Illinois Climate Impacts and Costs

Climate change in Illinois is manifesting as increased precipitation, rising temperatures, and intensified summer droughts, leading to significant infrastructure damage and public health risks. Since the 20th century, average annual precipitation has risen by 12-15%, while extreme events have increased by 40%, causing frequent flooding and sewage overflows in cities like Chicago. Rising temperatures are most pronounced in winter, with a predicted average increase of up to 9°F by 2100, which threatens agricultural yields—potentially reducing corn yields by 23-34% by mid-century—and necessitates an estimated $6.1 billion for school air conditioning by 2025. Additionally, intensified summer droughts threaten crop yields and river navigation, notably impacting barge transportation on the Mississippi River, while increasing the risk of wildfires and health issues from Canadian wildfire smoke.

• Illinois has seen a significant rise in precipitation and extreme weather events since the start of the 20th century, with average annual precipitation increasing by 12-15% and extreme precipitation days (over 2 inches) increasing by 40%.
• Flooding and severe storms have caused substantial economic losses in Illinois; flood losses have averaged approximately $260 million annually since the 1980s, and severe storms led some insurance companies, such as Pekin and Secura Insurance, to stop writing or drop homeowners policies in 2023.
• Illinois experienced a record number of tornadoes in 2023, totaling 118, which was more than any other U.S. state.
• Rising temperatures are expected to significantly impact Illinois' education infrastructure and agriculture; the state may need to spend $6.1 billion by 2025 to install air conditioning in schools, and corn yields could drop by 23-34% by mid-century due to heat stress.
• The Great Lakes are experiencing warming and declining ice cover, with winter ice coverage decreasing by 63%, leading to water level fluctuations and coastal flooding.
• Intensified summer droughts are threatening the Mississippi River's navigability, contributing to a U.S. economic loss of approximately $20 billion due to shipping delays since 2021.

APA

Center for Climate Integrity (2025). Illinois Climate Impacts and Costs. https://climateintegrity.org/uploads/media/CCI_Illinois_Climate_Impacts_Costs_2024.pdf

Chicago

Center for Climate Integrity. Illinois Climate Impacts and Costs. 2025. https://climateintegrity.org/uploads/media/CCI_Illinois_Climate_Impacts_Costs_2024.pdf.

Wikipedia

{{cite report |author=Center for Climate Integrity |title=Illinois Climate Impacts and Costs |date=2025 |url=https://climateintegrity.org/uploads/media/CCI_Illinois_Climate_Impacts_Costs_2024.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{centerforclimateintegrity2025illinois, author = {{Center for Climate Integrity}}, title = {{Illinois Climate Impacts and Costs}}, institution = {Center for Climate Integrity}, year = {2025}, url = {https://climateintegrity.org/uploads/media/CCI_Illinois_Climate_Impacts_Costs_2024.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }