Great Lakes are a chain of freshwater lakes located in eastern North America, on the Canada – United States border. This group consists of Lakes Superior, Michigan, Huron, Erie, and Ontario, and they form the largest group of freshwater lakes on Earth. Great Lakes are experiencing serious decline in ice cover due to warmer years. In the last 40 years Great Lakes lost 30 % of its ice cover, which is worrying information because according to National Oceanic and Atmospheric Administration this leaves Great Lakes open to evaporation and lower water levels.
Results of their study showed that although the total amount of ice cover can vary substantially from year to year, the overall ice coverage on the world's largest system of freshwater lakes is diminishing, especially in the deepest, middle portions of Erie, Huron, Michigan, Ontario and Superior.
The reason why deep water is mostly affected is because of the fact that the deeper the water, the greater the heat storage from summer, and it freezes later than the shallow areas. As one of the researchers Ray Assel said: "Now, increase the air temperature and the lake takes in more heat and stores it longer, to the point that many of the midlake areas are freezing over less."
On the long run this could have serious negative impact though there could be short-term advantages because this trend could make shipping possible in the winter months.