Scientists at MIT have published findings that the "first fingerprints of healing" are evident in the ozone layer over the Antarctic. In the published paper they show that the hole in the ozone (first discovered in 1985) has shrunk over 4 millon square kilometers since its peak in 2000.
Credit is given to the ongoing decrease in atmospheric chlorine as a result of ever diminishing use of CFCs (chlorofluorocarbons). If you recall, the world essentially banded together 30 years ago and agreed to the Montreal Protocol, a global effort to ban production of CFCs and other ozone depleting chemicals. (No small feat by the way, at the time, CFCs were in essentially everything from air conditioning, to aerosol hairspray, to chemical solvents)
I wrote an article for the August issue of Oil & Energy Magazine discussing the paper and the history of the ozone hole and the effort to ban CFCs as a result. You can read that article here: "The Hole in the Ozone is Getting Smaller"
As interesting as the ozone changes are, it is worth noting that there may be a takeaway lesson here for alternative energy efforts in the future on other fronts, in terms of proving the effectiveness of global agreement on limiting or banning harmful chemicals or their by products and its potential positive impact on the environment. Time will tell.