Researchers at the Potsdam Institute for Climate Impact Research recently concluded that changes in Earth's orbti might have initiated the formation of the Sahara Desert. Using a new research model, the CLIMBER-2, scientists discovered that the Sahara's transition from a grassy, shrub-covered area to an arid region occured relatively quickly during two periods, according to a press release issued by the American Geophysical Union (AGU)on July 7.