In the Polar Regions, the main projected biophysical effects are reductions in thickness and extent of glaciers and ice sheets (e.g. Ayles Ice Shelf in the Arctic and Larsen Ice Shelf in Antarctic ). Changes are also taking place in natural ecosystems with detrimental effects on many organisms including migratory birds, mammals and higher predators (polar bears).

In the Arctic, additional impacts include reductions in the extent of sea ice and permafrost, increased coastal erosion, and an increase in the depth of permafrost seasonal thawing. For Arctic human communities, impacts, particularly resulting from changing snow and ice conditions, are projected to be mixed. Detrimental impacts would include those on infrastructure and traditional indigenous ways of life. Beneficial impacts would include reduced heating costs and more navigable northern sea routes.

In both regions, specific ecosystems and habitats are projected to be vulnerable, as climatic barriers to species’ invasions are lowered. Already Arctic human communities are adapting to climate change, but both external and internal stressors challenge their adaptive capacities. Despite the resilience shown historically by Arctic indigenous communities, some traditional ways of life are being threatened and substantial investments are needed to adapt or re-locate physical structures and communities.