26 December 2014

Mitigation of Short-lived Climate Pollutants Slows 21st Century Sea-Level Rise


Under current growth rates of emissions of greenhouse gases and black carbon (BC) aerosols, global mean temperatures can warm by as much as 2°C from pre-industrial temperatures by about 2050. Mitigation of the four short-lived climate pollutants (SLCPs), methane, tropospheric ozone, hydrofluorocarbons (HFCs) and BC, has been shown to reduce the warming trend by about 50% by 2050. Here we focus on a topic that has not been addressed so far - the potential impact of this SLCPs 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 model4 is also used to estimate SLR trends due to just the ocean thermal expansion. Our results show that SLCPs 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 2oC by 2050 and the impact of mitigation actions on SLR is reduced by about a third.

A. Hu
Hu, A, Y Xu, C Tebaldi, WM Washington, and V Ramanathan.  2013.  "Slowing Down 21st Century Sea Level Rise Through Mitigation of Short-Lived Climate Pollutants, Nature Climate Change."  Nature Climate Change 730-734, doi:10.1038/NCLIMATE1869.