Not good: In the latest issue of Science, a bunch of climatologists argue that climate models may actually be understating the rate of global warming.

One favored tactic of climate-change "skeptics," of course, is to argue that climate-change models are uncertain. Now, the models are far more accurate than the deniers imply, but to the extent that there is uncertainty, as Andrew Dessler points out, it can cut both ways. Things may actually be much worse than, say, the IPCC says. (And given the conservatism inherent in the IPCC process, the latter possibility seems more likely.)