Ozone treaty accidentally slowed global warming
http://m.dailykos.com/story/2013/11/17/1253398/-Ozone-treaty-accidentally-slowed-global-warming?detail=facebook
Ozone treaty accidentally slowed global warming
by VL Baker Nov 17, 2013 7:00pm PST
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There has only been one global climate treaty which has had a record of success and that was the Montreal Protocol, a treaty enacted in 1987 to protect the Earths thinning ozone layer. The treaty has had the unintended benefit of helping to slow the rate of global warming since the mid-1990s, according to a new study. The study, published in the journal Nature Geoscience, relies on a statistical analysis of global average temperatures as well as greenhouse gas emission trends, including chlorofluorocarbons or CFCs, which both break down ozone in the upper atmosphere and help warm the climate.
The study provides evidence that the Montreal Protocol was an effective climate treaty, albeit an accidental one, and it is the first to link the treaty to the recent slowdown in warming. At the time the treaty was negotiated, CFCs were known to be greenhouse gases, but the treaty was not initially meant to address global warming, an issue that was just starting to gain public attention.
According to the study, the phase down in the use of CFCs during the 1990s into the early twenty-first century, which was solely intended to reverse the loss of Earths protective ozone layer in the upper atmosphere, has shaved nearly 0.2-degrees fahrenheit of global warming since that time. While that may seem small, considering that the world has warmed by an average of about 1.6-degrees fahrenheit between 1901-2012, it is not a trivial amount.
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According to a study published in the journal Nature Climate Change, reducing emissions of a portfolio of short-lived climate pollutants, including soot and methane in addition to HFCs, by 30 to 60 percent by 2050 would slow the annual rate of sea level rise by about 18 percent by 2050. Combining reductions in short-lived pollutants with decreasing CO2 emissions could cut the rate of sea level rise in half by 2100, from 0.82 inches to 0.43 inches per year, while reducing the total sea level rise by 31 percent during the same period, the study found.
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