Chicago, IL Uses Green Infrastructure to Reduce Extreme Heat

Chicago, Illinois Uses Green Infrastructure to Reduce Extreme Heat

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.


As a first step, Chicago conducted a vulnerability assessment of future risk from climate exacerbated extreme heat events. Chicago's Climate Action Plan Impacts Report (PDF) (22 pp, 2.5 MB) projected the future climate under varying emissions scenarios to identify expected future temperatures. 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 to analyze 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. Furthermore, the City simulated an extreme heat event, using data from the 2003 European heat wave, to better understand the impact on the city.

Following the vulnerability assessment, Chicago targeted efforts to reduce its urban heat island. To begin, the City 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 U.S. Environmental Protection Agency ENERGY STAR Cool Roof Standards, supported commercial green roofs with a tax increment financed improvement fund and promoted reflective roofing. In addition, the City provided incentives for the adoption of green infrastructure through an expedited permit process and provided grants for small projects.

Chicago also promoted adaptation actions that would provide co-benefits. The City 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.

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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.