The Great Lakes Environmental Research Laboratory in Ann Arbor, Michigan released data recently which indicates ice coverage is steadily decreasing on the Great Lakes. According to the National Oceanic and Atmospheric Administration (NOAA), ice coverage across the Great Lakes has decreased over thirty percent in the last four decades.
Concerns are high regarding the Great Lakes’ decrease in ice coverage as it is the world’s largest system of freshwater lakes. Due to the lesser ice coverage, there is greater open water which can lead to a number of issues. In addition to open water is the increased likelihood of evaporation diminishing the water levels in the lakes.
The deeper parts of the lakes are where the largest decrease of ice coverage has been noted in Lake Erie, Huron, Michigan, Ontario and Superior. Ray Assel, a researcher for the laboratory in Ann Arbor, stated: “The deeper the water, the greater the heat storage from summer, and it freezes later than the shallow areas. Now, increase the air temperature and the lake takes in more heat and stores it longer, to the point that many of the mid-lake areas are freezing over less.”
Shore areas have also experienced decreased ice coverage, but not to the extent that deeper areas of the lakes have. This shore ice actually protects the coastal areas during the winter and without the coverage some areas may see degradation and other issues.
In addition to the aforementioned problems associated with decreased ice coverage, fish and recreation are also being affected. Spawning fish can be impacted when their eggs are not protected by the ice coverage- instead the eggs are harmed by waves in the uncovered areas of the lakes. Recreation is also harmed when ice is either nonexistent or too thin to enjoy snowmobiling, ice fishing or even ice skating on the lakes.
Environmental issues are not the only concern. Recently, 134 fishermen were rescued by the U.S. Coast Guard when a few mile-wide piece of ice broke off in Lake Erie, stranding the fishermen. Not only were lives in danger but the rescue cost the Coast Guard nearly $250,000. However, many shipping companies see less ice as a potential profit– enabling them to ship for more time out of the year than usual.
