High ambient temperatures are associated with urban crime risk in Chicago

Examining the Association between Heat Exposure and Crime in Cities across the United States: A Scoping Review

Growing evidence suggests exposure to high temperatures may result in increased urban crime, a known driver of health and health inequity. Theoretical explanations have been developed to describe the heat-crime relationship without consensus yet achieved among experts. This scoping review aims to summarize evidence of heat-crime associations in U.S. cities. Further examination of empirical and translational inconsistencies in this literature will ensure future studies of urban heat-crime relationships in the U.S., and their policy impacts are informed by a thorough understanding of existing evidence. We performed a comprehensive literature search of empirical studies on heat-crime relationships in U.S. cities published between January 2000 and August 2023. The included studies were qualitatively synthesized based on operationalized exposures, outcomes, covariates, methodologies, theoretical framing, and policy implications. In total, 46 studies were included in this review. Most studies (93%) reported significant, positive associations between urban heat exposure and both violent and non-violent crime outcomes. The shape and strength of these associations varied based on operational definitions of urban heat exposures, crime outcomes, and relevant covariates in employed methods. We also found inconsistencies in the theoretical explanations and policy implications reported across studies. Climate-driven extreme heat events are projected to increase in frequency and severity. Our findings underscore the urgency of refining the understanding and translation of the complex relationship between urban heat and crime. In this review, we highlight opportunities to improve the methodological quality and responsible policy translation of future research in U.S. cities, which has implications for research globally.

Temperature, violent crime, climate change, and vulnerability factors in 44 United States cities

Biological and psychological theories suggest complex impacts of heat on aggression and violence. Most previous studies considered temporal intervals of months to years and assumed linear associations. Evidence is needed on daily impacts of temperature on crime, applying non-linear models across different locations. This observational study examined non-linear relationships between daily summer temperature (May-September) and violent crime in 44 cities across 33 US states, 2005-2022. We calculated city-specific average temperature for the event day and previous day (lag0-1) and daily temperature anomalies (deviation from 1985 to 2010 average) using PRISM data. The Uniform Crime Reporting Program data were used to calculate daily city-specific number of violent crimes (n = 2,447,458 incidents). Generalized additive modeling was used to estimate relative risks (RRs) of violent crime. We identified three distinctive shapes (J-shaped, inverted J-shaped, linear) for relationships. The inverted J-shaped curve, indicating higher crime rates at high temperatures below extremely hot temperatures, was most predominant (26 cities). Across all cities, violent crime was 1.03 times higher at high compared to moderate temperatures (90th vs. 50th percentiles) (RR 1.03, 95 % CI: 1.02-1.04). Violent crime was also higher at moderate compared to cold temperatures (50th vs. 10th percentiles) [RR 1.04 (95 % CI: 1.03-1.06)], whereas risk did not differ between extremely high and hot temperature (99th vs. 90th percentiles). Risk during hot days versus moderate temperature days was significantly lower for cities with lower latitude, higher median temperature, higher urban greenspace, and higher percentage of occupied housing units with air conditioners. Risk was higher in cities with 90th percentile temperature anomalies that deviated from the historical temperature record, suggesting implications of climate change on heat-related violence. High daily temperatures are associated with violent crime with differences across locations. Disparities in risks by city-level social and environmental characteristics have implications for climate change strategies.

Temperature, Crime, and Violence: A Systematic Review and Meta-Analysis

BACKGROUND

Heat is known to affect many health outcomes, but more evidence is needed on the impact of rising temperatures on crime and/or violence.

OBJECTIVES

We conducted a systematic review with meta-analysis regarding the influence of hot temperatures on crime and/or violence.

METHODS

In this systematic review and meta-analysis, we evaluated the relationship between increase in temperature and crime and/or violence for studies across the world and generated overall estimates. We searched MEDLINE and Web of Science for articles from the available database start year (1946 and 1891, respectively) to 6 November 2023 and manually reviewed reference lists of identified articles. Two investigators independently reviewed the abstracts and full-text articles to identify and summarize studies that analyzed the relationship between increasing temperature and crime, violence, or both and met a priori eligibility criteria. PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were used to extract information from included articles. Some study results were combined using a profile likelihood random-effects model for meta-analysis for a subset of outcomes: violent crime (assault, homicide), property crime (theft, burglary), and sexual crime (sexual assault, rape). This review is registered at PROSPERO, CRD42023417295.

RESULTS

We screened 16,634 studies with 83 meeting the inclusion criteria. Higher temperatures were significantly associated with crime, violence, or both. A 10°C (18°F) increase in short-term mean temperature exposure was associated with a 9% [95% confidence interval (CI): 7%, 12%] increase in the risk of violent crime (I 2 = 30.93 % ; eight studies). Studies had differing definitions of crime and/or violence, exposure assessment methods, and confounder assessments.

DISCUSSION

Our findings summarize the evidence supporting the association between elevated temperatures, crime, and violence, particularly for violent crimes. Associations for some categories of crime and/or violence, such as property crimes, were inconsistent. Future research should employ larger spatial/temporal scales, consistent crime and violence definitions, advanced modeling strategies, and different populations and locations. https://doi.org/10.1289/EHP14300.

Health risks from extreme heat in China: Evidence from health insurance

Global warming has accentuated the effects of extreme heat on health. Health insurance, functioning as a risk management tool, has the potential to alleviate these impacts. Consequently, this paper investigates the correlation between extreme heat events and the demand for health insurance in China. Using data from the China Health and Nutrition Survey, we have observed a substantial increase in the likelihood of residents purchasing health insurance during extreme heat events. To be specific, for every extra day of extreme heat events annually, there is a 0.3% increase in the probability of purchasing health insurance. This effect is not uniform across different demographic groups. It is particularly pronounced among middle-aged and elderly individuals, rural residents, those with lower educational levels, higher income brackets, and individuals residing in underprivileged areas with limited access to green spaces and healthcare facilities. Furthermore, our study indicates that the increased frequency of extreme heat events not only impacts individuals' physical health but also triggers negative emotions, which in turn drive risk-averse behavior related to health insurance purchases. These findings carry substantial policy implications for mitigating the economic consequences of climate change.

A nationwide time-series analysis for short-term effects of ambient temperature on violent crime in South Korea

Psychological theories on heat-aggression relationship have existed for decades and recent models suggest climate change will increase violence through varying pathways. Although observational studies have examined the impact of temperature on violent crime, the evidence for associations is primarily limited to coarse temporal resolution of weather and crime (e.g., yearly/monthly) and results from a few Western communities, warranting studies based on higher temporal resolution data of modern systemic crime statistics for various regions. This observational study examined short-term temperature impacts on violent crime using national crime data for the warm months (Jun.-Sep.) across South Korea (2016-2020). Distributed lag non-linear models assessed relative risks (RRs) of daily violent crime counts at the 70th, 90th, and 99th summer temperature percentiles compared to the reference temperature (10th percentile), with adjustments for long-term trends, seasonality, weather, and air pollution. Results indicate potentially non-linear relationships between daily summer temperature (lag0-lag10) and violent crime counts. Violent crimes consistently increased from the lowest temperature and showed the highest risk at the 70th temperature (~ 28.0 °C). The RR at the 70th and 90th percentiles of daily mean temperature (lag0-lag10), compared to the reference, was 1.11 (95% CI 1.09, 1.15) and 1.04 (95% CI 1.01, 1.07), indicating significant associations. Stratified analysis showed significant increases in assault and domestic violence for increases in temperature. The lagged effects, the influences of heat on subsequent crime incidence, did not persist 21 days after the exposure, possibly due to the displacement phenomenon. We found curvilinear exposure-response relationships, which provide empirical evidence to support the psychological theories for heat and violence. Lower public safety through increased violent crime may be an additional public health harm of climate change.

High temperatures and urban entrepreneurship levels: Evidence from China

This paper performed as a frontier try to investigate the effect of high temperatures on entrepreneurship, assessed from an urban perspective. This paper estimated the impact of high temperatures on urban entrepreneurship levels using data from 281 prefecture cities in China, during the period 2000-2017. This paper found that a single day with a temperature of above 30 °C led to a decrease of 0.47 % in urban entrepreneurship levels, compared with a single day recording comfortable temperatures. Following a series of robustness tests, the results were found to be significant. Next, this paper conducted a series of heterogeneity analyses and discovered that cities with advanced industrial structures, larger sizes and more essential hierarchies were less affected by high temperatures. Finally, this paper further analyzed the potential influence mechanisms of high temperatures on entrepreneurship. This paper found that high temperature affects urban entrepreneurship levels by worsening the entrepreneurial environment, especially by reducing human capital, hindering innovation, decreasing the financial support available to enterprises, and hindering economic development. The results of our study have thus enriched the literature on entrepreneurship by exploring the impact of climate change on entrepreneurship.

A study of the thermal comfort in urban mountain parks and its physical influencing factors

Urban thermal comforts are increasingly holding people's attention due to global warming and urban heat islands. Urban parks can absorb sunlight radiation, which reduces air temperature, improving urban microclimates. Various factors in the park are confirmed to be effective in heat mitigation. However, there are few studies on thermal comfort in urban mountain parks, and mountain areas might cause peculiar climatic conditions owing to their particular landforms. To fill this gap in the research, this study explored thermal comfort in mountain parks and the environmental factors that would affect thermal comfort. A field measurement in the summertime (July & August) of 2018, it was found that trees, the river, and the area of parks could adjust the thermal comforts of mountain parks. Their effects varied throughout the day, and the impacts of trees were most pronounced at noon and late afternoon, while the influence of rivers and park areas was most pronounced at noon. Increasing the leaf area index by 1 point could result in decreases in physiological equivalent temperature, land surface temperature, and solar radiation level by 3.90 °C, 2.69 °C, and 270.10 W/m2, respectively. The findings have practical implications for future urban mountain park design works.

Spatiotemporal Analysis of Injury Events Against Doctors in Guangdong Province by Geographic Information System

Background

Violence against doctors is a global concern. Violent injuries against doctors occur periodically in China. At least one violent injury event was witnessed by 54% of medical staff against doctors in 2020. Analyzing this phenomenon and establishing preventive measures is a common concern of the medical and criminal communities.

Methods

This study comprised 712 injury events against doctors in Guangdong Province, China, from January 2019 to October 2022. The spatial distribution and spatiotemporal changes of these events were analyzed using ArcGIS and Excel software.

Results

Considering the geographical distribution, the injury events against doctors showed a three-level concentric circle pattern where, Guangzhou and Shenzhen, adjacent cities, and distant cities were ranked as high, medium, and low-risk areas, respectively. In temporal distribution, the periods of high incidence were 9-11, 14-15, and 20 o'clock, and the incidence tended to be similar daily, with the peaks in June and July.

Conclusion

We found that the risk level of injury events against doctors was positively correlated with the medical resources level in the areas. The injury event incidence was higher during the daytime working hours. Temperature may have a strong positive effect on injury events against doctors.