Great Lakes states are warming faster than the rest of the country, more flooding is in store, new report says
The Great Lakes — already feeling the impacts of climate change — face more threats in the coming decades, ranging from increased flooding and higher temperatures to deteriorating water quality and fluctuating lake levels.
Scientists predict the impacts will affect the ecology of the lakes, stress water infrastructure systems and pose problems for recreation. The region is already warming faster than the rest of the country.
A report released Thursday, largely from scientists at Midwestern universities including the University of Wisconsin-Madison, highlights current and future effects of climate change on the Great Lakes.
It follows other studies, including the federal government’s national climate assessment released last fall, showing how global warming is already affecting the United States.
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Don Wuebbles, a professor of atmospheric science at the University of Illinois and the lead author of the report, said the Great Lakes have faced significant impacts over the past 200 years.
“Climate change is now adding more challenges and another layer of stress,” Wuebbles said in a statement. “This report paints a stark picture of changes in store for the lakes as a result of our changing climate.”
The findings are an amalgamation of climate-related research and its impacts on the Great Lakes.
A key finding: The region has warmed more than the country as a whole.
Between 1901-1960 and 1985-2016, the temperature of the Great Lakes basin increased 1.6 degrees in annual mean temperature compared to a 1.2-degree increase for the rest of the continental U.S.
By the end of the century, global average temperatures are projected to rise by 2.7 degrees to 7.2 degrees, depending on how much greenhouse gas emissions are produced. The authors said the Great Lakes will experience corresponding changes.
Temperature changes will differ within the region. On average, the Great Lakes regions are projected to see slightly higher increases in the summer than in the winter.
But these seasonal changes are expected to be reversed in the northern Great Lakes, where winter temperatures will rise more than summer's. The northern Great Lakes states could see a month or so fewer days where the temperature does not get above freezing.
Some of these findings include research from the Wisconsin Initiative on Climate Change Impacts at UW-Madison.
“As I read through (the report), it’s a comprehensive assessment of impacts of climate change on the Great Lakes, not only on the lakes themselves but to a certain extent on regions around the lake as well,” said Daniel J. Vimont, a climate scientist at UW-Madison, whose work is included in the report.
The report was commissioned by the Environmental Law & Policy Center of Chicago and the Chicago Council on Global Affairs — and thus has a political context.
The center says that it will use the findings to highlight climate impacts on the region.
In Wisconsin, it says it will provide the information to Gov. Tony Evers, a Democrat, and the Legislature, which is controlled by Republicans, to push for more solar and wind development, improve energy efficiency, accelerate electric cars and reduce runoff that pollutes the lakes and their tributaries.
Solar and wind development are growing in Wisconsin, driven largely by falling prices. But lawmakers in recent years have been wary of efforts calling for a larger hand by state government.
In a sign that water issues are a growing concern in the state, Evers' two-year budget includes more money and attention to limit runoff pollution. Meanwhile, a legislative task force held its first hearing Wednesday in Madison on water quality issues.
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The report’s findings are separate from the policy recommendations.
An outcome of rising temperatures is that a warmer atmosphere contains more moisture, which the report said would increase the frequency and intensity of heavy rains and snow.
This is especially true for the Great Lakes states. Nationally, from 1901 to 2015, annual precipitation rose 4 percent. But in the Great Lakes states, precipitation rose nearly 10 percent, with more of it coming from large storms.
The report projects precipitation patterns will change, with wetter winters and springs, and by 2100, summer precipitation should decrease by 5 percent to 15 percent for most of Great Lake states.
This could mean disruptions for agriculture, which is already seeing a shift north in the Corn Belt, due in part to warmer temperatures. Wetter springs could delay planting and put crops at risk in hotter and drier conditions later in the season. This could increase demand for irrigation, which could tax groundwater supplies, the report said.
More precipitation could also spur increased runoff, sending more nutrients and bacteria into the lakes. The influx of nutrients and higher water temperatures could lead to more algal blooms, such as those in Green Bay where scientists are tracking a seasonal "dead zone" where there is virtually no oxygen. Municipal water systems might also face higher costs in removing the nutrients, the study found.
How all of this will affect lake levels is unclear. The report noted that scientists' projections on lake levels have “undergone a major change of course” in recent years.
The old paradigm: There would be large drops in lake levels from evaporation. More recent research has shown smaller drops on average and the possibility that there could be a small rise in lake levels through the end of the century.
“There is a lot more uncertainty around that initial projection,” UW's Vimont said.
Read the report