Winter also Sees Arctic Caps Melting

by Tanya Thomas on Oct 28 2008 10:25 AM

The Arctic ice caps aren’t diminishing in size only in summer, it’s been shrinking at record rates in winter too; says a new research by British scientists. This is only adding to the already devastating melting at the North Pole.

According to a report in The Times, the research was undertaken by Dr Katharine Giles, who led the study and is based at the Centre for Polar Observation and Modelling at University College London (UCL).

Her team found that the widely reported summer shrinkage, which this year resulted in the opening of the Northwest Passage, is continuing in the winter months with the thickness of sea ice decreasing by a record 19 percent last winter.

Usually, the Arctic icecap recedes in summer and then grows back in winter. These findings suggest the period in which the ice renews itself has become much shorter.

Dr Giles said that the thickness of Arctic sea ice had shown a slow downward trend during the previous five winters, but then accelerated.

"After the summer 2007 record melting, the 2007 were cold enough that they could not have been the cause.

This suggests some other, longer-term change, such as a rise in water temperature or a change in ocean circulation that has brought warmer water under the ice.

If confirmed, this could mean that the Arctic is thickness of the winter ice also nose-dived. What is concerning is that sea ice is not just receding but it is also thinning," she said.

The cause of the thinning is, however, potentially even more alarming.

Giles found that the winter air temperatures in likely to melt much faster than had been thought. Some researchers say that the summer icecap could vanish within a decade.

This region saw the Northwest Passage become ice-free and open to shipping for the first time in 30 years during the summer of 2007.

"This enormous ice retreat in the last two summers is the culmination of a thinning process that has been going on for decades, and now the ice is just collapsing," said Peter Wadhams, professor of ocean physics at Cambridge University.

At the heart of the melting in the Arctic is a simple piece of science.

Ice is white, so most of the sunlight hitting it is reflected back into space. When it melts, however, it leaves open ocean, which, being darker, absorbs light and so gets warmer.

This helps to melt more ice. It also makes it harder for ice to form again in winter. The process accelerates until there is no more ice to melt.

"This is one of the most serious problems the world has ever faced," Wadhams said.