Testing 100-year global warming potentials: Impacts on compliance costs and abatement profile

The comprehensive approach adopted in the Kyoto Protocol relies on the use of 100-year Global Warming Potentials (GWPs) to convert emissions of variou s gases to `carbon dioxide (CO2) equivalents'. This particular set of weigh ts, or metric, has a limited capacity to handle the large variations in atm ospheric adjustment times, and emissions of various gases that are equal in terms of `CO2 equivalents' will not result in equal climatic effects. In t his study, the 100-year GWP metric is assessed in the context of implementi ng the Kyoto Protocol. Using data from Norway, we explore how abatement pol icy formulated on the basis of 100-year GWPs compares to policies based on other metrics in terms of compliance costs and abatement profile, that is, the composition of the basket of gases reduced. We found that the costs for Norway change significantly when other metrics are used, but changes in th e composition of the basket of gases are moderate. However, since complianc e costs can be controlled through other mechanisms for post-Kyoto Protocols , the use of 100-year GWPs versus other metrics has little impact on the ge neral formulation of Norwegian climate policy.