THE BENEFITS OF BASING SHORT TERM CLIMATE PROTECTION POLICIES ON THE 20 YEAR GWP OF HFCS

摘要

The short-term global warming contribution of HFCs is more accurately accounted for through the 20-year global warming metric (GWP_(20)) than through the 100-year global warming metric (GWP_(100)) that is conventionally used. The GWP_(20) metric better reflects the true potency of HFCs during their actual time in the atmosphere. Since global warming induced climate change is already happening it is essential to take all available measures to reduce greenhouse gas emissions. Depending on variations in emission scenarios, at a business as usual trajectory, HFC emissions are projected to be between 7 to 19% of total greenhouse gas emissions by 2050. Under a 450ppm C02 stabilizations scenario combined with un-curtailed HFC emissions, in 2050 HFCs could represent between 18 to 45% of global CO2 emissions (UNEP Synthesis Report, 2011). Phasing out the use of HFCs by 2020 is one of the readily available measures to combat global warming. The climate benefits of such phase out are better understood when the GWP_(20) of HFCs is used in policy formulation. The intent of this paper is to reignite discussion on the benefits of basing policies on the 20-year global warming potential of HFCs rather than on the current standard of 100 year GWP.