Arctic Ice Cap Melting in Winter

The Arctic ice cap melts in the summer but then refreezes in the winter. Not now. Not according to the latest research carried out by Dr Katherine Giles, of the Center for Polar Observation and Modeling, which is based at the University of London. They have found that it is taking longer for the ice cap to refreeze in winter.

They have found that the ice cap is thinning at an alarming rate, both in the winter as well as the summer. In 2007, the North West Passage was opened to shipping for the first time in 30 years, but as winter approached it took longer for the North West Passage to refreeze. When it did they found that the ice cap thickness was down by 10-19%. For the last five years the ice cap has narrowed, but it was a slow downtrend, however, this trend has started to accelerate.

The cause for this thinning is a major cause for concern. If winter temperatures are stable then the cause has to be a rise in the temperature of the water, or a change in ocean circulation. In other words warmer water is now flowing under the ice.

If warmer water is flowing under the Arctic it means it will melt much faster then we had previously bargained for. The ice cap may not be around ten years from now.

The research measured sea ice thickness between 2002 and 2008, and was carried out by satellites. They focused on the period between October and March and over half the Arctic ice cap was measured. Their work has confirmed the findings of Professor Wadhams, Professor of Ocean Physics at Cambridge University.

Since 1976 Wadhams has been using submarines and echo soundings to measure the thickness of the ice. He found that the ice had thinned by 15% between 1976 and 1987. His last survey in March 2007 found that the winter ice was now 50% of the 1976 thickness. He feels that the ice has been thinning for so long that it is now collapsing.

Every winter the ice cap should expand to about 5.8 square miles, before it shrinks to about 2.7 square miles in summer. However, in 2007 the sun shone far longer than normal and the water temperature rose by 4.3C above average. It had also lost, by September, some 1.1 square miles extra. This does not sound a lot, however, 1.1 square miles of the Arctic Ice cap is about 12 times the total areas of Great Britain.

One explanation is because the ice is white it reflects sunlight, but when the sunlight hits the sea it absorbs the sunlight. As a result the sea starts to warm up and this melts more ice.

What ever the explanation, whatever the science, or despite what we think causes this shrinking and thinning. We have to accept that it is happening, and we have to accept emergency measures to get it put right. When it is gone, it will be too late.