These data are outputs from climate simulations carried out using HadGEM3-GC3.1 described in the associated journal article. The three simulations that constitute the STANDARD ensemble described in the article are u-as371, u-as372, u-as373, and the three simulations that comprise the GREASE ensemble in the article are labelled here as u-bj941, u-bn121 and u-bn122. Outputs from the sea ice and ocean components of the model are archived here separately (labelled '_ice' and '_ocean'). These data were produced by University of Otago, New Zealand, in collaboration with the UK Met Office for a project funded by the New Zealand Deep South National Science Challenge using the Monsoon system, a collaborative facility supplied under the Joint Weather and Climate Research Programme, a strategic partnership between the Met Office and the Natural Environment Research Council.