What kinds of crises was he trying to describe? Global warming, collapse of an endangered species, economic meltdown, and so on...
You can read his paper on the talk here [PDF], but here are the three factors that determine whether a bump in the road turns into a full-fledged crisis:
- Is there a tipping point? That is, some point beyond which decline inevitably leads to fall?
- Is governance limited? That is, a central authority that's too weak to coordinate counter-action?
- Are there positive feedback effects? That is, is something more likely to happen each time it happens?
Bottom Line: Economic theory can provide a useful framework for understanding problems. After the theory, however, you need action to address them.