A new Associated Press data analysis shows that over the past 20 years, Americans have been twice as likely to sweat through record-breaking heat rather than shiver through record-setting cold. (March 19) AP


The Great Lakes Basin has warmed more over the last 30 years than the rest of the contiguous United States — and could warm dramatically more by the end of the 21st Century, a new, first-of-its-kind study of how climate change has impacted the Great Lakes region finds.

Among the study's other findings:

  • The number of cold winter days that never reach a 32-degree high temperature could drop significantly — by almost two months under some scientifically modeled scenarios.
  • Areas within the Great Lakes Basin could see an increase of 17 to 40 extremely warm days, with temperatures above 90 degrees, by century's end.
  • More spring flooding and rainfall in extreme precipitation events could occur, disrupting agriculture and causing expensive infrastructure damage and runoff into rivers and lakes that leads to beach closings and algae blooms.
  • Some fish species will be negatively impacted, a cause for concern for Michigan's $5 billion annual sport-fishing economy.

The study was produced by 18 university researchers, most of them from institutions around the Great Lakes, including Michigan State University and the University of Michigan. It was commissioned at no cost by the nonprofit Environmental Law and Policy Center, based in Chicago, and the Chicago Council on Global Affairs, a nonprofit public policy organization.

The study looks both backward and forward, examining historical temperature data, then doing scientific modeling based on that data to come up with different scenarios for the decades to come. 

"The federal government has been stepping back from its climate change responsibilities and ignoring climate change realities," said Howard Learner, president and executive director of the center, a public interest, environmental legal advocacy organization. 

"This is a fact-based, sound science report. The facts of what's happened, in terms of temperature and impact to the Great Lakes, in terms of increased storms and ecological impacts, gives us a basis to project what will happen in the future, unless policies are changed to reduce carbon emissions and greenhouse gas emissions."

Extreme weather is one of the impacts of climate change. Overall, U.S. annual precipitation increased 4 percent between 1901 and 2015, but the Great Lakes region saw an almost 10-percent increase over that interval, with more of
that precipitation coming in unusually large events.

A few of the projected changes — at least temporarily — may be welcomed by some, such as far fewer days below freezing in the winter by the end of the century, and expanded small-mouth bass habitat ranges. Many others, however, will be undesirable: expensive flood damage to roads and other infrastructure, more extreme heat days in the summer, more sewage overflows and algae blooms in waterways, and negative impacts to other, prized fish species.

"This is one of the most serious problems humanity faces — I just say this as a scientist who's been studying this now for 30 years, and what the science is telling us," said study lead author Don Wuebbles, professor of atmospheric science at the University of Illinois and former assistant director of the Office of Science and Technology Policy under President Barack Obama.

The past data and projected climate changes come from data sets and modeling produced by the National Oceanic and Atmospheric Administration for the fourth National Climate Assessment, released last November. The assessment, which looks at the state of knowledge on climate change and its current and future impacts, is required by federal law, and submitted to Congress and the president.

"It's entirely data-driven," Wuebbles said. "We look at how well the models represent what we've already seen, so it gives us some confidence to make projections about the future. And we provide different potential outcomes, as it depends so much on what humans choose to do."

The study released Thursday "is a much more extensive look at what's going on with the Great Lakes than was possible in that National Climate Assessment," he said. "We have 17 top experts in earth and natural sciences, engineering, social sciences and economics — most from the six states bordering the Great Lakes."

Temperatures rising, less ice cover 

Though the new study projects warmer average temperatures, less ice cover on the Great Lakes and fewer freezing days by the end of the century, many skeptics — including President Donald Trump — point to winters like this one, when a polar vortex brought record-cold temperatures to Michigan in February. Lake Superior also completely froze over this winter, a rare occurrence in recent years. 

Wuebbles, however, said that doesn't mean climate change isn't occurring. 

"If you looked at the rest of the planet while that polar vortex was happening, Europe was extremely warm," he said. "Australia was breaking heat records, 120-degree days."

A warming, but still quite cold, Arctic is causing volatility in the jet stream that typically holds the colder air north of the Midwest. That volatility will cause occasional events like this winter's polar vortex, he said.

"Gradually, we'll have less snow — maybe more lake-effect snow in places, as the Great Lakes will be less ice-covered,"  he said.  Cold air moving over the relatively warmer Great Lakes often injects moisture in the atmosphere, which converts to snow as it makes it to colder landfall in the winter.

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According to the study: 

  • Between 1901-1960 and 1985-2016, the Great Lakes Basin warmed 1.6 degrees in annual mean temperature, exceeding average changes of 1.2 degrees for the rest of the contiguous United States.
  • By the end of the 21st Century, global average temperatures are expected to rise an additional 2.7 degrees to 7.2 degrees, depending on future greenhouse gas emissions.

The temperature rise in the recent past, combined with the one that could be coming if high use of fossil fuels and other greenhouse gas emissions continue, could be more than 10 degrees Fahrenheit.

Wuebbles put that in perspective.

"If you look at the last Ice Age, we had hundreds of feet of ice over where I'm sitting now at the University of Illinois," he said. "That was about 15 degrees colder than now. We're talking an increase of as much as 10 degrees by the end of this century — a very extensive change in the climate."

Winters projected to get less severe

The number of winter days with a minimum temperature less than the freezing point, 32 degrees, is projected to decrease dramatically over the century because of wintertime warming in the states bordering the Great Lakes, the report finds.

By the 2030s, the Great Lakes Basin is projected to see 15-16 fewer days where the temperature dips below freezing per year.

 The number of even colder days, when the day's high temperature does not get above freezing, are also projected to decrease, by as many as 56 days in the Great Lakes Basin by the end of the century for the higher continued greenhouse gas emission scenario and 31 days for the lower scenario.

By the end of the century, annual total snowfall over the Great Lakes states is projected to decrease by 50 percent for the higher continued greenhouse gas emissions scenario and by 30 percent for the lower scenario. This results in substantial reductions in snow cover, with days of snow depth greater than 5.9 inches reduced from the historical average of 61 days for the entire region to 19 days for the higher scenario or 35 days for the lower scenario by the end of the century.

In localized areas of the "snow belt," however, lake-effect snowstorms charged by Great Lakes that are less ice-covered will mean less of a snowfall reduction, Wuebbles said.

Summers to get hotter, more rain

Areas within the Great Lakes Basin will see an increase of 17 to 40 extremely warm days, with temperatures above 90 degrees, as annual average temperatures continue to rise, the study projects.

The already existing trend of more precipitation falling in major events will get worse, the study projects — such as the Aug. 11, 2014, deluge that brought up to 6 inches of rain to some areas of metro Detroit in just four hours. Infrastructure was overwhelmed, with more than 10 billion gallons of overflows of storm water combined with sewage into local waterways. Damage to freeways, bridges and other infrastructure totaled more than $1 billion in Wayne, Oakland and Macomb counties.

Changes in seasonal precipitation are already affecting farmers in Midwestern states, with planting delays caused by spring flooding and excessively wet soil conditions. Those same conditions lead to increased agricultural runoff, causing nutrient-loading in water bodies, a leading fuel for the annual algae blooms on western Lake Erie. It also increases E.coli and other bacteria loading in waterways, leading to chronic beach closings in areas such as Lake St. Clair.

Rising temps likely to affect sport fish

The Great Lakes and other water bodies in Michigan are already seeing rising water temperatures. From 1994 to 2013, summer surface water temperatures on every Great Lake increased — most dramatically by more than a half-degree Fahrenheit on the coldest Great Lake, Superior.

That changes how, and when, the lakes stratify into different water temperatures. And that impacts fish and other aquatic species, said Dana Infante, an associate professor in Michigan State University's Aquatic Landscape Ecology Lab.

Evidence already exists that some fish species, including bluegill, largemouth bass and brown bullhead, have expanded their ranges northward, as waters that were historically too cool for their preference no longer are, she said. 

"In this particular set of species, it could be a good thing for anglers," she said. 

But it's not good news for all fish.

"If you want to fish for trout, or cool-water species like walleye and smallmouth bass, you might have fewer opportunities," Infante said.

Cisco, a fish typically found in colder inland lakes, has a population on the decline in Michigan, Wisconsin and Minnesota, because of warming temperatures, she said.

Waters that warm earlier in the spring will lead to continued problems with fish egg-hatching and the tiny aquatic organisms upon which the young fish feed no longer syncing up, Infante said.

There are indirect impacts as well, she said. As fish move into new ranges, they will compete for available food, possibly with fish species that aren't used to competing, she said. 

"As these changes become more complicated, it's going to become more difficult for us to predict what's going to happen," Infante said.

As an example, she pointed to the different responses to two populations of Great Lakes yellow perch to rising water temperatures. In Lake Michigan near Milwaukee, yellow perch have been documented as spawning about 13 days earlier than their historic average since 1988, raising concerns about the availability of food for the hatchlings. 

In Lake Erie, yellow perch have not changed the date at which they spawn, but females are producing smaller eggs than they do in cooler waters, leading to smaller hatchlings that have less of a chance of survival.

"It's the same species, the same driver — warming water — and two different responses by the organism," Infante said.

It remains to be seen whether the fish simply adapt to their changing conditions, but conditions in a world with further climate change will work against them.

"That adaptability can change for different species, depending on if it isn't facing additional stresses like increased nutrient loads, or pollution from urbanized landscapes," she said. 

"Fish trying to adjust to a changing climate, while dealing with all of these other changes, makes adaptation to climate change that much harder."

A pitch to new governors in the region

The Trump administration has downplayed climate change's importance, removing references to climate change from the EPA and other departmental websites.

But the information in the Great Lakes regional study still has another audience of policy-makers to which it may prove useful, Learner said.

"There are five new governors of the Midwestern states around the Great Lakes, as well as new premiers in Canada," he said. "There's a new audience of bipartisan Great Lakes governors who can use sound, science-based information for policy solutions."

That includes Democratic Gov. Gretchen Whitmer in Michigan, who, in February, proposed a restructuring of the State Department of Environmental Quality to include an office of Climate and Energy.

The worst scenarios in the future modeling involve an America that largely doesn't change its ways on fossil fuel burning and greenhouse gas emissions. But Wuebbles remains optimistic that it won't come to that.

"Automakers will catch up," he said. "I understand people's attraction to SUVs; I drive a plug-in, hybrid SUV. We're getting to the point where we can have electric SUVs — we're just in a transition phase.

"I expect emissions to greatly change for the better over the next few decades."


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