When Al Gore became a Nobel laureate on Friday, it was the second time in four years that the prize for peace had gone green. In 2004, its recipient was Wangari Maathai, a Kenyan politician responsible for planting millions of trees to combat soil erosion. The day after she was recognized, I asked Maathai what reforestation had to do with ending conflict. "What the Nobel committee is doing is going beyond war and looking at what humanity can do to prevent war," she answered. "Sustainable management of our natural resources will promote peace."
This year's award, which Al Gore shared with the Intergovernmental Panel on Climate Change, took Maathai's sentiment to a global scale. "Indications of changes in the earth's future climate must be treated with the utmost seriousness," said Ole Danbolt Mjøs, the committee chairman. "There may be increased danger of violent conflicts and wars, within and between states."
But does global warming really cause war?
The idea of a connection between conflict and climate change is fairly new, and one that had been mostly relegated to academic journals until earlier this year. Then, in June, U.N. Secretary-General Ban Ki-moon went on record to suggest global warming as a cause for the fighting in the Darfur region of Sudan. He pointed out that warming in the tropical and southern oceans, fueled in some part by climate change, led to a decades-long drought and clashes between herders and farmers over the degrading land. When a rebellion broke out against the central government, Sudan's leaders fought back by arming and supporting the herders against the farmers—and the entire region fell into war. If global warming did cause the Sudanese drought, then it's also responsible for the 200,000 to 450,000 lives that have been lost over the last four and a half years. We may very well be watching the first major conflict caused by emissions from our factories, power plants, and cars.
Other early hot spots for warming-related conflict are likely to be in sub-Saharan Africa, Central Asia, or the Caribbean—places where institutions are weak, infrastructure is deficient, and the government is incompetent or malevolent. The crisis in Darfur has already stretched into Chad and the Central African Republic. Nomads from Sudan, spillovers from Sudan's desertification, are pushing deep into the Congolese rain forest. In Ghana, nomadic Fulani cattle herdsmen, forced by the expanding Sahara desert into agricultural lands, are buying high-power assault rifles to defend their animals from angry farmers.
Climate-change conflict is even spreading into the Arctic, where normally pacific Canada and Norway have joined the United States, Russia, and Denmark in a five-way tussle over mineral and shipping rights unlocked by the melting ice. Thus far largely symbolic, the conflict could take a more serious turn as the waters warm and military traffic increases. Norway and Russia already face each other down over fish in the Barents Sea. And Canada and Denmark take turns pulling up each other's flag on Hans Island, a stretch of icy rock the size of a football field. These countries may be arguing over small fries right now, but what happens when oil is at stake?
These emerging examples suggest that global warming might lead to increasing conflict around the world. But a look back through the last thousand years shows how quickly even a mild, natural shift in the climate can produce a period of cataclysmic violence. David Zhang, a professor at the University of Hong Kong, scoured China's dynastic archives for records of war and rebellion and compared them with historical temperatures in the Northern Hemisphere. In the span between the 11th and 20th centuries, Zhang counted 15 periods of intense fighting. All but three of them occurred in the decades immediately following a period of unusual cold. Plunging agricultural yields, Zhang concluded, led to famine, rebellion, and war. He also found that dynastic collapses tended to follow the oscillations of the temperature cycle.
But what rattled Zhang most was the scale of these historical climate changes, as compared to the warming the world has experienced this century. The upheavals in China occurred when the average temperature had dropped just 0.5 degrees Fahrenheit, less than half the magnitude of the change we've experienced over the last century.
Of course, modern societies have capabilities far beyond those of the medieval Chinese, and the countries of today—at least the richer ones—are likely to be able to ride out any early climate shocks. Indeed, even in medieval China, the conflicts triggered by man-made climate change didn't happen immediately. In his study, Zhang saw a lag of 10 to 30 years between the temperature shifts and the outbreaks of war—it takes time for a society to deplete its resources and for tensions to build. In the modern world, it will be the poor countries that suffer the first serious effects. Drought-stricken Australia can spend billions on wind and solar-powered desalinization plants, but the Pakistanis who rely on melting glaciers for their water supply will be able to do nothing but suffer the shortages.
Once a region does succumb to war, the same climate factors that created the conflict make it harder (and more expensive) to reverse course. In Darfur, the drought has eased, but water remains scarce; now U.N. officials are scratching their head over how to provide each of the planned 26,000 peacekeepers with at least 85 liters a day. (Meanwhile, humanitarian groups struggle to provide the displaced with enough water for drinking and cooking.) The peace mission is likely to require 20 daily flights just for water. Even if the mission is successful, Darfur's environmental degradation means that a lasting end to the violence is a long way off: There's no longer enough good land to allow for an easy return to the status quo.
In awarding the prize, the Nobel committee emphasized that time is running out. "Action is necessary now, before climate change moves beyond man's control," said Mjøs, the committee chairman. We may not yet know with certainty what this means for conflict in the world—in terms of where, when, and if fighting will break out. But the evidence is mounting that climate change will lead to more and longer-lasting wars. Do we really want to wait for the data to pile up?