Sept. 26 - Researchers in California say climate change could spur an increase in global violence by as much as 50 percent over the next 40 years if current temperature trends continue. The UC Berkeley study links climatic shifts to historical outbreaks of violence, such as wars and riots, and says the trend is on an upward trajectory. Ben Gruber reports.
Protesters clash with police. It's a scene that repeats itself on a regular basis, all over the world. And as the world gets warmer such outbreaks are likely to become even more frequent, according to UC Berkeley's Solomon Hsiang and Marshall Burke. The researchers say their studies demonstrate a link between climate change and violence. After gathering historical data identifying incidents of conflict and comparing those accounts to climate data from the same period, Hsiang says a pattern emerged. (SOUNDBITE) (English) SOLOMON HSIANG, ASSISTANT PROFESSOR OF PUBLIC POLICY, UC BERKELEY, SAYING: "So what we find is that around the world and throughout history, whether we look at the very small scale or the very large scale climatic fluctuations appear to have an influence on the likelihood of human conflict." For thousands of years, Hsiang says large scale conflicts from wars to the collapse of civilizations have taken place under the influence of climate change. While not the sole reason, he says significant climatic shifts, which can effect agricultural production or economic stability, were present when the violence occurred. On a smaller scale Marshall Burke says the link between heat and violence is a lot clearer. (SOUNDBITE) (English) MARSHALL BURKE, POLICY RESEARCHER, UC BERKELEY, SAYING: "We also look out personal conflicts, so this is things like murders and domestic violence. So these seem to be driven by a very different mechanism. What it looks like here is that these are driven by a physiological response to increases in temperature. So you get a really hot night or a really hot day and people just freak out and do crazy things." Using this data from the past and present, the researchers began looking to the future, and what it could mean for violent conflicts as the pace of global warming increases. (SOUNDBITE) (English) MARSHALL BURKE, POLICY RESEARCHER, UC BERKELEY, SAYING: "Our results suggest that one of the impacts of future climate change is a dramatic increase in violence around the world." The study found that an increase in temperature of 2 degrees centigrade over the next 50 years, which is what most climate models predict, could increase the rate of small scale violence by 20 percent and large scale violence by as much as 50 percent in many parts of the world. And according to Stanford University climatologist Noah Diffenbaugh, global warming IS real. He says the question isn't if it's occurring but how fast. (SOUNDBITE) (English) NOAH DIFFENBAUGH, CLIMATOLOGIST, STANFORD UNIVERSITY, SAYING: "We really do have agreement that global warming is occurring. We do have agreement scientifically that that global warming is due to human activities, we have a very large basis of direct observations that have provided that evidence." Hsiang and Burke are now working to better understand the relationship between climate change and violence. They're aware that many will treat their research with scepticism, but say they're taking a cool, considered approach to an extremely hot topic.