There have been positive trends for many years now, but the release of the new UN report is a good time to catch ourselves up on what the models say when it comes to solving the issue. Models are dependent on several factors, so these dates are subject to change, but the report estimates that we’ll return the ozone layer to its 1980 condition by 2045 in the southern hemisphere and 2035 in the northern hemisphere. As for the literal hole in the ozone above Antarctica, estimates are that it will completely close sometime between 2049 and 2077.
Even the large media outlets are running this story as a win, which we are pleased to see. Certainly we can take from it a positive view of international cooperation as well as a keener excitement for the next time dry-sounding environmental agreements are inked.
The road hasn’t been totally smooth—just like with climate change, we wasted some years waffling about the science before taking global action. But also just like with climate change, there were pockets of movement much earlier than the Montreal Protocol that would eventually set the tone for success. On the state level, for instance, Oregon banned aerosol sprays in 1975, and United States federal entities followed up soon after.
Climate change is a bigger, deeper challenge than the ozone, to be sure, and we haven't been met with success yet. We can take a look back in the past, though, and be driven by the knowledge that over time, concentrated efforts do pay off.
If you're interested in a longer treatment of the history and science of fixing the ozone, as well as the notable individuals involved in getting the Montreal Protocol over the finish line, Kelsey Piper has the details here in Vox.