Sustainability is as much about personal decisions as it is about broad social movements or top-down government rules. Those personal decisions are rooted deeply in how we behave as human beings, and that is something that science is far from understanding.
Adam Smith once said “we are not ready to suspect any person of being defective in selfishness (Smith 1804). In many neoclassical economics studies, humans are assumed to act rationally – that is, they act in their own self-interest (known as rational choice theory. Self-interest is generally calculated by financial gain, but more progressive economists will include other factors in the formation of their utility curves such as time resources. The idea spreads beyond economics, however, into other disciplines such as evolutionary biology. For example, Richard Dawkins has argued for the “selfish gene”(2006) attributing all animal behavior to propagation of their genes. He goes so far as to say that any observed “altruism” is actually benefitting individuals with shared genes, so is still essentially selfish behavior.
Perhaps the most cited example of the rational actor is Garrett Hardin’s “Tragedy of the Commons” (1968). Hardin describes the scenario of a common field in which people have the opportunity to graze their cows. Each person adding an additional cow degrades the field a little more, but the costs are split among all users while the benefits go solely to the owner of the cow. According to the rational choice model of human behavior, people then have the incentive to add more and more cows until the field is no longer useable. He concludes his analysis by implying only two solutions – privatization or strong central governmental control.
A small news article from Science has been taped above my desk for the last few years. I don’t remember who originally gave it to me, or why I even hung it up, but there it is, nestled between a couple 
