The significant influence of the Atlantic multidecadal variability to the abrupt warming in Northeast Asia in the 1990s

Abstract

Northeast Asia experienced unprecedented abrupt warming in the 1990s since the last century. Based on a robust time series and rank frequency evaluation, the Max Planck Institute for Meteorology Grand Ensembles of CMIP5 (MPI-GE5), CMIP6 (MPI-GE6), EC-Earth3 and IPSL-CM6A-LR were identified as the models that best simulate the external forcing and internal variability in observations and represent observations most adequately. The negative-to-positive phase transition of the Atlantic multidecadal variability (AMV), combined with the external forcing, can explain 88% [60%−111%] of the 1990s warming. With prescribed anthropogenic emissions in the near future, a phase shift in the AMV to +2 (-2) standard deviation will amplify (weaken) the warming over Northeast Asia by 37% [29%−49%] (19% [15%−25%]). This highlights the importance of natural climate variability in Northeast Asia’s government decision-making and risk management, and emphasizes that only climate models with an adequate representation of forced warming can quantify these contributions correctly.