The 2014 National Climate Assessment, the single largest attempt to compile the science and data concerning climate change’s impact on the United States, was released on Tuesday. For the American Midwest, the report comes with some stark projections: more extreme heat, along with heavier downpours and flooding, and serious consequences for the ecosystems of the Great Lakes and for large portions of the region’s economy.
“Climate change is really the single largest issue that we’re dealing with not only as a country but particularly here in Michigan,” Nic Clark, Michigan Director of Clean Water Action, told ThinkProgress. “It’s impacting our way of life here and how people make a living.”
Temperatures in the Midwest have already risen over 1.5°F from 1900 to 2010, with the increase speeding up in the last 30 years.
The NCA bases its projections on whether we make significant cuts to the carbon emissions that drive climate change, offering a low-emission and high-emission scenario. The former, which assumes a more coordinated global economy going forward and significant cuts to carbon emissions, already projects another increase of 5.6°F from the 1979–2000 average by the end of the century. For the high-emission scenario, which assumes a more business-as-usual path for the global economy and humanity’s atmospheric carbon output, the projection for 2100 is 8.5°F.
Here’s how the effects of that warming will shake out for Michigan and the rest of the Midwest:
Crop Reductions. For the Midwest’s agriculture, climate change will bring a mix of competing effects — some good, some bad. Higher average temperatures bring a longer growing season, but that also increases the risk of sudden cold snaps in the spring. Michigan’s $60 million cherry crop industry took a massive hit in 2012 thanks to an unexpected freeze.
“We had a 90 percent crop loss in our cherry and apple crops,” Clark said. “That has a huge economic impact.”
Heat waves during pollination can cut down crop yields, and seasonal periods of hotter temperatures tend to be accompanied by drier conditions, which are especially likely to increase in the region’s southern portion around Missouri. What it all washes out to is lower crop yields as warming goes up:
More Drought And Heavier Rains. The Midwest is not nearly as dry as the drought-stricken Southwest, but as climate change accelerates, already dry regions will likely get drier and wet regions wetter. The NCA cites studies showing a 10 to 20 percent increase in spring and winter precipitation by 2099 under the higher emission scenario, with no attendant changes in the summer and fall.
But those increases won’t be evenly spaced out over time. Rather, drought duration will actually become longer, with the added precipitation packed into more isolated bursts and deluges. Meanwhile, precipitation for the Midwest has already shot up 37 percent since 1958.
All of this means more flooding for the region. “We’ve had some of the state’s most historically high flash floods,” Clark said. “There was a rain event [in Grand Rapids, Michigan] that was so heavy that the infrastructure that exists there to handle the storm water couldn’t take all the rain at once. The Grand River overflowed, and the office buildings, their first floor windows, you could see fish swimming by out of the first floor windows. Right downtown.”
Increased flooding can lead to sewer overflow, which means contamination of rivers and streams and the Great Lakes. The runoff from the downpours also carries more fertilizers and other chemicals into the lakes as well. As a result, the west side of Lake Eerie is now often overrun by algae blooms during the summer.
More Heat Waves. Heat waves could also become a problem for the Midwest as global warming ramps up. Most of the housing in the region is designed for colder temperatures, so buildings tend to hold heat in rather than shed it.
“We’ve seen some of the highest temperatures on record here in the state of Michigan,” Clark said. “We’ve had to open up cooling centers across the state for the low-income and elderly so they can have a healthy space to beat the heat.”
The climate assessment cited one particular study that projected business-as-usual carbon emissions over the next hundred years could drive up heat wave deaths in Chicago alone by 2,217 per year. By comparison, the city’s heat waves in 1995 and 1999 killed 700 and 114 people, respectively.
Danger For The Great Lakes. Water levels in the Great Lakes have fallen significantly over the last decade or two. According to Clark, harbors for 26 communities along Michigan’s shoreline had to be dredged in 2013 to keep shipping lanes open. The NCA noted that projections for water levels going forward are uncertain under the various emission scenarios, though the algae blooms and the higher water temperatures could also harm the fish populations that play a major role in Michigan’s economy, for example.
In another likely sign of climate change, ice coverage on the Great Lakes dropped dramatically from the 1973–1982 period to 2203–2013. Less ice can also leave shorelines more vulnerable to floods and erosion.
According to the National Climate Assessment, the Midwest emits 22 percent more greenhouse gases per person than the national average — mainly thanks to its reliance on burning coal for electricity. Combined with the higher temperatures, that means more air pollution and ozone, which means more health problems for Midwesterners.
The region’s electrical grid is also older and not entirely reliable, which leaves it vulnerable to physical damage from extreme weather, and more likely to fail as the heat drives up electricity demand.
As clean energy gains popularity in the region, the Midwest has one quarter of the United States’ wind capacity and also a sizable potential for solar, but still has a very long way to go in cleaning up its electrical generation.