Second to last in my personal list of the top 10 TED Talks on Sustainability, we have David Keith, with what is probably the most salient conversation I have seen on the web on the issue of geoengineering (which should really be called macro-climate engineering, but I don't get to pick the words). For those of you new to the conversation, the basic principle of geoengineering is that we could counter the effects of climate change by doing something drastic to the atmosphere, like pumping a lot of sulfur dioxide into the higher levels. SO2 in the stratosphere would reflect light, very much not at all like a bunch of "tiny mirrors," reducing the amount of energy getting into the lower levels of the atmosphere and having a net cooling effect.
Most of the media on geoengineering falls into one of two camps. The first is people in favor of doing it radically and preemptively instead of solving emissions problems (like the Freakonomics guys, who lost all of my respect when they did) and call everyone who disagrees with them wimps and idiots who either can't face or don't grasp the facts. The second is people who think that any and all geoengineering is basically Jurassic Park, half-assed scientists messing with things they don't understand that are going to get us all eaten by dinosaurs.
The truth, as always, is a whole mess of gray. Keith, however, lays out some very logical analysis of what it is, how to evaluate if it is a good idea, and raises some very good points e.g. whether or not it is a good idea, shouldn't we at least have an international treaty that says no one country can do it unilaterally?
The fact is that geoengineering is an idea, and ideas don't go away. So we have to deal with it, like it or not. And what Keith is arguing for here, essentially, is having a grown up conversation about the idea of messing with things that we don't really, fully understand.