[jbotz]

And in a very real sense AGW is a resource shortage problem... the natural resource that's being depleted here is the natural carbon cycle that that kept CO2 levels fairly stable and gave us temperatures at the near optimal levels they were at during the time that civilization developed. We are "depleting" this resource by overloading it with excess CO2 and by destroying natural carbon sinks.

Natural resources aren't limited to materials, natural processes also qualify. So it is also with fresh water... we won't "run out" of water, but we are exceeding the water-recycling capacities of the biosphere and thus this absolutely essential natural resource is becoming quite scarce in a lot of places. Theoretically you can replace it with artificial processes (desalination, treating contaminated water, etc) but to do that on a scale that can replace that natural water cycle is completely beyond our technology for now.