The Story of O
Ozone Hole Reaches Turning Point, Scientists Say
For the first time, scientists have found evidence that worldwide efforts to halt the destruction of the ozone layer are working. Although the protective atmospheric layer has not begun repairing itself, the rate of its destruction has slowed considerably, presumably thanks to the global phase-out of ozone-destroying chemicals mandated by the 1989 Montreal Protocol. Because these chemicals take a long time to break down, no improvement in the condition of the ozone layer had been measured until now — and even at present, the changes only affect the uppermost part of the stratosphere, which is home to less than 20 percent of the layer. Scientists expect it will be 40 to 50 more years before the ozone layer fully repairs itself. Still, environmentalists welcomed the news and called it proof of the efficacy of coordinated international action against long-term environmental threats.