• Kevin Elliott

Climate change impact on state of Michigan


Extreme weather events like the polar vortex that iced over Michigan and much of the Midwest in late January are expected to become more commonplace in the future as global temperatures trend progressively warmer, spurring major disruptions in farming, forestry, infrastructure, the environment, local economies and public health.

The predictions and evidence that climate change is already impacting the way we live are included in a 1,500-page, Congressionally-mandated, National Climate Assessment report released in late 2018 by the U.S. Global Change Research Program. The report, now in its fourth iteration, assesses the science of climate change and variability and its impacts across the country now and throughout this century. Further, the latest report places a greater emphasis on a dozen impacts to different regions across the country, including the Midwest, with a highlight on the Great Lakes region.

“It really does a good job of taking climate change and tying it to people,” said Jenna Jorns, program manager for the Great Lakes Integrated Sciences and Assessments (GLISA), who contributed to the national report.

The report draws past and current research by dozens of local, state and federal scientists, including the National Oceanic and Atmospheric Administration (NOAA), the Center for Disease Control and Prevention (CDC), the United States Department of Agriculture (USDA) and National Forest Service, NASA, the National Academy of Sciences, Engineering and Medicine, national laboratories, universities and the private sector. In total, more than 300 experts contributed to the report, as well as more than a thousand individuals in over 40 cities through regional engagement workshops.

Jorns, who wrote a specific case study about the Great Lakes region for the national report, said changes in lake temperatures and ice coverage have sweeping impacts to ecosystems, public health and economies.

“We are seeing an increase in water temperatures, as well as a very drastic decrease in lake ice cover, and changes in water circulation in the lakes. That effects everything from fish communities to algal blooms,” she said. “In some instances, warmer temperatures could be good for growth rates for certain fish, but also good for invasive species. The sea lamprey, for instance, is now in the Great Lakes and are the target of control efforts. There is a lot of good work being done in the region, but climate change and uncertainty of future projections makes all of that complicated.”

In an effort to help readers comprehend the information presented in the assessment, and further localize those findings, we have distilled key messages of the report here. Further, we spoke with current and former officials in the state to go beyond the report's findings to showcase past and current efforts to combat climate change in Michigan.

Despite increasing evidence that climate change is happening, there are many people who remain skeptical. That sentiment was illustrated in the midst of the polar vortex in a tweet by President Trump: “In the beautiful Midwest, windchill temperatures are reaching minus 60 degrees, the coldest ever recorded. In coming days, expected to get even colder. People can't last outside even for minutes. What the hell is going on with Global Warming? Please come back fast, we need you!”

Politics aside, the president's tweet asks the basic question that many have: how can there be global warming while we're still suffering through record-breaking cold snaps?

Scientists describe climate change as changes in average weather conditions that persist over multiple decades or longer. It includes both increases and decreases in temperature, as well as shifts in precipitation, changing risks of certain types of severe weather events and changes to other features of the climate system.

Nationally, annual average temperatures have increased by 1.8 degrees across the contiguous United States since the beginning of the 20th century, according to the most recent assessment. Alaska, however, is warming faster than any other state and has warmed twice as fast as the global average since the mid-20th century.

Local WDIV Meteorologist Paul Gross said warmer global temperatures contribute to weather extremes because the Earth's north and south poles warm disproportionately faster than lower latitudes.

“The jet stream results largely from a contrast in temperature from far north and middle and southern latitudes. So, if we warm the poles more than we lower the lower latitudes, that weakens the jet stream. When we weaken the jet stream, that promotes peaks and valleys that result in more extreme weather,” he said. “The long-term trend is that all four seasons are warming, but here's an interesting statistic: spring, summer and fall are warming at almost the same rate; winter, however, is warming at a much faster rate than the other three seasons.

“That may be hard for people to believe considering the polar vortex we just had, but remember, the polar vortex just affected the Northeastern United States. Other parts of the world are setting heat records. Australia is having day after day of 120 degree weather with all sorts of wildfires. People don't understand it's 'global' warming, not just Detroit or Michigan. It's the entire planet. Every region won't have the same weather at any given time. People have already forgotten we had a very mild December and first part of January.”

In terms of local climate, Gross said a study of daily high and low records during the 1990s in the Detroit area show heat records have outpaced cold records by a ratio of three-to-one.

“That by itself is unusual,” he said. “Then, in the next decade, from 2000 to 2009, the ratio jumped to six-to-one hot-to-cold. In the current decade, we think we are about three or four-to-one,” he said. “That's an undeniable signal of a warm force on our climate.”

In the Great Lakes Region, average annual temperatures have increased by 2 degrees since 1900. Temperatures are expected to increase by 1.8 to 5.4 degrees by 2050, and average air temperatures are projected to increase by 3.6 to 11.2 degrees by 2100, according to the Great Lakes Integrated Sciences Assessments (GLISA), which is one of 11 NOAA-funded regional centers that studies climate change in the Great Lakes. The center, which is located in Ann Arbor, operates as a partnership between the University of Michigan and Michigan State University.

While milder winters and warmer overall weather may be appealing to some, the lack of an annual cold snap has consequences greater than a reduced heating bill.

“We need an occasional arctic blast because that severe cold will create higher attrition for some of the pests that bother us over the summer, things like ticks and mosquitoes,” Gross said. “Temperature increases on Isle Royal has been attributed to warming winters, resulting in more ticks. Now, the moose population on the island is being affected, and that's affecting wolf population on the island.”

In his own backyard, Gross said the Black-Eyed Susans at his home used to bloom in August when he moved into his home in 1993. Now, the flowers bloom in mid-July and are finished by mid-August.

“If you have a heat wave in the spring, which has happened, like getting to the 70s or 80s in March, then your fruit tree buds come out. Then, you get a hard freeze and you've destroyed the fruit crop. That's happened twice in the past 20 years.”

BIODIVERSITY & ECOSYSTEMS

The ecosystems of the Midwest support many native species and provide people with essential services, such as water purification, flood control, resource provision, crop pollination and recreational opportunities.

“Species and ecosystems, including important freshwater resources of the Great Lakes, are typically most at risk when climate stressors, like temperature increases, interact with land-use change, habitat loss, pollution, nutrient inputs, and non-native species,” the assessment's authors wrote. “Restoration of natural systems, increases in the use of green infrastructure, and targeted conservation efforts, especially of wetland systems, can help protect people and nature from climate change impacts.”

Some species are already responding to environmental changes over the last several decades, with rapid climate change over the next century expected to cause or further amplify stress in ecological systems in the Midwest, according to the national assessment. Those changes include species range shifts, populations, size and growth rates and timing of seasonal events.

As an example of shifting ranges, scientists say about 78 plant species in Wisconsin that were sampled in the 1950s and again in the 2000s, shifted in by about 30 miles over the 50-year period. The dominant direction was northwest, matching the direction of the change in climate conditions associated with the distribution of the species.

“While this shift suggests the potential for successful adaptation to changing conditions, the rate of change for most species was much less than the amount of change in climate metrics over the same period, raising concern that the climate is changing too fast for species to keep up,” the report stated.

Similar studies found that spring green-up, an indicator of when plant-feeding insects emerge, and the timing of migratory bird arrivals are shifting earlier in the Midwest, with birds arriving before plants emerge. Such a shift could pose a threat to birds. Scientists recommend implementing new land management strategies to help maintain or increase plant variations in key migratory and breeding habitats, such as the Great Lakes coastline.

“Many species and ecosystems, especially in the upper Midwest, are best suited to survive when winter conditions are harsh and growing seasons are short. As winter warms and growing seasons extend, species from the south-central United States, as well as outside the country, are expected to increase and take advantage of these changes, increasing the rate of loss of native species,” the national assessment stated. “For insect pests, the impacts may be compounded as extended growing seasons allow additional generations to be produced in a single season.”

Likewise, the Great Lakes themselves are undergoing changes as a result of climate change.

Brent Lofgren, a physical scientist with NOAA's Great Lakes Environmental Research Laboratory in Ann Arbor, said water temperatures in the Great Lakes have led to a lack of turnover in the water column in some areas, a phenomenon that hasn't been recorded in recent history.

Turnover in the water column happens when freshwater reaches its maximum density at just below 39 degrees. When surface water reaches that point, the entire water column below the surface mixes vertically, bringing oxygen from the surface to lower depths, and nutrients from the bottom toward the top.

“It's really an ordinary process, with turnover essentially happening twice a year, in fall and spring,” Lofgren said. “There were two winters – 2012 and 2017 – in which there was a large area in southern Lake Michigan and a large area throughout Lake Ontario, where the surface water never got that cold, so there was no turnover.”

Lofgren said the events marked the only record that mixing of the water column didn't happen throughout the lakes.

“We need to take a closer look at what might have happened to biological acidity for those years,” he said.

Without proper turnover of the water column, the lack of oxygen and nutrients in some areas of the lake may lead to population declines in some species in both the upper and lower zones. For instance, algae and zooplankton that form the basis of the aquatic food web may be disrupted, leading to a chain of potential results.

Warmer water may also impact coldwater fish species, such as trout and salmon, which could result in population and range shifts. However, the extent to which climate change impacts fish species also depends on other stressors, such as pollution, habitat loss and degradation, invasive species, and land uses that may impact water.

Another indicator of climate change in the Great Lakes is the overall decline of ice coverage throughout the lakes over the past 40 years.

Ice coverage tracked by NOAA showed the largest decreases between 1973 and 2013, while summer surface water temperatures increased the most between 1994 and 2013. The greatest decreases in seasonal ice cover were near shorelines, with less occurring in deeper central parts of Lakes Michigan and Ontario, which rarely have ice cover. Meanwhile, the greatest summer water temperatures occurred in deeper water.

Lofgren said while the downward trend of ice coverage started several years ago, there was higher ice coverage in 2014 and 2015, with the potential for increases in 2019.

In terms of Great Lakes projections, Lofgren said it's difficult to tie global projections to the Great Lakes basin. That, he said, may give extra emphasis to reductions in ice cover and water turnover. Likewise, he said water levels in the Great Lakes aren't tied to rising sea levels in the Earth's oceans. The difference, he said, is that the Great Lakes have an outlet or outflow, with the ultimate being Lake Ontario and the Moses-Saunders Power Dam, in the St. Lawrence River.

“The levels of the lakes are determined by the balance between water coming in from runoff and precipitation on the lake versus the amount taken away by evaporation and outflow,” he said. “That outflow is a self-correcting mechanism. If the lake gets lower, it decreases and restores an equilibrium. In the ocean, there's not outflow, it's really a factor of how dense the water is, which is caused by temperature, and if there is an addition of water from large ice sheets. Also, the melt of water from ice that is already floating has no effect on water levels.”

AGRICULTURE & FORESTRY

Overall, the frost-free season in the Midwest has lengthened by nine days from 1958 to 2012, and may be up to one to two months longer by 2100, according to GLISA. Still, by mid-century 2050, a longer growing season and higher carbon dioxide concentrations will likely have a positive effect on many crop yields. By 2100, the negative effects of increasing storm activity, flooding, extreme heat, summer drought risk and pests may outweigh the benefits of climate change.

Annual precipitation in the Great Lakes region has increased by 10.8 percent since 1900, and is expected to increase, according to researchers. Precipitation will increase during wet seasons, but may remain stable or decrease during the summer. Further, reduced ice coverage on the Great Lakes will result in more exposed water and more opportunity for lake-effect precipitation. The amount of precipitation falling in the heaviest one percent of storms increased by 37 percent in the Midwest from 1958 through 2012.

Scientists believe increases in warm-season humidity and precipitation have already eroded soils, created favorable conditions for pests and pathogens, and degraded the quality of stored grain. Projected changes in precipitation, coupled with rising extreme temperatures before mid-century, will reduce Midwest agriculture productivity to levels of the 1980s without major technical advances, according to the assessment.

According to the National Climate Assessment, warm-season temperatures are projected to increase more in the Midwest than any other region in the United States. The frost-free season is projected to increase by 10 days by early this century (2019-2045), 20 days by mid-century (2036-2065), and possibly a month by the late century, compared to the period from 1976 to 2005.

“There has been a lot of work for adaptation with a lot of the trends that we are seeing,” said Laura Campbell, manager of the Agricultural Ecology Department at the Michigan Farm Bureau. “There are invasive species and tests that are moving forward.”

For instance, Campbell said Spotted Wing Drosophila, an East Asian fruit fly, is a major pest in the fruit industry. Likewise, species of pigweed that have typically established in warmer climates to the south are now creeping into Michigan farmlands.

“We've been working at the state and national level to come up with solutions to keep outbreaks at a minimum,” Campbell said. “We've also increased our efforts on managing water. When looking at trends over the past several years, we have seen increases in springtime storm intensity. That has a big impact on water quality. If your field is flooded, it doesn't matter what you did in terms of practices, anything on the field is going into the water.”

Likewise, Campbell said there is increasing uncertainty when looking at when frost will impact fruits and vegetables.

“For instance, if we get a late freeze and lose the entire crop – and that has happened a number of times,” she said. “That puts a lot of uncertainty on the fruit and vegetable crop, which is incredibly important to Michigan.”

In 2012, a mix of a late frost and warm spring weather killed much of Michigan's cherry and apple crops, Campbell said.

Increased precipitation may also have other impacts. Increased spring precipitation and higher temperatures and humidity may lead to more fungus and disease outbreaks and the prevalence of bacterial plant disease. Increased soil moisture in warmer climates may also lead to an increased loss of soil carbon and degraded surface water. Transitions from extreme droughts to floods, in particular, may increase nitrogen levels in rivers and lead to harmful algal blooms.

Scientists say the agriculture industry may adapt to climate changes by diversifying plantings and implementing soil-erosion suppression methods.

Despite the undeniable impacts of climate change to agriculture, Campbell said the Farm Bureau doesn't support a hard set of specific rules to address climate change across the board.

“Our members don't want to see a bunch of mandates and regulations coming through that will increase the difficulty and expense that makes it too difficult to farm,” Campbell said. “The policy our members developed talks about how they want to emphasize research and legislation, but want to make sure there's not mandatory restrictions and mandatory cap and trade programs. Trying to focus on requiring emissions regulations and other things that can make it unaffordable and unattainable for farmers in the United Staes.”

Midwest forests provide economic and ecological benefits, yet threats from a changing climate are interacting with existing stressors, such as invasive species and pests to increase tree mortality and reduce forest productivity.

“Without adaptive actions, these interactions will result in the loss of economically and culturally important tree species such as paper birch and black ash, and are expected to lead to the conversion of some forests and other forest types, or even to non-forested ecosystems by the end of the century,” the assessment stated. “Land managers are beginning to manage risk in forests by increasing diversity and selecting for tree species adapted to a range of projected conditions.”

Forests cover more than 91 million acres in the Midwest, from oak-hickory forests in the Ozarks to northern hardwoods in the north. Michigan itself is home to three national forests and six state forest lands. Economic output of Midwest forestry totals about $122 billion per year.

While the latest national assessment found that tree growth rates and forest productivity have benefited from longer growing seasons and higher atmospheric carbon dioxide concentrations, continued benefits are only expected if moisture and nutrients are available to support enhanced growth rates. As growing season temperatures rise, reduced tree growth or widespread mortality is expected.

“Late growing season heat and drought related to vegetation stress is projected to shift the composition and structure of forests in the region by increasing mortality of younger trees, which are sensitive to drought,” the assessment's author's said. “Warming winter will reduce snowpack that acts to insulate soil from freezing temperatures, increasing frost damage to shallow root trees and reducing tree regeneration.”

Within suburban areas of Michigan, the invasion of the Emerald Ash Borer has decimated ash tree populations in the state. Insects and tree pathogens are anticipated to intensify as winters warm, increasing winter survival of pests and allowing them to expand into new regions.

The Michigan Department of Natural Resources (DNR) has been involved in the Northwoods Climate Change Response Framework since 2010. The program has executive sta