The loss of a great ice shelf from Canada's northern territory is another example of the consequences of climate change. According to scientist Derek Mueller from Trent University in Ontario, the Markham Ice Shelf – approximately 19 square miles in area – broke off from the Canadian Arctic Ice Shelf in early August 2008. This event, coupled with increasing ocean and atmospheric temperatures, amplifies the likelihood that the formation of sea-ice in the winter season will not be enough to offset the loss of sea-ice during these summer months.
Ice shelves are large platforms of thick ice that are the result of thousands of years of snow accumulation and freezing water. They float on the ocean's surface, but are connected to land, acting like shelves jutting out over the ocean. Much of the sea-ice in the northern hemisphere is connected to land in just this way; but increases in ocean temperatures make them vulnerable to breaking away from land and being destroyed.
Arctic Ice Shrinking
Recent studies have shown that Arctic sea-ice has been thinning and decreasing in area for the past three decades. An article published in 2008 in the Journal of Cold Regions Science and Technology titled, “The Rapid Decline of the Sea-Ice in the Russian Arctic,” reports that 30 years worth of data confirm the annual averages of the sea ice extent in the northern hemisphere have decreased by about 8%.
Data from this study recording the loss of sea-ice during summer months are even more striking. From 1979 to 2005, sea-ice extent during the month of September – a time when the Arctic transitions from its summer climate to its winter climate – decreased by 25%. Moreover, according to J. Rodrigues - the author of this article - from 2001 to 2007 the decline in the September sea ice extent has been faster than in any period since 1979, highlighting the dramatic shift in Arctic climate change within the past decade.
The loss of sea-ice could have global climate-changing implications. The albedo of a hemisphere directly relates to the extent of sea-ice coverage – the more ice cover, the higher the albedo. The albedos of the northern and southern hemispheres are extremely important for reflecting solar radiation back into space, which helps to regulate the temperature of our oceans and atmosphere.
The Loss of an Ecosystem
According to Muller, the Markham Ice Shelf had half the biomass for the entire Canadian Arctic Ice Shelf ecosystem. With the loss of the ice shelf, this ecosystem is negatively impacted. Algae and microbial life that are unique to the Arctic and able to thrive on these ice shelves are lost as the shelves melt away into the ocean. This event marks the verge of extinction for these cold-tolerant ecosystems.
Sources:
“4,500-year-old ice shelf breaks away”, CNN
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