'Comparison of Polar Amplification in CMIP5 Against Observations'

Climate change has led to amplified warming in the Arctic region compared to the global average, a phenomenon known as polar amplification (PA). In this study, historical monthly averaged 2-m surface air temperatures from the Coupled Model Intercomparsion Project Phase 5 (CMIP5) are compared with three observed datasets (HadCRUT4.4, Cowtan and Way’s Kriging version of HadCRUT4.4, and GISTEMP) in order to determine the models’ ability to accurately characterize polar amplification on multidecadal to centennial time scales (1880-2005).  The CMIP5 models show a wide spread of Arctic PA, with changes in Arctic temperature ranging from 0.27 to 3.3 times the global mean warming.  Observations are spread in a narrower range between 1.7 and 2.3.  A slight majority of the 48 CMIP5 models used in our study overestimate Arctic amplification over this timescale.