At the annual American Geophysical Union meeting this week in San Francisco atmospheric scientists reported that the ozone hole in the Earth’s atmosphere above Antarctica isn’t clearly shrinking every year. Instead scientists said fluctuations in the ozone hole on a year-to-year timescale are likely caused by natural variations in wind patterns that bring ozone depleting chemicals from the tropics down to the South Pole.
Scientists did say that the hole was stabilizing, but that it may take until 2070 to fully recover. The Montreal Protocol, whose purpose is to save the ozone layer and prevent dangerous ultraviolet radiation from reaching people, was first signed in 1987. However the ozone hole has reached near record size several times in recent years. According to the LA Times, in 2006 the ozone hole reached its largest size ever, and then in 2012 it shrunk to its second-smallest. Two NASA studies found that these fluctuations were primarily due to natural meteorological conditions.
“It’s not going to be a smooth ride,” said Susan Strahan, a senior research scientist at NASA, told the LA Times. “There will be some bumps in the road, but overall the trend is downward.”
The ozone hole was caused by the widespread use of chlorofluorocarbons (CFCs) for refrigerants and aerosols which deplete ozone molecules through chemical reactions.
Countries are now trying to use the Montreal Protocol the curtail the use of Hydrofluorocarbons (HFCs), which are used as a refrigerant and coolant, and can be up to a thousand times more potent of a greenhouse gas than carbon dioxide. In June the U.S. and China agreed to support this measure, but certain developing countries, with India being the lack big holdout, are yet to get on board. If agreed upon, a reduction in HFCs could help avoid up to half a degree Celsius of human-caused warming by 2100.
A New York Times article about the Montreal Protocol from earlier this week says that, “the Montreal Protocol is widely seen as the most successful global environmental treaty:”
“It incorporates pragmatic, business-friendly principles that have allowed it to operate smoothly for more than two decades, achieving its goals — and then some — with little controversy … If production (of CFCs) had been allowed to continue, a batch of scientific studies show, the planet would most likely be warming a lot faster than it is.”
If countries can agree to use the Montreal Protocol to reduce HFCs it would be a powerful move toward measures to phase out or reduce other super pollutants — which are more powerful greenhouse gases than CO2, but also don’t have as long of an effect — such as methane and black carbon.