posted on Aug, 31 2005 @ 05:28 PM
We've actually discussed this before. While there's no conclusive evidence for the complete cause, it seems to be a combination of things -- civil
problems (people moving out of the cities), climate changes (these were global about this time), and other peoples moving into the area.
It's a slow decline -- not an immediate collapse.
A Dreadfully Scientific paper on the climate change about 2000 BC and the changes in monsoon patterns: