That the title includes a reference to the global cooling myth should give one a hint to the problem with the new book. As with their previous book, the authors take a contrarian position on the issue of global warming, except this time they're working outside their area of expertise and get it seriously wrong.
Superfreakonomics, on the other hand, misrepresents the scientific literature on global warming. The difference here is that the papers cited by Freakonomics were Levitt's own work and he understood them, while Levitt and Dubner do not understand the climate science literature. This by itself would not be fatal, but what has taken them off the cliff is the Freakonomics formula: "What you thought you knew about X is wrong!". If you want to apply this formula to global warming you can easily find many superficially plausible arguments on why the mainstream science is wrong. Bang those into your chapter on global warming without bothering to check their accuracy and the only work that remains is the tour to promote your book.Lambert goes on in that link to explain some of the errors with the work. The Intersection also has a round-up of responses to the book.
Despite the quick response of such knowledgeable figures denouncing the misinformation in the book, the damage will still be done to the public understanding of the issue. One, the authors are not partisan hacks like, say, Sean Hannity and will thus be seen as more credible on the issue to non-partisans. Secondly, these authors are more popular than the critics rebutting them, meaning that it is more likely that a larger audience will hear of the book's contrarian wrongness than they will the corrections.