[blam]

"Egypt was "wet" up until about 7,000 years ago."

The last 'surge' of the Ice Age melt was 7-8,000 years ago...probably changed the climate.

[SunkenCiv]

Here's an oldie (7 Jul 99):

Sahara's abrupt desertification
by Harvey Leifert

German scientists, employing a new climate system model, have concluded that this desertification was initiated by subtle changes in the Earth's orbit and strongly amplified by resulting atmospheric and vegetation feedbacks in the subtropics. The timing of this transition was, they report, mainly governed by a global interplay among atmosphere, ocean, sea ice, and vegetation... the model led to the conclusion that the desertification of North Africa began abruptly 5,440 years ago (+/- 30 years). Before that time, the Sahara was covered by annual grasses and low shrubs, as evidenced by fossilized pollen.