Environmental Issues

Global warming has meant that in autumn 2007 the North Pole ice cap has shrunk northwards to leave a surviving 'core' area of sea ice, which is substantially less than ever before. Average surface temperatures in the high Arctic region are also rising twice as fast as they are elsewhere in the world due to a variety of localised processes. These processes are set in motion by the ever-warmer surfaces, which in turn further accelerate the heating up of the surfaces. Consequently the Arctic Ocean's core area of sea ice - the perennial 'polar pack ice' which normally survives the late Spring, Summer and early Autumn melt period - is getting smaller in area and reducing in thickness - and is therefore increasingly prone to total melt-down.

Why are global warming specialists watching the Arctic Ocean so closely? Warming near the North Pole is much faster than the global average, with the result that the Arctic region's ice caps and glaciers have lost 400 cubic kilometres of ice in only 40 years. It's a highly sensitive region, and is being profoundly affected by the changing climate. Scientists view what's happening now in the high Arctic as a sign of things to come.

The disappearance of the protective heat shield provided by the North Pole ice cap, which helps to maintain the Earth's current temperature in the biosphere, will disrupt global ocean and atmospheric circulations - and therefore weather systems worldwide. How quickly and how greatly these systems are affected is the focus of scientists, some of whom are partners in this project.

Why is the North Pole ice cap so susceptible to climate change? One of the biggest reasons is simply because of differences in the reflectivity of the Earth's surface - something which is dependent on colour! Polar pack ice is so reflective that, if covered by snow (white), 80-85% of the sun's energy which reaches it is simply bounced back through the atmosphere and out into space, taking most of its energy with it. However the increasingly revealed Arctic Ocean water beneath the ice cap (which is relatively dark in colour) is far more absorbing of this solar energy, absorbing 70% more energy than if it had its protective ice cap shielding it. The more energy (i.e. heat) the ocean water retains, the warmer the water around and under the remaining ice cap gets, with the result that it is melting at an ever-accelerating rate. This self-reinforcing effect is known as a positive feedback loop. It's these newly discovered feedback loops that are dramatically changing the melt rate estimates.