NOAA Great Lakes Environmental Research Laboratory (GLERL) scientists recently shared their insights on the great lakes water levels in an article in Science Magazine (March 7, 2014, issue).
In the past, water level fluctuations have been the result of varying amounts of precipitation. Now with global climate change, new factors are driving level changes.
A summary of their work is available on line at the NOAA OAR Research website. Or read the article in Science for a thorough discussion of their work and findings.