Present and future aerosol impacts on Arctic climate change in the GISS-E2.1 Earth system model

Abstract. The Arctic is warming 2 to 3 times faster than the global average, partly due changes in short-lived climate forcers (SLCFs) including aerosols. In order study effects of atmospheric aerosols this warming, recent past (1990–2014) and future (2015–2050) simulations have been carried out using GISS-E2.1 Earth system model aerosol burdens their radiative impacts over (>60∘ N), anthropogenic emissions from Eclipse V6b Coupled Model Intercomparison Project Phase 6 (CMIP6) databases, while annual mean greenhouse gas concentrations were prescribed kept fixed all simulations. Results showed that underestimated observed surface levels, particular black carbon (BC) sulfate (SO42-), by more 50 %, with smallest biases calculated for atmosphere-only simulations, where winds are nudged reanalysis data. CMIP6 performed slightly better reproducing parameters, compared addition, atmosphere ocean fully coupled had smaller levels without nudging. BC, organic (OA), SO42- decrease significantly 10 %–60 % following reductions 7 %–78 emission projections, ensemble showing larger ensemble. For 2030–2050 period, simulated a forcing aerosol–radiation interactions (RFARI) -0.39±0.01 W m−2, which −0.08 m−2 1990–2010 (−0.32 m−2), -0.24±0.01 was attributed RFARI −0.35 −0.40 same −0.01 −0.06 m−2. scenarios little no mitigation (worst-case scenarios) led very small RFARI, medium large mitigations increases negative mainly positive BC forcing. accounted −0.24 −0.26 net ensembles, respectively. Finally, an increase air temperatures throughout simulation period. By 2050, projected 2.4 2.6 ∘C 1.9 ensemble, mean. Overall, results show even largest leads similar impact on sea-ice extent reductions, implying still necessary mitigate change.