Temperatures peaked at 104 degrees during the deadly 1995 Chicago heat wave, according to NOAA data.
With hot temperatures flaring across the United States in the coming days – 21 states have extended heat alerts and cities along the East Coast are hitting high temperatures starting Friday – this AdaptNY case study of the Chicago heat wave of 1995 looks at how the urban heat island effect is exacerbated by socio-economic factors and poor city planning. These are concerns not unique to Chicago, but also to places like Harlem, where we are currently running our Harlem Heat Project.
The heat wave of July 1995 in Chicago was one of the worst weather-related disasters in Illinois history, with over 700 deaths over a five-day period, according to the state’s climatologist, Dr. Jim Angel. The 1995 heat wave also had a heavy impact on the wider Midwestern region, with additional deaths in St. Louis and Milwaukee.
In Chicago, local temperatures soared to record highs that July, with the hottest weather occurring from July 12 to July 16. The high of 106 °F on July 13 was the second warmest July temperature since record keeping began at Chicago Midway International Airport in 1928. Nighttime low temperatures were unusually high — in the upper 70s and lower 80s °F.
Record humidity levels also accompanied the hot weather. The heat index reached 119 °F at O’Hare Airport, and 125 °F at Midway Airport. Humidity was reportedly a more significant factor in 1995, as opposed to earlier regional heat waves.
Impacts of the heat wave on the Chicago urban center were exacerbated by an “urban heat island effect” that raised nocturnal temperatures by more than 3.6 °F. Urban heat islands are caused by the concentration of buildings and pavement in urban areas, which tend to absorb more heat in the day and radiate more heat at night into their immediate surroundings than comparable rural sites. Therefore, built-up areas get hotter and stay hotter.
Aggravating factors
Establishing an official “death toll” for the 1995 Chicago heat wave was highly contentious. But most of the victims of the heat wave were elderly poor residents of the inner city, who could not afford air conditioning and did not open windows or sleep outside for fear of crime. By contrast, during the heat waves of the 1930s, many local residents slept in parks or along the shore of Lake Michigan.
Further epidemiologic analysis showed that blacks were more likely to die than whites, and that Hispanics had an unusually low death rate due to the heat. One explanation given is that many blacks lived in areas of sub-standard housing with numerous social stresses, while Hispanics lived in places with higher population density, and more social cohesion.
Hundreds of Chicago residents died alone, behind locked doors and sealed windows, out of contact with friends, family, and neighbors, unassisted by public agencies or community groups. There’s nothing natural about that. – Eric Klinenberg
Other factors that contributed to the high death rate, the state’s climatologist argued, were an inadequate local heat wave warning system, power failures, inadequate ambulance service and hospital facilities, and the aging of the population in urban areas.
No official heat emergency warning was released until the last day of the heat wave. Thus, emergency measures such as Chicago’s five cooling centers were not fully utilized. The city’s health-care system was severely taxed as thousands were taken to local hospitals with heat-related problems, such as dehydration, heat stroke, and heat exhaustion.
Another powerful factor in the heat wave was that a “temperature inversion” grew over the city, and air stagnated. Pollutants and humidity were confined to ground level, and without wind, temperatures grew even hotter- indoor temperatures were reported to exceed 90 °F at night. This was especially noticeable in areas which experienced frequent power outages.
A ‘social disaster’
From the moment the local medical examiner began to report heat-related mortality figures, some political leaders, journalists, and even the mayor, actively denied the disaster’s real significance. Critics of the city argued that better preparation could have averted some of the deaths that occurred. But underlying societal weaknesses were another, more complicated factor.
Eric Klinenberg, author of the 2002 book, “Heat Wave: A Social Autopsy of Disaster in Chicago,” has noted that the map of heat-related deaths in Chicago mirrors the map of poverty and urban abandonment — a deeper cause, he says, the city did not want to acknowledge.
“Of course forces of nature played a major role. But these deaths were not an act of God,” said Klinenberg in a 2002 interview. “The most sophisticated climate models ‘failed to detect relationships between the weather and mortality that would explain what happened in July 1995 in Chicago.’”
“The death toll was the result of distinct dangers in Chicago’s social environment,” he added, “Hundreds of Chicago residents died alone, behind locked doors and sealed windows, out of contact with friends, family, and neighbors, unassisted by public agencies or community groups. There’s nothing natural about that.”
Could it happen again?
Klinenberg maintains that “the city did learn from its mistakes. In 1999, when Chicago experienced another severe heat wave, the city issued strongly worded warnings and press releases to the media, opened cooling centers and provided free bus transportation to them, phoned elderly residents, and sent police officers and city workers door-to-door to check up on seniors who lived alone.”
That “aggressive response” drastically reduced the death toll of the 1999 heat wave: 110 residents died, a fraction of the 1995 level but “still catastrophic. … There are limits to what any emergency plan can accomplish,” Klinenberg observed, referring to Chicago’s ongoing social stresses.
The state’s climatologist Jim Angel agrees that Chicago will continue to be vulnerable to heat waves because of rising temperatures associated with climate change, the urban heat island effect and the socio-economic makeup of the area- its high percentage of lower-income, elderly residents.
But Angel adds, the number of deaths may be reduced by: a) implementing an early-warning system that takes local conditions into account, b) better defining the heat island conditions associated with heat waves to improve forecasts, c) developing a uniform means for classifying heat-related deaths, and d) increasing research on the conditions of heat stress and heat waves.
Subsequent policy response?
Since the heatwave in 1995, Chicago has updated its heatwave emergency response policies in several ways. The Office of Emergency Management and Communications now houses under one roof its emergency responders unit, 311 Call Center, and the Traffic Management Authority, all to help the city mobilize during an extreme heat event and to better collect data that helps the city identify its most vulnerable areas.
Chicago has also initiated several adaptation-related policies to reduce the urban heat island effect. For instance, the city has installed more than 100 green alleys, using a porous gravel structure that eliminates dark, heat-absorbing surfaces. It has also established grants to promote green roofs and the installation of trees, plants, compost bins, and rain barrels. And a landscape ordinance mandates that trees be planted on parkways, parking lots and loading docks.
Interview excerpt with Eric Klinenberg, 2002
“The city set new records for energy use, which then led to the failure of some power grids—at one point, 49,000 households had no electricity. Many Chicagoans swarmed the city’s beaches, but others took to the fire hydrants. More than 3,000 hydrants around Chicago were opened, causing some neighborhoods to lose water pressure on top of losing electricity. When emergency crews came to seal the hydrants, some people threw bricks and rocks to keep them away.
“The heat made the city’s roads buckle. Train rails warped, causing long commuter and freight delays. City workers watered bridges to prevent them from locking when the plates expanded. Children riding in school buses became so dehydrated and nauseous that they had to be hosed down by the Fire Department. Hundreds of young people were hospitalized with heat-related illnesses. But the elderly, and especially the elderly who lived alone, were most vulnerable to the heat wave.
“After about forty-eight hours of continuous exposure to heat, the body’s defenses begin to fail. So by Friday, July 14, thousands of Chicagoans had developed severe heat-related illnesses. Paramedics couldn’t keep up with emergency calls, and city hospitals were overwhelmed. Twenty-three hospitals—most on the South and Southwest Sides—went on bypass status, closing the doors of their emergency rooms to new patients. Some ambulance crews drove around the city for miles looking for an open bed.
“Hundreds of victims never made it to a hospital. The most overcrowded place in the city was the Cook County Medical Examiners Office, where police transported hundreds of bodies for autopsies. The morgue typically receives about 17 bodies a day and has a total of 222 bays. By Saturday—just three days into the heat wave—its capacity was exceeded by hundreds, and the county had to bring in a fleet of refrigerated trucks to store the bodies. Police officers had to wait as long as three hours for a worker to receive the body. It was gruesome and incredible for this to be happening in the middle of a modern American city.”
The full interview can be read at: http://www.press.uchicago.edu/Misc/Chicago/443213in.html
EDITOR’S NOTE: AdaptNY prepared this case study for a 2014 workshop in Chicago that explored risks that different regions must grapple with in the face of climate change.