For a good recent summary of the upsides, downsides, and governance challenges posed by geoengineering, see this report from The Daily Climate.
And for a great illustration of just how repugnant some environmentalists find the very thought of geoengineering, consider this scathing review of our book in The New Yorker. The author, Elizabeth Kolbert, seems to disdain everything we’ve ever written on any topic, and claims we utterly fail to understand climate science (unless of course we don’t). She is a feeling and passionate environmentalist who, seemingly so disturbed by geongineering, is compelled to cast our own horse-dung story right back at us with a splat. Here is my favorite line from the review: “Neither Levitt, an economist, nor Dubner, a journalist, has any training in climate science — or, for that matter, in science of any kind.”
The time has probably come to admit that neither of us were Ku Klux Klan members either, or sumo wrestlers or Realtors or abortion providers or schoolteachers or even pimps. And yet somehow we managed to write about all that without any horse dung (well, not much at least) flying our way. Kolbert, meanwhile, has written widely about the perils of global warming, both in The New Yorker and in book form (see Field Notes From a Catastrophe: Man, Nature, and Climate Change), and seems to be extremely well-regarded in the field of environmental journalism. And yet, if her Wikipedia page is correct, she somehow accomplished all this with a degree from Yale in … literature.
Which kinda gets to a point that I made in the comments: is Superfreakonomics a book of journalism, advocacy, provocation or is it somehow otherwise authoritative? Kolbert is an exceptional journalist but one with an obvious agenda and to me that is fine. She reports on the science and effects of climate change and accepts that the debate about human induced climate change has been settled (as do Dubner and Levitt). She is mad that they report something that Myhrvold says without checking that his science is right.
But if the book is designed to give a forum to the geoengineering types, what is wrong with that? Instead of attacking the messengers, debate the claim, in my ever so humble opinion. Perhaps it is the economist in me, but while I find the geoengineering stuff fanciful, I am fascinated to learn about it and am not threatened by new ideas. I guess I believe in markets even for ideas. After all, the debate about climate change is essentially over, isn't it? The truth will out.