Early risers

North America’s Great Lakes are reaching their spring high-water levels a
month earlier than they did when records began in 1860. Levels normally rise in
the spring as snow melts, but regional temperatures have been rising for the
past 90 years, and winter ice cover has been shrinking. “The changes are
consistent with predictions made by global climate models,” John Lenters, a
climatologist at the University of Wisconsin in Madison, told an International
Association for Great Lakes Research meeting last week.