Large changes in Arctic sea ice cover have occurred in the last few years, though whether they are part of a long-term natural variability or are related to increased radiative forcing from anthropogenic greenhouse gases is unclear. Knowing how sea ice changes have affected, and will continue to affect, climate (through changes to the surface albedo and through alterations to the ocean-atmospheric exchange of freshwater and heat) may be crucial for making future climate predictions.
Processes in the Arctic that affect climate include melt-ponds, lead fractions, brine rejection, and ice-ice interactions. Quite a number more may exist. But, however many, they operate at relatively small scales that cannot be directly incorporated into current climate models. The high latitudes are expected to be the most sensitive regions to possible anthropogenically forced climate changes, yet observations of polar climate and understanding of polar processes have not proceeded as fast as our appreciation of their importance.