Historically, changes in climate have not only been tied to increased food prices, but also economic crises, social upset and wars, new research suggests.

"Climate is the ultimate cause, and economy is the direct cause, of large-scale human crises," study researcher David Zhang, of the University of Hong Kong, told LiveScience in an email. "The issue of environmental change is one that involves our daily life, such as food, health and savings."

Zhang has studied the effect of climate change on humans, specifically on cultural turmoil and wars. His previous work found that swings in temperature were correlated with times of war in eastern China between 1000 and 1911, and also correlated with climate swings and war records worldwide.

Now, he has taken these studies several steps further by looking at all major aspects of human society during times of climate shift. This work also was able to draw a direct link between climate and social factors. [Top 10 Ways Weather Changed History]...