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Don Sawruk, president of Edison Sault Electric, inspects pieces of pine that have broken loose from the lining of the plant's water canal.Warmer climate will change Lakes
Some say global warming will lower lake levels; others fear devastated crops
The hydro plants at Sault Ste. Marie, including Edison Sault Electric, run only at peak hours when lake levels get low because of international rules that control how much water can flow out of Lake Superior.
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Global warming could suck enough water from the Great Lakes to send their levels plunging several feet, wiping out wetlands and wounding commercial shipping.
Or the water line could rise a little.
Torrents of rain and hordes of new bugs brought here by a reshaped climate could devastate the region's farms.
Or soybean harvests could be better than ever.
One way or another, scientists say it's certain the Great Lakes will feel the effects of a changing climate that's slowly raising temperatures around the globe. They might be feeling the effects already. But where and when and how those changes will play out have proven almost impossible to predict.
"When you look on a regional scale, we can feel pretty confident that temperatures are going to increase and precipitation is going to increase, ... but we're still at the 'I don't know' stage when it comes to the full extent of the consequences," said Brent Lofgren, a climatologist who studies climate change at the government's Great Lakes Environmental Research Laboratory in Ann Arbor.
To predict how global warming will transform the Lakes, scientists feed their estimates of how the climate will change into computers that test them against everything from rainfall to wind speeds and the effects plant life has on water levels. The results have been all over the map.
Studies on the impact of climate change don't just disagree, they outright contradict one another, though almost all contend that climate change will have some impact. Among the effects various studies have predicted:
• Most of the time, computer models predict that lake levels will drop by a foot or more during the next century because warmer weather will cause more water to evaporate off the Lakes. One suggested they could fall up to 8 feet. But a few newer models suggest lake levels could actually increase a little because the climate is likely to get wetter, too.
• One study hinted at a bonanza for soybean farmers; thanks to a better growing season, their harvests could double. Another study suggested the new climate would bring new pests and heavier bouts of rain, which would hurt farming.
• Snow Belt cities such as Buffalo and Syracuse, N.Y., could get less snowy, because lake-effect storms that bury them every winter could lose some of their punch.
• Changes in water temperatures could cost some cold-water fish their habitats and force other fish to relocate. It could also reduce stirring effects in the water that carry oxygen to different parts of the lakes.
Even figuring out how the climate will change hasn't been easy, though most of the studies now point toward warmer, wetter weather. One, by the Union of Concerned Scientists, suggests that by the end of the century, summertime in Illinois will feel a lot like summertime in east Texas today.
For years, whether that change was occurring at all was a subject of debate. Now scientists largely agree some transformation is taking place. And there's a growing sense that people are mostly to blame. That's mainly because of releases of carbon dioxide and other "greenhouse gases," many caused by burning fossil fuels, that trap heat in the atmosphere.
Still hotly contested is what to do about it.
The Canadian government has signed a United Nations-brokered agreement known as the Kyoto Protocol, which limits emissions of gases thought to cause global warming. The U.S. government has not, fearing it would deal too great an economic blow.
"We know it's happening, but I don't believe Kyoto was the solution," said Dennis L. Schornack, who was appointed by President Bush to head the U.S. side of the International Joint Commission, which monitors issues in the Lakes. He said industries have already made huge voluntary cuts in greenhouse gas emissions.
If global warming does suck water out of the Lakes, it could leave coastal wetlands high and dry, wiping out areas that help filter pollution out of the Lakes and provide a breeding ground for fish and wildlife.
It could force Great Lakes freighters to lighten their loads to avoid running aground in the lakes' shallow channels. And it could dim the amount of electricity produced by the region's hydroelectric plants.
The hydro plants at Sault Ste. Marie run only at peak hours when lake levels get low because of international rules that control how much water can flow out of Lake Superior, said Don Sawruk, president of Edison Sault Electric, which runs one of the generating stations there. The massive U.S. and Canadian power plants near Niagara Falls are subject to similar restrictions.
Part of the difficulty in measuring what global warming could do to the Great Lakes is picking out its effects among the normal fluctuations in temperatures and water levels, said Thomas Croley, a hydrologist at the Great Lakes Environmental Research Laboratory.
Some of the changes could be taking place already, Croley and other researchers said, but the only way to see them for sure is with hindsight, over a long period of time.
Fishermen secure their boats to the discharge wall at the Edison Sault Electric plant, fishing for Atlantic salmon that return to the plant where they were raised. Global warming may affect fish habitats.
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The Detroit News.
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