Arctic Trouble

The other shoe had to drop sooner or later. For five years, atmospheric scientists have known that a 3,000-mile hole in the ozone layer develops over Antarctica during the southern spring. The phenomenon is dramatic evidence of ozone loss in the upper atmosphere, caused largely by man-made chemicals called chlorofluorocarbons, which could leave the earth more vulnerable to cancer-inducing rays from the sun. Now, it seems, there is mounting evidence that the Arctic has its own ozone hole, albeit a smaller one. At the American Geophysical Union meeting last week in Baltimore, W.F.J. Evans, an atmospheric physicist with the Canadian Department of the Environment, announced that an ozone "crater" 1,500 miles wide may be developing over the North Pole.

Evans' findings are based on the release in 1986 of a series of research balloons at Alert, Canada, near the North Pole. Scientific instruments aboard the craft detected a significant loss of ozone between January and March of that year. Unlike the Antarctic ozone hole, however, the Arctic crater formed only patchily in 1987 and scarcely appeared at all in 1988. For now, Evans' colleagues have reserved judgment about his discovery until further studies of the Arctic atmosphere can be made.