We use the United Kingdom Earth System Model simulations from the Coupled Model Intercomparison Project 6 to analyse the dynamics of the Ross Gyre, West Antarctica, under historical and projected climate-change scenarios. During the historical period, the modelled Ross Gyre is relatively stable, with an extent and strength that are in reasonable agreement with observations. The projections exhibit an eastward gyre expansion into the Amundsen and Bellingshausen seas that starts during the 2040s. The associated cyclonic ocean circulation enhances the onshore transport of warm Circumpolar Deep Water into the eastern Amundsen Sea, a regime change that increases the subsurface shelf temperatures by up to 1.2◦C and is independent of future forcing scenario. The Ross Gyre expansion is generated by a regional surface stress curl intensification associated with anthropogenic forcing. If realised in reality, such a warming would strongly influence the future stability of the West Antarctic Ice Sheet.