I respect Al Gore for many reasons, but I'm concerned by what appears to be a "propagandistic" rather than "scientific" lean to this film (this is based on clips and comments by those who have seen the film). I do not think Gore is a clear thinker on this topic and sees himself more as a "prophet".
If we focus on addressing the many global problems like health and economies of the developing world we can get a spectacular return on the investment of mental and monetary capital. Collateral advantages will be reductions in terrorism and a huge boost in good will and personal satisfaction.
Investing in alleviating human causes of global warming has no clear path to success, yet the costs are simply staggering.
Tim replied to my concerns, which I posted over at his blog. I love the internet for letting little old me, and thousands of others, actively engage with some of the world's best and brightest. Whatever one's views on the *most* pressing problems, certainly the collective application of innovation has the power to bring us the solutions.
I see you've read The Skeptical Environmentalist. And I certainly agree with Bjorn Lomborg that there are other pressing problems where there is a great return on investment. But it also seems to me that many of the things that would be required to help with global warming could have enormous payoff. Critics talk about enormous costs, but it seems to me that the costs of the current way of doing things are always hidden.
A great example of this is railroads vs. automobiles. There's always been a huge debate about rail from the north bay down to San Francisco, with critics talking about the $150 million projected cost as a subsidy. But no one talks about the tens of billions of dollars of subsidy represented by the creation and maintenance of the highway system. Railroads are expected to carry their costs and described as uneconomic because they need subsidies, but the automobile industry managed to get much larger subsidies baked into the economy and hidden so that they no longer even appear as subsidies.
I agree with Tim that some hidden economic subsidies are not always identified in discussions, but Economists do talk about and study these relationships. Unfortunately these observations are almost always buried in the politically/emotionally motivated budgeting processes. Political budgeting is not rational budgeting.
He's also right that greenhouse alleviation *might* have a big payoff, especially from things like alternative energy innovations that we might not explore unless we tackle global warming more aggressively. Still, the benefits seem so very unclear that I'd rather have the government spend my money on alleviating the abundant clear, present, and (most importantly) CHEAP-to-fix dangers like global health and poor education. (I'm against much of the excessive military and security spending as well as potential global warming big spending.)
I'd even suggest that the positive technology spinoffs from $250,000,000,000 towards global health and development would simply dwarf those from that investment in Greenhouse gas alleviation (or military or first world health care, etc, etc).