New insights into natural variability and anthropogenic forcing of global/regional climate evolution
Wu, T., Hu, A., Gao, F., Zhang, J., & Meehl, G. A. (2019). New insights into natural variability and anthropogenic forcing of global/regional climate evolution. Npj Climate And Atmospheric Science, 2, 18. doi:10.1038/s41612-019-0075-7
Because of natural decadal climate variabilityâAtlantic multi-decadal variability (AMV) and Pacific decadal variability (PDV) âthe increase of global mean surface air temperature (GMSAT) has not been monotonic although atmospheric greenhouse-gas (GHG) concentrations have been increasing conti... Show moreBecause of natural decadal climate variabilityâAtlantic multi-decadal variability (AMV) and Pacific decadal variability (PDV) âthe increase of global mean surface air temperature (GMSAT) has not been monotonic although atmospheric greenhouse-gas (GHG) concentrations have been increasing continuously. It has always been a challenge regarding how to separate the effects of these two factors on GMSAT. Here, we find a physically based quasi-linear relationship between transient GMSAT and well-mixed GHG changes for both observations and model simulations. With AMV and PDV defined as the combination of variability over both the Atlantic and Pacific basins after the GHG-related trend is removed, we show that the observed GMSAT changes from 1880 to 2017 on multi-decadal or longer timescales receive contributions of about 70% from GHGs, while AMV and PDV together account for roughly 30%. Moreover, AMV contributes more to time-evolving GMSAT on multi-decadal and longer timescales, but PDV leads AMV on decadal timescales with comparable contributions to GMSAT trends. Show less