Posted by: Dan | September 8, 2009

The Retreating Arctic

Words not required, just satellite imagery and data, via NASA on Youtube:



And data on age of the ice here, showing the centuries-old areas of ice shrinking (Rigor and Wallace, 2004):


Sea ice tracking 1978-2008 (Natl Snow and Ice Data Center)

Sea ice tracking 1978-2008 (Nat'l Snow and Ice Data Center

Sea ice thickness 2004v2008 (NASA JPL)

Sea ice thickness 2004v2008 (NASA JPL)

For more, check out the National Snow and Ice Data Center, and especially the section on Arctic Sea Ice News and Analysis.


Update: New from ScienceDaily, Dramatic Biological Responses To Global Warming In The Arctic:

The study led by Post shows that many iconic Arctic species that are dependent upon the stability and persistence of sea ice are faring especially badly. Loss of polar ice habitat is causing a rapid decline in the numbers of ivory gull, Pacific walrus, ringed seal, hooded seal, narwhal, and polar bear. The researchers found that Polar bears and ringed seals, both of which give birth in lairs or caves under the snow, lose many newborn pups when the lairs collapse in unusually early spring rains. These species may be headed for extinction.

The research also reveals that species once confined to more southerly ranges now are moving northward. Among the most visible invaders are red foxes, which are displacing Arctic foxes from territories once too cold for red foxes. Some of the less showy invaders that the scientists found also are moving northward include the winter moth, which defoliates mountain birch forests, and species of Low Arctic trees and shrubs, which affect the dynamics of trace-gas exchange. The presence of more shrubs and trees promotes deeper snow accumulation, increasing soil temperatures during the winter, and more microbial activity in the soil, which in turn makes the habitats more suitable for shrubs. Increasing the shrub cover may lengthen the period during the plant growing season when the tundra acts as a carbon-dioxide sink.

Countering this change, the research reveals, are musk oxen and reindeer, which browse on shrubs, limiting their carbon-soaking capacity and northward expansion to the High Arctic. Grazing, trampling, and defecation by these herbivores promote the growth and spread of grasses, which further attract geese. The geese in turn influence the productivity of lakes, where they rest and graze. The research indicates that complex aquatic and marine food webs like these are extremely vulnerable to alteration due to changes in temperature, precipitation, and nutrient load from the land. [Emphasis mine]


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