It was a little weird to see Tom Friedman, of all people, dabble into ecological economic thought as much as he did in his column last week; even so, it was refreshing to see a mainstream pundit grapple seriously with the idea that our consumption of natural resources can't go on forever at its current rate -- not without significant changes to our economy. At the same time, transitioning to a new state of affairs, as Geoffrey Styles points out, is going to take a long time, and (at least in the energy sector) it will take the form of gradual shifts, rather than something cataclysmic. This means developing a more sustainable energy regime will require overcoming the natural human urge to pay more attention to cataclysmic events, while still maintaining a sense of urgency when it comes to dealing with climate change and other ecological threats.
I want to also make two points related to this. First, Styles talks about moving from fossil fuels to renewable energy, but it's worth mentioning that the question of ecological limits encompasses a lot of things, including minerals (e.g., phosphorus), water, and arable land, and there are not necessarily close substitutes available (certainly not for the latter two things) if we cannot provide enough to feed, clothe, and house the world's population -- which is expected to reach 7 billion by 2012 and 9 billion by 2050. Second, any discussion of ecological limits has to take into account the question of lifestyles: A developed world lifestyle likely isn't possible for everyone on Earth; but it's also intolerable to say that Europeans and Americans should downgrade their lifestyles, or that Africans and Asians should be barred from enjoying the fruits of industrial civilization to the same degree that we have. It's an extremely delicate question, at least for those of us in the developed world, but if we're going to leave a livable planet to our children and grandchildren, we'll need to screw up our courage and address it in one way or another.