Deserts and glacial regions have many similarities. They both extend over vast regions and have beautiful sceneries and features. Besides, they have adverse climatic and physical conditions that have limited man’s advance and invasion of their landscapes. Moreover, desert and glacial features are very important for us because they can be used to tell how the climate is changing. We have seen ice caps melt due to a greenhouse effect caused by the emission of carbon gases into the atmosphere by man. This is causing glaciers to recede. On the other hand, we have seen an increase in desert landscapes due to reducing rainfalls and cover crops. This is also caused by man’s activities like deforestation for example. (Glaciers and glaciations, n.d.)
Deserts have several features which are primarily caused by a process of wind erosion, transportation, and deposition. We, therefore, have features that have been formed either because of erosion or because of deposition. When wind moves in a desert, large grains of eroded particles are dragged on the desert surface, a process called surface creep. Lighter particles move by a series of light jumps by a process called saltation while very fine particles are carried in the air over long periods of time by a process called suspension. In abrasive erosion, large grain particles erode rocks to give them a distinctive shape and a surface polish. This distinctive shape depends mostly on the direction of the wind. For example, a protruding rock may acquire an inclined shape in the wind direction. Abrasion features are called wind artifacts (I think because they are formed by wind). When the wind blows in a relatively flat area with no vegetation, this wind moves loose and fine particles to erode a vast area of the landscape continuously in a process called deflation. This could form desert pavements-continuous pavements of course particles. (Milankovitch Cycles, n.d.)
The most common feature formed by the wind deposition process is a sand dune. This is formed when wind flowing in a desert encounters an obstacle. This causes the wind to move up and around the obstacle forming a small area where the wind moves with low velocity. Reduction in wing velocity causes deposition to occur around the obstacle which continues to grow as wing velocity decreases further. (Kusky, n.d.)
Like in deserts, glacial features are formed by a process of erosion, transportation, and deposition. The major difference is that, unlike wind, snow moves slowly and can transport very heavy particles. The result is a faster and more efficient erosion process. When ice moves by basal sliding- a process by which ice at the base of a glacier moves across its bed, ice at the base of the glacier contains large rocks and particles that scrub the underlying rock to produce long and parallel scratches called glacial striations. (Glaciers and glaciations, n.d.)
Glaciers deposit rock fragments in an unsorted or rounded manner. A glacial till formed by glacial deposition consists of a heterogeneous mixture of crushed rock, sand, pebbles, cobbles, and boulders deposited by a glacier. When boulders in a glacial till are not similar to the surrounding bedrock, the feature is called an erratic. When boulders, rock fragments, and other particles are deposited around the margins of a glacier or at its terminus, they form a ridge called a moraine. When two glaciers intersect, they form a central moraine which provides important geological information to scientists. A periglacial ice-wedge forms by a process of repeated freezing and melting of ice. During summer, water enters rock cracks near the surface. This water freezes later during winter and expands due to the anomalous behavior of water that contracts when heated and expands when it is cooled. This increases the size of ice of the crack to allow in more water during summer and consequently more amount of ice inside the crack during winter. (Kusky, n.d.)
Although people are very worried about climatic changes that are thought to be leading to an increase in temperatures meaning an increase of deserts and a decrease of glaciers, scientific evidence in the last 60 million years shows that the opposite is likely to happen. The overall trend in the last 60 million years has been an increase in glaciations and a decrease in deserts. Although the overall trend has been a decrease in temperatures, the earth has been experiencing alterations of ice age periods and a warm inter-ice age period of about 100 thousand years in the last eight hundred thousand years. We are currently in an interglacial cycle period. The earth has experienced a total of about 20 glacial periods in the last 2 million years. (Kusky, n.d.)
I think that the earth is going to go through a period of an increase in global temperatures in the range of between 1.5-4.5 degrees in the next fifty years due to increasing emissions of carbon gas in the atmosphere causing a greenhouse effect. The fact that these increases will be greater around the ice caps means a recession of glaciers causing ocean rise. This however will change and the earth will enter into the next ice age any time after fifty years in the future or even earlier.
References
Glaciers and glaciations. (n.d.).Types of glaciers. 2010, Web.
Kusky, M.T. (n.d.). Climate change: Shifting Glaciers, Desert, And Climate Belts. 2010, Web.
Malankovitch Cycles. (n.d.).Desert, Glaciers, and Climate change, Chap 13, pp.378-414