NASA has just reported that the ozone hole over Antarctica is the smallest it’s been in 20 years.
On September 22 2012, the ozone hole reached its maximum seasonal size for the year of 21.2 million square kilometres, which is the same size as the USA, Canada and Mexico combined. This size is down from the maximum size of 29.9 million square kilometres reached in September 2006.
There isn’t much talk about the ozone hole these days but it was often in the news in the 1980s, just as “climate change” is in the news now.
Ozone in the atmosphere helps to protect the Earth from ultraviolet (UV) radiation. As we all know, increased exposure to UV causes skin cancer. In the 1980s when the ozone hole first appeared, the fear of an expanding hole in our protective shield was not good news for Australia, given our proximity to Antarctica.
The chlorine-containing substances (chloroflourocarbons or CFCs) that destroy ozone were included in many sprays (deodorants, fly spray etc) and refrigeration units.
After the usual arguing among environmentalists, scientists, governments and others who thought it was a beat-up, the world got together and delivered an international treaty. The treaty, known as the Montreal Protocol, regulates use of CFCs.
In the 1980s, the projections of ozone depletion from the atmosphere were dire but the Montreal Protocol appears to have at least reversed the trend (see figure below). NASA says that the ozone hole will not shrink to the size that it was in the early 1980s until 2065.
On the NASA website, scientist Paul Newman of NASA’s Goddard Space Flight Center says that natural fluctuations in weather patterns resulted in warmer stratospheric temperatures in 2012 and that this made the ozone hole smaller.
It would be nice to think this is an environmental success story, but it seems there is still some way to go. At a minimum, the ozone hole story is a case study in what governments around the world can do when they really try.