The ozone layer, which develops a hole over Antarctica every year that grows to its largest extent in September and October, is about average this year, but overall not closing at the rate scientists had hoped for in the years since the landmark 1987 Montreal Protocol regulated ozone-depleting chemicals worldwide, according to a BBC report.
Still, given the all-out ban on most ozone-depleting chemicals by next year in 100 signatory countries, the prospects are good for a smaller hole by mid-century. World leaders met recently to renew and expand the treaty's reach.
At 16.8 million square miles, the ozone hole is bigger than North America. The hole allows UV radiation to penetrate the stratosphere, leading to an increase in cancer risk and other health and environmental problems on the Earth's surface.
The Montreal Protocol, signed in 1987, is heralded not only as a success, because it resulted in nations across the globe agreeing to phase out the use of chemicals that cause ozone depletion, but also as a global warming bellwether: If the world can tackle this atmospheric problem, it can also tackle climate change.
The most important lesson from the treaty might be this: Don't expect fast results.
Enter your city or zip code to get your local temperature and air quality and find local green food and recycling resources near you.