are allegedly going to happen. But one can imagine the cruise ships are already lining up for the boom in visits to the North Pole.

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