科学美国人60秒:Ozone Hole History Offers Climate Lesson

In the 1970s, chemists Mario Molina and Sherwood Roland found that mundane household items posed a serious worldwide threat. The two chemists discovered that chlorofluorocarbons, or CFCs, from air conditioners and canisters of hair spray could destroy the ozone layer. That insight got them a Nobel Prize.

By the 1980s, folks like then Secretary of State George Shultz woke up to the threat, despite a campaign of denial from scientific doubters. He convinced President Reagan that the danger was real and that action was necessary. By 1989, the U.S. and the rest of the world had crafted an international treaty to curb CFCs known as the Montreal Protocol.

As a result, the hole in the ozone layer that forms above Antarctica has mostly stabilized.

Now we know that Montreal also bought us a little more time to deal with another air pollution problem: climate change. That's according to a new analysis in the journal Nature Geoscience. The study found a statistically significant correlation between the onset of the Montreal Protocol and a reduction in the pace of global warming. Because CFCs are also greenhouse gases.

The finding is good news. It shows that cutting back on greenhouse gas pollution can slow catastrophic climate change. Sadly, the campaign of denial against global warming continues, denying us the chance to make the necessary response.

—David Biello

[Scientific American is part of Nature Publishing Group.]