The polar regions are experiencing some of the most rapid change from greenhouse gas warming. This presentation addresses some of the working being done with CESM to understand sea ice changes in the Arctic and Antarctic and how these may impact local ecology. In the Arctic, the long term, consistent sea ice loss has led to changes in phytoplankton productivity as well as opportunities for subsistence hunting activities. In the Antarctic, high sea ice variability has made ecological responses less definite. However, the importance of polynyas - openings in the sea ice - are consistently important for the ecosystem and could be valuable for protection.