It is no longer debatable whether humans are capable of trashing the environment on a global scale. Lately, the more pertinent question is: Can we clean up our mess? A recent study of ozone levels suggests we can, but only when we feel like it and only if solving the problem doesn't require too much effort.
A recent environmental analysis using satellite and ground-based recordings of ozone concentrations in the atmosphere, found evidence that the ozone layer is starting to recover. Not only that, scientists were able to attribute its rebound to the effects of the Montreal Protocol—the 1989 international agreement to phase out ozone depleting chemicals, like chlorofluorocarbons.
"This story shows that, whereas we can muck up the world in a global way, we can—when we decide to,—really do something positive and work towards cleaning up the mess we make," said Elizabeth Weatherhead, the study's lead author and a climatologist at the University of Colorado. "The governments listened to the scientists back in the late 1980s. This is a clear response to that collaboration."
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Like the weather, ozone levels fluctuate over time, but according to Weatherhead's analysis, they've begun steadily improving over the past decade. The rise of global ozone concentrations is due almost entirely to the decline of atmospheric chlorine, which breaks apart ozone molecules in the stratosphere.
Not only has international cooperation helped avert more damage to the ozone layer, it also succeeded at a much lower cost to the economy than experts originally predicted.
"The neat thing about the story of ozone protection is that all of us were wrong about how much it would cost and how disruptive it would be," said Drusilla Hufford, director of the EPA's Stratospheric Protection Division. "Not only have we phased out CFCs, we've actually found, in a lot of cases, cheaper and better ways to do things."
Although there has been a definite improvement in the ozone layer, Weatherhead says the levels are unlikely to return to what they were pre-1980 anytime soon. She also warns that they may never fully bounce back until the issue of global warming is addressed.
"In the short term, we just need to be diligent and keep maintaining this agreement not to produce ozone-depleting substances," said Weatherhead. "In the long term, we need to take care of things like greenhouse gas buildup and the buildup of nitrogen compounds in the atmosphere."
The success of the Montreal treaty stands in marked contrast to the Kyoto Protocol for controlling greenhouse gas emissions. For one, the Montreal Protocol got the support of nearly every country in the world, while Kyoto has been hampered by the United States' disengagement from the process, which claims that the caps on carbon production mandated by the Protocol would hurt its economy.
Both Hufford and Weatherhead were quick to point out the drastic differences between the two situations.
"It's much easier to convince people to use a different refrigerant in their air conditioner than to ask them to give up the amount of energy we're all accustomed to using," said Weatherhead.
Still, Montreal will hopefully serve as a positive example of governments cooperating to address a growing environmental crisis.
"We caught this problem in time," said Weatherhead, "and did something positive to improve the atmosphere."