I'm not quoting Chairman Mao, believe it or not, but rather Brad Delong's blog. It's possible that this is hyperbole, but I'll take this literally for now, since he has a paragraph that elaborates this idea.
What bothers me is not so much that he is suggesting something economically harmful, though he may be doing that, but more that his justification for this policy is authoritarian in the extreme. He sums up his view thus: "So nationalize—not to expropriate or to penalize the shareholders, but to get this particular selfish and destructive political voice out of American governance." Let that marinate for a little while. If you can justify doing that, imagine all the other things you could justify. What voice is not selfish? Any political voice will eventually be considered destructive by someone, somewhere. Isn't one of the central tenets of liberalism that we tolerate opposing viewpoints in the political sphere even if we vehemently disagree with them? How can Delong continue to claim to be a liberal in any non-Orwellian sense of the word?
This is one of the things that bothers me about the environmentalist movement. They seem to see an existential threat around every corner, and so they can justify just about anything, no matter how extreme. And this didn't start with global warming. Fears of overpopulation have led people to advocate some absolutely unconscionable policies over the years. I hope that one day textbooks will refer to the period we live in as the Green Scare.
This is not to say that global warming isn't real or that there's no reason to do anything to fight it. But there has clearly been an enormous amount of exaggeration. I'm actually quite open to a carbon tax, but it might be nice to see some sort of demonstration first that warming does more harm on net than good. Or at least do a back-of-the-envelope calculation about this, somebody.