In 1985, scientists discovered something quite appalling above Antarctica: the ozone layer formed a hole in itself, letting in harmful radiation from the sun. Now, 40 years later, according to a recent report released by the World Meteorological Organization, the ozone layer is finally on a steady course of repair as a direct result of global efforts to reduce the use of substances known to break down the ozone molecules (O3). The report reveals that the average ozone levels over the course of 2024 were higher than the average from 2003-2022 for the majority of the planet — save a strip near the equator and a piece of Antarctic coastline south of Africa, which still both fell short of the average. However, research has revealed that potentially even more promising results are yet to come.
The ozone layer is a broad region in the stratosphere, about 9-19 miles from Earth’s surface, where the molecule is concentrated. It is most commonly referred to as “Earth’s sunscreen” due to its ability to shield Earth’s surface from ultraviolet radiation that can cause adverse health effects such as skin cancer. When scientists first discovered in the 1980s that a huge hole would develop in the ozone layer, an international treaty called the Montreal Protocol was adopted to phase out chlorofluorocarbons (CFCs) in 1987. These molecules were used in refrigeration, air conditioning, insulation, and aerosol propellants due to their ability to break down ozone in certain conditions when drifting up into the atmosphere along with similar adverse substances after Susie Solomon, a chemistry and environmental studies professor, and other researchers, part of the National Oceanic and Atmospheric Administration (NOAA) determined their harmful effects in 1986. With the ozone layer now slowly recovering, how much of it really has to do with measures such as this?
Interestingly enough, this is not the first time the ozone layer has been identified as recovering. In 2016, Solomon took part in a study analyzing the ozone layer and determined that it seemed to be shrinking, but there wasn’t enough evidence to suggest how effective the cuts on harmful substances like CFCs really were due to other factors such as year-to-year weather variability from El Niño, La Niña, and the polar vortex. In a new MIT study, however, a revolutionary new technique called “fingerprinting” pioneered by Klaus Hasselmann (who won the 2021 Nobel Prize in Physics for it), which focuses on isolating the influence of particular climate factors from natural, meteorological noise, was deployed. Solomon stated that “the atmosphere has really chaotic variability within it,” explaining how “what we’re trying to detect is the emerging signal of ozone recovery against that kind of variability, which also occurs in the stratosphere.” In order to perform the “fingerprinting” simulations of the same global atmosphere with different starting conditions, such as no increase in greenhouse gases or ozone-depleting substances, were used to enable the researchers to map and identify a key pattern of ozone recovery as a result of phasing out of substances harmful to it.
This pattern was compared with satellite footage starting from 2005 to present day, with it becoming even clearer over time and most significantly in 2018 — allowing the team to conclude with 95% confidence that the ozone’s recovery was not only a direct result of the reduction of harmful substances but was the main contributor to its health. Future predictions have been even more promising, with some foreseeing the ozone layer recovering to its previous state in 1980 by 2040 over tropics and midlatitudes, by 2045 for the Arctic, and by 2066 for Antarctica. Solomon stated that if trends continue how the team has observed, the ozone layer will eventually be completely intact.
Looking at the very hopeful new results and predictions, Solomon has remarked that “by something like 2035, we might see a year when there’s no ozone hole depletion at all in the Antarctic. And that will be very exciting for me…And some of you will see the ozone hole go away completely in your lifetimes. And people did that.”
