Summary/Abstract
According to the CMIP5 simulations, 2016’s record global January–December warmth would not have been possible under climate conditions of the early 1900s—anthropogenic forcing was a necessary condition (Hannart et al. 2016) for the event. Anthropogenic forcing contributed most of this warmth (relative to 1881–1920 conditions), while natural forcings and intrinsic variability (including El Niño) made relatively small contributions to the January–December 2016 global mean.