Another link post, to a worthwhile article by Veronique Greenwood for Aeon (emphases mine):
For much of the thousands of years of human existence, our species has treated the world more or less as an open system. [...] the general faith was that there were, say, more whales somewhere [...] more trees somewhere [...]. Even today, in the face of imminent climate change, we continue to function as though there’s more atmosphere somewhere, ready to whisk off our waste to someplace else. It is time, though, to think of the world as a closed system. When you look at the resources involved in maintaining even a single member of a developed society, it’s hard to avoid the knowledge that this cannot continue. Last year, Tim De Chant, an American journalist who runs the blog Per Square Mile, made striking depictions of the space required if everyone in the world live liked the inhabitants of a number of countries. If we all lived like Americans, even four planet Earths would not be enough.The article does suggest, however, that a change of mindset will push us to inventive solutions to our environmental problems. I hope she's right.