By Laura Shin
Posting in Energy
A first-of-its-kind study reveals that the number of tropical conflicts doubles during hot, dry El Nino years, indicating that global climate shifts can destabilize modern-day societies.
People have long speculated that changes in climate can affect human society. For instance, many ancient civilizations, including the Mayan, are thought to have collapsed due to drought.
Now, a study shows that shifts in global climate can also destabilize modern-day societies.
Columbia University researchers have found that an El Niño, which brings hot, dry weather, doubles the likelihood of a civil war in more than 90 tropical countries affected by this climate cycle.
The authors, who are publishing their study in Nature on Thursday, say that El Niño may have played a role in one in five civil conflicts since 1950.
"We're extending the general hypothesis that throughout history human societies used to be influenced by the climate to say that, now, modern society continues to be influenced by the modern climate .... It wasn't so difficult to convince people that maybe Angkor Wat or Mayan civilizations collapsed due to climatic changes, but I think it's harder for people to accept that we still depend on the climate to a very large extent," author Solomon M. Hsiang, who is now at Princeton, said. (Disclosure: I know Hsiang from a class I took at Columbia University for my master's four years ago; he was the teaching assistant.)
While Hsiang and his co-authors emphasize their study focuses on the El Niño climate pattern, not climate change, their work could shed light on the potential consequences of global warming, which will make the world more El Niño-like: hotter and drier around the middle.
The connection between El Niño and warfare
El Niño and La Niña are two sides of a weather pattern that oscillates every three to seven years. During El Niño years, tropical parts of the globe become hotter and thirstier than they are during comparatively cool, rainy La Niña years.
The researchers found that the likelihood that a country in the tropics erupts into a civil conflict is 3% during a La Niña year, but 6% during an El Niño year. Countries whose climates are largely unaffected by El Niño only had a 2% chance of experiencing a civil conflict no matter the year.
Hsiang and his co-authors, Kyle C. Meng of Columbia and Mark Cane of Columbia's Lamont-Doherty Earth Observatory, did not analyze international conflicts because civil wars constitute the vast majority of all conflicts since 1950.
The map below shows, in red, the 93 countries that become warmer in El Niño years, and the 82 unaffected countries in blue.
While Hsiang does not say that El Niño causes these conflicts, he asserts it creates the conditions that make warfare more likely. He compared the presence of El Niño during a conflict to the presence of ice on a road during a car accident:
When there is more ice on the road, there are clearly more car accidents .... Does the ice cause car accidents? The truth is that drivers and their mistakes create car accidents, and the ice is not necessarily at fault, but the ice increases the likelihood with which drivers will make errors.
He, Meng and Cane speculate that the hotter, drier conditions of an El Niño indirectly lead to conflict in several ways: drought could cause large crop losses, which would in turn increase food prices and spark unemployment -- and the unemployed have more time to contemplate injustices and act on them. The researchers also cite evidence that hotter temperatures have physiological effects on people, making them more likely to instigate violence.
Import for climate change
Although this study did not look directly at the consequences of global warming, it could portend its impacts and be used to improve preparedness for humanitarian crises, because strong El Niños, which have the greatest connection to warfare, can be predicted up to two years in advance.
Hsiang, Meng and Cane learned from and built upon a widely criticized 2009 study by Marshall B. Burke and others that examined the effect of local climate cycles on conflict in Africa. In anticipation of similar attacks, Hsiang's team controlled for factors such as country's income, level of democracy, population, etc. They ran all the checks that the Burke study ran, as well as all the checks that a subsequent opposing study ran. Even then, the El Niño influence persisted.
Hsiang says that Burke's study tried to see what might happen in the future climate of individual countries by looking at local weather and rainfall -- i.e., if a country became slightly hotter than its neighbors, would it be more likely to have a civil conflict?
"But local weather and local rainfall are not good approximations of global climate change," he says, noting that global climate causes large patterns of environmental changes. For instance, a spate of recent related weather disasters has led to a spike in food prices. "When an El Niño event occurs, it leads to warming and drying throughout the entire tropics. It leads to a reduction in agricultural output throughout the entire tropics. And it is very likely that ... each individual society is affected ... when agricultural production is falling everywhere at the same time."
We can’t say what will happen for sure with climate change, but it does show beyond a doubt that even in the modern world, climate variations have an impact on people’s propensity to fight. It is difficult to see why that wouldn’t carry over into a world disrupted by global warming.
photo: Nubian desert in Sudan (Bertramz/Wikimedia)
map: Hsiang et al. Nature
Aug 24, 2011
I remember a study thirty or thirty-five years ago the matched violent crime statistics against temperature in several large cities. There is a very similar correlation. Interestingly, though, there was a break point somewhere around 95 degrees Fahrenheit; hotter than that, the numbers started dropping again. Maybe it was just too hot to do anything.
If this were true, you would expect to a delay by a couple of years from the onset of El Nino. It takes a year for crops to fail, and more time for a country to go through its food stores. For example, the current crisis in Somalia didn't just happen this year, famine (again) has been building there for years. So rather than occurring the same year as El Nino, you might have conflicts start even as La Nina is beginning. The degree of conflicts is also influenced by the weather. During wet, rainy years it's difficult to mount a major campaign, especially with the poor infrastructure of many of these countries. There's a reason why the war in Afghanistan shuts down every winter. The same happened with the Civil and Revolutionary Wars in America. Most of the major conflicts of this period (Korea, Vietnam, the two Iraqi wars, the two wars in Afghanistan, the former Yugoslavia, etc.) were not motivated by food shortages. They were either proxy wars between the US and the Soviet Union, or wars over terrorist acts. Hence most of the wars in this article have to be the small regional wars that erupted in Africa and elsewhere. Many of these were former British Commonwealth or French controlled countries in Africa and Asia. While these countries deserved their independence, most of them were left with very weak governments that fell apart under regional and tribal pressures. They were powder kegs just waiting for a spark. Developed areas such as the US and Europe have lots of ways to deal with the stresses of crop failures. While the situation there could break down to the point you have active civil unrest, it won't happen for a long time. There's no evidence El Nino caused any conflicts there because there have been no conflicts (the article conveniently left out that agricultural production in the US at least is very much affected by El Nino). Rather than climate change, the biggest factor by far in causing future conflicts will be global population growth. The global population by 2050 will grow to about 9 billion, which is beyond the current means of the planet to feed itself even without global warming.
It's good to put some quantitative numbers on this but it's a pretty obvious conclusion that when resources shift, particularly water and arable land the chance of conflict is going to go up. Climate change has probably been a factor in the Darfur conflict. When people become desperate they can do horrible things.
Dear Mrs Zackers, This article is about 93 countries affected by El Nino. I am color blind so I might just be way off, but I do belive North America is NOT infected by the red coloration of these so called war zones from people being just TO DANG OH HOT. Food shortage my lily white no entry exit only! I been in places where when it gets HOT people get ANGRY, FAST. Hello 911? We got problems here better send more cops. Ok hold please,. long time after holding, you get asked. What is your location? What the HECK, Don't you know it's HOT, and your gonna ask me a ignorant question like that? Let me ask you something, Whats YOUR location?
Climate change moves the location of arable land, which in turn changes the economic relationships between areas. Within a large nation like the USA, farming can migrate. That may not be possible across borders or even between areas of a nation occupied by people of different ethnicities and/or religions. Ideology is justification for conflicts that are generated by economics.
...although the various "proxy wars" that took place during the "cold war" were pretty much strategic ideological conflicts that had little to do with climate.
Historians have noted the connection between weather and conflict going back to The Decline and Fall of the Roman Empire with Volume 1 written in 1776. It is well known that the conditions of famine that fueled the French Revolution were brought on by the Little Ice Age.
The so called proxy wars during the Cold War were local conflicts between local players who found a global players to arm & finance them. Sometime it was necessary to claim ideological allegiance to a global player, sometimes not. It's a pattern that persists to the present day, only the names have changed.
But at times conflict has grown out of conditions beyond politics. I would say the fight would often be more internal rather than nation verses nation. As in the French Revolution. Poor harvets over an extended period of time brought on by the Little Ice Age mixed with a bad government incapable or unwilling to deal with the situation brought on food riots that grew out of control.