Thursday, February 03, 2005
Arctic Ozone Hole
Last Updated Tue, 01 Feb 2005 18:56:23 EST
IQALUIT - Unusually cold temperatures above the Arctic could cause a record loss of ozone over the Arctic this year, increasing the danger from ultraviolet radiation, European scientists warn.
Temperatures in the stratosphere – about eight kilometres above the Earth's surface – have plunged much lower than normal in the last two months and the ozone layer that shields the planet is already being affected, the European Commission scientists say.
Widening holes in the ozone layer could let more UV radiation hit bears and other creatures in polar regions.
Ozone depletion is usually blamed on chlorofluorocarbons, or CFCs, but scientists are pinning this year's loss on unusual cloud formations caused by the frigid weather.
"We get a lot of these polar stratospheric clouds forming, but the problem is they accelerate, or lead to ozone depletion," said Dr. Neil Harris of Cambridge University in England, who heads the international team of scientists monitoring the ozone layer.
If the subnormal temperatures continue until spring, it could lead to the biggest loss of ozone in more than 50 years, Harris warned.
"That's the big 'if' here," he said. "But if it stays cold – and there's no sign of it warming up in our 10-day forecasts – then these large losses are very likely to happen.
"At particular altitudes, it would be 50, 60, 70 per cent."
Harris said the greatest loss in ozone would likely occur above the Arctic Circle, posing more health hazards for people and animals there. They're already exposed to higher than average ultraviolet radiation, which has been linked to a rise in some types of skin cancer.
While there's a debate over what caused the low temperatures, Harris is one of many scientists who blame global warming.
"Just as the polar regions are probably most affected by climate change at the ground, there may well be a strong link in the upper atmosphere, as well."