When the Sahara turned to sand

[Still Waters]

The Sahara wasn't always a desert. Trees and grasslands dominated the landscape from roughly 10,000 years ago to 5,000 years ago. Then, abruptly, the climate changed, and north Africa began to dry out.

Previous research has suggested that the end of the African Humid Period came gradually, over thousands of years, but a study published last month in Science says it took just a few hundred.

http://phys.org/news...ahara-sand.html

[Doug1029]

The African Wet Period lasted about 400 years. There's not much room in that time-span for anything to happen "gradually." I guess whether it was "rapid" or "gradual" depends on how you define "rapid" and "gradual."

Doug

[lightly]

The African Wet Period lasted about 400 years. There's not much room in that time-span for anything to happen "gradually." I guess whether it was "rapid" or "gradual" depends on how you define "rapid" and "gradual."

Doug

But the tree and grassland period lasted much longer? I think there are 8000 yr. old rock paintings showing grazing animals ... mostly antelope , some Bison.

[Doug1029]

But the tree and grassland period lasted much longer? I think there are 8000 yr. old rock paintings showing grazing animals ... mostly antelope , some Bison.

The Altithermal lasted from about 11,000 BP to around 8200 BP - 3800 years. The African Wet Period came at the end of the Altithermal. There followed a serious drought that some anthropologists are telling us provided the impetus for the development of agriculture. That drought brought down the Akkadian Empire. Egypt originated at about this time, too.

Doug

Edited November 13, 2013 by Doug1029