Climate and the Great Lakes

Recent reports from the National Oceanic and Atmospheric Administration (NOAA) and the Army Corps of Engineers (the Corps) suggest that water levels in the Great Lakes are likely to stay at or above the long-term average over the next six months.  With the exception of Lake Ontario, lake levels are currently above the seasonal long-term average.  That average was compiled using data from 1918 through 2014.  Lake levels are subject to significant fluctuations.  The peak level, recorded in 1986, was approximately 5 feet higher than the 2013 low.

The Great Lakes are important.  Together they form the largest group of freshwater lakes on Earth, accounting for 21% of the world’s surface fresh water, by volume.  In addition, the Great Lakes make the U.S. heartland accessible to ocean shipping and provide exceptional recreational opportunities to millions.

Representatives from both NOAA and the Corps pointed out that water levels are influenced by a number of variables, with the onset of the El Nino event in the Pacific further complicating matters.  For example, similar strong El Nino events in 1982-83 and 1997-98, saw water levels react in completely opposite ways.

In looking beyond the next six months, both organizations indicated that they did not know how things will end up, not only for late next year, but for the next several years.  Long-term climate modeling suggests that despite global warming, the Great Lakes will continue to oscillate between their already-reached record high and low levels for the coming decades.

All comments and suggestions are welcome.

Walter J. Kirchberger, CFA®