The more I learn about sustainability* the more it's apparent that the common problem we face is ourselves. I know it's no groundbreaking discovery, but it seems imminent that the common denominator to fix all of our sustainability issues is to make our numbers more sustainable (aka population control).
Since this is a touchy subject and since people (generally) are not willing to consider this currently, I can only assume that our population will be naturally forced to a sustainable level within the next millennium. That's what happens when there are not enough resources to go around.
Thus, I see two options: 1) We can either be responsible and proactive by instituting population control; or 2) Try to tackle a multitude of problems, which even if all solved, will need to be continuously re-solved in perpetuity due to an ever-growing population. My point is that it's a fact of nature that if the resources are available, humans will proliferate to meet them. So we will be playing a constant game of catch-up while the net value of our resources aren't replenished fast enough.
Let the ethical debate begin. For the record, I don't see how allowing a shortened, suffering life is more ethical than not allowing a life in the first place. At the same time, it's an easy call for me since I'm grandfathered in.
*Environment (water, climate, biodiversity), Health (disease, famine), Social Change (urban living), Political (conflict), Energy