The macroeconomics textbook I'm using for my class this semester (Macroeconomics in Context) has a section on renewable and non-renewable resources. While it's nice they include this, their definition of a "sustainable economy" worries me. They define a "sustainable socioeconomic system" as "a system in which the overall quality and quantity of the resource base required for sustaining life and well-being do not erode."
That's fine as far as it goes, but my worry is, "How the heck are we supposed to know if this base is eroding or not?" I mean, we are running out of oil, or sooner or later we will be, but is that good or bad for sustainability? On the one had, current cars will become useless, but on the other, if burning oil is causing global warming, maybe it's very good if we run out of it.
Or what if some space aliens had shown up in 1600 and announced, "Citizens of Earth: under your ground are giant pools of disgusting black goo. We are a galactic service that cleans up planets such as yours contaminated with such foul goop." We let them "clean up," only to find, in the 20th century, that our economy is much less sustainable because the aliens have taken 90% of our oil.
What do we know about what will be a resource in 100 years? What do we know about what will be an unwanted waste product?
So, I wonder, is there really any sense in worrying about "sustainability," or should we just deal with obvious problems as they arise? ("Man, that pond smells like crap and all the frogs have died -- you'd better stop dumping that sh*t in it.") Sustainability oriented folks, I sympathize, I do: I'm just not very confident about our ability to get sustainability right.