Diamond's five factors that contribute to collapse: climate change, hostile neighbors, collapse of essential trading partners, environmental problems, and failure to adapt to environmental issues.
I'd throw resource depletion into the "environmental problems/issues" bucket (interesting that he distinguishes this from "climate change" now that I look at it again).
My own off-the-top-of-my-head list: Overpopulation, resource depletion, environmental contamination, anthropogenic climate change, societal inequities, WMD proliferation (particularly to non-state actors and rogue states), general systemic fragility/complexity, social intransigence in the face of many such issues (e.g.: US counterfactual denial political movements, rightist movements in various EU states, militant Islamist movements, etc.), government / corporate / social corruption, breakdown of social institutions, failures in universal education (primary, secondary, and higher). In no particular order.
