"Will non-sustainable developments (i.e., atmospheric change, deforestation, fresh water use, etc.) become halted in pleasant ways of our choice, or in unpleasant ways not of our choice?"

To my mind, by far the most important question concerns the way in which our currently non-sustainable course gets resolved in the next several decades. Our present course with regards to many of our demands on the environment cannot be sustained for more than several decades. Those demands include atmospheric change, deforestation, fresh water use, global warming, overfishing, production of toxic materials, utilization of available photosynthetic capacity, and utilization of topsoil. Hence the interesting question is whether these non-sustainable developments become halted in pleasant ways of our choice, or in unpleasant ways not of our choice.

Jared M. Diamond is Professor of Physiology at the UCLA School of Medicine, is the Pulitzer Prize-winning author of the widely acclaimed Guns, Germs, and Steel: the Fates of Human Societies.