Robert L Kleinberg 

The Global Warming Potential (GWP) is a widely used metric used to compare the climate change effects of various greenhouse gases. Although GWP has an established role in international climate agreements, GWP does not, in general, describe any specific identifiable impact of greenhouse gas emissions on climate. It is argued here that GWP is unphysical, unintuitive, arbitrary, ignores the time dependence of emission sources, and is in some cases misleading. Therefore it has no place in describing the effects of climate change mitigation strategies beyond a 20 year horizon. This paper argues for the broader use of global mean temperature change trajectories in educating policy makers and the public about greenhouse gas control, thereby making climate policy discussions more scientifically rigorous while demystifying the criteria upon which policy choices are made. Examples provided include multiyear emissions, venting versus flaring of natural gas, electric power generated by natural gas versus coal, European gas supply by LNG versus pipeline, European electric power by imported gas versus coal, and livestock reduction.