Climate Change Linked To Civilization Collapse

"Two Massachusetts scientists have linked climate variations to the collapse of societies around the globe. Sometimes slight, sometimes intense, the scientists argue in a recent issue of the journal Science that the changes were enough to forever alter the lifestyles of the people living under changed conditions...The scientists note that although some of the world's population?expected to reach up to 10 billion by 2050?lives in a different manner than past societies, most of the world's people live as subsistence or small-scale farmers."