"Study the past if you would divine the future." - Confucius
In the July 15, 1999 paper published by the journal, Geophysical Research Letters, the Sahara desert's arid climate change occurred quickly and dramatically 4000 to 3600 years ago. A team of researchers headed by Martin Cluassen of Germany's Potsdam Institute for Climate Impact research analyzed computer models of climate over the past several thousand years. They concluded that the change to today's desert climate in the Sahara was triggered by changes in the Earth's orbit and the tilt of Earth's axis:
