Short-lived climate forcers have long-term climate impacts via the carbon–climate feedback

Short-lived climate forcers (SLCFs) like methane, ozone and aerosols have a shorter atmospheric lifetime than CO 2 and are often assumed to have a short-term effect on the climate system: should their emissions cease, so would their radiative forcing (RF). However, via their climate impact, SLCFs can affect carbon sinks and atmospheric CO 2 , causing additional climate change. Here, we use a compact Earth system model to attribute CO 2 RF to direct CO 2 emissions and to climate–carbon feedbacks since the pre-industrial era. We estimate the climate–carbon feedback contributed 93 ± 50 mW m −2 (~5%) to total RF of CO 2 in 2010. Of this, SLCF impacts were −13 ± 50 mW m −2 , made up of cooling (−115 ± 43 mW m −2 ) and warming (102 ± 26 mW m −2 ) terms that largely cancel. This study illustrates the long-term impact that short-lived species have on climate and indicates that past (and future) change in atmospheric CO 2 cannot be attributed only to CO 2 emissions. Short-lived climate forcers (SLCFs) are thought to have short-term impacts relative to CO 2 . A compact Earth system model estimates SLCFs have caused substantial, long-term impacts via carbon–climate feedbacks since the pre-industrial era but species-dependent impacts of opposite sign largely cancel.