A lot of people are probably OK with leaving their parkas behind and enjoying balmy weather that's predicted across much of the Midwest this week.But the Great Lakes take a beating from these on-again, off-again winters.They will be the norm instead of the exception if predictions about global warming come true, according to Jeff Reutter, director of the National Oceanic and Atmospheric Administration's Ohio Sea Grant program and the leader of Ohio State University's Stone Laboratory on Lake Erie's Gibraltar Island.Even if this had been a normal winter, the lakes would be under stress. The largest one, Lake Superior -- which holds more water than the other four combined -- last year was the lowest it has been since its low-water record was set in 1926.Lakes Michigan and Huron -- hydrologically viewed as one lake that feeds Lake Erie -- approached their low-water mark set in 1964, according to NOAA's Great Lakes Environmental Research Laboratory records, which date to 1860.Eighty percent of Lake Erie's water comes down the Detroit River from Lake St. Clair and those three upper Great Lakes.But the story doesn't end there. Although Lake Erie only receded to its historic average in 2007, scientists believe it's headed for trouble if it doesn't get a lot more ice soon.Many people believe the lakes evaporate more in the summer. They don't.Winter is the cruelest time, with zigzagging temperatures and high winds causing the most problems.Evaporation is greatest during the winter because of the greater difference between air and water temperatures, said Cynthia Sellinger, deputy director of NOAA's Great Lakes Laboratory.Ice is the knight in shining armor as it seals the lakes, halting evaporation.Stiff winds keep the water from freezing, and churn the lake's water, allowing warmer water below the lake's surface to rise to the top. Mud in shallow areas is stirred up and becomes suspended in the water. The dirt particles prevent good, thick ice from forming.Jia Wang, a NOAA ice climatologist, said Lake Erie's ability to hold water this winter "will depend on the ice cover.""As long as there's open water, the water will receive heat from the atmosphere and solar radiation," he said.The only real freezing so far is near the Lake Erie Islands, the first area where ice normally forms. The amount out there now would have been formed by mid-December several years ago."But is it good enough? The answer is no," Bud Gehring, a South Bass Island fishing guide, said.He and another South Bass guide, John Hageman, said the ice is so spotty they need to wait before taking people out on it.Gehring, who has been fishing Lake Erie since the 1960s, said he wouldn't be surprised if this winter's ice fishing is a bust.To the novice, all ice is the same. But not to savvy fishermen.Hageman said that although there's now eight inches of ice near the islands -- generally thought of as the minimum thickness for safety -- that doesn't mean it's stable.Gehring said anything with mud particles in it isn't reliable."That's bad ice," he said. "That's punk ice. You don't want that."Hageman said there was limited ice fishing on Lake Erie in 2002, 2004, and 2006 because of the lack of good, thick ice.Last year, ice fishing was great -- but only for a brief time.Fishermen got out onto the lake in mid-February. They found fish biting but had to get off the lake, as they normally do, by mid-March, Hageman said.So they had a month. Years ago, they would have had nearly three months, he said."We're really not in normal times," Sellinger said.Although a new report she co-authored with other researchers from NOAA and Duke University starts off by acknowledging that Great Lakes water levels have fluctuated over thousands of years, it says lower water levels "are consistent with many global climate change scenarios."It also raises questions about the current evaporation rate.Lake levels have gone in 30-year cycles since 1860, according to NOAA's records.But the report, a peer-reviewed paper that made the Jan. 15 cover of Environmental Science & Technology, said it's possible the "low levels may be sustained" by global warming.(Contact Tom Henry at thenry(at)theblade.com)(Distributed by Scripps Howard News Service, www.scrippsnews.com.)
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