You heard a lot about the hole in the ozone layer back in the 1970s and ‘80s, but not much since then. It’s because we identified the culprit, did something about it, and moved on. But the Earth takes a long time to heal from such damage. Scientists have announced that the hole has shrunk by four million square kilometers, or about 14%, since 2000.
The authors used “fingerprints” of the ozone changes with season and altitude to attribute the ozone’s recovery to the continuing decline of atmospheric chlorine originating from chlorofluorocarbons (CFCs). These chemical compounds were once emitted by dry cleaning processes, old refrigerators, and aerosols such as hairspray. In 1987, virtually every country in the world signed on to the Montreal Protocol in a concerted effort to ban the use of CFCs and repair the ozone hole.
It’s possible that the hole may close for good by mid-century. A discussion at reddit gives the short version of how the hole came about, and how the nations of the world came together to fix the problem. However, the very different problem of climate change due to burning fossil fuels won’t be as simple. -via reddit
(Image credit: NASA's Goddard Space Flight Center/altered by MIT News)