The connection between hot weather and increased crime: A worrying trend

Hurricane Milton has officially made landfall in Florida, United States, leaving more than 3 million residents without power – and thousands lost, injured and even presumed dead.

In addition to the real-time effects of the violent weather event that has rocked North America, residents must contend with another concern – weather-related crime.

In fact, studies have shown a link between extreme weather conditions and increased crime, as individuals can take advantage of vulnerable people, easy access to public areas and belongings, and distracted support workers.

So what comes first – crime or unprecedented weather events? More and more studies are showing a link between severe weather and criminal activity, particularly in scorching climates – like Australia.

The connection between weather and crime

A study conducted in Chicago between 2012 and 2017 found that crimes, particularly violent crimes like assault, increased significantly on days with higher temperatures.

And a study in the United Kingdom between 2012 and 2018. The London Metropolitan Police found that violent crime was almost 15% higher on high temperature days above 20 degrees than on days when temperatures fell below 10 degrees.

Similarly, a study by Drexel University in the US city of Philadelphia found that crime rates are highest during the warmest months of the year and highest on the hottest days.

But why? Is there a biological and chemical reaction in humans at oppressive temperatures that leads to stress reactions? Actually yes.

Studies have shown that heat has physical effects on the human body and people are more likely to have more intense reactions than in mild temperatures. Excessive heat triggers the body’s “flight-or-fight” response, a natural reaction to perceived threat or danger that can lead to hasty decisions and hostility.

The increase in hostility, testosterone and lack of clear thinking in humans are the key indicators that heat causes violent crime. In fact, the University of Iowa found that there are 2.6% more murders in the US during the summer months.

And closer to home, a study conducted in Byron Bay in northern New South Wales also showed that crime rates are significantly higher in the summer. And another study conducted in nearby Ballina came to the same conclusion.

Urgent need to address climate change in Australia

Because hotter days lead to irrational decisions, higher testosterone levels, and hostility toward those in the immediate area, there is the potential for increased crime rates in scorching climates. In the warmer countries of the world, there is therefore a high probability that the behavior of their inhabitants is worrying – and one of them happens to be Australia.

As temperatures continue to rise due to global warming, Australian residents are suffering from increasingly hotter summers. And although our residents are used to warm temperatures, there is an argument that climate change may cause discomfort even for local Australians.

A study conducted from 2001 to 2019 considered average crime rates and the standard deviation of average temperature. The results showed that an increase in average temperature led to a 0.008-0.011 standard deviation increase in crime rates, resulting in more than 70,000 additional crimes per year in the country.

The results of this study not only address the connection between heat and crime, but also consider the following:

1. The total cost of crime in the country is more than $35 billion per year.
2. Climate change is becoming an increasingly serious global challenge
3. The results can help states allocate police resources to search for “hotspot” areas.

The incidence of domestic violence increases as temperatures rise

One of the most common crimes increasing as temperatures rise in Australia is domestic violence.

With domestic violence already at epidemic levels in our country, there are concerns that the situation could worsen as our climate gets hotter and heatwaves and extreme weather events such as bushfires become more severe and frequent.

A study conducted over a 13-year period between 2006 and 2018 in New South Wales showed that violence increased in warmer weather – and domestic violence in particular compared to other types of crime.

The data suggests that the projected daily rate of domestic violence was much higher than the rate of non-domestic violence or sexual assault. With temperatures reaching 44 degrees, there were more than 30 incidents of domestic violence per day, compared to 20 incidents of non-domestic violence and fewer than 10 sexual assault crimes.

But why? We know that hot weather can lead to spikes in testosterone and a lack of mental clarity. Looking specifically at domestic violence, hot weather correlates with aggression and irritability, which can lead to targeting another person in the same household.

Additionally, during heatwaves or hot days, Australians may choose to “cool off” with a drink – often it is alcohol. Alcohol is responsible for more than 40% of domestic violence cases, with three out of four cases of violence being caused by a partner’s drinking.

Understanding the connection between violent crime and weather in Australia

There is a strong connection between violent crime, air temperature, “urban” heat and green spaces. Simply put, due to the urban form, urban areas tend to be hotter than rural areas, which can be combated by adding green spaces to existing infrastructure.

A Greater Sydney study conducted between 2013 and 2018 found that outdoor crime rates were higher in an urban area, but not necessarily indoors. In areas with higher levels of vegetation, such as rural areas or forested areas, crime rates were lower.

Queensland Study

A study conducted in Queensland that examined the seven climate zones over a 12-year period and examined how climate change affected people in each zone. The study found that an increase in rainfall is directly inverse to violence, whereas an increase in temperature is proportional to the increase in violence.

The results of the study confirm the current literature and highlight the need for support, routine activities, adequate nutrition and activities on hot days to avoid boredom, lack of fulfillment and irritability. “Routine activities” refer to the regular, everyday activities that people engage in, for example at work, school or in their leisure time. They can help distract individuals from the inconveniences of hot weather and reduce the likelihood of criminal behavior.

Flooding in New South Wales

One of the most well-known Australian weather events in recent years has been the unimaginable flooding in Queensland and New South Wales. In New South Wales in particular, flooding made access to many homes, neighborhoods, businesses and emergency centers almost impossible.

There were numerous reports of women experiencing domestic violence, assault and sexual assault as a result of the northern river floods due to a lack of emergency shelter and adequate treatment.

A report prepared after the flood showed that women needed to rise to leadership positions to help other women feel safe and comfortable during their health crises. Flood witnesses and health care workers noted that other women were most at risk of trauma, threats to themselves, and threats to their property.

In the immediate aftermath of the 2022 NSW floods, women were extremely unsafe in the emergency shelters designed to house and protect them following the weather event. The support was essential to getting people off the streets and into a dry place, but the disorganization led to unmitigated risks in the system.

Women and children were required to share common areas with domestic violence offenders, those accused of sexual offenses, and those who could behave irrationally during drug withdrawal.

Many women in the shelters reported gender-based violence, sexual assault, and lack of medical care, resulting in injuries, trauma, and pregnancies.

Does hot weather contribute to crime?

According to the research, there appears to be a significant relationship between crime rates and the weather.

The temperature aggression hypothesis, coupled with the way weather events can lead to opportunities for physical interactions between potential perpetrators and victims, helps people understand who is most at risk during intense weather phenomena.