International Ozone Day

Today is International Ozone Day, the 20th anniversary of the signing of the Montreal Protocol, which was signed by 24 countries in 1987. The agreement, which now include 191 nations, calls for the phasing out of the use of chlorofluorocarbons and other gases that deplete the thin stratospheric ozone layer, which shields the Earth -- and us -- from harmful ultraviolet radiation. A dramatic thinning in the ozone layer -- called the ozone hole -- occurs seasonally over Antarctica, and that hole is reaching its maximum extent for the year. NASA

The treaty is considered a resounding international success, and its success is looked at as a model that could be expanded to fight global warming since it brought together so many nations around a common goal that none could solve on its own. "Twenty years ago, the community of nations came together to adopt a global strategy for the global challenge of ozone depletion. Today, we at EPA join our international partners in celebrating the anniversary of the Montreal Protocol -- a shining example of how human ingenuity, leadership and determination can create a healthier, better world," said EPA Administrator Stephen L. Johnson.

Thanks to the treaty's regulation of ozone-depleting substances, the level of CFCs detected in the lower atmosphere peaked in 1995, and in the Antarctic stratosphere in 2001. But the story isn''t over. Though industrialized nations stopped producing most CFCs in 1996, and developing nations stopped in 2006, the ozone hole reached its greatest ever recorded area -- the size of North America -- just last year. That''s because CFCs last in the atmosphere for about 40 years, so while the United Nations expects incremental improvement every year, the ozone layer isn''t expected to fully recover for another 50-70 years. "The goal now is to ensure that CFCs and other emissions continue to fall to below the levels that produce an ozone hole," said NASA Goddard Institute's Anne Douglass, the deputy project scientist for Aura, a satellite that monitors the ozone hole over Antarctica. "This won't happen until about 2070."

COMMENTS ()