Hole in ozone opens wide as polar ice melts By MIKE TONER The Atlanta Journal-Constitution Published on: 10/20/06 http://www.ajc.com/news/content/news/stories/2006/10/19/1020meshozone.html The ozone hole over Antarctica reached record proportions this fall, breaking several years of relative improvement that followed the worldwide phase-out of ozone-destroying chemicals, NASA scientists announced Thursday. NASA also reported Thursday that Greenland's polar ice cap, in an apparent response to changing climate, has undergone "dramatic ice mass losses" over the past two years. The research, the geography, and the underlying causes of each development are distinct, but the reports from opposite ends of the Earth underscore the growing role of the polar regions in taking the pulse of global environmental changes. "The average area of the ozone hole was the largest ever observed," said atmospheric scientist Paul Newman of NASA's Goddard Space Flight Center. By late September the hole â a severely depleted area of the protective ozone that shields the Earth's surface from harmful solar radiation â stretched over nearly 11 million square miles, which was 10 percent more than scientists were expecting. David Hofmann, of the National Oceanic and Atmospheric Administration said by early October, ozone levels in the critical region of the stratosphere between eight and 13 miles of altitude were "virtually gone." "It appears that the 2006 ozone hole will go down as a record setter," Hofmann said. "These numbers mean that the ozone is virtually gone from this layer of the atmosphere." The seasonal ozone "hole," which appears early in the Antarctic spring, has been a closely watched phenomenon since it was first detected in the 1970s. Because stratospheric ozone shields the Earth's surface from damaging solar radiation, which can cause skin cancer and disrupt biological processes, its depletion quickly became a cause for worldwide concern. When man-made compounds, called chlorofluorocarbons or CFCs, were identified as the cause of ozone depletion, more than 180 nations, including the United States responded. In 1987, they signed a treaty to curb the production of CFC-containing refrigerants and other products. Because the chemicals can persist in the atmosphere for 40 years, scientists have predicted that the ozone layer won't fully recover from the effects of CFCs until 2065. The shrinking size of the springtime hole over the Antarctic since 2002 had encouraged them that the situation was improving, but NASA scientists say ozone losses also vary with fluctuations in the Antarctic stratosphere, which was colder than usual this year. Satellite measurements of ozone losses show that the hole covers nearly all of Antarctica and reaches almost as far north as the southern tip of South America. Meanwhile, satellite measurements of the Earth's other pole have provided precise new evidence about the rate at which climate change is shrinking Greenland's polar ice sheet. Researchers have long believed that any warming of the polar regions would produce two effects â increased melting of ice during the summer and an increase in the winter snows that replenish it. At least in Greenland, they now say the melting is easily outstripping winter snowfall. In a report in the journal Science they conclude that since 2003, Greenland has lost 41 cubic miles of ice along the coast and gained only 14 cubic miles from increased snowfall in the interior. If Greenland's ice sheets melted completely, it would raise sea level around the world by more than 20 feet. Scientists don't think such a massive change is likely, but they note that even the current imbalance is equivalent to six years of average water flow from the Colorado River. "The new results show a dramatic speed up in the rate of ice mass loss since the 1990s," says NASA researcher Jay Zwally. "This is a very large change in a very short time."