Chicago, IL Uses Green Infrastructure to Reduce Extreme Heat

Chicago, Illinois Uses Green Infrastructure to Reduce Extreme Heat

Equity & Justice

When people are exposed to extreme heat and minimal air movement for prolonged periods of time, their health and safety is at risk. Depending on the intensity and duration of high temperatures, as well as a population’s preparedness and infrastructure, heat waves can cause heat exhaustion, heat stroke, swelling of the limbs, heat rashes, dehydration, and can contribute to blood clotting. Extreme heat is the leading weather-related killer in the United States, and heat waves can trigger heart attacks and strokes.   

Although extreme heat events pose a threat to all people, they are particularly dangerous to older populations and children, as their bodies are less able to adapt to heat or handle the stress of high heat. People with preexisting respiratory, cardiovascular, diabetic, and chronic conditions are also particularly vulnerable, along with lower-income communities who often do not have access to well insulated housing or air conditioning systems. Data from the Center for Disease Control and Prevention also suggests higher risk among Black communities. According to the National Black Caucus Foundation, there were 50 percent higher mortality rates among non-Hispanic Black people than non-Hispanic white people during the 1995 Chicago heat wave. 

Green infrastructure solutions not only help mitigate extreme heat by lowering local temperatures, but urban green spaces can also increase equitable access to parks and urban forests, providing areas for outdoor leisure and community life, creating safer and more livable streets, improving local air quality, and mitigating flooding. 

Project Summary

In 1995, Chicago experienced an extreme heat event that led to the deaths of several hundred people over the course of five days. Recognizing climate change will affect extreme heat events among many other weather events, Chicago decided to conduct a vulnerability assessment to better understand the threat. Chicago conducted a vulnerability assessment that projected future expected temperatures and estimated the magnitude of threat to future heat related mortality. In anticipation of these future threats, Chicago adopted a comprehensive Climate Change Action Plan. The city’s first priority under the Chicago Climate Action Plan: Adaptation Strategy Report is to adapt to extreme heat events.

Chicago’s approach assessed vulnerability to extreme heat and promoted resiliency and adaptation actions to reduce climate risk. Specifically, Chicago is promoting resiliency through emergency response procedures, specifically including it as a specific criterion within the county's (Cook County) Hazard Mitigation Plan and identifying that its Extreme Weather Operations Plans have scalability to deal with projected changes.

In order to adapt to future extreme heat events, Chicago is identifying urban heat areas ('heat islands') of concern and then adopting heat island reduction strategies through a variety of municipal programs including: building codes and green infrastructure projects. These green infrastructure strategies provide Chicago with mutual benefits including increasing extreme heat emergency preparedness and improving stormwater management for extreme precipitation events.

How did they do it?
Action Applicable Resources

Conducted vulnerability assessment of future risk from climate exacerbated extreme heat events

  • Chicago's Climate Action Plan Impacts Report projected the future climate under varying emissions scenarios to identify expected future temperatures, note this analysis projected that by 2050, Chicago could be seeing extreme heat events equivalent to the 1995 heat-wave up to twice per decade.
  • Chicago developed an algorithm which analyzed past and future climate changes and residents ability to acclimate to anticipated future changes. This analysis allowed for an estimation of future risk for heat-related mortality.
  • Chicago simulated an extreme heat event, using data from the 2003 European heat wave, to better understand the impact on the city.

Chicago Targeted Efforts to Reduce the Urban Heat Island

  • Chicago identified urban heat island “hot spots” to target with heat reduction strategies such as green infrastructure, reflective roofing, and rooftop gardens.
  • The city required new flat roofs meet EPA Energy Star Cool Roof Standards, supported commercial green roofs with a Tax Increment Financed Improvement Fund, and promoted reflective roofing.
  • The city provided incentives for the adoption of green infrastructure through an expedited ”Green Permit Process” and provided grants for small projects.

Promoted Adaptation Actions that Would Provide Co-Benefits

  • Chicago incorporated heat island reduction strategies - such as green or cool roofs, cool pavements, or increased vegetation and trees - into long-term planning efforts to help lower urban temperatures as well as provide substantive benefits for other programs, including stormwater management.

Similar Case Studies

  • To see how Chicago has modified its Heat Emergency Response Programs to reduce deaths from extreme heat events, view the Chicago case study on developing a heat response plan.
  • To view another region’s example of extreme heat adaptation planning view the Minnesota or the New York City case studies on assessing climate risks to public health.
  • Chicago implemented green infrastructure projects that would provide both heat reduction and stormwater management benefits. For additional examples of how adaptation strategies can promote mutual benefits, view the Salt Lake City case study about air quality and the Gary, Indiana case study on green infrastructure and its multiple benefits.