Jared Diamond, probably best known for his best-selling book Guns, Germs and Steel has ideas on what forces some civilizations to collapse and others to prosper. His main theme of GG&S was wrapped around the idea of geographic luck.
Geographic luck wrestles with the idea that civilizations in certain places were able to advance and prosper because of the natural resources available to them. Some cultures were never able to overcome their primitive ways and couldn't be part of the Neolithic Revolution, because they didn't have the ability to cultivate crops and domesticate animals because the climate and/or animals needed to do so, just weren't available to them.
His theory for the collapse of civilizations could follow that same path... it deviates slightly however. Diamond believes there are outliers, and geography isn't the only thing to make or brake a civilization, but many of his five interacting factors leading to a collapse are geography based.
1. Damage that people have inflicted on their environment;
2. Climate change
4. Changes in friendly trading partners
5.The society's political, economic and social responses to these shifts.
It is factor #5 which is most important, as this is the crux the determines a civilization's fate. I haven't read Diamond's book on the subject, but have discussed his theory in class with my students.
We read this article: http://www.nytimes.com/2005/01/01/opinion/01diamond.html?_r=3&pagewanted=print&position=
...and then had them answer some discussion questions. It worked well enough to explore the theory further and modify it for next year.
In class we're currently studying the fall of Rome and comparing its factors to the modern day United States. I was impressed when some of the students used Diamond's theory to support some of their own thoughts on the fall of the Roman Empire.