I don't know if anyone else has addressed your post, but I will.
The root causes of terrorism are not poverty, disease, or environmental degradation.
Terror has one root, one cause. It's called Islam.
Thanks, carton253. All of the hijackers were wealthy. Bin Laden is extremely wealthy. The Arab world sits on top of enormous oil wealth. What do they do with it except spend enormous resources subjugating their own people and fostering hate for everyone else.