High-resolution climate models can resolve more climate variability, including ocean eddies and climate extremes, which are projected to be more prominent with sea ice retreat. They are therefore important for studying the interactions of climate variability at different scales in the polar oceans. Although the meridional overturning circulation in high-resolution climate model shows a smooth weakening on a basin scale, there are abrupt shifts on regional scales only in the high-resolution model, such as a strengthening towards the Arctic. This is induced by resolved ocean eddies that increase the heterogeneity of density at ocean boundary, highlighting the disproportionate and interconnected cross-scale climate tipping points in high-resolution models. The Arctic marine heatwaves, as resolved in high-resolution climate models, would induce stronger future Arctic Ocean warming than current projections, as a feedback from the extreme events to the climate. In the Southern Ocean, marine cold spells are projected to intensify in the future. This is due to the resolved eddies that show a strengthening of northward movement and carry high-latitude cold water.