Global warming is a phenomenon by which global temperatures are increasing in response to the thickening layer of greenhouse gases in the Earth's atmosphere. The term global warming, however, leads one to believe that the only effect of increased greenhouse gases is increased temperatures. Global climate change is a more appropriate term which encompasses all the weather-related phenomena that are occurring in response to increased global temperatures.
Much of the attention in polar regions regarding increased global temperatures is focused on the effects an increase may have on melting ice packs and glaciers. The impacts of warmer global temperatures on ice floes and icebergs are sensational and noticeable to even the casual observer. Conversely, little attention is given to the effects of global warming on permafrost which is an equally important part of polar ecosystems.
Permafrost Defined
Permafrost is a layer of frozen soil that occurs in cold climates. It can go through periods of freezing and re-thawing, but always results in frozen ground when the temperatures are below freezing for any length of time. In polar regions, permafrost may never thaw and can reach depths of ten feet or more.
Negative Aspects of Melting Permafrost
So, what are the consequences of thawing permafrost in response to global warming? While building infrastructure on permafrost is not ideal, many structures in northern latitudes are built on permafrost. Many man-made structures, including roads, homes, and other buildings are built on permafrost and risk significantly shifting or collapsing if the ground beneath begins to thaw. Money is already being spent rebuilding such structures because of melting permafrost.
Because permafrost holds a lot of water in ice, when this ice melts it can result in flooding that will impact not only humans but wildlife habitat as well. In regions with a lot of permafrost the entire hydrologic nature of the area will be altered significantly. Water may pool in areas where formerly there was no standing water, which could result in stands of trees and other types of flora becoming waterlogged and drowning.
Marshes that were permanently frozen will release methane into the atmosphere upon thawing. Additionally, habitats that were formerly frozen year-round will become marshy and create good habitats for soil microbes, which will use oxygen and generate carbon dioxide. These soil microbes will be viable all year long in a permafrost-free environment and generate methane. Both methane and carbon dioxide compounds are powerful greenhouse gases, which will serve to speed up the process of global warming even further.
The ramifications of global warming go beyond the sensational pictures of melting ice caps and glaciers. While the process of global warming may be impossible to stop, slowing it down is important to maintain a layer of permafrost in northern latitudes and high altitudes. Permafrost is a critical part of these ecosystems and is, thus, important to conserve.
 |
