Many smart people take the idea of sustainability seriously. I do not know how they do it. Julian Simon and many others have worked hard to emphasize the obvious, that the "ultimate resource" (human ingenuity) is not scarce. So we simply require institutions that do not frustrate its natural expression. Thomas McCraw (Prophet of Innovation) masterfully reminds us that Joseph Schumpeter had made this point three-quarters of a century ago.
John Bratland ("Resource Exhaustibility: A Myth Refuted by Entrepreneurial Capital Maintenance", Independent Review, Winter, 2008) delivers an elegant statement of economic common sense to show, once again, that economic doomsday makes no sense.
But it is not enough to urge smart people to learn some economics. As Bratland points out, many economists are also wrong on this issue. "The myth of resource exhaustion has persisted from the nineteenth century to the present. It has been discernable in the work of different economists ranging from the neoclassical to the Austrian to the institutionalist." The paper is clear, not long -- and contains no math.