Climate Change and Your Health

The report finds that the U.S. Midwest has experienced a significant increase in dangerously hot, humid, and dry summer days, as well as more frequent heat waves, over the last 60 years. Analysis of ten cities indicates that nighttime temperatures and humidity are rising, reducing the relief typically found overnight. These trends are linked to higher risks of hyperthermia and dehydration, particularly for vulnerable populations such as the elderly and low-income urban residents. The document argues for a combination of local adaptation strategies, such as heat-response plans and cooling centers, and aggressive global action to reduce fossil fuel emissions to mitigate future extreme heat events.

• Dangerously hot summer days, specifically those associated with moist tropical+ (very hot and humid) and dry tropical (hot and dry) air masses, have become more common on average across the Midwest over the last six decades.
• Heat waves consisting of three or more consecutive days of hot air masses are increasing in frequency. For example, St. Louis saw an average of three such heat waves annually in the 1940s, which has increased to an average of seven per year today.
• There is a declining trend in cool, dry summer days (dry polar air masses) across the region, reducing the available relief from summer heat. In Chicago, the number of such days dropped by 40% from 1948 to 2012, while Detroit averages 10.5 fewer cool, dry days per summer than it did in 1959.
• Overnight temperatures are rising more notably than afternoon temperatures. In Detroit and St. Louis, overnight temperatures for dry tropical air masses rose by 4.3°F and 4.4°F respectively over the study period.
• Nighttime humidity and the overnight heat index are increasing. In St. Louis, overnight dew point temperatures for dry tropical weather rose by more than 7°F, increasing average relative humidity from 63% to 71%.
• The observed warming trends are likely driven by regional climate change rather than solely by urban heat island effects, as smaller cities (such as Lexington, Peoria, and Toledo) recorded similar increases in hot summer days.
• Extreme heat poses severe health risks, including hyperthermia from hot, humid weather and dehydration from hot, dry weather. Vulnerable groups include the elderly, children, outdoor workers, and low-income urban residents who may lack access to air conditioning.
• Under a higher-emissions scenario, the Midwest is projected to face significantly more extreme heat by the end of the century. Chicago could see more than 70 days above 90°F annually, and St. Louis could face more than 100 such days.

APA

Perera, E. M., Sanford, T., White-Newsome, J. L., Kalkstein, L. S., Vanos, J. K., & Weir, K. (2012). Climate Change and Your Health. Union of Concerned Scientists. https://www.ucs.org/sites/default/files/2019-09/Heat-in-the-Heartland-Full-Report.pdf

Chicago

Perera, Elizabeth Martin, Todd Sanford, Jalonne L. White-Newsome, Laurence S. Kalkstein, Jennifer K. Vanos, and Kirsten Weir. Climate Change and Your Health. Union of Concerned Scientists, 2012. https://www.ucs.org/sites/default/files/2019-09/Heat-in-the-Heartland-Full-Report.pdf.

Wikipedia

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BibTeX

@techreport{perera2012climate, author = {Perera, Elizabeth Martin and Sanford, Todd and White-Newsome, Jalonne L. and Kalkstein, Laurence S. and Vanos, Jennifer K. and Weir, Kirsten}, title = {{Climate Change and Your Health}}, institution = {Union of Concerned Scientists}, year = {2012}, month = jul, url = {https://www.ucs.org/sites/default/files/2019-09/Heat-in-the-Heartland-Full-Report.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }