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,
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,"
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,"
"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."