Some scientists argue the warming might be caused by changes in the sun, or ocean currents, or changes in cloud cover, or other things we don't yet understand. The debate is not over.
But who's to say that yesterday's temperature is the perfect one?
"The fact is, when climate changes, there are gains and there are losses," said Tim Ball, who studies the history of climate change. But, he points out, all we generally hear about is the bad news from the IPCC — that massive group of climate scientists.
Paul Reiter of the Pasteur Institute participated in one of the IPCC drafts and Christy was a contributing author. Both say that this Nobel Prize-winning group is not what people think it is.
"The IPCC is the Inter-governmental Panel on Climate Change," Reiter said. "It is governments who nominate people. You'll find in many chapters that there are people who are not scientists at all." Reiter claims that some of these scientists are "essentially activists" and there are some members with affiliations to groups like Greenpeace.
When the IPCC report came out, not all its members agreed with what was said. "We were not asked to look at a particular statement and sign our names, at all," Christy said.
Reiter felt his objections were ignored and says he resigned in frustration. But in a draft of the report, the IPCC still listed Reiter as a "contributing author" — part of the so-called consensus.
"I contacted the IPCC and I said, 'Look, I've resigned. I don't want to have anything more to do with this.' And they said, 'Well, you've been involved, so you're still on the list.'" Reiter says he had to threaten to sue to get his name removed from the report, although the IPCC denies that.
In all the confusion surrounding the global warming debate, one thing is clear: Global warming activists don't welcome the skepticism.
Those who call their extreme projections into question are compared with Holocaust deniers and accused of being paid off by big business. I've questioned the extreme global warming predictions in the past, and for that I've been branded a "corporate toadie" and a "flat-earther." I don't mind being called names, but is this what the global warming debate has come to? One side saying, "Shut up. Dissent should not be heard?"
The truth is, that while everyone agrees that the earth has warmed, lots of good scientists don't agree that it's mostly our fault, and don't agree that it's going to be a catastrophe. So when Gore says, "The debate is over," I say, "Give Me a Break!"
Andrew G. Sullivan and Patrick McMenamin contributed to this report.