Hotter Temperaments: Prisons and Violence in a Warming World

By and ·November 10, 2021
University of Wisconsin-Madison and Cornell University

The Issue:

Record heat waves in 2021 highlighted the danger of heat-related deaths. In addition, more frequent and intense heat waves can bring a series of less-known social challenges ranging from disruptions in learning to increasing levels of aggression. These effects can be difficult to observe, as people change their behavior to avoid the heat or employ mitigation strategies, such as installing air conditioning. But these actions aren't free, and they aren't available to everyone. Many correctional facilities in some of the hotter areas of the United States lack even basic climate control. We find very hot days mean more conflict, assaults, and killings among the incarcerated, highlighting previously unobserved social costs of outdated prison infrastructure with uncontrolled climate conditions.

Days above 80F raise daily violent acts by about 20% in Mississippi correctional facilities, causing an estimated additional 44 serious assaults and killings per year in the state’s prison system.

The Facts:

  • The mortality effects of heat exposure are often in the news, but intense heat also impacts and changes behavior in more subtle ways. The summer 2021 heat wave across the Pacific Northwest wreaked havoc on facilities never designed to handle triple-digit temperatures and contributed to nearly 200 premature deaths, according to official reports. Such intense heat also means reductions in agricultural output and learning, elevated health risks, and reduced fertility, among other effects. People studying the costs of climate change often focus on adaptation: how people can make changes to their daily lives, from running the air conditioning on hot days to moving to cooler climates, to try and avoid some of the dangers of heat. Lower socioeconomic status (SES) groups possess fewer options for dealing with rising temperatures. 
  • Intense heat correlates with aggressive and destructive behavior in a diverse array of settings. Studies on Major League Baseball and National Football League athletes show players exhibit more hostile behavior in extreme temperatures. Heat increases the likelihood a pitcher hits a batter with a pitch, and raises the prevalence of aggressive penalties in football. In a laboratory setting, turning up the heat caused individuals to engage in destructive behavior in social modeling games. And violent crime levels rise on hot days, even more so in lower income areas. But challenges associated with accounting for avoidance and mitigation strategies, as well as other confounding factors, make it difficult to show the extent to which exposure to higher temperatures causes violent behavior when situations limit opportunities for adaptation.
  • Correctional facilities in many states lack any air conditioning. Climate control in correctional facilities is a contentious issue. During hot days, the indoor heat index in some prisons can reach 150 degrees Fahrenheit. Several legal cases argue severe temperatures in correctional facilities led to prisoner deaths, and staff members have suggested high temperatures contribute to prison violence. In Texas, where at least 13 men have died of heat stroke while incarcerated over the last decade, 70% of the state’s nearly 100 prison facilities did not have air conditioning in living areas as of 2021, according to the Texas Tribune. The state recently passed a law to air condition prisons by 2029, but a lack of guaranteed funding for the installation makes climate control in the state’s prisons an ongoing policy dilemma (see here). The issue isn't unique to Texas; courts in Wisconsin, Arizona, and Mississippi ruled incarceration in extreme temperatures violates the Eighth Amendment barring cruel and unusual punishment. While localities cite cost issues as a barrier to addressing temperature mitigation, some may withhold air conditioning in prison as a policy tool to appear "tough on crime." Estimates suggest some states have spent more fighting prison air conditioning than it would cost to install (see articles on Texas and Louisiana).
  • Our research shows that hotter days mean more violence in Mississippi correctional facilities. We analyze incident-level misconduct data from the Mississippi Department of Corrections from 2004 through 2010, combined with daily information on temperature. We study 36 facilities located around the state. No correctional facility in our analysis provides any temperature controls to incarcerated individuals over the period. We find that a day with an average outdoor temperature above 80F raises both the count of daily violent acts and the probability of occurrence of any violent act by approximately 20% of baseline. While 80F may not sound particularly hot, days with an average outdoor temperature of 80F and above have an average maximum daily temperature of 93F, and can reach maximum heat index levels of over 120F. Based on Mississippi climate, we estimate that this translates to heat causing an additional 44 serious assaults and killings per year in the state’s prison system. These are severe violent events with substantial social costs. The system typically processes these acts as new crimes, generating extended sentences for those instigating violence. Identifying the link between heat and violence requires isolating the effects of temperature from other factors driving prison conditions, like seasonality (facilities tend to have higher rates of violence during the holiday season, for instance). Our research addresses this by using variation in temperatures both within season and across different parts of the state of Mississippi (comparing hotter days in June to cooler days in June, for example) to show hotter days mean more violence. 
  • Constrained conditions tell us something more general about the true costs of climate change. The steps people take to avoid high temperatures – staying inside and turning on the air conditioning, avoiding exercise or strenuous work, etc. – aren't without costs. People have to change their routines, give up their favorite activities, or spend money on electricity generating additional carbon emissions. When we study the effects of rising temperatures, we see results net of these costly adjustments, making it harder to properly attribute social costs to rising heat. While prison infrastructure does not reflect the conditions of the larger population, it tells us something about how the unobserved actions people take might bias estimates of heat and violence. The results we find in prisons represent percentage increases in violence that are approximately twice as large compared to other studies linking heat to crime and gun violence in less constrained settings, suggesting the steps we can't see people take are blunting the true dangers of heat in other studies.
  • The case of the incarcerated highlights the inequalities of adaptation – a population with no mobility, limited income, and little to no options for temperature control, faces a different picture in a world with more frequent heat waves. While prison conditions are unique on some dimensions, billions around the world have limited tools of adaptation at their disposal. This makes the link between heat and intense violence in constrained conditions an additional social consequence of rising global temperatures.

What this Means:

Hotter temperatures mean hotter temperaments. Studies of climate and conflict regularly find more heat means more violence, and more so with lower financial resources and more constrained adaptation. The contentious nature of current prison infrastructure, devoid in some cases of almost all opportunities for adaptation, provides a rare picture of how the effects of heat can escalate in extreme situations with little option for avoidance. While the incarcerated are not representative of global populations, the situation of limited resources and constrained adjustment opportunities show up across the globe. Infrastructure built without the expectation of extreme heat is facing record-setting temperatures with buildings and electricity grids ill-prepared to address the problem. Without substantial investment and planning, more people around the world will be facing temperatures conducive to rising conflict.

  • Editor's note: The analysis in this memo is based on: Mukherjee A. and Sanders N. “The Causal Effect of Heat on Violence: Social Implications of Unmitigated Heat Among the Incarcerated.” NBER Working Paper 28987, July 2021.

  • Topics:

    climate change / Crime and Criminal Justice / Environment
    Written by The EconoFact Network. To contact with any questions or comments, please email [email protected].
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