Geology Reference
In-Depth Information
A
B
Figure 15.6. Predicted changes to the boreal forest following global climate warming. (A) Western
Canada, based on a mean annual growing degree days (above 5 °C). From Wheaton and Singh
(1988). (B) Northern Sweden, based on a 3 °C mean annual temperature increase, showing north-
ward movement of northern limit of oak and the present limit of coniferous (boreal) forest. From
Boer et al. (1990).
Closely linked to changes in vegetation zonation will be shifts in wildlife migratory
patterns, and aquatic and marine habitats. Warmer and wetter winters, for example, may
decimate populations of caribou and muskoxen, since heavier snowfall will bury the
tundra mosses and lichens on which these animals depend. In contrast, most marine life
and migratory birds are expected to fl ourish, and warmer temperatures would increase
fi sh populations in rivers, lakes, and the ocean. Native settlements initially chosen for
proximity to hunting or fi shing grounds may no longer be ideally suited for such activities
as wildlife and mammal migratory patterns evolve.
15.4. THE URBAN INFRASTRUCTURE
A conservative estimate is that between fi ve and eight million people live in the periglacial
domain. In addition to indigenous populations in Alaska, northern Canada, Greenland,
northern Scandinavia, and northern Russia, there are a number of cities with populations
in excess of 20 000-50 000 persons. In North America, these include administrative centers
such as Fairbanks, Iqualuit, and Yellowknife. In Russia, there are nearly a dozen mining
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