Unstoppable Global Warming

The Facts Behind the 1,500-year Climate Cycle
Authors' Blog by Dr. S. Fred Singer and Dennis T. Avery

Monday, November 13, 2006

Hunting in the Sahara Grasslands 10,000 Years Ago

When the Earth's 1500-year global warmings occur, the Sahara Desert often gets wetter. The tropical rain belts shift hundreds of miles north. Ten thousand years ago, during the Holocene Warming, Saharan hunters fed on rabbits, porcupines, gazelles and Barbary sheep. Soon, they were herding flocks of sheep, and also cattle, across the new grasslands of what is now desert.

Egypt, in contrast, had such heavy rainfall 10,000 years ago that the Nile Valley was too swampy and flood-ravaged for farming. Archeologists call it the "Wild Nile" period.

By 7000 years ago, however, the climate was shifting back to a cold phase. The regular rains had disappeared and the region was drying out. The hunters and herdsmen had retreated into the Sudanese plains where rainfall was still adequate. About the same time, the Nile Valley began to be peopled with farmers growing wheat and barley.

We thank archeologists Rudolph Kuper and Stefan Kropelin of the University of Cologne for this reminder of the planet's constantly-changing climate parameters. Their new study was published in Science, Vol 313, in August, 2006.

The tropical rainbelts apparently move northward in other parts of the world as well during the 1500-year warmings. That may have something to do with the very long droughts that have been found in ancient California tree rings from the Medieval Warming by Scott Stine of Cal State/Hayward.


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