At www.eurekalert.org/pub_releases/2013-09/plos-pas090613.php … we have a story about migrations through the Sahara when it had rivers. The full article can be dowloaded in full for free at http://dx.plos.org/10.1371/journal.pone.0074834 'When rivers flowed across the Sahara during the last interglacial? implications for human migration through Africa.'
Now, although this comes about from a search for migrations routes Out of Africa the big thing to bear in mind here is that they are saying these rivers were active during the last interglacial – when temperatures are thought to have been warmer than the Holocene. Why was the Sahara wet at this time? Consensus theory is that wet weather in the Sahara during the first half of the Holocene was due to the monsoon track – and arid conditions ensued when that changed. In turn, the strength of the monsoon was due to oscillations in the orbit of the Earth and the amount of solar insolation. Does this imply that during the last interglacial the latitude of the Sahara was somewhat different than it is today?
In the financial disclosure we learn the authors have no support or funding to report – which is somewhat refreshing in comparison to some of the stuff bring churned out by the spam machine, the AGW gravy train. PLOS ONE has a lot of articles worth looking at – and they don't appear to come with a activist veneer.