The third dangerous heat wave this year has settled over 16 states affecting over 65 million people and weather experts say to brace yourself for more. While these triple-digit temperatures increase the likelihood of heat-related illnesses, studies have found that significant seasonal pattern trends lead to more people becoming violent.
Heat has been a major component of violent crimes historically. In the United Kingdom, between April 2010 and 2018, there was 14% more violent crime at 20° Celcius than there was at 10º Celcius. In Mexico, there is more organized crime in warmer weather and some academics suspect this is because it creates a “taste for violence”. In South Africa, scientists have discovered that, for every degree that the temperature goes up, there is a 1.5% increase in the number of murders.
In Greece, one study found that more than 30% of 137 homicides reported in a particular region occurred on days with an average temperature of more than 25° Celcius. When the first wave of protests erupted in Ferguson, Missouri, following the shooting of Michael Brown in August 2014, it looked as if unrest might spread to other American cities, echoing the “long hot summers” of 50 years before.
Throughout the 1960s, a seasonal pattern of racial riots developed across urban America, leading observers to hypothesize about an association between summer heat and urban unrest. The Kerner Commission, tasked by President Lyndon Johnson with investigating the causes of the more than 150 riots that broke out in 1967, lay the blame on a toxic combination of poverty and racial politics. However, the Commission also noted that anger in urban America was being stoked by the uncomfortable heat of summer.
Related: Anatomy of a Breakdown
This trend of increased violence during extreme heat conditions has led more researchers to look into the correlation between the two. In fact, a 2014 U.S. Department of Justice report accumulated data for nearly two decades that experts say lead to more people becoming violent crime victims during June, July, and August.
In a recent study, researchers suggest that rising temperature increases some violent crimes, such as intentional homicides,3 sex offenses, and 4 assaults. In a retrospective study in seven US cities, every 5° Celcius rise in daily mean temperature between 2007 and 2017 was associated with a 4·5% increase in sex offenses in the following 0–8 days. A nationwide analysis in Japan between 2012 and 2015 found that ambulance transports due to assault increased linearly with the rise in daily temperatures. Violent incidents also showed a seasonal distribution by which most crimes happened in the summer or hot seasons than in winter. Hence, interpersonal violence in hot weather is likely to continue and increase in the future with increasing temperature due to climate change. In a 2014 paper, Matthew Ranson found that there could be an additional 22 000 murders, 1.2 million aggravated assaults, and 2.3 million simple assaults because of heat rises in the USA by the end of this century as compared with 2010.
Two Theories Can Explain Why Warmer Temperatures Lead To More Aggressive Behavior
There are two main theories that can help explain a positive association between ambient temperature and violent crime. According to The Lancet, the first theory, known as biological theory or temperature-aggression theory, explains that hot weather induces interpersonal violence by increasing discomfort, frustration, impulsivity, and aggression. However, this theory does not explain the increases in violent crime in areas where the temperature has risen from cold to warm, as temperature rise in this range is unlikely to cause uncomfortableness.
The second theory known as routine activity theory, suggests that changes in ambient temperature can alter people’s routine activities (eg, outdoor events and social contacts) and increase interpersonal conflicts or create suitable crime environments. Evidence for this theory can be found in a separate study conducted in 2021. Researchers at Stanford University detailed in Heat, Crime, and Punishment, the relationship between heat impacting the behavior of all individuals involved in criminal events, such as the defendants and police officers alike. The researchers found that with temperatures above 90 degrees Fahrenheit, arrest rates increased by approximately 5 percent relative to days between 60-65 degrees Fahrenheit with a day above 100 degrees Fahrenheit increasing violent crimes by more than 10 percent. Both aggravated assaults and assaults increase by between 10 and 20 percent at high temperatures. Lastly, Stanford University researchers found that arrests increase by up to 15 percent on extremely hot days, driven by increases in violent crime rather than by changes in police behavior.
Mental Health Is Also Affected
According to another study, one’s mental health is also affected by bouts of extreme heat. That research found that increased heat is associated with suicide, psychiatric hospital visits and ER visits, and increased anxiety, depression, and stress. Studies have also linked higher summer temperatures to decreased happiness.
Why is any of this important? If preparedness is a mindset, it is important to factor in the psychology and frame of mind of those who you may encounter in emotionally flared situations brought on by heat. Knowing this can help you diffuse the situation you are in and find safety. As well, given other factors like a global pandemic, production, and good scarcity, inflation, socio-economic issues, political strife, war, famine, etc., All these add to stress factors that could only lead to further increased crime.
How To Defuse Emotional Conflict
Keeping your emotions in check requires mental training on your part and is something you can practice daily in different situations.
Resist the mimic reflex. People tend to mimic the behavior of others, especially during a tense, emotional situation. The first step in defusing a conflict is to remain calm. If you remain calm, you can move on to the next step in neutralizing the conflict. Talk about the process rather than the conflict.
Focus on their interests. If you can focus on what other people want from the situation, you can keep their emotions from boiling over. Listen to understand rather than listen to respond and focus on solving the problem or walking away.
Learning to diffuse and stay calm can help you avoid getting into situations that can quickly spiral out of control. As the temperatures keep rising, it’s important to keep our emotions in check and know how we can help rather than adding to the already stressed situation.
Additional Reading:
The Heat is On: How to Stay Cool Without Air Conditioning
10 Blackout-Proof Preps You Need To Get Through Extreme Weather Emergencies
Proper spelling: Celsius.
While I agree with the theme that hot weather increases violence I take issue with your statements in paragraph 3. You wrote “In the United Kingdom, between April 2010 and 2018, there was 14% more violent crime at 20° Celcius than there was at 10º Celcius.
Perhaps you didn’t bother to do your research. 20 degrees C is only 68 degrees Fahrenheit. 10 degrees Celsius is 50 Fahrenheit. So the original study from the UK is terribly misleading, as well as your repeating it. 50 F is chilly, while 68 F is comfortable, so criminals would be more likely to be out doing crimes, but 68F is hardly a heat wave, is it?