A WELFARE-BASED INDEX FOR ASSESSING ENVIRONMENTAL-EFFECTS OF GREENHOUSE-GAS EMISSIONS

THE global warming potential (GWP) index(1-3) is a measure of the rela tive contribution of the emissions of different greenhouse gases to th e radiative forcing of the atmosphere-and thus to climate change-over a given time period. But this index does not represent the effects of climate change, and therefore does not provide an adequate basis for p olicy decisions about emissions reductions. This inadequacy has led to the proposal of an alternative, the economic-damage index (EDI)(4-7). This index compares the effect of different greenhouse-gas emissions on global economic welfare. Here we use a simple climate model to calc ulate the EDIs for a range of climate-change/greenhouse-gas emission s cenarios, and compare the values to the corresponding GWPs. Although t he values of these indices are, at this stage, broadly similar in both magnitude and uncertainty, the prospects of reducing these uncertaint ies by future research are better for the EDI.