Climate Change and the Sahara Desert

There has not been an area much more drastically affected by climate change other than the Sahara Desert in Africa. The huge desert's sudden geographical transformation centuries ago was one of the planet's most dramatic climate shifts. You see, 5,000 years ago the area that is now the vast Sahara Desert was a vast land of grasslands and lakes with hippos, lions and giraffes.

A new study shows that the transformation was immediate and took place nearly simultaneously across the continent's northern half. The results will appear in an upcoming issue of the journal Earth and Planetary Science Letters.




Researchers sifted through 30,000 years of dust and ocean bottom muck retrieved with ocean drilling ships. The changing levels of windblown dust in the ocean sediments provide scientists with clues to Africa's climate and how it has changed over time. Simply put, a lot of dust means drier conditions and less dust means a wetter environment.

The wet period, called the African Humid Period, started and ended suddenly, confirming previous studies by other groups, the sediments revealed. However, toward the Humid Period's end about 6,000 years ago, the dust was at about 20 percent of today's level, far less dusty than previous estimates, the study found.

The study may give scientists a better understanding of how changing dust levels relate to climate by providing inputs for climate models, David McGee, an MIT paleoclimatologist, said in a statement.  The dust from the Sahara dominates modern ocean sediments off the African coast, and it can travel in the atmosphere all the way to North America.