Hotter World Means Hotter Tempers, More Violence

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Climate change may be one of the factors contributing to violence within and among societies, according to the latest study.

Whether it’s a drought in India, a heat wave in the U.S. or an extreme change in rainfall in Africa, Asia or South America, the outcomes tend to be the same: more wars, more murder, more riots and more domestic violence.

The intimate connection between climate and human interaction has long been documented, and could have contributed to the downfall of Chinese and Mayan empires, say the study’s authors. Reporting in the journal Science,  lead author Solomon Hsiang, assistant professor of public policy at the University of California in Berkeley. and his colleagues analyzed 60 studies of climate change and human conflict at several levels, from domestic violence to the collapse of entire civilizations. “All around the world across different societies in the modern world as well as throughout history, we find that human conflict seems to be linked to changes in climate,” says Hsiang.

Rising temperatures have the greatest effect on human conflict; the equivalent of a five degree Fahrenheit increase in an average U.S. county over a month, for example, could raise the odds of personal violence such as assault, murder and domestic violence by 4%, and the risk of civil war, riots or ethnic violence by 14%.

Rainfall and drought can also contribute to conflict; the researchers found spikes in domestic violence in India, as well as higher murder rates in the U.S. and in Tanzania and civil wars in tropical regions tied to relatively small changes in rain or temperature.

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The findings reinforce previous studies that linked climate change to human affairs, and raise concerns about the potential impact that changing environmental conditions will have on the stability of societies in coming decades. Most climate change estimates predict a rise of two to four standard deviations in temperature, rainfall or drought by 2050, which suggests a 30% greater risk of intergroup conflicts, says Hsiang.

“It’s a very, very impressive review of the literature,” says Dr. Mark Shapiro, chief of acute care surgery at Duke University Medical Center, who has published research on the link between heat and assaults, but was not associated with the latest study.

Heat could provide fertile ground for interpersonal violence by bringing people into closer contact indoors to seek relief. Assault, rape— even the number of baseball pitchers who retaliate against batters by hitting them with pitches — all rise with temperature, studies show. Even noise can become a more anger-inducing irritant, according to Dutch researchers.

On a population level, climate change may have more indirect effects on social stability; as crops fail due to drought or flood, for instance, migration may provoke conflicts as communities compete for more limited resources.

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However, Shapiro says it’s not clear that rising global temperatures will necessary lead to ever-escalating conflict. His own work found a direct, linear relationship between assault and temperature, but other studies suggested there may be a threshold at which violence starts to decline.

Still, says Hsiang, his data show that man is historically ill-equipped to cope with changing climate, and may continue to fall prey to the influence that higher temperatures and more rainfall can have on the stability of both personal and society relationships. “We need to understand why climate changes cause conflict so we can help societies to adapt to these events and avoid the violence,” he said in a statement.

9 comments
MikeWilliard
MikeWilliard

I live in Phoenix, Arizona with the temperature often exceeding 110 degrees F.  If this study were true, we would be one of the most violent cities in the country. But we have average violence rates.

FredSmith3
FredSmith3

Of course, there is the study that says crime falls because of less lead in gasoline. They followed many countries and says it takes about twenty years. So as more and more countries move away from leaded gas we will pretty much have a washout. 

GeraldWilhite
GeraldWilhite

The German newspaper's 'Spiegel Online Science' strongly criticizes this paper, citing a lack of robustness of its statistics as the main problem.

Twenty seven studies were examined. Eleven of the statistically reliable studies said climate change could increase risk of conflicts in some cases, lower in others, or have no effect. Of these, only three were considered in the study even though the authors were well aware of them. 

Distorting the data was not the only problem. Predictions of climate-enhancing aggression were said to be greatly exaggerated. 

You will need Google's translator to read the paper (unless you are fluent in German, of course):

http://www.spiegel.de/wissenschaft/natur/klimawandel-studie-ueber-gewalt-anstieg-stoesst-auf-heftige-kritik-a-913966.html


EldrickWo
EldrickWo

funny,just last week a read an article about violence being on the decline.guess if you pay enough scientist will say what you want them to

Madman2001
Madman2001

Wow, if this is true, then it's a good thing global temperatures have not risen in the last 15 years.  Whew !

PhillipNoe
PhillipNoe

As if dealing with a deteriorating biosphere wasn't enough!  We need to change the ways we generate and use energy for the sake of our future generations.  Contact your reps in Congress and insist they work harder to reduce global emissions, and in the long run, global populations.  If they drag their feet, they should be replaced in the next election cycle.

PhillipNoe
PhillipNoe

@EldrickWo @PhillipNoe  Yea, those scientists don't know what they're talking about.  You tell em all about how you just know you are right and that's that.