Emission metrics such as GWP or GTP are used to put non-CO2
species on a
scale. In the fifth IPCC report the metrics are inconsistent, as the climate–carbon feedback is included only for CO2
but not for non-CO2
species. Here, we simulate a new impulse response function for the feedback, and we use it to correct the metrics. For instance, 1 g of CH4
is equivalent to 31 g of CO2
(instead of 28 g) following the corrected GWP100 metric. It is 34 g if other factors are also updated.