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As the climate changes, what’s in store for Iowa?
Researchers attempt to predict what Iowa will be like decades from now
The Gazette offers audio versions of articles using Instaread. Some words may be mispronounced.
Three decades ago Iowa State University published a cheeky description of an invasive plant that was of no concern to Iowans because it can't flourish this far north.
"Imagine a horror movie depicting a plant species that grows everywhere, consuming cars, buildings, and everything in its path," the article by ISU Extension and Outreach said.
The fear-inducing weed is kudzu, a vining plant from eastern Asia that was briefly coveted in the South as livestock feed. It can grow about a foot per day and produces pleasant smelling flowers and pea pods.
But it is unwieldy. Left unchecked, it "kills or degrades other plants by smothering them under a solid blanket of leaves, by girdling woody stems and tree trunks, and by breaking branches or uprooting entire trees and shrubs through the sheer force of its weight," according to the Iowa Department of Natural Resources.
Kudzu lore includes a warning to be careful where you park your car, lest it disappear from sight.
Thirty years ago Iowa was too cold for the plant. But now?
"I have found a couple instances of kudzu in our southern counties," said Jim Coffey, a forest wildlife biologist for the DNR.
While Iowa — and other upper Midwest states — have been billed as havens for climate change, the area is facing challenges. The changing climate is expected to make Iowa more palatable to certain plants, insects and animals that had long eschewed its cold winters.
Those climate change effects and others — such as trouble for agriculture and human health — are among the topics that will be discussed as part of the Iowa Ideas free virtual conference, hosted by The Gazette on Oct. 10 and 11.
Warming has accelerated
Iowa's average temperatures have risen by more than a degree since the early 1900s, due in large part to greenhouse gas emissions from burning fossil fuels.
The warming trend has accelerated in recent decades, said Justin Glisan, the state climatologist. Average temperatures are increasing at about three-tenths of a degree Fahrenheit per decade.
Much of that increase is higher nighttime lows, and the months of winter and fall are warming more quickly than other times of the year. There is not a discernible trend in daytime highs, and summer temperatures have been stagnant, Glisan said.
The Midwest is in what’s referred to as a "warming hole" — a region that hasn't followed the increasing temperature patterns of those in surrounding states. The cause is believed to be rooted in increased temperatures in water of the Gulf of Mexico that have resulted in more water vapor in Iowa's and surrounding states’ atmosphere.
"You get this big dome of moisture over the Gulf, and then in the evening this low-level jet (stream) increases, and it shoots that air directly into the Midwest," said Gene Takle, a longtime climate researcher at Iowa State University who is a co-author of a comprehensive climate assessment for Iowa that may be released late this year.
The result has been increasingly intense nighttime storms that help depress daytime temperatures. But the warming hole anomaly in Iowa is not expected to persist. It might collapse in the coming decades and accelerate the state's temperature rise, Glisan said.
The warmth and increased air moisture has led to more thunderstorms and heavier rainfall across narrower areas. In recent years there have been areas of Iowa with significant drought adjacent to areas that had plenty of soil moisture, according to U.S. Drought Monitor reports.
The year 2018 was the wettest year on record for the northern third of the state, but southeastern Iowa had extreme drought — the second-to-worst dryness classification.
The wet and dry conditions also have swung to extremes over longer periods, Glisan said. The four-year period from 2007 to 2010 was Iowa's wettest, which was followed by widespread pervasive drought from 2011 to 2013. Then the single-wettest years on record, 2018 and 2019, were followed by the state's longest drought in about 50 years, which ended in May.
"We're seeing extended periods of either extreme," Glisan said.
Derechos — the straight-line windstorms that can last for hours, or even days — had previously been known to occur in Iowa about once every other year. But they have been about twice as frequent in the past five years, including the one in August 2020 that devastated Cedar Rapids and was estimated to have caused about $11 billion worth of damage along its 700-mile, multistate path.
Iowa also has had a record number of tornadoes this year, surpassing the previous high mark of 121. Those statistics won't be finalized until the end of the year.
While the weather has worsened, the mitigation of greenhouse gas emissions has slowed in Iowa in recent years, said Charles Stanier, a University of Iowa researcher who studies their effects.
"We were sort of a leader when we were really ramping up wind turbine construction," he said. "Now we've kind of plateaued."
Predicting the future
The climate assessment that Takle is compiling with the help of many other researchers is not yet finished, but he gave a glimpse into what it likely will contain.
Some of it will mirror predictions made by experts in other states, including Nebraska and Illinois. They largely focus on similar broad topics that include:
Agriculture: "Iowa has the luxury of kind of being in the center of production," Takle said, but that might change with warming temperatures.
It's likely that yields have benefited in some ways from the changing climate. The growing season has elongated, and farmers in some parts of the state — namely central and northeast Iowa — have had more rain.
At some point those benefits might shift when the heat is too intense and winds and flooding destroy crops too often. It might be more difficult to keep poultry and livestock cool.
"When you look at the total agricultural production, the projection is that by 2040 we will have lost all of the (economic) gains from yields and production that we have gained since the 1980s," Takle said.
The Nebraska assessment — published in 2014 by researchers at the University of Nebraska-Lincoln — predicts declines in crop and livestock production due to diseases, pests and weeds: "Animal productivity is optimized within narrow environmental conditions."
The Illinois assessment predicted that heat and drought would reduce corn yields by midcentury, and that soybeans would initially benefit from more carbon dioxide in the environment but would encounter long-term yield declines.
"Illinois is expected to face a much different climate than any experienced in the state’s history, and agriculture is likely to face significant hurdles adapting to this new climate," according to the assessment, which was published by The Nature Conservancy in Illinois in 2021.
Human health: Illinois researchers predict an increase of heat- and flood-related illnesses and injuries, an expansion of parasitic insects, more allergens, and added stress that will affect people's mental health.
"When agriculture is affected, a lot of people get under stress," Takle said.
Adding to that stress might be extreme weather events, wildfires and poor air quality, Nebraska researchers concluded, which will have greater effects for children, seniors, those who are impoverished and other vulnerable populations.
Ecosystems: "Landscapes and seascapes are changing rapidly, and species, including many iconic species, may disappear from regions where they have been prevalent or become extinct, altering some regions so much that their mix of plant and animal life will become almost unrecognizable," Nebraska researchers concluded.
Temperature increases have already altered plant hardiness zones, which are used as a guide especially for planting trees. Some existing trees might benefit from the increases while others will be harmed.
Illinois researchers predict that warmer water temperatures also will alter how aquatic species grow, survive and reproduce.
It’s unclear whether climate change or a persistent northward expansion has caused this, but armadillo sightings in Iowa have increased, said Coffey, the DNR wildlife biologist.
Iowa has long been predicted to be on the northern edge of the leather-backed mammal’s habitable zone, and Coffey has found evidence of the creature’s attempts to stay for the winter in recent years — some residents have reported armadillo carcasses in the spring.
The DNR began tracking reports of armadillo sightings about eight years ago when reports were on the rise, and it was about that time that Coffey’s mother called him about a strange-looking animal she found. She thought it was perhaps a hairless opossum.
“If my mother can see an armadillo in Iowa, we should probably document it,” Coffey said.
Sightings so far this year total 39, up from about 27 in each of the past three years.
Register to participate in Iowa Ideas
Iowa Ideas, the annual free virtual conference hosted by The Gazette, will be Thursday and Friday, Oct. 10 and 11. More than 50 panel discussions and keynote addresses are planned over the two days of programming. Find a full schedule and register at iowaideas.com.
Comments: (319) 368-8541; jared.strong@thegazette.com
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