At the latest by 2066
In a report unveiled on Monday, a group of experts mandated by the United Nations indicated that the hole in the ozone layer would be reduced before the end of the century. The scientists conclude that “if current policies remain in place, the ozone layer is expected to return to 1980 values (before the ozone hole appeared) by 2066 over Antarctica, by 2045 over the Arctic and by 2040 in the rest of the world”. The most recent assessment was carried out by a group of experts drawn from the World Meteorological Organization (WMO), the National Oceanic and Atmospheric Administration (NOAA) and the National Aeronautics and Space Administration (NASA), among others.
A warning from 1974
The ozone layer absorbs some of the sun’s ultraviolet rays. Without it, life on Earth would be virtually impossible. Between 1975 and 1984, several sounding balloons were launched on the initiative of British geophysicist Joseph Farman. The results are worrying: we then observe a gradual drop in ozone levels in the stratosphere, above the scientific base of Halley Bay, in Antarctica. This “hole” in the ozone layer appears periodically during the austral spring at the South Pole. However, in 1974, two chemists from the University of California, Mario Molina and Sherwood Rowland, issued a warning about the destructive effect on ozone of industrial gases such as chlorofluorocarbons or CFCs, used in refrigerators and aerosols. The two researchers won the Nobel Prize in Chemistry in 1995 for their research.
“A real spearhead”
“According to the latest quadrennial report, the recovery of the ozone layer is on track, which is fantastic news. The impact of the Montreal Protocol on mitigating climate change cannot be overstated. Over the past 35 years, the Protocol has become a true spearhead of environmental advocacy,” said Meg Seki, Executive Secretary of the Ozone Secretariat of the United Nations Environment Program (UNEP) on Monday. ). An assessment shared by Caroline Brouillette, director of national policies at the Climate Action Network. “It shows that public policies to deal with the environmental crisis work when we attack the cause of the problem. »
SOURCE: AGENCE FRANCE-PRESSE, LA PRESSE INFOGRAPHY
The importance of the Montreal Protocol
The Montreal Protocol, adopted on September 16, 1987, provided for a 50% reduction in the use of CFCs and halon gas, both dangerous for the ozone layer, over a period of 10 years. Initially signed by nearly 40 countries, the agreement was finally ratified by 196 States in addition to the European Union. After a record hole was observed in 2006 above the South Pole, a new agreement was approved in 2007, again in Montreal, to accelerate the ban on gases harmful to the ozone layer. “The phasing out of almost 99% of banned substances that destroy ozone has helped to preserve the ozone layer and contributed significantly to its recovery in the upper stratosphere and to a reduction in human exposure to radiation. harmful ultraviolet (UV) rays from the sun,” the UN-mandated experts noted in their report released on Monday.
A breath of fresh air
According to Caroline Brouillette, this news is a breath of fresh air at the start of 2023. “In a world where cynicism is a dominant posture in the face of international agreements, it feels good,” she said, noting that global cooperation is the source of this success. The expert, however, insists on emphasizing that progress is possible “when we name things clearly”. In the case of the hole in the ozone layer, “we clearly named the source of the problem, ie CFCs,” she specifies. “It shows that you can do it when the will is there. A will that has often been lacking in international climate negotiations. “Fossil fuels are the elephant in the room, notes Mme scramble. It is also an issue that is much more politicized than the CFCs. »
Beware of geo-engineering
Potential solar geoengineering projects intended to limit global warming could, however, have adverse effects on the ozone layer, scientists warned on Monday. The idea would be to intentionally add suspended particles in the stratosphere to reflect some of the sun’s rays. One of these projects would involve injecting a considerable amount of sulfur particles into the upper layer of the atmosphere. But an injection of particles into the atmosphere “could result in a serious drop in ozone levels,” said John Pyne, co-chair of the UN science panel working on ozone. “The easiest thing to do is to stop releasing greenhouse gases into the atmosphere,” he said.
With Agence France-Presse
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- 0.5°C
- An injection of particles over Antarctica would certainly reduce the global temperature by 0.5°C over 20 years, but the hole in the ozone layer would return to levels close to those of the 1990s.
Source: UN