Antarctic ozone hole appears to be shrinking

Nature : Three decades after the introduction of the Montreal Protocol, the ozone hole over the Antarctic is beginning to disappear. The hole was first observed in the late 1970s, when scientists realized that the use of chlorofluorocarbons and similar substances in aerosol spray cans and cooling systems was having an adverse effect on Earth’s ozone layer, which shields the planet from the Sun’s UV radiation. Now Susan Solomon of MIT and colleagues, who have been monitoring polar ozone with weather balloons, say that since 2000 the Antarctic ozone hole has been shrinking in the month of September—a key time of year because it marks the beginning of the Antarctic spring and the return of more sunlight to the region. Although no measurable improvement has been seen in the hole over the Arctic, the researchers say the improvement in the Antarctic is a sign that the Montreal Protocol is having a positive effect. “We as a planet have avoided what would have been an environmental catastrophe,” says Solomon.