This is the blog site for the Intro to Environmental Policy and Planning course (UAP 3354) at Virginia Tech.
Monday, March 23, 2009
Great Lake’s Ice Cover is Declining
According to scientists of the National Oceanic and Atmospheric Administration, “ice cover on the Great Lakes has declined more than 30 percent since the 1970s, leaving the world’s largest system of freshwater lakes open to evaporation and lower water levels.” This is happening especially in the deepest, middle portions of Erie, Huron, Ontario and Superior. The ice is diminishing in these parts the most because the deeper the water is, the more heat it can store from the summer, which makes it freeze later than the shallow areas. The lack of ice increases solar input which makes the deep waters of the lake get warmer. This leads to less ice cover, which leads to more evaporation, which leads to shallower waters that warm faster and the cycle starts all over again.
The amount of ice cover can vary from year to year. It is said that, “global climate change and regional climate patterns are competing over the Great Lakes.” But the reality is that no one thing takes over. In fact, this winter had a very large and long-lasting ice cover at the Great Lakes but the overall trend is still showing a decline. Having the global climate change and regional climate patterns different makes it hard to separate the two. This might be why some people don’t believe global climate change is happening, even though it is. Proof of temperature elevation can be showed at Lake Superior. Researches found that the lake’s surface temperate has warmed by 2.5 degrees Celsius since 1979.
Ice loss can cause a lot of problems at the Great Lakes. Eggs of fall-spawning fish can be destroyed by winter waves from an open lake, which could affect certain species. Erosion of the coastal areas can also occur because the shore ice is unprotected. Less winter recreation on the lakes will have to take place. Just last month, a miles-wide ice floe broke off from Lake Erie’s shoreline. It trapped 134 fishermen offshore who had to wait for hours to be rescued by helicopters are air boats that can glide across the ice.
Even though the ice cover is different from year to year, the overall coverage on the lakes is decreasing more and more. This could certainly be an effect from global climate change so the research needs to continue on the lakes to help them before it is too late.
in species. Erosion of the coastal areas can also occur because the shore ice is unprotected. Less winter recreation on the lakes will have to take place. Just last month, a miles-wide ice floe broke off from 
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