I disagree with criticism by Stoat and many others about Gore's "jet-setting" lifestyle, consisting of his riding commercial airplanes to give presentations about global warming, and occasional travel to exotic locations to see the effects of warming.
First and less important, Gore buys offsets to balance his carbon footprint, a fact noted by Stoat's commenters. Stoat makes a legitimate point that Gore might have addressed his lifestyle in his movie, but in turn, any critique of his lifestyle should also address his attempt to fix the problem.
There are questions about the effectiveness of the offsets, but it's unlikely that they're completely useless. I expect the market for voluntary purchases of emission credits will be driven by quality, and chintzy frauds will find themselves exposed by their competitors. Early adopters speed up this process. And yes, the whole world can't buy carbon offsets. I really wish that were the problem we face right now, though - we'd be in a much better shape if it were.
But more important than offsets is the better question to ask of Gore - whether he's doing the best possible job of reducing emissions overall (another issue noted by a Stoat commenter). I suppose that instead of travelling to presentations, Gore could stay home and do them by live teleconference feeds. He'd then get less than half the people to attend, and there would be no movie that has now been seen by millions worldwide. Overall, emissions would be worse.
Travelling to the South Pole is a somewhat closer question, but it has its justifications. One of the few things I remember from reading Earth in the Balance fifteen years ago was Gore's description of flying over the Amazon treetops in a tiny plane, watching clouds develop from the moisture of the rainforest. Instead of travelling there, he could've reproduced a conversation about the rainforest that he had with some professor, but bozos like me would retain no memory of that lesson. Eyewitness testimony is much more memorable.
Of course I've got my own biases, having travelled on two volunteer vacations to Montana and Alaska related to global warming. I certainly have less justification than Gore in travelling - millions of people won't learn about melting glaciers from me. I probably could have done more about global warming from home than by adding a tiny amount of data by lugging a GPS unit around glacier edges. But I'm imperfect, not a saint, and would not have spent my two-week vacation writing letters to the editor. Given the alternative, it was pretty good. Given how Al Gore chooses to spend his time compared to the vast majority of the elite, what he does is more than pretty good.
UPDATE: Stoat's response is here.