13.5: Digging Deeper- Relevance of glaciers in the modern world

Impacts of Glaciated Landforms on Humans 

On the mountain slopes of Scandinavia, glaciers have removed most of the topsoil and thus the region does not have much vegetation. Glacial drifts in valleys not affected by glaciers have created good pasturelands in summer. Cattle are seasonally moved there to graze. Such seasonal movement of cattle is called transhumance. Glaciers grind the bedrock into fine  glacial flour which is transported and deposited by winds to create Loess Plains. The Loess plains of Europe and Central U.S.A, are rich in humus and are very good for farming. Glacial landforms often control the type of farming technique that can be used. Erratics in Alberta act as an obstacle and making the use of machinery difficult. Damming by moraines may create lakes which further inconvenience large scale farming. However it is important to note that glacial lake beds are made up of rich alluvium which is very favorable for farming. Glaciers have helped increase the fish population in fjords by causing an upwelling of nutrient-rich water. As a result, fishing has become a very important activity in the Norwegian fjords. 

Great Lakes of North America were created as a result of glaciation. These lakes act as very significant waterways sometimes connecting the interiors to the oceans like the Hudson-Mohawk Gap. Waterfalls from hanging glacial valleys have often been harnessed for hydroelectric power. Sand and gravel from eskers have also been used for construction. Glaciers have also created spectacular scenery which have often attracted tourists and earned foreign revenue for many countries like United States, Switzerland, France and Canada. 

The Fate of Permafrost in a Warming World

Permafrost refers to ground that remains permanently frozen at temperatures at or below 0^oC (32^oF) for 2 years or more. With global warming, the fate of permafrost in the future is dire. You may not think much about if you live outside the Arctic regions, where permafrost is common. Scientists predict that 40 percent of the world's permafrost could thaw if temperatures rise 2^oC (3.6^oF). Thawing of the permafrost could allow carbon that has been stored for thousands of years to be released into the atmosphere fueling additional warming. In addition, thawing results in land subsidence and mass movement. Buildings and infrastructure-like roads, landing strips, and pipelines, upon which residents depend have been constructed to account for the expansion and contraction that takes place in the active layer of permafrost. Rising temperature due to climate change threatens structures built under a different permafrost freeze-thaw regime.

The Arctic has experienced a significant rise in air temperature over the last few decades and the permafrost that underlines much of the surface is undergoing substantial changes. Continuous permafrost on Alaska's North Slope has warmed 2.2^o-3.9^o C (4^o - 7^o F) over the last century making it more susceptible to erosion and mass movement. Some places in Alaska have subsided by 4.6 meters (15 ft) due to thawing of the permanently frozen subsurface. Accompanied by rising sea level, Alaskan coastal communities near the Arctic Ocean and Bering Sea are being threatened.