Remember the ozone layer? It’s that thing in our stratosphere that keeps us from getting all the radiation our sun is constantly bombarding us with? Well, we’ve been hearing for decades that the spreading of chlorofluorocarbons in the atmosphere had been punching holes in the ozone layer. Fortunately the laws passed by the Montreal Protocols, which were meant to curb the spread of chlorofluorocarbons by industrial production have been limiting the toxins in the atmosphere and having a positive effect on the ozone layer.
An article by Popular Science goes into detail.
Thanks to the 1987 Montreal Protocol, the ozone layer continues to recover, according to the 2018 Scientific Assessment of Ozone Depletion released Monday by the World Meteorological Organization and the United Nations Environment Programme.
This includes the “hole” over Antarctica where the ozone layer is exceptionally thin, which has been gradually shrinking since the early 2000s and is projected to heal by the 2060s. This year, the hole spanned about 9 million square miles, an area slightly smaller than the entire North American continent.
"Generally, it's good news," says Paul Newman, co-chair of the new assessment and chief scientist of earth sciences at NASA Goddard Space Flight Center. Ozone-depleting gases are decreasing and have continued to fall since the mid-1990s. "The projections into the future are pretty positive as long as parties continue to comply with the Montreal Protocol."
Ozone, a molecule made of three oxygen atoms, occupies two regions of the atmosphere. Ten percent of atmospheric ozone is found in the troposphere, which extends from ground level to an altitude of about seven miles. At ground-level, ozone is an air pollutant in smog that's formed from byproducts in vehicle exhaust and fossil fuel combustion.
It’s not all perfect though. There is some evidence that countries in Eastern Asia are not obeying the protocol. The chemical chlorofluorocarbon-11 is decreasing more slowly than expected, and there is questions about where the source is coming from. Climate change litigation does work, but only if everyone works together.
For more on the specific science behind ozone depletion, check out the National Geographic video below.