Emission metrics and sea level rise

Artikel i vetenskaplig tidskrift, 2014

Here we present two new metrics used for comparing climate impacts of emissions of different climate forcers: the Global Sea level rise Potential (GSP) and the Integrated Global Sea level rise Potential (IGSP). The GSP represents the Sea Level Rise (SLR) at a given time horizon due to an emission pulse of a forcer; the IGSP is similar but represents the time integrated SLR up to a given point in time. The GSP and IGSP are presented relative to the SLR caused by a comparable emission pulse of carbon dioxide. The metrics are assessed using an Upwelling-Diffusion Energy Balance Model (UDEBM). We focus primarily on the thermosteric part of SLR, denoted GSP(th). All of the examined climate forcers - even black carbon, a very Short-Lived Climate Forcer (SLCF) - have considerable influence on the thermosteric SLR on the century time scale. For a given time horizon and forcer, GSP(th) lies in between the corresponding metric values obtained using Global Warming Potential (GWP) and Global Temperature change Potential (GTP), whereas IGSP(th) ends up in the opposite end to GTP in the spectrum of compared metrics. GSP(th) and IGSP(th) are more sensitive for SLCFs than for the long-lived Greenhouse Gases (GHGs) to changes in the parameterization of the model (under the time horizons considered here). We also use a Semi-Empirical (SE) model to estimate the full SLR, and corresponding GSP(SE) and IGSP(SE), as alternatives to the thermosteric approach. For SLCFs, GSP(SE) is greater than GSP(th) for all time horizons considered, while the opposite holds for long-lived GHGs such as SF6.