Thawing permafrost - Term Paper Example

99 percent of Greenland, 40 to 50 percent of Canada, and about 20 percent of Far East especially in China is permafrost. This distribution is affected by air temperature close to the ground and to a smaller degree the depth of snow, the direction the sun is facing, vegetation, types of soil, adjacent water bodies, and heat emanating from earth’s core. Permafrost may occur in any area with an annual average air temperature that is below freezing that is air temperature that is below 32F (0C) or what is commonly known as subzero air temperature.

Snow on the surface of the permafrost, insulates and compliments the effective effect of the temperature of the air close to the ground, this results in air temperatures of up to 42.8 F, this might be higher than the local mean annual air temperature. The process of permafrost happen in millennia , this mostly happened during the ice age period and they include the contents of the ground before they were frozen such as solid rock, soft soil deposits, gravel, and other organic materials in the soil.

Introduction The occurrence of permafrost is not universal, that is the reason that permafrost are categorized into different zones, the categorization takes into account the percentage of land area covered by permafrost. The continuous permafrost zones contain permafrost that is 90 -100 percent of the land area; discontinuous zones have permafrost of between 50 to 90 percent ; sporadic permafrost have between 10 to 50 percent and finally isolated patches have underlying permafrost content of less than 10 percent (Salvatore et al. 76). In permafrost regions, the outlying layer is known as the active layer, it is on the surface of the soil, it usually thaws at the beginning of spring through the summer, attaining maximum depth in the late summer.

At the onset of winter, the active layer freezes extending until very late in the season or just at the beginning of spring. The thickness of the active layer stretches from a mere 15 cm or less usually found in the coast of the Arctic coast to about 3 meters or even more in Southern Siberia, European Alps and in the Qinghai-Tibetan Plateau. The thickness or depth of the permafrost from the permafrost table to the permafrost base is determined by two factors, first, active layer freezing; secondly, the heat emanating from the earth core, the unfrozen layer.

Temperatures of permafrost at greater depths reveal unpredictability in climate conditions for extended time durations; this is because heat spreads gradually throughout permafrost. In addition, the report further says that the temperatures in the ground implies the inconsistency in the air temperature, but becomes increasingly inactive with increasing depth. Temperatures of the permafrost are not affected by seasonal variations, such as summer and winter, at all. The mean annual ground temperature that are below the depth of zero annual amplitude reflect past and present long term in changes in mean climate conditions or regimes(Woods and Alter 92).

The depth of zero annual amplitude varies from a few meters in discontinuous permafrost zones to over 20 meters in continuous permafrost regions (Thomas and Andrew 365). The purpose of this paper is to attempt to have a deeper understanding of the concept of permafrost thawing, and the consequences of such an eventuality; on the people and the environment. The impacts of permafrost thaw Thawing of permafrost results in