A recent study suggests that the famous hole in the ozone layer above the Antarctic may be finally closing. The news comes three decades after the Montreal Protocol which has banned ozone depleting chemicals in refrigerators and spray bottles.
Two scientists first learned how dangerous those chemicals can be for the ozone layer in 1974. Sherwood Rowland and Mario Molina of the University of California found that chlorofluorocarbon gases used as coolants in refrigerants at the time were extremely detrimental to ozone layer.
In 1995, the two chemists were awarded the Nobel Prize for their research into CFCs. The duo wrote in a study that the planet’s atmosphere could absorb only a limited amount of the gases.
In 1985, a group of British researchers spotted a huge hole in the ozone layer in the southern hemisphere triggered by CFC accumulations. If the ozone layer is compromised, more harmful solar radiation reaches the planet, which could boost the incidence of skin cancer.
Two years later, the Montreal Protocol phased out the production of chemicals that affect the ozone layer. The international treaty came into effect Jan. 1, 1989. Forty-six states signed the protocol and 196 ratified it. Former Secretary-General of the U.N. Kofi Annan called the treaty “perhaps the single most successful international agreement to date” due to its wide-spread implementation.
A recent study confirms Annan’s intuition. A research team from the Massachusetts Institute of Technology found fingerprints that the ozone hole may be “healing.”
The study was published June 30 in the journal Science.
Scientists explained that the ozone hole emerges on a yearly basis over Antarctica, starting in August and reaching its peak in October.
For the study, lead author of the study Susan Solomon, who is a climate scientist at MIT and her fellow researchers sifted through ozone layer data taken by satellites and weather balloons.
Next, the research team compared the data with statistical computer models that predict ozone evolution over the years. Scientists found that in September the ozone hole is smaller than in past years since it doesn’t exceed the 12-million-square-kilometer limit.
Scientists’ calculations show that the ozone hole has shrunk more than 4 million square kilometers over the last few decades. Additionally, it doesn’t have the depth it once used to.
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