Senior Fellow Charles Kenny's weekly Foreign Policy column on extreme weather and war.
From the article
As the East Coast of the United States was pounded by a hurricane over the weekend, mere days after an earthquake had cracked monuments and upset lawn furniture from Virginia Beach to Baltimore, Mother Nature was once again front-page news across the country. So it was fortuitous that last week's issue of the scientific journal Nature included a much-talked-about article linking the wrath of nature to the wrath of man. "Climate Shifts Cause War" and "First Proof that Climate Is a Trigger for Conflict," the headlines suggested.
In the paper, Princeton University researcher Solomon Hsiang and colleagues argue -- as paraphrased by a Nature news article -- that "tropical countries face double the risk of armed conflict and civil war breaking out during warm, dry El Niño years than during the cooler La Niña phase." El Niño and La Niña (collectively known as ENSO, for the El Niño Southern Oscillation) are the warm and cool parts of the variation in temperatures that occurs every few years in the Pacific Ocean. In different parts of the tropics, El Niño can cause conditions ranging from floods to droughts -- in turn potentially linked to lower agricultural output and other risks. Hsiang and his co-authors looked at data on the timing of ENSO and civil conflict in the tropics and concluded that as many as one in five civil wars worldwide over the last 60 years may be related to El Niño.
Given that climate change is likely to be associated with warmer, drier tropical regions, the study's findings led numerous commentators to warn that the world's future could be increasingly violent. Thankfully, the study -- for all its careful design and academic interest -- provides little evidence that human-induced climate change will have any such effect. The nature of the relationship between the weather and violence in the past remains open to question, and the study itself suggests reasons why we'd expect any impact to decline in the future.