Climate change is expected to worsen existing conditions and introduce new health threats by increasing the frequency and intensity of poor air quality days, extreme high temperature events, and heavy rainfalls; extending pollen seasons; and modifying the distribution of disease-carrying pests and insects (very likely, very high confidence). By mid-century, the region is projected to experience substantial, yet avoidable, loss of life, worsened health conditions, and economic impacts estimated in the billions of dollars as a result of these changes (likely, high confidence). Improved basic health services and increased public health measures—including surveillance and monitoring—can prevent or reduce these impacts (likely, high confidence).

This finding is from chapter 21 of Impacts, Risks, and Adaptation in the United States: The Fourth National Climate Assessment, Volume II.

Process for developing key messages:

The chapter lead authors were identified in October 2016, and the author team was recruited in October and November 2016. Authors were selected for their interest and expertise in areas critical to the Midwest with an eye on diversity in expertise, level of experience, and gender. The writing team engaged in conference calls starting in December 2016, and calls continued on a regular basis to discuss technical and logistical issues related to the chapter. The Midwest chapter hosted an engagement workshop on March 1, 2017, with the hub in Chicago and satellite meetings in Iowa, Indiana, Michigan, and Wisconsin. The authors also considered other outreach with stakeholders, inputs provided in the public call for technical material, and incorporated the available recent scientific literature to write the chapter. Additional technical authors were added as needed to fill in the gaps in knowledge.

Discussion amongst the team members, along with reference to the Third National Climate Assessment and conversations with stakeholders, led to the development of six Key Messages based on key economic activities, ecology, human health, and the vulnerability of communities. In addition, care was taken to consider the concerns of tribal nations in the northern states of the Midwest. The Great Lakes were singled out as a special case study based on the feedback of the engagement workshop and the interests of other regional and sector chapters.

Note on regional modeling uncertainties

Interaction between the lakes and the atmosphere in the Great Lakes region (e.g., through ice cover, evaporation rates, moisture transport, and modified pressure gradients) is crucial to simulating the region’s future climate (i.e., changes in lake levels or regional precipitation patterns).fe83e7d3-3f29-4aef-81ae-28abd70dda2e^,94a4d51e-96a4-4155-926d-31be60e2206a Globally recognized modeling efforts (i.e., the Coupled Model Intercomparison Project, or CMIP) do not include a realistic representation of the Great Lakes, simulating the influence of the lakes poorly or not at all.9db319af-7cec-440e-8dda-41526fed6cd0^,5295673e-703b-42f8-9792-4ccf8e3cf747^,03f91fdd-6d7d-431b-997b-91f63f52fe45^,ee7f8311-bd00-4353-87a9-61ffb7813bf0^,1cd8ac44-e9d5-4a2e-ab8e-e48c8988bbc2 Ongoing work to provide evaluation, analysis, and guidance for the Great Lakes region includes comparing this regional model data to commonly used global climate model data (CMIP) that are the basis of many products practitioners currently use (i.e., NCA, IPCC, NOAA State Climate Summaries). To address these challenges, a community of regional modeling experts are working to configure and utilize more sophisticated climate models that more accurately represent the Great Lakes’ lake–land–atmosphere system to enhance the understanding of uncertainty to inform better regional decision-making capacity (see http://glisa.umich.edu/projects/great-lakes-ensemble for more information).

Description of evidence base:

There is strong evidence that increasing temperatures and precipitation in the Midwest will occur by the middle and end of the 21st century.dd5b893d-4462-4bb3-9205-67b532919566 The impacts of these changes on human health are broadly captured in the 2016 U.S. Global Change Research Program’s Climate and Health Assessment.f1e633d5-070a-4a7d-935b-a2281a0c9cb6 Air quality, including particulate matter and ground-level ozone, is positively associated with increased temperatures and has been well-documented to show deleterious impacts on morbidity and mortality.5ec155e5-8b77-438f-afa9-fbcac4d27690 Likewise, increased temperatures have been shown in communities in the Midwest, as well as across the United States, to have substantial impacts on health and well-being.dac369a3-921e-426f-b4a2-5798dfb9c515^,6b3cd0ec-1e3e-42e8-ad82-5c12ed7ab0e8^,e518fff1-caa5-4ed1-8fdc-b512da7cbe3b^,4aaadb0b-7eb3-43fa-863d-89f01f55f5fc^,28b8aa29-bfe6-4d88-b73f-fe736f5042b6^,b00a1349-fb5f-4e2d-b1bc-cfceb0863de2 The frequency of extreme rainfall events in the Midwest has increased in recent decades, and this trend is projected to continue.e8089a19-413e-4bc5-8c4a-7610399e268c Studies have shown that extreme rainfall events lead to disease, injury, and death.1db82525-813a-488c-ab9b-8e726b05eac1 Increases in seasonal temperatures and shifting precipitation patterns have been well documented to be correlated with increased pollen production, allergenicity, and pollen season length.2d1ffd71-6c31-4d2e-9867-bdf330be45c1^,5ec155e5-8b77-438f-afa9-fbcac4d27690 Similarly, there is agreement that shifting temperature and precipitation patterns are making habitats more suitable for disease-carrying vectors to move northward toward the Midwest region.3d6b2a18-fbfd-4751-8eb9-a35b7502ac9f^,7f78088e-7e0d-429b-ba67-eeaac737f8fa^,9463d1f1-764f-4185-9a2b-41fb7d2071d7^,2471c8e7-348f-40c2-9a28-0d46d3d1f1df^,93155d7a-31a3-4d21-9d39-f438ecc7d372^,4a53940c-0aa5-4ef3-b11b-06ea45277445 The disease burden and economic projections primarily are based on EPA estimates.0b30f1ab-e4c4-4837-aa8b-0e19faccdb94

Access to basic preventive care measures quantifiably reduces disease burden for climate-sensitive exposures.327a1728-7992-448b-9e5b-267328259994^,851e275f-5e31-42ef-93e5-eed46db465aa Gray literature indicates that public health practitioners are dedicated to increasing capacity for adapting to climate change through classic public health activities such as conducting vulnerability assessments, employing communication and outreach campaigns, and investing in surveillance efforts.f1e633d5-070a-4a7d-935b-a2281a0c9cb6^,99b4f914-06f7-4489-836a-04ea02b99ded^,2a412bb3-bcc0-47f7-aef0-5c098c61ffa5^,4f2b76ca-aaf0-4f09-9b76-d6aa021e979a^,8cf8bbe8-0eac-4ec0-abb3-d84b483606ea^,e3139f21-797c-4d60-8099-6efe715f64bc

New information and remaining uncertainties:

While the modeling performed by the EPA was completed using the best available information, there is uncertainty around the extent to which biophysical adaptations will protect midwestern populations from heat-, air pollution-, aeroallergen-, and vector-related illness and death. Likewise, while there is a general consensus regarding habitat suitability for disease-carrying vectors in the eastern and western United States, the degree to which the disease burden may increase or decrease is largely uncertain.

Assessment of confidence based on evidence:

Based on the evidence, there is very high confidence that climate change is very likely to impact midwesterners’ health.

Provenance

This finding was derived from scenario rcp_4_5
This finding was derived from scenario rcp_8_5