New data reported by the National Oceanic and Atmospheric Administration (NOAA) reveal that the hole in the ozone layer is at its fifth-smallest size since 1992. That’s great news, and a massive endorsement for the efforts first begun in 1987—and projected to reach completion by 2050.
The 1987 effort in question is the Montreal Protocol, an international treaty that received unanimous support in banning over 100 ozone-depleting chemicals. The most famous of these were the chlorofluorocarbons (CFCs) common in aerosol products, but there were others as well. It was an easy-enough ban with a big-enough impact that it found support even from traditionally anti-regulation economies.
In the years since, the Montreal Protocol has been incredibly successful in stopping and even reversing the trend of human-made chemical ozone depletion. This is generally measured in the cold months, when the hole is at its maximum size due to a combination of low temperatures, high vortex speed, and high levels of UV radiation triggered by the onset of spring.
At its largest (in 2000), the ozone hole was an astonishing 28.3 million square kilometers, making it roughly 116% the area of North America. This year, during the height of the ozone depletion season, the 2025 ozone hole averaged 18.71 million square kilometers—still about twice the area of the United States, but also a reduction of about a third.
This is how the ozone hole over the South Pole on the day of its 2025 maximum extent.
Credit: NASA/Lauren Dauphin
Even better, the seasonal growth in the ozone hole is already breaking up about three weeks earlier than over the past decade. This not only lessens the magnitude but also the length of the effect of increased UV exposure.
As a result of these efforts, the ozone hole is on track to recover more quickly each year, with projections predicting a complete closure as early as 2050. That would be an incredible achievement, to so completely heal such an enormous aspect of the planet in just 63 years from implementation.
Right now, the biggest source of ongoing ozone depletion is legacy tech, in particular, old tech breaking down in landfills. From old forms of building insulation to pre-1990s fridges and air conditioners, the past just keeps piling problems onto the present—but that’s thankfully only a temporary trend.
One of the big reasons for the 2050 timeline is that, with every year that passes, CFC-releasing technology decays a little further, and there are fewer of them left to follow.
So, as the ozone hole trends toward complete closure, we should reflect on the fact that it was only possible because of collective global cooperation over decades of sustained effort.
There is little profit incentive for companies to trend back toward CFCs, and so the ban will most likely remain in place as long as needed. The problem with using the Montreal Protocol as a model for, say, the Paris climate agreement, is that the proposed regulations have very different implications for global industry.
In the ozone layer, we have proof that collective action can work when it’s possible. All we need now is proof that collective action is possible when it can work.