November 3, 2017 Ozone hole shrinking
For the first time, scientists have shown that levels of ozone-destroying chlorine are declining. Resulting from an international ban on chlorofluorocarbons (CFCs), this decline has led to about 20 percent less ozone depletion during the Antarctic winter than there was in 2005, the first year that NASA began taking measurements. “We see very clearly that chlorine from CFCs is going down in the ozone hole, and that less ozone depletion is occurring because of it,” says Susan Strahan, Senior Research Scientist at NASA’s Goddard Space Flight Center in Greenbelt, USA. The Antarctic ozone hole was discovered in 1985. Two years later, nations of the world signed the Montreal Protocol on Substances that Deplete the Ozone Layer. Later amendments to the protocol phased out production of CFCs globally. These international agreements are often seen as positive examples of how nations together can successfully tackle global environmental problems.