Hole in Ozone Layer over Antarctica Reaches Greatest Size Ever

The World Meteorological Organization (WMO) announced that data from the U.S. National Aeronautics and Space Administration (NASA) shows the hole in the ozone layer over Antarctica to be 28.3 million square kilometers (11 million square miles). The hole is its greatest size yet since measurements were first taken. It is three times the size of the United States. The previous record was two years ago, when the hole was 27.2 million square kilometers (10.5 million square miles).

Scientists have been studying the ozone layer since 1970, when it was first spotted by British Antarctic scientists. The hole is now closely monitored by satellites and ground-based instruments, and its size is measured every year around September and October. When this year’s measurement results were announced, scientists around the world were shocked.

Dr. Michael Kurylo, manager of NASA’s Upper Atmosphere Research Program, said, "These observations reinforce concerns about the frailty of Earth’s ozone layer." Recent research suggests that the problem of the thinning ozone layer may be on a much larger scale than scientists thought previously. "Although production of ozone-destroying gases has been curtailed under international agreements," Kurylo said, "concentration of the gases in the stratosphere are only now reaching their peak."

The ozone layer filters out dangerous ultraviolet rays from the sun that damage vegetation and can cause skin cancer and cataracts. Ozone depletion is believed to contribute to high rates of skin cancer in Australia and other countries south of the equator. The chief cause of ozone depletion is a family of man-made gases, mostly CFCs, which were widely used in aerosols and refrigeration. Other gases, including halons and methyl bromide, have also contributed to the problem.

Ozone loss is calculated by measuring the area and depth of the ozone hole in the stratosphere, about 25 kilometers about the Earth’s surface. The chemical reaction that thins ozone reaches its peak with colder higher altitude temperatures in the southern hemisphere winter, normally in late August to October. It was hoped that the Montreal Protocol in 1987, which restricted the release of man-made pollutants such as CFCs, would lead to a recovery of the ozone layer by 2050.

But there is a growing belief that 2006 will be a bad winter for the Antarctic ozone layer, and large ozone holes are expected to persist for the next couple of decades because of the amount of pollutants already stored in the atmosphere.