Scientists determine the Great Lakes are nonrenewable

By Derek Davis – earth.com

Lakes Superior, Michigan, Huron, Erie, and Ontario together hold about 21 percent of the fresh surface water on the planet. The five lakes spread across more than 94,000 square miles (243,000 square kilometers) and meet roughly 9,000 miles (14,500 kilometers) of shoreline shared by eight U.S. states, one Canadian province, and dozens of tribes and First Nations.

That share is not an allowance the lakes earn back each year. Retreating ice sheets left it behind, and almost none of it returns.