If the oceans rise substantially due to global warming, will the St. Lawrence River cause the Great Lakes to rise?
Bob Kozlik, Riverwoods
The Great Lakes are land-locked bodies of water that drain via the St. Lawrence River into the Atlantic Ocean. Lake Ontario, the lowest of the Great Lakes, sits 246 feet above sea level. It (and the other four Great Lakes at elevations of 571 feet for Lake Erie, 577 feet for Lakes Michigan/Huron and 600 feet for Lake Superior) will not be affected by rising oceans, whose rise will be only about one foot by the year 2100. Oceans have been rising at an average rate of 0.14 inches per year in recent years, but the rise is expected to increase slightly in coming years. The levels of the Great Lakes fluctuate a few feet in cycles that are independent of ocean levels.