Rank them in the short/medium term as well as long-term. My guess is:
In terms of direct costs, radical Islam in the short-term is the hands-down winner, as well as in terms of secondary costs (political ramifications, etc.). As far as long-term, it's a tougher call, since we don't know the probability of a terrorist group obtaining a nuclear weapon, but I would guess it's sufficiently small enough that global warming is the larger threat.