Changing climate, extreme weather will have significant effect on Michigan agriculture, Great Lakes ecology
When climate change is discussed, its impact is often presented in global terms – the rising of ocean levels or the melting of polar ice sheets. In Michigan, the Great Lakes also are being effected in significant ways that fewer people seem to be aware of.
According to a U.S. Environmental Protection Agency report published in January, ice cover on the Great Lakes is forming later and melting sooner as a result of rising global temperatures. That could impact life in Michigan in several ways – including a lack of snow for winter tourism and precipitation carrying more contaminants into the lakes through runoff.
“While we’ve seen a decrease in the amount of regular snow received, we’re seeing an increase in lake effect snow," said Daria Kluver, a meteorology professor studying lake effect snow.
Michigan is receiving more lake effect snow because of warmer lake temperatures. The temperature in Michigan has increased by 1.3 degrees Celsius since the 1980s, Kluver said, and it is predicted to get warmer.
When cold air crosses over, moisture from the warm lake is picked up and is condensed into clouds. Those systems dump snow downwind of the lake when it passes over the cold land. As global and national temperatures continue to rise, less precipitation in Michigan will fall as snow and more will fall as rain. Total precipitation across the Great Lake states has increased by 11 percent since the beginning of the century.
Data released by the National Oceanic and Atmospheric Association (NOAA) suggests the Great Lakes could remain ice-free for longer periods of time.
Changing climate, changing Great Lakes
Heavier rain storms are projected to increase as the impacts of climate change become more profound, according to NOAA. This increase becomes problematic to areas prone to flooding.
“The biggest issues facing the Great Lakes (are) an interplay between pollution and climate change,” said Donald Uzarski, director of the CMU Institute of Great Lakes Research. "Climate change has drastically increased the occurrence and magnitude of extreme storm events causing excess runoff to enter the Great Lakes.”
The runoff of pollutants plays a critical role in how invasive species, algal blooms, pollution and climate change are connected. According to Uzarski, invasive species are often able to take over an ecosystem because “nutrient pollution has artificially elevated primary productivity (algal blooms).”
Severe rainstorms and extreme precipitation events, like the rainstorm that affected Mount Pleasant this summer, are becoming more frequent. In late June, Central Michigan experienced severe flooding due to excessive rainfall that occurred during a concentrated amount of time – it rained very hard during a short amount of time and overwhelmed the infrastructure designed to handle stormwater.
On average, the city of Mount Pleasant receives about 32 in of precipitation a year. On June 22, it received 6.5 inches in less than 20 hours. On Aug. 2, President Donald Trump declared a state of disaster for Isabella, Midland, Gladwin and Bay counties.
“That is 20.3 percent of the annual precipitation in one day,” Uzarski said.
The storm resulted in $6.1 million in damage in the city of Mount Pleasant. In Isabella, Midland, Gladwin and Bay counties, the storm caused more than $100 million in damages throughout Mid-Michigan. That total includes $21 million to public property and at least $10-$15 million in agriculture losses. Fifty-one buildings on Central Michigan University's campus were affected by the flooding. An estimate by the Facilities Management Administration placed the cost of on-campus damage between $7-10 million. Repairs were covered by the university's insurance.
While damage to private and public buildings can be cataloged and repaired, the damage done to the ecosystem of the Chippewa River is less easily measured.
“When that much water hits the landscape at once, it does not percolate into the water table but instead runs off into lakes and streams carrying massive amounts of pollution with it,” Uzarski said.
Streams and rivers then deliver the pollution that’s been introduced to the system into the Great Lakes. Much of the pollution that enters the streams are in the form of very soluble nitrogen. Increased levels of nitrogen can result in the excessive growth of algae and aquatic plants. When those organisms overtake the ecosystem they can block light to deeper water, effect oxygen levels and harm the food and habitat fish rely on.
While costal wetlands are still doing a good job of removing the added nitrogen, over 50 percent of the state’s wetlands have been developed over and filled. When Uzarski and his research team took samples to test the water quality, about 80 percent of the wetlands they sampled were nitrogen limited.
Uzarski and his team are currently working on a paper that would explain their findings. He believes that nitrogen is going to be just as much of a problem as other nutrient pollutants, such as phosphorus. The nitrogen content in the lakes is so high that a reactive-oxygen species toxic to even algae was produced.
“We experimentally added phosphorus, we did not see an algal bloom. When we added nitrogen we did,” Uzarski said. “That is, in these systems, it is the excess nitrogen causing algal blooms, not excess phosphorus yet the 2012 Water Quality Agreement does not even contain the word ‘nitrogen’ in it.”
Algal blooms affect more than just fish habitat or recreation. In 2011, the city of Toledo issued a “Do Not Drink" advisory for more than 400,000 area residents served by Toledo Water. Chemical tests confirmed an increased, unsafe level an algal toxin in treated water.
Expect more flooding in Central Michigan
Martin Baxter a meteorology professor at CMU who researches precipitation systems, believes Mount Pleasant will experience a more significant impact every time a heavy rainstorm move into the area because the Chippewa River is already prone to flooding.
The “tremendous” amount of water vapor present in the atmosphere and an uplift caused by a front is likely to have caused the flooding seen in Mount Pleasant.
“With the changing climate we’re seeing warmer air masses that are able to hold more water vapor which can then potentially precipitate out into the heavy rainstorms we’re seeing,” Baxter said.
As the Earth’s surface and its oceans warm, the amount of water vapor in the atmosphere due to the increase in water evaporating from lakes, oceans and other reservoirs. Sea-surface temperatures today are the highest on record according to a State of The Climate report published in 2016 by the National Centers for Environmental Information (NCEI) and the American Meteorological Society (AMS).
Dry places will become even drier, Baxter said, as warmer temps lead to less vegetation that can hold in water. Humid places will become more moist as they warm, as warmer air can hold more water vapor.
“There are models now that are capable of predicting where something like this will happen,” Baxter said. “The trouble is they aren't always accurate enough to give us the confidence to warn people of the potential impact of a storm like that.”
This year Michigan experienced one of its warmest Septembers on record. The state also experienced one of its wettest Octobers, which Baxter said isn’t a coincidence.
“There was a large warm and moist air mass caused by the evaporation over the Gulf (the Gulf of Mexico),” Baxter says. “There was no troughs or upper-level disturbances that could cause the air mass to lift and precipitate. You need to lift the air in order to get clouds to precipitate. In October two troughs were able to lift the air mass and cause rain.”
Climate changing agriculture
Warmer weather brings changes to more than just the distribution of water, it can affect the demographics of plants and animals. Joanne Dannenhoffer a botany professor at CMU, said as Michigan becomes warmer and experiences increased rainfall, she expects these changes to alter the composition of Michigan’s forests.
“Here in Mount Pleasant we live in a transition zone where the vegetation in the southern half of the state merges into the vegetation found in the northern half of the state,” Dannenhoffer says. “With warmer weather there might be a change in the migration of the transition zone, to say, somewhere farther north like Gaylord.”
According to the EPA populations of northern species such as paper birch, quaking aspen, balsam fir and black spruce may decline while oak, hickory and pine trees will increase.
"Plants have a general theme of adaptation, they've always been at the mercy of what happens in their environment," Dannenhoffer explained.
Dannenhoffer, who researches the kernel development of corn, says that increases in average temperatures could have both beneficial and harmful effects on farming in the state. The June flood ruined her research yield because crops, like corn, are intolerant to oversaturated soil caused by flooding.
“Corn doesn’t do well in a lot of rain,” Dannenhoffer said. “Flooding will affect the yield of corn and so will frequent hot days.”
Michigan’s lower peninsula, where most of its corn is grown, is likely to have five to 15 more hot days during the summer with temperatures above 95 degrees Fahrenheit. Though higher temperatures mean a longer growing season, it also increases risk for droughts can negatively impact the yield of corn and soybeans.
Union Township farmer Jerry Neyer said his corn and soybean fields took the hardest hit from the flooding which occurred in June. Unlike his fields of hay, which have a larger root mass beneath them, the ground covering the soybeans and corns is easily washed away. This is problematic because nutrients essential to the growth of these crops is washed away.
"In July, things looked pretty good, but in August, especially towards the end of August, you could see the crop was starting to slow down and running out of energy," Neyer said. "It just didn’t finish out like it should – the corn was short, ears weren’t fully-developed at all in some cases."
The severity of climate impacts are still uncertain despite the advancement in climate and weather models.
There lies certainty in the projection of rising global temperatures, however just how hot and how fast it will get by the end of the century and the impacts it'll have will be determined by time.
"I have kids and I hope to someday have grandkids," Kluver explained. "Some of these changes are going to happen no matter what we do and I want my kids and my grandkids to be okay. I'm a scientist and I look at the data and all of the numbers show what is happening and project what could potentially happen. I don't know how a responsible leader can ignore that."
