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Impact of the choice of emission metric on greenhouse gas abatement and costs

Article | 26-01-2015

This paper analyses the effect of different emission metrics and metric values on timing and costs of greenhouse gas mitigation in least-cost emission pathways aimed at a forcing level of 3.5 W m−2 in 2100. An emission metric determines the relative weights of non-CO2 greenhouse gases in obtaining CO2-equivalent emissions. For the first commitment period of the Kyoto Protocol, the UNFCCC has used 100 year global warming potential (GWP) values as reported in IPCC's Second Assessment Report. For the second commitment period, the UNFCCC has decided to use 100 year GWP values from IPCC's Fourth Assessment Report.

We find that such a change has only a minor impact on (the optimal timing of) global emission reductions and costs. However, using 20 year or 500 year GWPs to value non-CO2 greenhouse gases does result in a significant change in both costs and emission reductions in our model. CO2 reductions are favored over non-CO2 gases when the time horizon of the GWPs is increased. Application of GWPs with time horizons longer than 100 year can increase abatement costs substantially, by about 20% for 500 year GWPs. Surprisingly, we find that implementation of a metric based on a time-dependent global temperature potential does not necessary lead to lower abatement costs.

Author(s)Maarten van den Berg, Andries F Hof, Jasper van Vliet, Detlef P van Vuuren
Publication date26-01-2015
PublicationEnvironmental Research Letters