If we wanted to play the hypocrite game, I could start shouting at George W. Bush for sending people into war without ever having seen a day of combat in his life. But I don't hold that against him, and neither should anybody start slamming Al Gore for having two large residences. He's had those houses long before he got into global warming, and although I suppose it would be nice if he had bulldozed his own houses and installed solar panels in their place, we can't expect him to be a saint. Besides, I'll bet that whenever he's not in his house, he turns the power off. This is why I questioned the point of even bringing up this kind of ad hominem attack. Even if Al Gore is the worst kind of hypocrite imaginable, that means nothing with regard to the question of global warming just like George Bush's National Guard service has nothing to do with whether it was right to go into Iraq.
Anyway, everything I've read on the matter indicates that there is now a consensus among climatologists that global warming is real and is caused by humans. As recently as two years ago I would say that such a consensus didn't exist, but it now does as much as any consensus can exist in the scientific community. Yes, there are intelligent and reasonable detractors, and their opinions should be taken into account. But every survey and panel since 2004 has said
global warming is occurring in the long term and its causes are at least partly human. The survey by Science magazine is probably the one Gore is citing when he says that there is a general consensus on the issue. The question now is simply to what degree humans are responsible and what percentage of global warming is a natural process.
Scientists are not unanimous, but they never are. However, the fact that the people who oppose the consensus view on global warming are all individuals whereas the ones in support of it are all large professional scientific organizations (
Source) suggests to me that we have the closest thing we're ever going to get to a general consensus. Strangler's JunkScience article is a great read, and I definitely recommend it for everyone. However, that article is also guilty of stating claims as fact from time to time. It contends, for example, that Urban Heat Islands may be a significant factor in the temperature increase we are measuring. And while some studies have claimed to compensate for the UHI effect, JunkScience dismisses those claims as, "not entirely convincing" without really providing data or sources to support their position. I'm not saying that UHI's have nothing to do with how we measure the global temperature, but JunkScience seems to take the position that since UHI's exist and since we don't know how much or whether it affects our measurements, all such measurements are suspect. In my view, that's not a justifiable position.
One good thing JunkScience points out, though, is that it's not all about carbon. There is evidence that even changing the color of the land (for example, cutting down trees and replacing them with wheat fields, effectively changing the land from green to yellow) can affect local temperatures. There are still way too many factors to deal with, and it doesn't help that climatologists can't exactly conduct controlled double-blind experiments. But when we have this much consensus on the issue, I think that we can no longer afford to ignore it. It used to be that a large percentage of scientists said that the earth's temperature isn't even rising, but now there isn't a single respectable one who says that. It used to be that a large percentage of scientists didn't think that global warming was caused in any way by humans. Those ranks have now been reduced to a few dozen individuals while the overwhelming majority of their colleagues now think that global warming is caused at least a little bit by humans. The detractors may still be right, but what if they're not?