ABSTRACT
Climate-change policies aim to prevent ultimate adverse climate-change impacts, stated explicitly by the UNFCCC as “preventing dangerous anthropogenic interference with the climate system.” This has led to the adoption of specific climate-change targets to avoid exceeding certain temperature thresholds, such as the “2° target” agreed to in Copenhagen in 2009. The UNFCCC also stated that this aim should be achieved through measures that are “comprehensive and cost-effective.” To achieve comprehensive and cost-effective climate-change mitigation requires an assessment of the relative marginal contribution of different greenhouse gases (GHGs) to ultimate climate-change impacts.
