Sept. 8, 2006 -- Severe climate change was the main driver behind the birth of civilisation, a scientist says.
An increase in harsh, arid conditions across the globe around 5,000 years ago forced people to start living in stable communities around remaining water sources. The major shift in climate, caused by natural fluctuations in the Earth's orbit around the sun, weakened the monsoon systems in the northern hemisphere, where humans had previously enjoyed a fruitful hunter-gatherer existence.
"We can certainly say that the earliest civilisations arose on the backdrop of increasing aridity, which are driven by natural, global-scale changes in climate," said Nick Brooks of the University of East Anglia. "The cultural transitions track changes in environmental conditions quite closely."
Speaking at the British Association festival of science in Norwich, Dr Brooks said his research turned traditional ideas of how the world's first civilisations - such as those in Mesopotamia, Egypt, China, the Indus Valley region and South America - on their head.