Wednesday, October 10, 2007

Don't believe everything you read Ancient African Megadroughts May Have Driven Human Evolution -- Out Of Africa
From 135,000 to 90,000 years ago tropical Africa had megadroughts more extreme and widespread than any previously known for that region, according to new research.

Learning that now-lush tropical Africa was an arid scrubland during the early Late Pleistocene provides new insights into humans' migration out of Africa and the evolution of fishes in Africa's Great Lakes.

. . .

The new finding provides an ecological explanation for the Out-of-Africa theory that suggests all humans descended from just a few people living in Africa sometime between 150,000 and 70,000 years ago.


Which is very interesting. But:

Migration of Early Humans From Africa Aided By Wet Weather
Science Daily — The African origin of early modern humans 200,000--150,000 years ago is now well documented, with archaeological data suggesting that a major migration from tropical east Africa to the Levant took place between 130,000 and 100,000 years ago via the presently hyper-arid Saharan-Arabian desert.

This migration was dependent on the occurrence of wetter climate in the region. Whereas there is good evidence that the southern and central Saharan-Arabian desert experienced increased monsoon precipitation during this period, no unequivocal evidence has been found for a corresponding rainfall increase in the northern part of the migration corridor, including the Sinai-Negev land bridge between Africa and Asia.


Not precisely opposite conclusions, but one wonders whether hyperaridity in subsaharan Africa jives with wetter conditions north.

And for even MORE see here.