Many climate scientists content that 5,000 years ago or so, as rainfall suddenly declined across North Africa, the verdant grasslands that supported vast herds of wildlife became "lifeless sand" in a mere century or two.
These scientists have recently analyzed thousands of ocean cores drilled off the northwest African coastline. They found that a large amount of dust and sand had blown off the continent over a relatively short period of time suggesting a rapid shift from grasslands to desert.
A 2013 study found significant evidence of a similar abrupt climate shift in northeast Africa. According to David McGee, a paleoclimatologist at the Massachusetts Institute of Technology, this study showed "some kind of tipping point," perhaps tied in with a change in the Earth’s position in orbiting the sun, ‘Chandler’s Wobble,’ or other factors.
Climate scientists at NASA’s Goddard Institute for Space Studies states that approximately 8,000 years ago, the tilt of the Earth, which is currently 23.5 degrees, was around 24.1 degrees, which put the Sahara Desert closer to the Equator, an area of higher rainfall. Also, the Earth may have had its closest approach to the Sun in August during that time. Today, our orbit around the sun puts us closest to our star in January. It’s the tilt toward and away from the sun that contributes to our seasons.
But, Dr. Stefan Kropelin, a geologist at the University of Cologne in Germany, one of the world’s leading explorers of the Sahara Desert for more than 40 years, thinks otherwise.
Dr. Kropelin’s analysis of various lake core samples in North Africa suggests that there was "no tipping point" and that "the climate change was gradual over hundreds of years or more." He says that his studies of the Sahara are likewise "supported by many archaeologists."
For example, recent digs in the Sahara have indicated that the people in the region migrated south over a millennia, not just in a few desperate decades devoid of water.
According to Dr. Kropelin, "humans are very sensitive to climate changes," especially severe mega-droughts. They can’t live without water, so they migrate to find abundant supplies. He adds, "If the Sahara had turned to desert quickly, the human migration pattern would have been completely different."
But, despite these different opinions on just how long it took for North Africa to become a hot, parched desert, it certainly proves what I’ve been saying for the last 50 years or more.
The climate of the Earth has always been CYCLICAL. Over the centuries, there have been frequent major climate changes. These shifts in weather patterns have occurred ‘like clockwork’ long before there were coal-burning plants producing electricity, people driving automobiles or fluorescent light bulbs. Human beings only recently have reached the 7 billion mark in population. In the past, they were mere ‘specks on the landscape.’