Great Lakes Article:

Arctic melt won't flood the Great Lakes
But there are other climate shift dangers
By Anita Weier
Capitol Times (Madison, WI)
Published November 29th, 2004

If you've been wondering whether rapidly melting ice in the Arctic will eventually flood Green Bay and Bayfield, stop worrying.

You see, the Great Lakes are higher than the Atlantic Ocean, about 600 feet higher at Lake Superior, said Michael Donahue, president and chief executive of the Great Lakes Commission. So the water flows downhill to the ocean, not uphill to the lakes.

It is possible that a higher Atlantic might affect the St. Lawrence River in terms of where fresh water becomes brackish and then becomes salt, he said.

However, the much-publicized Arctic Climate Impact Assessment stressed that Arctic ice is melting rapidly because the climate is warming more rapidly, and this climate change will affect the Great Lakes profoundly in other ways.

"Global climate change generally indicates a significant rise in ocean levels, but could potentially result in precisely the opposite effect for the Great Lakes," Donahue said.

The Great Lakes Commission, a public agency whose members include the eight United States and two Canadian provinces that border the lakes, works to promote sound public policy decisions on issues affecting the Great Lakes.

"In general terms, researchers and the policy leaders in the Great Lakes regions are increasingly concerned about the effects of climate change and climate variability on the Great Lakes water resources and how we use them," Donahue said.

"There has been a fair bit of research looking at global climate change and what its effects on the Great Lakes could be. Global warming has a subtle but pretty profound impact on precipitation patterns. With much less ice cover on the Great Lakes, they can evaporate year-round. Given that, as well as other anticipated changes in precipitation patterns, over time the Great Lakes could be permanently lowered by several feet."

Also, water availability and lake levels have a direct impact on environmental quality and economic productivity in the Great Lakes region, he said.

"Even slight reductions or increases in lake levels can have significant impact, both positive and negative. And we also know that there is a strong linkage between water quantity and water quality. The Arctic report is another reminder that any policy we consider concerning the long-term use and management of water resources has to accommodate issues of climate change. It is a huge mistake to ignore possible impacts of climate change, which can overwhelm other considerations."

John Magnuson, professor emeritus at the University of Wisconsin-Madison Limnology Department, said it is vital to remember that the climate is changing everywhere, not just in the Arctic.

"The major mode of action is the increase in greenhouse gases, so that warming is occurring globally and in Wisconsin. The Great Lakes are affected by changes in temperature and precipitation," Magnuson said.

He agreed with Donahue that the level of the Great Lakes is not directly affected by sea level because they flow downhill through the St. Lawrence River.

"The Great Lakes have fluctuated a lot over the last 100 years. There is no long-term trend in water levels," Magnuson said. "They are high for 10 or 15 years and then low. We are in a low period now. And in the future, the climate scenarios are suggesting there would be a lower Great Lakes level."

"The main message about the Arctic is that it is warming about twice as fast as the rest of the world."