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, according to scientists associated with the National Oceanic and Atmospheric Administration.In other news, a new study shows that timing is everything:
Lake Superior last froze over in 2003. It has now, again, frozen over. The frequency of freeze overs has historically been around once every 20 years. Now, in the last decade, we have seen two freeze overs.