He world effort that we have been doing for 38 years To reduce pollutants that undermine the integrity of the ozone layer It is really working: The “hole” in the ozone layer on Antarctica is closing thanks to the prohibition of Chlorofluorocarbons imposed by him Montreal protocol In 1987. This is demonstrated by first time A new studypublished in Naturemade by a MIT team (Massachusetts Institute of Technology) coordinated by Susan Solomon, one of the first to study and give the alarm about the dangers of the thinning of the ozone layer in the atmosphere.
The hole in the ozone layer and the Montreal protocol
For years, it was one of the most discussed environmental problems in the media: the “hole” of Ozone, that is, the thinning of the ozone gas layer (or3) In the stratosphere on Antarctica, life on earth exposed to Danger of solar radiation. The fault, as it was clear almost forty years ago, had the pollutant gases, in particular the Chlorofluorocarbons (CFC) that we use as refrigerants, insulating and in the propellants. These substances in the atmosphere were interfering with ozonebreaking their molecules and reducing the thickness of this natural filter To solar radiation. Fortunately, much time was not lost: countries joined and agreed to prohibit CFCs and other substances that exhaust the ozone layer in the hope of repairing the damage caused. It was the first attempt at global climate governance, which would later give rise to the conferences of the UN parties (COP).
38 years have passed since the entry into force of the Protocol Montreal: Since then, CFC concentrations in the atmosphere have been reduced and, as demonstrated by the data collected in recent years by the scientific community, Ozone is much better. The wound, in short, is healing.
Why is the hole closing?
They are very good news, of course, but the reality is that until now it had not been established with enough certainty why the ozone layer hole was closing. It must be said, in fact, that the thickness of the ozone layer is also affected by various environmental variablessuch as seasonality, polar vortex and the climatic phenomena of El Niño and the girl. “Although detecting a statistically significant increase in ozone is relatively simple, attributing these changes to specific factors is more difficult,” he said Peidong WangResearcher of the Department of Earth Sciences, Atmospheric and Planetary of the MIT.
The human footprint in the hole
However, Wang himself, together with colleagues from the Susan Solomon team, has succeeded in the task, and for the first time he has obtained quantitative tests that the determining factor In the recovery of the Antarctic ozone layer, it is indeed the world effort for Reduce CFC.
The scientists got it with an innovative approach taken from studies on climate change. The method (which, by the way, earned him the Nobel Prize in Physics in 2021 to Klaus Hasselmann, his creator) is known as’fingerprinting‘And it serves to isolate the influence of concrete climatic factors in an event, such as confirming and quantifying the footprint of the human being in climate change.
Wang and Solomon applied the fingerprinting for Identify the effect of pollutant reductions that interfere with ozone. Many simulations were necessary in which scientists mapped the changes in the ozone layer in response to different environmental conditions until patterns were identified. When comparing these patterns with the satellite observations From the ozone layer on Antarctica from 2005 to the present, they discovered that, with A 95% confidence levelthe pattern that resembles real data is due to CFC exhaustion In the atmosphere.
It is possible to solve environmental problems
This, the authors commented, gives confidence that environmental problems can be solvedin which the commitment of the international community can make a difference. In addition, according to Susan Solomon, if the recovery tendency of the ozone layer continues, In 2035 we could attend a year in which there will be no exhaustion of the ozone layer in Antarctica: “Some of you,” he concluded, “you will see the ozone hole completely disappear throughout your life. And it will be the people who will have made it possible.”
Article originally published in Wired Italy. Adapted by Mauricio Serfatty Godoy.
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