While summer days bring warm-weather activities we can’t enjoy in the winter, they also bring something else: heat. And climate change means average temperatures are getting hotter. The Midwest has warmed by 2 degrees Fahrenheit since 2000, and by the end of the century, temperatures in Illinois are expected to increase by 7 to 12 degrees Fahrenheit.

Just a few degrees’ change in average temperature greatly increases the risk and severity of extreme weather, heat, and drought. With rising temperatures come heat-related illnesses, ozone pollution, respiratory issues, and water and energy demand spikes.

While temperatures are already warmer during the summer, heat, drought, and air quality are particularly tough challenges that climate change is worsening. Learn why they’re important, how the Chicago Metropolitan Agency for Planning (CMAP) is working to mitigate these challenges, and what your community can do to prepare.

Northeastern Illinois is no stranger to heat waves and their negative effects on human health and the environment. Heat waves raise temperature and humidity, which can lead to heat stress. Extended periods of heat stress can cause heat-related illnesses and deaths.

As heat waves intensify due to climate change, vulnerable populations, such as children, the elderly, and people with certain medical conditions, are at increased risk of heat stress. Our region experienced this dramatically in July 1995, when a five-day heat wave led to the deaths of 739 people. In the following years, the City of Chicago improved its emergency responses and procedures, but buildings and infrastructure also play a role in worsening heat waves by trapping heat during the day and releasing it at night — a process known as the heat island effect.

Although our region has improved at predicting and responding to heat waves, decades of discriminatory housing policies and economic disinvestment have disproportionately put the burden of excessive heat risk on households with low income and communities of color. Fixing this requires years of financial commitment to overhaul zoning rules and put new practices into place.

Excessive heat likewise threatens our region’s natural and built environments. It disrupts ecosystems that provide invaluable services for human and environmental well-being. Additionally, excessive heat can damage transportation and energy infrastructure, and impact water supply.

The U.S. Environmental Protection Agency recommends strategies to mitigate and adapt to excessive heat. They include planting vegetation, installing green roofs, and using reflective materials on hard surfaces to reduce heat absorption. Steps to improve infrastructure resilience include upgrading transportation infrastructure with heat-resistant materials and conserving energy during heat waves.

To help identify priority areas for heat adaption and mitigation efforts, CMAP will create a heat susceptibility index, similar to our existing flood susceptibility index.

Climate change will increase the frequency of drought, which threatens crops, ecosystems, and drinking water supplies. Droughts reduce river flows and increase algae growth. Algae can clog water treatment filters, making the process more difficult and expensive. While safe to drink, algae can cause even treated water to taste and smell unpleasant.

Droughts also mean there is less water to refill — or recharge — groundwater aquifers. Dried soils can also increase runoff, which worsens recharge and water quality challenges. When aquifer withdrawals exceed the recharge rate, well water users have to compete for less water.

Summer months increase stress on our water supply. Temperatures are higher, and so is demand for water, which typically peaks in July. Drought aside, summer use can strain resources and infrastructure, cause peak usage to rise, and increase the need for costly infrastructure upgrades.

CMAP is developing a drought susceptibility index to determine which areas could be affected by decreasing groundwater recharge. CMAP also works with the Northwest Water Planning Alliance, a coalition of over 70 communities and their county governments, to collaboratively plan for shared groundwater resources. ON TO 2050, northeastern Illinois’ long-range plan, calls for water conservation that can promote more sustainable practices for communities grappling with water supply limitations.

Air quality in northeastern Illinois has improved over the last few decades, yet ozone pollution still poses a serious public health threat, as the region often exceeds acceptable ozone levels during the summer. Ozone forms when other pollutants, such as emissions from cars, trucks, power plants, and forest fires, react with heat and sunlight. Thus, summer days, especially in urban areas, are associated with higher ozone levels.

Ozone can damage the lungs, aggravate chronic respiratory problems like asthma, and compromise the body’s ability to fight respiratory infections. Even relatively low exposure can cause chest pain, coughing, shortness of breath, and throat irritation.

While poor air quality affects the entire region, some people are more at risk, such as those with asthma, seniors, children, and people with low income. Children whose lungs are still developing are of particular concern, as high ozone exposure can lead to increased cases of asthma when they become adults. People with low income may not benefit from good home ventilation and air conditioning, and may spend more time outside on days when ozone levels are higher, increasing their exposure.

The Illinois Environmental Protection Agency (IEPA) monitors ozone and announces when it predicts levels will be high. During these ozone action days, IEPA encourages residents to reduce ozone pollution, such as reducing driving, avoiding mowing the lawn, and conserving electricity.

CMAP is responsible for ensuring that transportation investments will not worsen air quality over time. CMAP also receives Congestion Mitigation and Air Quality funds to invest in transportation projects that reduce emissions, such as public transit, cleaner trains, bike paths, and sidewalks.

Climate change will significantly affect northeastern Illinois’ people, economy, ecosystems, and infrastructure. In ON TO 2050, CMAP set the goal of preparing the region for climate change by planning for resilience and intensifying climate mitigation.

There are things your community can do to prepare for and mitigate summer heat, drought, and air quality issues:

• Reduce outdoor water use: Communities can reduce outdoor water use by creating common watering guidelines, targeting high outdoor water users, and encouraging water-saving landscapes.

• Reduce ozone: Communities can reduce sources of ozone by supporting electric vehicles, biking, and walking. CMAP provides funding for these kinds of activities through the Congestion Mitigation and Air Quality Improvement Program and Transportation Alternatives Program.

• Monitor drought conditions: Municipalities should monitor drought conditions to help guide water conservation activities.

• Take action: Read the 2021 Climate Action Plan for the Chicago Region. Developed by the Metropolitan Mayors Caucus with CMAP and others, it is one of the first regional climate plans in the country. The plan’s objectives, from decarbonizing transportation to managing drought and water supply, were written for action at the municipal level.

• Create a drought action plan: Communities should develop municipal drought action plans. The American Water Works Association and U.S. Drought Portal provide guidance on drought planning and preparedness.