Beijing time, September 2, according tomedia reports, hot summer will make people eager to eat ice cream, sunbathing on beautiful beaches, but the hot climate will also lead to people become grumpy, depressed, why?
Is there a close connection between hot weather and violence?
According to the statistics, the hot climate and people’s mood and behavior changes have a certain correlation, such as in 1988, not only set a new record for the United States hot climate, the year of violence also set a new record, the number of murders, rapes, armed robberies and attacks is unprecedented, about 1.56 million violent incidents that year, hot weather and violence is closely linked?
For hundreds of years, the idea that hot climates can change people’s behavior has been embedded in our language, where we describe the use of “anger” when tempers are violent and the body parts under the collar become hot when angry. In 1597, Shakespeare described Verona’s sweltering summer as “crazy blood boiling.”
The earliest study of the link between climate change and human behaviour, which occurred at the end of the 19th century, coincides with the first reliable crime statistics, according to an analysis that showed that human violations peaked in the summer months and property thefts were more common in winter.
Since then there has been more and more evidence of climate and human behaviour, and every year we experience a collective shift, some of which are not extreme – people are likely to honk their horns when they are stuck in traffic; police officers find that violations are on the rise; and slowly people are less likely to help strangers…
But some things can be unsettling, with global heatwaves leading to widespread droughts and frequent Arctic wildfires in 2018; hot climates that force reindeer to come to Finnish beaches; and even a smaller mountain in Sweden; and worrying human events. A record number of 999 calls were made in the British summer, with police describing the public’s response to the hot summer as “very strange” and in some areas a 40 per cent increase.
Of course this is anecdotes, and there are many other explanations for these individual events, but this broader correlation seems to be supported by a wealth of academic research from around the world. In South Africa, the number of murders increases by 1.5 per cent for every 1 degree Celsius increase in temperature.
Violent crime rates in the UK between April 2010 and 2018 were 14 per cent higher than at 10 degrees Celsius, and in Mexico, the warmer the weather, the more organised crime there were, with some experts speculating that “violent tendencies” were developing as temperatures rose. In South Africa, scientists found a 1.5 per cent increase in the number of murders for every 1 degree Celsius rise in temperature, and a Greek study showed that more than 30 per cent of the 137 homicides in a particular area occurred at a time when the average temperature was above 25 degrees Celsius.
Patterns of similar violent crime and hot weather have also been observed in sub-Saharan Africa, Taiwan, the United States, Finland and Spain, and the association effect has been confirmed in hundreds of scientific studies.
In one study, scientists tracked riots around the world between 1791 and 1880 and found that the vast majority of riots occurred during the summer months, a phenomenon that was widespread in both the northern and southern hemispheres. In Europe, for example, riot uprisings are most likely to occur in July.
A number of recent studies have confirmed the link between social movements and the weather, and an analysis of more than 7,000 social movements over a 36-year period found that these events usually occur at higher temperatures and are more likely to turn violent as temperatures rise. More recently, 27 people have been arrested after civil unrest ended one of the hottest weeks on record in the Netherlands: a building was set ablaze and people threw fireworks at police.
It is clear that injustices and other triggers of social unrest can occur throughout the year, but people are more likely to react during periods of higher temperatures. Trevor Harley, emeritus professor of psychology at the University of Dundee, said: “It’s a warning that the U-shaped rule is followed between temperature changes and riots, so when the weather gets very hot or humid, people want to do something because it’s uncomfortable to move. “
In addition, outdoor temperatures are associated with the rate of human self-harm, and a survey of 132,0148 suicides in 12 countries found that, overall, higher ambient temperatures were associated with an increased risk of suicide, particularly in Western countries and South Africa. Overall, the highest risk occurs in temperatures of 27 degrees Celsius, with Australian studies showing a surge in hospital admissions around 27 degrees Celsius and an increase of about 7.3 per cent during the summer heatwave.
Why the weather has such a big impact on human behavior remains a mystery, but as global temperatures warm, scientists are struggling to find answers, and there is plenty of evidence that high temperatures make us more angry, nervous and unhappy.
One of the more obvious possibilities is that sweltering weather can make people uncomfortable, make our overall mood worse, and lead to extreme behavior. There is plenty of evidence that high temperatures make people more angry, nervous, and unhappy, and that professional NFL football players are more likely to commit offensive actions and foul play in hot weather; journalists are more likely to use negative language in their reporting; and people are more likely to strike and resign.
Weather may affect our brains by altering our biology, a finding that further supports the latest research. In 2017, scientists found that ambient temperatures in Finland are linked to human serotonin levels, an important brain chemical that regulates anxiety, happiness and overall mood. Serotonin circulates in the blood of healthy volunteers and violent criminals, and crucially, they also found a strong correlation between serotonin indices and monthly violent crime rates, suggesting that heat alters the body’s serotonin index, which in turn affects our aggressive behavior.
Another view is that hot weather increases men’s testosterone levels and makes us more aggressive, a fact that may partly explain why the rate of sexual and domestic violence increases dramatically as the summer days get longer. In the United States, summer “intimate partner violence (including physical, sexual, and emotional abuse)” is 12 percent higher than in winter.
However, there are many other explanations, and an important link is that most studies are based on correlations – they link certain factors, such as temperature, to crime, but that doesn’t mean that one factor necessarily affects the other. When the sun rises every day, we live in a completely different world, with some people taking part in crowded celebrations, people accepting alcohol at social events, and usually drinking alcohol makes people more active and excited.
Are these summer activities that engage us and stimulate emotions with others the real driving force behind our heatwave behavior?
The occurrence of extreme behavior and temperature changes are difficult to separate, there is a certain correlation between the two, if in terms of suicide rate, the rate of suicide will increase when the weather warms, because people are outdoors, suicide behavior is more likely to occur … But the phenomenon varies widely around the world, with One of the highest suicide rates in Russia, which may be related to the heavy drinking of alcohol by the country’s inhabitants rather than the higher temperatures.
The global spread of the new crown outbreak may help shed light on the answer, as many normal summer activities have been cancelled since the new crown virus appeared, and the pandemic has proven to be a natural experiment in solving many pressing problems.
Whatever factors drive the link between weather and human behaviour, there are some disturbing hints about the future, with scientists predicting that a rise of just 2 degrees Celsius in global average temperatures will increase violent crime rates in temperital regions such as Western Europe by more than 3 per cent, and many experts now believe that even if we achieve all our commitments to climate change through effective governance, temperatures will rise by more than 3 degrees Celsius.
While the weather’s impact on us remains a mystery, perhaps we should be prepared for all the changes that are coming.