We watch the ongoing COP19 climate talks in Warsaw with our usual hope that perhaps this year will be the year that the global community wakes up to the crisis of climate change. Historically there is no reason for optimism. The Kyoto agreement excluded the major polluters including the United States and China and we still have the dynamic of those most responsible for the current crisis refusing to be part of the solution to mitigation.

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 Earth’s 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 Earth’s 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.



This new study gives some optimism about the potential of reducing short-term climate pollutants which include: black carbon (soot), methane, tropospheric (ground level) ozone and chlorofluorocarbons (CFC's) to create a near-term cooling which buys us some time to reduce the much longer living legacy CO2 in our atmosphere. I have been writing about the risk-free reduction of the short-lived climate polluters as a solution to mitigating the worst effects of climate change for several years. And evidence is growing that taking that direction is gaining some consensus.

The U.S. has founded the Clean Air and Climate Initiative to reduce the short-lived climate pollutants, which now includes many countries and scientific global members. And this year the U.S. has also entered into agreements with both China and India to reduce HFC's (which have replaced CFC's). Because of their high global warming potential, reducing emissions of HFCs are viewed as a critical part of plans to reduce near-term global warming while negotiations continue within the U.N. to tackle carbon dioxide and other long-lived greenhouse gases.



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.

This is not enough, but it is a start. And with information that a major contributor to the short-lived climate pollutants is livestock production , we can all become a part of the solution to preventing the worst effects of climate change simply by reducing consumption of meat and animal products in our diets.