At Real Climate, Gavin Schmidt has a long, detailed, point-by-point rebuttal of a recent blog post by Judith Curry. In her post, Curry says that humans only account for half of observed global warming—with "natural factors" accounting for the other half—and that she's confused as to why other scientists don't agree with her.
Gavin's response is long, but he puts the bottom line up front: "multiple studies indicate with very strong confidence that human activity is the dominant component in the warming of the last 50 to 60 years, and that our best estimates are that pretty much all of the rise is anthropogenic."
While the rebuttal is much too technical for a lay audience, hopefully it will help Curry understand why other scientists don't agree with her.