This must be true, because it's in the New York Times, and they've got those layers and layers of fact-checking: “Global warming will itself almost certainly directly cause mass killing"

Clinton and Other Experts Discuss Ways to Avert Genocide - NYTimes.com

Climate change acts as a “multiplier of other resource crises,” according to Timothy Snyder, a professor of history at Yale University, causing uncertainty about resources, leading to “the ecological panic that I’m afraid will lead to mass killings in the decades to come,” Mr. Snyder told the symposium.

“We’ve entered into this moment of ecological panic,” he said. “Global warming will itself almost certainly directly cause mass killing, but it will likely indirectly cause it” as major states like China and the United States seek to feed their citizens, possibly touching off shortages elsewhere, in places that would then be at risk. China has already begun to act and, in a potential harbinger of future problems, has been investing in farmland in Ukraine and in parts of Africa for a few years.