A success story and cautionary tale
In the early ’80s, when scientists first noticed that levels of ozone over the Antarctic had depleted to just 30 percent of normal levels, they thought it was an instrument error. But a closer look revealed something shocking – a large hole in the ozone layer over the Antarctic pole.
Part of the stratosphere, the ozone layer protects us from damaging, cancer-causing UV rays and allows life on Earth to exist. After realizing that this protective layer would only continue to deplete without action, researchers alerted the world and “the hole in the ozone layer” quickly became a popular media topic and focal point for environmental action.
The cause of the hole was certain kinds of chlorinecontaining chemicals, most notably chlorofluorocarbons (CFCs), which were commonly being used in aerosols, refrigerants and solvents. Consumers were urged to boycott such products, and businesses using ozone-depleting substances were targeted. The movement culminated in 1987 with the Montreal Protocol, which now has 191 countries agreeing to phase out production and use of CFCs.
These measures worked. By the late ’90s, the concentration of CFCs had decreased, but it could be decades before the hole starts to repair itself.
“The hole is still there, in particular over the Antarctic,” says University of Toronto atmospheric physicist Dr. Kimberly Strong. “But we have done the right things; we are phasing out those chemicals.” Which is why the hole in the ozone rarely makes the news anymore, she says. “We expect the layer to repair itself by the middle of this century. This is in some senses a success story.”
It’s also a story that has taught us important lessons that could be used in the fight against climate change, points out Jean Langlois of the Sierra Club of Canada: “Firstly, the atmosphere takes time to recover from the damage – the greenhouse gases that we have put up there will be around for decades. But, secondly, international conventions can fix atmospheric problems. If we had not adopted the Montreal Protocol we’d have a much larger hole in the ozone and it would be getting bigger. The Canadian government, however, by not implementing Kyoto, is not heeding this message.”