After a report from the U.N. in September stated that the ozone layer could be healed by 2050, the U.S. Environmental Protection Agency began appealing last week to the Obama administration for further enforcement of the Montreal Protocol.
The report, published by the United Nations Environment Program and the World Meteorological Organization, said the ozone has been healing successfully in part because of the successful implementation of the Montreal Protocol, an international treaty that phased out the production of substances that are responsible for ozone depletion.
The Protocol was put into effect in the 1980s after scientists noticed the connection between harmful UV radiation and its effect on skin cancer rates, said Gunnar Schade, associate meteorology professor at Texas A&M.
“There’s a clear relationship in how much you got sunburned as a child and how likely it is for you to get skin cancer when you get into your 40s to 60s,” Schade said. “So you would actually, based on the maximum being only like 20 years ago, you expect skin cancer rates probably to maximize in the next two decades and then they should go down.”
According to the report, some greenhouse gasses are acting as a catalyst for the healing of the ozone layer rather than the depletion of the ozone layer. Schade said the connection exists but is not as strong as the report suggested.
“Depending on what we do with the emission of greenhouse gasses, it will lead to a different time-scale,” Schade said.
Schade said it is possible for this relationship to also create more ozone than the Earth originally had.
“The ozone layer is probably going to be thicker by the time this century ends, relative to before ozone-depleting substances affected it,” Schade said. “As we’re warming the lower layer of the atmosphere — it’s called the troposphere — that heat that usually would have radiated further up is not getting there, so that leads to the cooling of the layer above.”
Schade said greenhouse gasses tend to cool down the atmosphere, and this cooling has the tendency to slow down the chemistry that depletes the ozone. Schade said the stratosphere ultimately maintains a slightly higher level of ozone than if it were warmer.
“These molecules have a very long residence time in the atmosphere,” Andrew Dessler, meteorology professor said. “So, it’s taken this long for their abundance to start to decline and the ozone layer to start to recover.”
Schade said although ozone-depleting substances have been banned, there is a black market for chemicals banned under the Montreal Protocol, which are used to run old equipment still used in developing countries.
“[We need to] advocate for the rapid replacement of any stock that’s already out there,” Schade said. “So, foreign policy — basically the U.S. — is helping the other developed countries help those that are still using the old equipment to replace it.”
Victoria Benson, psychology senior and environmental issues committee chair, said the best way to help is to seek out environmental education.
“Becoming educated in order to have an informed opinion is the easiest thing one can do, from there you have to start changing your day-to-day habits,” Benson said. “Our generation is so positive. Once we set our minds to something, we go out and achieve it.”