The Heat Is Online

Climate Change Triggers Conflict: study

First proof that climate is a trigger for conflict: study

Agence France-Presse, Aug. 25, 2011

Climate shift has at times been fingered as a culprit in triggering conflict, fuelling for instance the 1789 French Revolution by wrecking harvests and driving hungry peasants to the city.
Evidence to back the theory has often been contested as sketchy or anecdotal -- but the case has been boosted by the first scientific study to declare an unmistakeable link between climate fluctuations and violence.
It says tropical countries affected by the notorious El Nino weather event are twice as likely to be hit by internal unrest compared to the phenomenon's cooler, wetter counterpart, La Nina.
The civil war and famine gripping the Horn of Africa is a typical example of what happens when a climate swing causes drought and overstresses an already fragile society, say its authors.
The inquiry, appearing in Thursday's issue of the journal Nature, focuses on a naturally occurring pattern of climate change.
But its authors say there is a disturbing lesson about violence driven by man-made warming, which is expected to bite deep in coming decades.
"What it does show and show beyond any doubt is that even in this modern world, climate variations have an impact on the propensity of people to fight," said Mark Cane, a climate scientist at the Lamont-Doherty Earth Observatory at Columbia University in New York.
"It's difficult to see why that won't carry over to a world that's disrupted by global warming."
Formally known as the El Nino-Southern Oscillation (ENSO), the cycle occurs every two to seven years and last from nine months to two years, often inflicting massive losses on agriculture, forestry and fishing.
It starts when warm water builds on the western side of the tropical Pacific and shifts across the ocean.
This part of the cycle, El Nino, can cause dramatic changes in rainfall patterns and temperatures, unleashing scorching heat or drying winds in much of Africa, South and Southeast Asia and Australia.
When the cycle goes into reverse, a phase called La Nina, the water in the eastern Pacific cools, often bringing heavy rain to those regions.
The study looked at ENSOs from 1950 to 2004 and overlaid this data with civil conflicts -- violence that had taken place within national borders, as opposed to cross-border wars -- that had killed more than 25 people in a given year.
The data included 175 countries and 234 conflicts, more than half of which caused more than 1,000 battle-related deaths.
In countries whose weather cycles are determined by ENSO, the risk of civil conflict occurring during La Nina was about three percent; during El Nino, this doubled to six percent, the paper says.
Countries not affected by ENSO remained at two percent regardless.
Overall, according to the study, El Nino may have played a role in 21 percent of civil wars worldwide, and nearly 30 percent in those countries that are specifically affected by El Nino.
Lead author Solomon Hsiang of Columbia's Earth Institute said El Nino was an invisible factor -- but not the only one -- in driving intra-border conflict.
By causing crop losses, hurricane damage or helping to spread epidemics of water-borne disease, it amplified hunger, loss, unemployment and inequality, which in turn fuelled resentment and division.
Other factors that could affect risk and the outcome are the country's population growth and prosperity and whether its government is able to manage El Nino events properly.
"Even though we control for all of these factors simultaneously, we still find that there's a large and pervasive El Nino effect on civil conflicts," Hsiang said in a teleconference.
Although the current crisis in the Horn of Africa occurred beyond the parameters of the study, it was a "perfect example" of the hidden destruction of an El Nino.
"Forecasters two years ago predicted that there would be a famine in Somalia this year, but donors in the international aid community did not take that forecast seriously," said Hsiang.
"We hope our study can provide the international community and governments and aid organisations with additional information that might in the future help avert humanitarian crises that are associated with conflict."

El Nino a factor in some country conflicts, study finds

'It is really the poorest countries that respond ... with violence,' co-author says

The Associated Press, Aug. 24, 2011

Global climate fluctuations bear some responsibility in violent conflicts, according to a new study that has linked the hot, drier weather brought by the El Niño climate pattern with civic conflicts within the affected countries.

Using data from 1950 to 2004, the researchers concluded that the likelihood of new conflicts arising in affected countries, mostly located in the tropics, doubles during El Niño years as compared with wetter, cooler years. The weather El Niño brings had a hand in roughly one out of five conflicts during this period, they calculate.

"We believe this finding represents the first major evidence that global climate is a major factor in organized violence around the world," said Solomon Hsiang, the lead author of the study who conducted the research while at Columbia University.

This conclusion — that fluctuations in climate can contribute to violence in modern societies — is a controversial proposal. In this case, the researchers admit they have yet to untangle the mechanisms that link a change in sea surface temperature with, for example, a guerilla war.

A natural climate fluctuation

El Niño refers to the irregular warming of the surface of the Pacific Ocean near the equator. This alters the behavior of the ocean and the atmosphere, disrupting weather around the planet — normally wet regions dry out, and dry regions become wet. El Niño happens roughly every four years, though it is not completely predictable, according to the National Oceanic and Atmospheric Administration.

The study focused on areas, primarily in the tropics, where El Nino brings hot, dry weather to land, as more rain falls over the ocean.

Hsiang and colleagues looked at civil conflicrs— in which more than 25 battle-related deaths occurred in a new dispute between a government and another, politically incompatible organization — in El Niño and other years.

Among nations that are strongly affected by El Niño, they calculated that the annual risk of conflict rose between 3 percent and 6 percent during an El Niño event. By modeling a world in a perpetually moist, peaceful state (no El Niño), they found that 21 percent fewer conflicts occurred during the 54-year-period. This doesn't mean that the climate cycle caused one in five conflicts, rather that it contributed to one in five, according to the researchers.

But not all countries warmed by El Niño responded the same way. 

"We find it is really the poorest countries that respond to El Niño with violence," said Hsiang, who is now a postdoctoral researcher at Princeton University. "There are a large number of relatively wealthy countries in the tropics, for example, Australia, that experience large climate fluctuations due to El Niño, but they do not lapse into violence."

Ice on the road

The researchers admit that they have yet to explain how unusually warm sea surface temperatures are connected with violence. El Niño can clearly lead to droughts and natural disasters such as floods and hurricanes, but connecting those effects through to human behavior becomes tricky.

There are theories: El Niño-influenced events can put a strain on societies, particularly on the poor, leading to income inequality and increased unemployment, which may make armed conflict more attractive, according to the researchers. Psychological factors may also contribute.

"When people get warm and uncomfortable, they get irritated. They are more prone to fight, more prone to behave in ways that are, let's say, less civil," said Mark Cane, a study researcher with the Lamont-Doherty Earth Observatory of Columbia University. "I think all of these things contribute, and they are all quite real."

Hsiang compared El Nino's role in violence to that of winter ice on a road in a car accident: The ice alone doesn’t cause the accident, but it contributes to it.

An earlier, controversial study lead by economist Marshall Burke linked civil war in sub-Saharan Africa with warmer-than-average temperatures.

Why do we fight?

Although we frequently engage in it, we still don't fully understand the causes of violent conflict, according to Halvard Buhaug, a senior researcher at the Peace Research Institute Oslo, who was not involved in the current study.

No conflict has a single cause, and researchers have come quite far in identifying a few common factors — poverty, inequality, political exclusion of minority groups and political instability — that can lead to civil violence, Buhaug said.

"From the recent study, one would be tempted to add climate or climate cycles. I think that would be premature," he said.

While it's possible that changes in climate brought down ancient civilizations — the collapse of ancient Egypt, the Mayan Empire and others have been linked to extreme climate fluctuations — Buhaug is less open to the same causal link for the modern world.

While Hsiang and colleagues show that El Niño and violent conflict tend to coincide, they do not provide the evidence that one can cause the other, he said. In order to establish a causal relationship, the researchers need to look at individual cases, and trace out precisely how an unusual climactic event, like El Niño, led to a specific conflict.

"Until we are able to do that, I don't think we are in a position to claim there is a causal relationship between climate and conflict," Buhaug told LiveScience.

Though scientists have yet to study that causal relationship in modern times, researchers have shown how environmental stress plays a role in violence — for instance, the influence of a drought in the Rwandan genocide, said Thomas Homer-Dixon, a professor at the University of Waterloo and chair of global systems at the Basillie School of International Affairs. Climate change is expected to behave like some other environmental stresses, said Homer-Dixon, who wasn't involved in the current research.

"This story is becoming clearer, it is not really told yet," he said. "[The current study] is a very important contribution to that overall story."

The future

If a natural climate cycle is contributing to violent conflict, what can we expect from climate change caused by humans, who are pumping greenhouse gases into the atmosphere?

The study itself doesn't address human-caused climate change, but its findings do have implications, according to Cane.

"It does raise the reasonable question: If these smaller, shorter lasting and by-and-large less serious kinds of changes in association with El Niño have this effect, it seems hard to imagine the more pervasive changes that will come with anthropocentric climate change are not going to have negative effects on civil conflict," Cane said. 

The research appears in the Aug. 25 issue of the journal Nature. Kyle Meng, of Columbia University, also contributed to the study.