AN excellent source for information about the condition of the Arctic ice cap is the National Snow and Ice Data Center in Boulder, Colorado. This organization publishes data and images associated with Arctic sea ice on a monthly basis, and has analyzed time series data to ascertain long term tends in addition to the monthly assessments.
Fundamentally, the arctic ice cap is disappearing. In the chart below, the average August ice extent was just over 8 million square kilometers, while the average August ice extent in August of this year, 2008, was around 6 million square kilometer, a 25% reduction in ice extent. The trend corresponds to an average loss of ice in the range of 8.7% reduction per decade. The prediction is that the sumer ice in the Arctic will completely disappear by about 2030.
Every year, the Arctic sea ice goes through an annual cycle of melting and freezing, reaching its minimum ice level in September. The lowest level of ice ever recorded took place in September of 2007. As of September 4, 2008, the amount of ice in the Arctic is above the lowest levels recorded last year but the experts suggest that the daily loss of ice is so high this year, that this year's lowest level may still surpass last year's. As can e seen in the graph below, the blue line is is getting very close to the dotted line that represents last year's ice extent. It can also be observed that the amount of ice in September is close to 4 million square kilometers, which is 50% the average level of ice over the period 1979-2000, suggesting that the complete loss of ice is not outside the realm of possibilities.
The dynamics and implications associated with the melting of the Arctic ice cap are not yet fully understood, although impacts will be felt by animals, additional climate implications and in the political realm. From the image below, the physical reduction of sea ice can be observed. One of the implications that has ben mentioned is the impact on polar bears habitat, reducing their habitat and endangering their survival. With regards to the climate, one of the dynamics is that the ice reflects sunlight back into space. As the ice disappears, the sunlight that would normally be reflected off the ice is then absorbed by the water, heating up the water. This is a positive feed back loop in that it accelerates further warming. The third broad implication is the expanding political positioning around access to the presumed resources in the Arctic ocean. This political struggle is being pursued by the major countries that ring the pole, namely Canada, Russia and the United States.
A few final notes. Because the polar ice cap is floating, its melting will not raise the level of the ocean. The key source for water that will raise the level of the oceans is the significant amount of freshwater frozen in Greenland. The ice in Green land is several miles thick, and will have a significantly adverse effect on both the sea level and the dynamics of water flow in the North Atlantic, impacting the Gulf Stream and weather patterns and temperatures for North America and Europe. Other significant ice melts are occurring in glaciers around the world, further contributing to rising sea levels. In addition, permafrost around the world is melting, transitioning a great deal of biomass from a frozen state into a non-frozen state. This biomass will be consumed by microbes that emit methane, further contributing to greenhouse gases and global warming.
The source for these images, and a great source for additional information, is the National Snow and Ice Data Center, which can be found at the following web address:
http://nsidc.org/index.html
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