Climate Change Connections: Michigan (The Great Lakes)
Climate change is impacting all regions and sectors of the United States. The State and Regional Climate Change Connections resource highlights climate change connections to culturally, ecologically, or economically important features of each state and territory. The content on this page provides an illustrative example. As climate change will affect each state and territory in diverse ways, this resource only describes a small portion of these risks. For more comprehensive information about regional climate impacts, please visit the Fifth National Climate Assessment and Climate Change Impacts by Sector.
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Introduction: The Great Lakes Play a Major Role in Regional Ecosystems and the Economy
The Great Lakes—Lake Superior, Lake Michigan, Lake Huron, Lake Erie, and Lake Ontario—form the largest freshwater ecosystem in the world. These lakes were carved by the movement of retreating glaciers about 20,000 years ago, and filled when ice from the glaciers melted.1 Native Americans have relied on the Great Lakes for cultural practices and food, including fish and wild rice.2 The Great Lakes support a variety of ecosystems and habitats, which in turn support more than 3,500 plant and animal species.3 They also play a vital role in the regional economy, providing drinking water, shipping routes, fisheries, recreational opportunities, and more.
Although eight U.S. states (Illinois, Indiana, Michigan, Minnesota, New York, Ohio, Pennsylvania, and Wisconsin) border one or more of the Great Lakes, Michigan is considered “The Great Lakes State.” Michigan borders four of the five Great Lakes, more than any other state, and has more than 3,000 miles of shoreline.4 The Great Lakes region contains seven national parks and lakeshores, three of which are located in Michigan: Isle Royale National Park, Pictured Rocks National Lakeshore, and Sleeping Bear Dunes National Lakeshore.5 Isle Royale was specifically recognized by the United Nations for the unique qualities of its native ecosystems.6
The Great Lakes contain 20 percent of the Earth’s supply of surface fresh water and provide drinking water to more than 35 million people.1 The Great Lakes also support the economies of Michigan and other bordering states through agriculture, fishing, food production, transportation, warehousing, manufacturing, tourism, and recreation.
Climate Impacts: Warming Temperatures Reduce Ice Cover, Change Water Levels, and Delay Lake Turnover
Climate change is already affecting the Great Lakes. In addition to amplifying the risk of existing threats (such as invasive species, land use change, and pollution), climate change will introduce new challenges to the Great Lakes region. The primary impacts of climate change on the Great Lakes include changes to the duration and extent of winter ice cover, lake water levels, and important annual cycles that affect ecosystems.7
Warming temperatures can affect ice formation on the Great Lakes in winter (area of ice cover) and how long that ice lasts before thawing (duration of ice cover). Years when a much lower than normal area is covered by ice have become more frequent in the past two decades, especially on Lake Erie and Lake Superior, which have a history of freezing almost completely. Since 1973, the duration of ice cover has declined on all five Great Lakes at rates ranging from about one-fifth of a day per year in Lake Huron to almost a full day per year in Lake Ontario and Lake Superior. This means the yearly duration of ice cover on the Great Lakes is at least one week shorter than it was in the early 1970s, with some areas as much as six weeks shorter.7 Reduced ice cover has wide-ranging implications for life and economic activity in the Great Lakes region: it can lengthen the shipping season, but it also extends the window for evaporation, which lowers water levels.7,8 Lower water levels negatively affect shipping by reducing the amount of cargo that ships can carry.2,9
Fluctuations in ice cover and water levels can also affect infrastructure. Low water levels can damage docks and piers. Reduced ice cover can make shorelines and coastal infrastructure more vulnerable to erosion and flooding, as ice suppresses waves and can protect shorelines.2 Additionally, sustained periods of low water levels encourage development to move closer to the lake. When lake levels go back up, rising waters threaten this development. Reduced ice cover and lower water can also affect recreational activities, such as ice fishing in the winter and boating in the summer.2
Rising temperatures are also affecting the timing of an event called destratification, or turnover, which may have implications for fishing and lake ecosystems. Fish and other lake animals need oxygen to survive, which lakes primarily receive from air at the surface. Species in deeper parts of the lake depend on seasonal boosts of oxygen-rich water through lake turnover, which mixes oxygen through the water column. Turnover mixes water carrying nutrients from the bottom of lakes with water carrying oxygen from near the surface. Projections show that turnover will begin happening earlier in the spring and later in the fall, lengthening the time before oxygen is replenished at depth.10 These changes can significantly affect ecosystems.2 Low oxygen levels can limit the growth of phytoplankton (algae) and zooplankton (microscopic animals) that form the base of the food chain, which in turn could harm species higher on the food chain, such as fish.
Warming air temperatures in the Great Lakes lead to warmer water temperatures, while more severe storms and precipitation contribute to higher rates of runoff.11,12 Together, these factors can undermine water quality and kill commercially and culturally significant fish by promoting the growth of freshwater harmful algal blooms, particularly in western Lake Erie. Cyanobacteria and green algae species, such as those in Lake Erie, can produce toxins that are hazardous to human health, or excessive amounts of biomass that can kill fish by clogging gills and boat motors.2,13 Harmful algal blooms can also be a health issue for those who get their drinking water from the Great Lakes. The Great Lakes Research Initiative, as well as federal, state, and local agencies, research and respond to harmful algal blooms in Lake Erie and other freshwater bodies to protect human and ecological health.2,14–16
Changing lake conditions can threaten species of fish, such as the walleye and lake whitefish, that hold particular significance for Tribal communities.17 Walleye is a traditional food source for the Keweenaw Bay Indian Community, and walleye spearfishing is an important cultural practice. Rising temperatures can affect the timing of walleye spawning, influencing the success of harvests.11,18
Taking Action: Managing Water Quality in a Changing Climate
Addressing climate change requires reducing greenhouse gas emissions while preparing for and protecting against current and future climate impacts. Communities, public officials, and individuals in every part of the United States can continue to explore and implement climate adaptation and mitigation measures. In Michigan, researchers and planners are taking steps to prepare for climate change in the Great Lakes, including:
- Partnerships and planning. Given the varied climate impacts on Great Lakes ecosystems and economies, planning for resilience requires collaboration. Universities; Tribal, state, and local governments; federal agencies; and community organizations are collaborating in regional networks to identify and implement adaptation priorities in the Great Lakes.12
- Water quality management. As climate change increases water temperatures and extreme precipitation accelerates runoff, managing nutrient flow becomes an important adaptive strategy. NOAA is leading the Runoff Risk Decision Support project, a collaborative effort with state agencies that uses data to provide recommendations on the most efficient time to apply fertilizers to minimize excess nutrient runoff.13 EPA and Environment and Climate Change Canada release a regular report about Great Lakes water quality to inform strategic priorities.2 The U.S. Department of Agriculture (USDA) Northern Forests Climate Hub emphasizes the importance of maintaining and restoring coastal vegetation to provide buffers and minimize erosion for Great Lakes coastal ecosystems.19
To learn more about climate change impacts in Michigan and the Midwest region, see Chapter 24 of the Fifth National Climate Assessment.
Related Resources
- EPA Climate Change Indicators: Great Lakes Water Levels and Temperatures
- EPA Climate Change Indicators: Great Lake Ice Cover
- Great Lakes Restoration Initiative
- Strategies for Adapting Great Lakes Coastal Ecosystems to Climate Change (USDA Northern Forests Climate Hub)
- Great Lakes Climate Adaptation Network (University of Michigan)
- Building Resilience in the Great Lakes (U.S. Climate Resilience Toolkit)
- Great Lakes Environmental Research Laboratory (NOAA)
- Michigan State Climate Summary 2022 (NOAA)
References
1 EPA. (2024). The Great Lakes. Retrieved June 12, 2024, from https://www.epa.gov/greatlakes
2 Wilson, A. B., Baker, J. M., Ainsworth, E. A., Andresen, J., Austin, J. A., Dukes, J. S., Gibbons, E., Hoppe, B. O., LeDee, O. E., Noel, J., Roop, H. A., Smith, S. A., Todey, D. P., Wolf, R., & Wood, J. D. (2023). Ch. 24. Midwest. In A. R. Crimmins, C. W. Avery, D. R. Easterling, K. E. Kunkel, B. C. Stewart, & T. K. Maycock (Eds.), Fifth National Climate Assessment. U.S. Global Change Research Program. https://doi.org/10.7930/NCA5.2023.CH24
3 NOAA. (2019). Great Lakes ecoregion. Retrieved January 10, 2024, from https://www.noaa.gov/education/resource-collections/freshwater/great-lakes-ecoregion
4 NOAA Office for Coastal Management. (n.d.). Shoreline mileage of the United States. https://coast.noaa.gov/data/docs/states/shorelines.pdf
5 National Park Service. (n.d.). Great Lakes. Oceans, Coasts & Seashores. Retrieved January 23, 2024, from https://www.nps.gov/subjects/oceans/great-lakes.htm
6 Gibb, T. (2015). Lakes Appreciation Month: The Great Lakes facts and features. Michigan State University Extension. Retrieved January 15, 2024, from https://www.canr.msu.edu/news/lakes_appreciation_month_the_great_lakes_facts_and_features
7 EPA. (2023). Climate change indicators: Great Lakes ice cover. Retrieved January 10, 2024, from https://www.epa.gov/climate-indicators/climate-change-indicators-great-lakes-ice-cover
8 U.S. Climate Resilience Toolkit. (2022). Great Lakes. Retrieved January 10, 2024, from https://toolkit.climate.gov/regions/great-lakes
9 EPA. (2021). Climate change indicators: Great Lakes water levels and temperatures. Retrieved August 21, 2023, from https://www.epa.gov/climate-indicators/great-lakes
10 Angel, J., Swanston, C., Boustead, B. M., Conlon, K. C., Hall, K. R., Jorns, J. L., Kunkel, K. E., Lemos, M. C., Lofgren, B., Ontl, T. A., Posey, J., Stone, K., Takle, E., & Todey, D. (2018). Ch. 21: Midwest. In D. R. Reidmiller, C. W. Avery, D. R. Easterling, K. E. Kunkel, K. L. M. Lewis, T. K. Maycock, & B. C. Stewart (Eds.), Impacts, Risks, and Adaptation in the United States: Fourth National Climate Assessment, Volume II (pp. 872–940). U.S. Global Change Research Program. https://doi.org/10.7930/NCA4.2018.CH21
11 NOAA. (2024). Continuing support for the Great Lakes region runoff risk decision support tool. GLRI Focus Area 3: Nearshore. Retrieved June 12, 2024, from https://www.noaa.gov/regional-collaboration-network/regions-great-lakes/about-glri/glri-focus-area-3-nearshore/continuing-support-for-great-lakes-region-runoff-risk-decision-support-tool
12 Whyte, K., Novak, R., Laramie, M. B., Bruscato, N. G., David-Chavez, D. M., Dockry, M. J., Johnson, M. K., Jones Jr., C. E., & Leonard, K. (2023). Ch. 16. Tribes and Indigenous Peoples. In A. R. Crimmins, C. W. Avery, D. R. Easterling, K. E. Kunkel, B. C. Stewart, & T. K. Maycock (Eds.), Fifth National Climate Assessment. U.S. Global Change Research Program. https://doi.org/10.7930/NCA5.2023.CH16
13 EPA. (n.d.). Great Lakes Restoration Initiative (GLRI). Great Lakes Funding. https://www.epa.gov/great-lakes-funding/great-lakes-restoration-initiative-glri
14 EPA. (n.d.). Learn about harmful algae, cyanobacteria and cyanotoxins. Harmful Algal Blooms (HABs) in Water Bodies. https://www.epa.gov/habs/learn-about-harmful-algae-cyanobacteria-and-cyanotoxins
15 NOAA National Centers for Coastal Ocean Science. (n.d.). Lake Erie harmful algal bloom forecast. https://coastalscience.noaa.gov/science-areas/habs/hab-forecasts/lake-erie/
16 EPA. (n.d.). Cyanobacteria Assessment Network (CyAN). Water Research. https://www.epa.gov/water-research/cyanobacteria-assessment-network-cyan
17 Lynch, A. J., Taylor, W. W., Beard, T. D., & Lofgren, B. M. (2015). Climate change projections for lake whitefish (Coregonus clupeaformis) recruitment in the 1836 Treaty Waters of the Upper Great Lakes. Journal of Great Lakes Research, 41(2), 415–422. https://doi.org/10.1016/j.jglr.2015.03.015
18 Kozich, A. T., Gagnon, V. S., Mensch, G., Michels, S., & Gehring, N. (2020). Walleye ogaawag spearing in the Portage Waterway, Michigan: Integrating mixed methodology for insight on an important tribal fishery. Journal of Contemporary Water Research & Education, 169(1), 101–116. https://doi.org/10.1111/j.1936-704X.2020.03335.x
19 Schmitt, K., Krska, R., & Deloria, C. (2022). Strategies for adapting Great Lakes coastal ecosystems to climate change. U.S. Department of Agriculture, Northern Forests Climate Hub. https://forestadaptation.org/sites/default/files/Great-Lakes-Coastal-Adaptation-Menu.pdf