The libertarian in me asks, "Why not internalize the costs and allow market forces to inspire sufficient environmental responsibility?" Scientists have devoted their careers to estimate the value, in dollars, that a particular ecosystem is worth to society. The commonly cited "economic trivia", if you will, is that the biosphere provides twice the global economy in services such as water filtration, pollution management, and crop pollination (among thousands if not millions of others). So the value is there, but how do we internalize it?
So the question becomes a "How do we represent these costs in our prices?" And where I'm stuck is exactly how marginalization breaks down regarding an ecosystem service. Ecology would suggest that a certain amount of exploitation can be sustained before a threshold is reached, though ecologists argue that knowledge of that threshold is unattainable. The overall value of the ecosystem can be gaged, though I'm skeptical that approximating average total cost as the marginal cost would work with many key issues. For example, carbon emissions might contribute only a minor environmental cost early on but eventually reach infinite environmental cost (and for those non-math majors, the average cost is going to end up being "infinity over total units", or... infinity). How can this be resolved?