[krisoft]

About North Africa: archeological findings seems to imply that what is now the Sahara desert was much more lush and wet relatively recently. We have human made cave paintings of river animals in areas which are very dry nowadays. It is thought that the area dried out relatively suddenly about 5k years ago. That is basically yesterday as far as geological timescales go.

When I learned about this I got kinda scarred. If the climate of an area can change this drastically all of a sudden that means to me that the climate system is a lot less stable than I previously have thougt.

[jandrewrogers]

Something similar happened on a smaller scale in North America with Lake Lahontan[0], which covered much of Nevada after the last ice age. If you walk the old shoreline up on the mountainsides, it is not uncommon to find evidence of the neolithic people that lived on its shores before it disappeared.

[0] https://en.wikipedia.org/wiki/Lake_Lahontan

[MayeulC]

https://en.wikipedia.org/wiki/African_humid_period

IIRC one of the causes might be orbital precession, which could lead to a re-greening in a few millenia.