Everybody knows about global warming and the effects which it is having on our planet. As the amount of greenhouse gases released into the atmosphere increases due to industrial activities and our love of burning fossil fuels, we are told that the planet as a whole is warming up, which is in turn causing environmental effects. As examples, the world’s weather is being affected and the ice caps of the North and South Poles are melting. This in turn is causing the world’s ocean levels to rise as more water from the melting ice is released into the oceans. However, we are never really given graphic examples of the so called effects of global warming, so it is perhaps understandable that the jury is still out about how extreme the effects of global warming are.
The levels of ice melting in Alaska seem to be a very graphic illustration of just how bad the situation has become. For whatever reason, Alaska’s glaciers and ice fields seem to be melting quicker than those elsewhere, which seems to fit in with the pattern of the Arctic being worst effected by global warming. Even so, the Alaskan melt is surpassing that found anywhere else within the Arctic. According to Climate Central, the amount of ice which had melted in Alaska between 2004 and 2007 was equivalent to three hundred and twenty billion metric tons of ice, which means that Alaska is one of the worst contributors to rising sea levels, which are generally rising about three centimetres every decade.
A research team led by Etienne Berthier has proved that the ice loss in Alaska has been perhaps a third less than what was believed to have melted over the last forty years, which has shown a slower than believed rate of melting. Nevertheless, this rate of melting has still doubled in the last two decades alone, which can be evidenced by the effects which the melting ice is having upon the local wildlife.
Worst affected seem to be the tens of thousands of Pacific walruses which live upon the ice in Alaska. As this ice is now melting fast, more and more of the walruses have been driven to move onto shore. This mass exodus of walruses from the ice onto the shore, of perhaps as many as twenty thousand walruses, has happened every year since 2007, during which time the levels of ice in Alaska have been at record lows.
This is also affecting the soil and vegetation which at one time would have been covered by ice throughout the summer as well as during the winter. Melting ice means more water run-off, affecting the water cycle which occurs over and under the land, which in turn leads to greater levels of erosion as less soil is hidden under the ice. This means it is open to the effects of this water run-off which can cause whole layers of soil to slip on inclines, leading to mud slides and the like. At the same time, as the water run-off accumulates in low areas, large bodies of sitting water are formed in depressions, leading to the sort of conditions suitable for the formation of marsh and swamp lands, altering whole ecosystems. This will often form on agricultural land which is often flat and low lying, leading to damage to the economy.
More surface run-off in turn leads to more water in the rivers, which will lead to increased erosion of the river banks, as well as more material from land erosion being washed into the rivers. This means silt can build up washed into the rivers from land erosion, which in turn can lead to silt accumulations which can alter the courses of rivers. Where this occurs near human habitations, this can be a real cause of concern.
As more soil is also now no longer encased in ice, the soil temperature will increase, which means that the rate of decomposition is increased. Soil respires, particularly in the presence of vegetation, so that the more soil exposed leads to the release of carbon dioxide into the atmosphere, dependant upon temperature and the difference between the levels of carbon dioxide in the air and in the soil, so that the amount of carbon dioxide released into the atmosphere will increase as more and more soil is exposed as the ice melts. Carbon dioxide is of course a green house gas.
So, the alarming rate at which the ice fields and glaciers in Alaska are melting is having numerous environmental effects upon Alaska and the world as a whole. Whilst problems such as erosion and rising sea levels are more long term, in the short term the threat posed to the walruses and other animals like ringed seals whose habitat is fast disappearing is enough of a concern that these creatures are very much being looked upon as endangered species, much like Polar Bears which are facing very much the same problem and which were added to the endangered species list in 2008. The melting ice is changing the whole environment of Alaska, perhaps slowly and imperceptibly, but inexorably.
References
http://www.climatecentral.org/gallery/graphics/alaska_total_ice_loss_2004-07
http://news.softpedia.com/news/Record-Arctic-Ice-Loss-Found-Walruses-at-Risk-156600.shtml
http://www.sciencedaily.com/releases/2010/03/100302123124.htm
