Simulations Show the Arctic's Extra Warming Fades in an Ice-Free Ocean

A team led from the Korea Polar Research Institute reports that the Arctic's extra warming weakens substantially in simulated climates where the Arctic Ocean has lost its sea ice, while the matching Antarctic pattern changes little.

The finding appears in Communications Earth & Environment, published open access on Oct. 26, 2026. Eui-Seok Chung and Seong-Joong Kim of the institute, with colleagues at Pusan National University and the University of Hawaiʻi at Mānoa, set out to narrow what they describe as large remaining uncertainties about how polar amplification, or faster warming at the poles, will change and why.

The authors report that both the strength and the seasonal rhythm of Arctic amplification weaken greatly in model runs of future sea-ice-free climates, and that a reconstruction of distant-past warm climates, which blends geological evidence with model physics, points the same way. Antarctic amplification in the same simulations is weaker to begin with and much less sensitive to the state of the climate, in the future cases and the deep-past ones alike.

The simulations do not agree throughout. The authors record pronounced cloud-related uncertainty in the summer-season Arctic signal in the distant-past runs, and say that uncertainty needs to be resolved. Even so, they judge that the agreement between the future and the deep-past results points one way: the contrast between the two hemispheres is likely to weaken as the Arctic approaches sea-ice-free conditions. That is a reading of simulations and of a reconstruction, not an observed trend.

The simulations are not the team's own. The paper credits the modeling centers behind the CMIP6 and DeepMIP projects, which pool model runs of future and of deep-past climates. It names the Korea Polar Research Institute, the Institute for Basic Science and the National Research Foundation of Korea among its funders. The journal is sharing the accepted paper early, ahead of the final version of record, and has posted the peer review file with it.