Projected biophysical conditions of the Bering Sea to 2100 under multiple emission scenarios

Abstract

A regional biophysical model is used to relate projected large-scale changes in atmospheric and oceanic conditions from CMIP5 to the finer-scale changes in the physical and biological structure of the Bering Sea, from the present through the end of the twenty-first century. A multivariate statistical method is used to analyse the results of a small (eight-member) dynamically downscaled ensemble to characterize and quantify dominant modes of variability and covariability among a broad set of biophysical features. This characterization provides a statistical method to rapidly estimate the likely response of the regional system to a much larger (63-member) ensemble of possible future forcing conditions. Under a high-emission [Representative Concentration Pathway 8.5 (RCP8.5)] scenario, results indicate that decadally averaged Bering Sea shelf bottom temperatures may warm by as much as 5°C by 2100, with associated loss of large crustacean zooplankton on the southern shelf. Under a lower emission scenario (RCP4.5), these effects are predicted to be approximately half their calculated change under the high emission scenario.