Mitigation of short-lived climate pollutants slows sea-level rise

Under present growth rates of greenhouse gas and black carbon aerosol emissions, global mean temperatures can warm by as much as 2C from pre-industrial temperatures by about 2050. Mitigation of the four short-lived climate pollutants (SLCPs), methane, tropospheric ozone, hydrofluorocarbons and black carbon, has been shown to reduce the warming trend by about 50% (refs,) by 2050. Here we focus on the potential impact of this SLCP mitigation on global sea-level rise (SLR). The temperature projections under various SLCP scenarios simulated by an energy-balance climate model are integrated with a semi-empirical SLR model, derived from past trends in temperatures and SLR, to simulate future trends in SLR. A coupled ocean-atmosphere climate model is also used to estimate SLR trends due to just the ocean thermal expansion. Our results show that SLCP mitigation can have significant effects on SLR. It can decrease the SLR rate by 24-50% and reduce the cumulative SLR by 22-42% by 2100. If the SLCP mitigation is delayed by 25 years, the warming from pre-industrial temperature exceeds 2C by 2050 and the impact of mitigation actions on SLR is reduced by about a third.