Lamont-Doherty Earth Observatory News: In the first study of its kind, researchers have linked a natural global climate cycle to periodic increases in warfare. The arrival of El Niño, which every three to seven years boosts temperatures and cuts rainfall, doubles the risk of civil wars across 90 affected tropical countries, and may help account for a fifth of worldwide conflicts during the past half-century, say the authors. The paper, written by an interdisciplinary team at Columbia University’s Earth Institute, appears in the current issue of the leading scientific journal Nature.In recent years, historians and climatologists have built evidence that past societies suffered and fell due in connection with heat or droughts that damaged agriculture and shook governments. This is the first study to make the case for such destabilization in the present day, using statistics to link global weather observations and well-documented outbreaks of violence. The study does not blame specific wars on El Niño, nor does it directly address the issue of long-term climate change. However, it raises potent questions, as many scientists think natural weather cycles will become more extreme with warming climate, and some suggest ongoing chaos in places like Somalia are already being stoked by warming climate.
...The scientists tracked ENSO from 1950 to 2004 and correlated it with onsets of civil conflicts that killed more than 25 people in a given year. The data included 175 countries and 234 conflicts, over half of which each caused more than 1,000 battle-related deaths. For nations whose weather is controlled by ENSO, they found that during La Niña, the chance of civil war breaking out was about 3 percent; during El Niño, the chance doubled, to 6 percent. Countries not affected by the cycle remained at 2 percent no matter what. Overall, the team calculated that El Niño may have played a role in 21 percent of civil wars worldwide—and nearly 30 percent in those countries affected by El Niño.
...The authors say they do not know exactly why climate feeds conflict. “But if you have social inequality, people are poor, and there are underlying tensions, it seems possible that climate can deliver the knockout punch,” said Hsiang. When crops fail, people may take up a gun simply to make a living, he said. Kyle C. Meng, a sustainable-development Ph.D. candidate and the study’s other author, pointed out that social scientists have shown that individuals often become more aggressive when temperatures rise, but he said that whether that applies to whole societies is only speculative....
Polish soldiers on maneuvers in 2008, Łukasz Golowanow & Maciek Hypś, Konflikty.pl, Wikimedia Commons
