Monday, August 29, 2011

El Niño linked to increased violence in the tropics

The Economist informs us of a study indicating that the level of violent conflict increases in tropical countries during El Niño climate events!
The work starts with two well-established sets of data, one on violence and the other on the weather. From the first the team calculated an “annual conflict risk” for violence within countries (as opposed to cross-border wars). From the second it produced a map of the world divided into 82 countries where the weather pays little heed to the presence or absence of Niños and 93 where the weather does pay such heed—a group that covers almost all of the tropics. Niños are sloshings of warm water across the equatorial Pacific that take place once or twice a decade. They mostly make themselves felt by increasing tropical temperatures and lowering rainfall around the tropical world, though the effects are not the same everywhere. Such semi-regular instability is not experienced in temperate climes, and it has deep repercussions. 
In years of El Niño, the researchers found, the annual risk of conflict in their 93 tropical countries was 6%. When the oscillation reached its other extreme, a situation known as La Niña, the risk was 3%. In other parts of the world it stayed pretty stable around 2%. This is not to say climate is the only or main factor behind conflict. But the researchers’ numbers suggest that as many as a fifth of the internal conflicts of the period were affected by El Niño.
This is a stunning result, suggesting some serious policy attention be payed to reducing conflict during the El Niño events. Of course, like all interesting research results, this suggests more research needs to be done with some urgency to better explore the links of climate and violence. Of course, one would also hope to see more historical analysis double checking the result.

For more on the original research, go to the website of its principal author, Solomon Hsiang.

Here is a good video from the National Geographic describing the El Niño and La El Niña cycle.

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