Article originally appeared on Sketchy Science.
Saving the world is a lot trickier than Bruce Willis makes it seem. The more we learn about humanity’s influence on the processes of nature, the more we understand that we live on a complex little marble full of very dynamic and challenging systems. For that reason, it is often very frustrating when we try to undo some of the harm we have caused. Climate change in particular is enough to make people switch off and wait for a new topic. It is a big unruly problem and it often seems like no matter what we do, we can’t fix it. However, recent evidence from Antarctica is beginning to show that the changes we make can have positive effects.
It all began back in the 1930’s with a name named Thomas Midgley who was inventor riding high on his creation of a new form of gasoline that prevented a problem called engine knocking. His handy solution was to put lead in the gas. Little did he and everyone else on the planet know but eventually his invention would expand the amount of lead in the atmosphere (and consequently in the bodies of every man woman and child alive) so much that it would eventually be outlawed.
But back in 1930 everything was going well for old Thomas. Following his success with tetraethyl lead Midgley took a job with General Motors who hoped he could come up with a chemical to use in refrigerators. Back in the early 20th century your fridge was a dangerous thing. The chemicals used to cool it were so poisonous that a small leak could result in your whole family suffocating in their sleep. GM had high hopes that Midgley could fix the problem.
As it turned out, their confidence was well placed and in no time at all Thomas Midgley had his name attached to the invention of chlorofluorocarbons (CFCs). CFCs were harmless to humans and nowhere near as flammable as the old chemicals so they quickly became the molecules of choice for keeping your leftovers cool and delicious.
However, along with leaded gasoline, CFCs would eventually become the scourge of the Earth. As is happens, when CFCs get into the atmosphere they destroy the chemical called ozone. Ozone itself is a bit of a handful. It is just three oxygen molecules stuck together, instead of the usual two. At ground level, ozone is not your friend. Your body confuses it with pure oxygen gas and binds it to you red blood cells where it very swiftly kills you. Up in the atmosphere however, where it makes up a layer 3 millimeters thick all around the earth (about the thickness of 2 pennies stacked on top of each other), ozone is the best. It blocks harmful UV rays from reaching the surface and causing skin cancer and sunburns.
As developed nations cranked out CFCs at every increasing rates through the 50’s and 60’s they found their way into the atmosphere in ever increasing quantities. Eventually they destroyed enough ozone to create a massive hole in the ozone layer over Antarctica between September and December of each year. The hole is isolated to the bottom of the planet because wind currents create the vortex of super-cold air over the South Pole and cold air multiplies the effect of CFCs on ozone.
Clearly something needed to be done before the entire atmosphere was ozone depleted and we were all dying from cancer. In 1987, leaders from nations all over the world came together and drafted the Montreal Protocol, a document that would phase out the use of CFCs all across the world. The agreement was reinforced in 1997 with the Kyoto protocol. The people of the world crossed their fingers and hoped for the best.
So what was the result? Well, in 2012 measurements of the ozone hole revealed that it was the smallest it had been in over a decade. The ban of CFCs is actually working in ways we can see on time scales we can comprehend. In the world of environmental science, that is a slam dunk. Scientists estimate that by the middle of this century ozone levels will rebound to where they were in the 1960’s and the ozone hole should be completely gone sometime in the next 20 years.
To put a slight downer on an otherwise happy ending, it is possible that the shrinking of the hole we are observing is due to warmer air temperatures caused by climate change mitigating the ability of CFCs to break down ozone, but the effect is larger than you would expect from that alone. The news is still good.
The lesson to take away from the patching of the ozone hole (aside from not hiring Thomas Midgley to do anything ever again) is that we can make a difference. When humanity puts its mind to something, we are able to get it done. We should all go out for a beer to celebrate and then get to work eliminating fossil fuels.