The global financial system consists of firms in the financial services sector - banks, hedge funds, insurance companies and the like - and various governmental agencies who are charged with regulating these firms.

If you ask which of the scenarios I think is most dangerous, though, I will give a different answer. In that form of the question, I regard a nuclear attack, terrorist-generated or otherwise, as the most threatening combination of likelihood and long-term damage to modern life today.

My own guess is that quite quickly the machine intelligence will start dreaming machine dreams and thinking machine thoughts, both of which would totally incomprehensible to us. This would then lead to each species, we and the machines, moving off on to its own separate life trajectory.

In fact, the very nature of an X-event is that it is both rare and surprising. So I would not say that any specific X-event is likely. What I would say, though, is that some X-event is not only plausible, but very likely in a time scale of a few years.

When the next big problem comes online, be it the Euro crisis, nuclear proliferation, an overstretched Internet, a killer flu, or any of the other possibilities I consider in X-Events, we will suffer a complexity overload.

At some point, the world is going to have to bite the bullet and accept a huge downsizing in its way of life to bring the assets-to-debt ratio back in touch with reality.

I do not believe that there is any person, method, or tool that can consistently and reliably predict specific human events, X- or otherwise.