Nature Climate Change: New use of global warming potentials to compare cumulative and short-lived climate pollutants

chimneyIn this latest study published in Nature Climate Change an international team of researchers, including SMURPHS Investigators Keith Shine and Piers Forster, considered how the choice of metric can affect the relative emphasis placed on reductions of ‘cumulative climate pollutants’ such as carbon dioxide versus ‘short-lived climate pollutants’ (SLCPs), including methane and black carbon. The research showed that the widely used 100-year global warming potential (GWP100) effectively measures the relative impact of both cumulative pollutants and SLCPs on realized warming 20–40 years after the time of emission. If the overall goal of climate policy is to limit peak warming, GWP100 therefore overstates the importance of current SLCP emissions unless stringent and immediate reductions of all climate pollutants result in temperatures nearing their peak soon after mid-century, which may be necessary to limit warming to “well below 2?°C”. See Chris Mooney’s comments on the study in the Washington Post.