A bit off topic, but such "climate changes" are cyclic on an almost pre-history to present scale. Many theorize that the "High Desert" Anasazi (sp?) civilizations developed during a "wet spell" and were forced to move down to the lower desert to morph into the Pueblos. Irrigation (which causes salt deposits in the irrigated fields) in past civilizations is theorized to have been the cause of deserts such as the Sahara. Carthage certainly didn't grow to become a major world power in a desert and probably would not have been founded in one.

But this is a topic for the lounge!