Anomalies of Arctic surface temperature.
Model simulations are with anthropogenic plus natural (ALL) forcing, greenhouse gas (and ozone forcing in five models; GHG) forcing, natural (combined solar and volcanic; NAT) forcing and other anthropogenic (OTH) forcing. Red curves show 100 realizations of near-global HadCRUT4 observations12 and the green curve shows North Polar Area (NPA) observations13. Black (blue) curves are ensemble-averages over the six CMIP5 simulations with the best (worst) agreement between simulated and observed piecewise linear approximations. Grey shading is ± one standard deviation over the full ensemble of 18 CMIP5 models. Anomalies are relative to the 1961 to 1990 climatology.