Warming blamed for Great Lakes decline

Martin Mittelstaedt in the Toronto Globe and Mail: The water levels of Lake Huron and Lake Michigan have been falling steadily compared with those on Lake Erie, and no one knew why. But a major report financed by the U.S. and Canadian governments suggests an answer: The fingerprints of climate change are starting to be found in the Great Lakes, the world's largest body of fresh water, causing a discernible drop in their levels.

The report, released Tuesday, estimated that Lake Huron and Lake Michigan have fallen about a quarter metre relative to Lake Erie since the early 1960s, with 40 to 74 per cent of the reduction due to recent changes in precipitation patterns and temperatures. The alteration in climate is “the most significant factor” in the water level drop and “could be a more substantive issue for the future on the Great Lakes,” said Ted Yuzyk, Canadian co-chair of the International Upper Great Lakes Study Board, which compiled the report.

Previous studies have projected a decline in the amount of water in the Great Lakes due to climate change, but the board is the first to suggest the trend is already happening. The fall in water levels is attributed to such factors as less precipitation and the persistent, long-term decline in the lakes' ice cover each winter.

The report said generally drier weather and drought-like conditions from 1998 to 2008 in the central part of North America led to a drop of about 20 per cent in the quantity of water flowing into Lake Huron and Lake Michigan, compared with the average since 1948….

The 12th hole at Arcadia Bluffs Golf Club, Arcadia, Michigan. Lake Michigan is on the left. Shot by Dan (golfpro1), Wikimedia Commons via Flickr, under the Creative Commons Attribution 2.0 License.