Regional Health Effects - Midwest

Temperature-related death and illness

Increased daytime and nighttime temperatures are associated with heat-related diseases and death in the Midwest. High rates of heat-related illness also have been observed in rural populations, where occupational exposure to heat and access to care is a concern. A July 2012 extreme heat event in Wisconsin was associated with approximately $290.3 million (in 2022 dollars) in damages due to loss of life, hospitalizations, lost wages, and other health-related costs.

Compared to other regions where worsening heat is also expected to occur, the Midwest is projected to have the largest increase in extreme temperature-related premature deaths under the very high emissions scenario. Climate mitigation strategies would have a great benefit to Midwesterners, as approximately 1,200 deaths related to extreme heat would be avoided by the end of the century under an intermediate emissions scenario compared to a very high emissions scenario. Northern Midwestern communities and populations disproportionately at risk that historically have not experienced high temperatures may be at risk for heat-related disease and death. The risk of death from extremely cold temperatures will decrease under most climate projection scenarios.

Air quality impacts

Increases in ground-level ozone and particulate matter are associated with the prevalence of various lung and cardiovascular diseases, which can lead to missed school days, hospitalization, and premature death. Ground-level ozone concentrations are projected to increase across most of the Midwest, resulting in an additional 200 to 550 premature deaths per year by 2050, some of the highest in the United States. Simultaneously, rising temperatures are leading to increased pollen counts, which can worsen allergies and trigger asthma attacks in those who are sensitive, particularly in children. By 2050, increased oak pollen is projected to lead to a 7% annual increase in asthma-related emergency room visits for the Midwest under a very high emissions scenario. Other threats to respiratory health include flooding and wildfires. Flooded buildings can experience mold growth, which can trigger asthma attacks and allergies during cleanup efforts. Further, many Midwest counties will experience increased exposure to wildfire smoke, a known asthma trigger.

Non-Hispanic Black, Hispanic, and Indigenous populations tend to be disproportionately exposed to air pollution and have the highest rates of asthma and asthma-related deaths and hospitalizations in the United States.

Extreme events

The Ohio River, upper Mississippi River, and lower Missouri River are susceptible to floods and droughts based on projected changes in precipitation, evapotranspiration, and soil moisture. Already, there has been increased flooding in these rivers and their tributaries, which flood surface streets and low-lying areas, resulting in drinking water contamination, evacuations, damage to buildings, injury, and death. Additionally, projected increases in extreme precipitation events have been linked to an increased risk of traffic crashes.

Midwest droughts develop in response to precipitation deficits or extremely high temperatures and evapotranspiration. Groundwater recharge is projected to be variable in the Midwest, with water imbalances resulting from precipitation and evapotranspiration changes. Failure of private wells is expected to increase during droughts as water tables drop with increased irrigation and water usage.

Vector-borne diseases

Rising temperatures, particularly in winter, and increasing precipitation contribute to the geographic spread of disease-carrying vectors (e.g., ticks and mosquitoes) into and across the Midwest. Climate-related changes in habitats for disease-carrying insects are associated with higher rates of infection in humans and increased healthcare costs. Warmer temperatures are linked to increased numbers of deer ticks (Ixodes scapularis) in the upper Midwest, leading to earlier and longer seasonal exposure to Lyme disease. Further, northern expansion of the Culex species of mosquito (C. pipiens and C. tarsalis) in the Midwest is expected to result in upwards of 450 additional West Nile virus cases above the 1995 baseline by 2090.

Water-related illness

Extreme precipitation events cause dramatic shifts in water quality that can challenge the resilience of drinking water treatment systems. Likewise, large intrusions of precipitation and runoff can overwhelm wastewater treatment systems resulting in release of untreated wastewater into natural bodies of water. These events can allow contaminants to increase in groundwater and surface water sources (i.e., untreated groundwater in private wells, the Mississippi River, and the Great Lakes) eventually impacting drinking water quality. By midcentury, precipitation changes are projected to increase the rate of gastrointestinal illness among children due to contaminated drinking water.

Simultaneously, increasing precipitation may intensify nutrient loads in the Mississippi River system, potentially contributing to harmful algal blooms (HABs). Contact with and consumption of water contaminated with cyanobacteria from HABs has been associated with skin and eye irritation, respiratory illness, gastrointestinal illness, and liver and kidney damage. However, research has been inconsistent about whether HAB severity and magnitude in the Midwest have been increasing, remaining constant, or decreasing.

Food safety, nutrition, and distribution

Increasing temperatures and oscillations between extreme droughts and floods threaten field crops, specialty crops, and animal production across the Midwest, which have direct and inequitable impacts on global food supply and security. Temperature increases directly affect crop development, plant physiology, and crop stress during dry conditions, and intense precipitation increases soil erosion and leaches nitrogen fertilizer, thereby affecting water quality. Animal production in the Midwest is also vulnerable to climate change. Livestock impacts include feed shortages, loss of shade structures, nutritional restrictions, disease transmission, and biosecurity concerns. Further, heat stress limits livestock production and impacts dairy quality, while increased precipitation creates muddier paddocks and pastures, which can decrease fetal growth during late gestation.

Evidence suggests that pest distributions have shifted northward since the early 20th century, and projections indicate that increasing temperatures will allow pests (e.g., brown marmorated stink bug, corn earworm, Japanese beetle, Mexican bean beetle, and potato leafhopper) to continue expanding northward across the Midwest.

Mental health and well-being

Stress associated with experiencing climate-related disasters is impacting the mental health of people living in the Midwest and is expected to increase as the frequency of extreme events rises. The trauma caused by a disaster, such as losing one’s home, livelihood, or community, can contribute to chronic depression, anxiety, and post-traumatic stress disorder. In addition, people may suffer a loss of social connections, witness traumatic events, see homes destroyed, and confront an uncertain future, any of which can trigger or intensify adverse mental health conditions. Farmers and others dependent on agriculture for their livelihood are particularly at risk. Many rural Midwesterners already experience obstacles to utilizing healthcare services, including mental health services.

Populations of concern

Tribes in the Midwest have been among the first to feel the effects of climate change as it impacts their culture, sovereignty, health, economies, and ways of life. Simultaneously, an individual’s exposure and sensitivity to climate change is influenced by preexisting health conditions, age, gender, race or ethnicity, income, social connectivity, access to resources, and local adaptive capacity. For those who are chronically ill or reliant on electronic medical devices, the increased cost of electricity, which contributes to energy insecurity, may introduce financial and health burdens.

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