The Arctic marine food web is very complex and is susceptible to disturbance both by the increasing in temperature as well as due to the loss of sea ice. For instance, there is species of algae that grow underneath the ice, and which other organisms lower on the food chain depend upon for nourishment. With a loss in the ice layer, the fate of the algae and the primary consumers that depend upon them is uncertain. Likewise, there could be significant changes in species composition, the consequences of which are uncertain (3).

Across the northern hemisphere, it has already been found that 130 species (including many species of plants of animals), have already been responding to spring temperatures arriving earlier during the period of 1970-2000 (5).

In the polar regions, quite a few shifts in the balance of ecosystems as well as the shifting of entire ecosystems are expected. Both terrestrial and marine species are expected to shift their ranges to the north, creating increased ranges for some and decreased ranges for others. Moving ranges may cause secondary difficulties for a variety of species, because with species shifting their ranges towards higher latitudes, more temperate diseases may invade, infestation by new insect species, and displacement by and competition from migrant species (14, 6).

Different vegetation zones are expected to move northward, with deciduous forests pushing out boreal forests, boreal forests pushing out tundra, and tundra encroaching on polar deserts. It is predicted that huge tracts of tundra will change over to taller and denser vegetation, increasing ability for forest to encroach. The northward rate of this shift may be 0.2 km/year, which would make it extremely difficult for most species to keep up with shifting ranges (14).