Climate and Conflict

Climate and Conflict Photo Credit: Clipart.com

Climate change may precipitate violence, according to a historical analysis.


Climate and violence. I'm Bob Hirshon and this is Science Update.

Climate change may be setting us up for a more warlike future. This according to to the most comprehensive study of the issue yet. Professor of public policy Solomon Hsiang, of the University of California, Berkeley was on the team.

Looking across ten thousand years, they analyzed the relationship between hotter temperatures and heavier rainfall to all kinds of human conflict, from one-on-one violence to long, protracted wars. And unlike past studies, they also looked at it on all kinds of spatial scales.

So we’ve been looking at climatic shocks that occur to an entire region, or to the entire globe, and we also look at the same climatic variables within a building or a stadium.

Across the board, they found that when things get hotter and wetter, violence increases—whether it’s over a span of hours or millenia. I’m Bob Hirshon for AAAS, the Science Society.

Making Sense of the Research

As the climate continues to warm—currently at a rate 10 times faster than any time since the extinction of the dinosaurs—there are many serious concerns about the abrupt change will affect human civilization. Examples include damage to cities from rising sea levels and more frequent superstorms, food shortages caused by crop failures, and the spread of diseases into new areas.

One major area of concern is the effect of climate on violence, warfare, and political stability. Generally, when this has been studied, the conflict has been framed as a second-hand effect of climate change. For example: if climate change causes food and water shortages, it may lead to conflicts and wars over increasingly scarce resources. 

This study looks at climate's direct effect on human conflict. In other words: Do rising temperatures themselves predict increases in violence? That question has been asked in previous studies, but in relatively limited circumstances: for example, a 2011 study in the journal Nature found that since 1950, armed conflict in tropical countries has been higher during unusually warm years than in unusually cool ones.

This study asked the same question in as many different circumstances as possible: How do temperature changes affect violence in a small, enclosed space over the span of an hour or two? What about in an entire region, over the course of thousands of years? No matter which way they looked at it, the researchers found that as a rule, hotter temperatures mean more conflict. 

It's important to remember that the temperature changes in this study had any number of causes, most of them natural. But seeing that high temperatures predict more violence doesn't bode well for the future—especially since the trends held up even over long periods of time, when societies presumbaly were able to adjust to the changing climates.

Now try and answer these questions:

  1. What is the basic finding of this study?
  2. How does it differ from past studies of climate and violence?
  3. What does it mean to say that the researchers studied different scales of time and space?
  4. Why does this add to concerns about climate change in the future?
You may want to check out these related resources:

In the Science Update Early Climate Change, learn how humans may have affected the Earth's climate even thousands of years ago.

The 12-minute video Communicating and Learning about Climate Change features a number of experts on global climate change talking about its impacts on our planet.

Going Further

For Educators

In the lesson Abrupt Climate Change, learn how scientific knowledge changes in the context of rapid climate change.

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