I think I remember something about grapes in England during the medieval warming period that we're talking about, pj, as you may have read as well. That lines up in an interesting way with a recent news story that I saw -- apparently, changing weather conditions in the UK are once again making grape-growing a worthwhile endeavor.
Also, thanks Miguel for your historical insights on China. Your point on losing sight of solutions because we're so wrapped up in arguing about the problems is very well put. That's really where things get interesting -- from an optimist's perspective, global warming offers some great opportunities for the world as a whole. It's a problem that has the potential to unite nations and spur fascinating technologocal advances. For example, there are scientists out there right now pioneering technologies that actually pull greenhouse gases out of the atmosphere. That's pretty cool, if you ask me, and it shows that dedicated people are already working hard to fix a problem that many people (including our dear president) dismiss as hocus-pocus. And if scientists are wrong, and global warming is just a naturally occuring event? Or if global warming doesn't progress as expected? What have we lost by making the changes that scientists recommend? Well, the coal industry will have lost some money, as will the petroleum industry (although BP has already positioned itself as a major provider of solar energy). And I'm sure there are other costs that will need to be addressed. What have we gained? Cleaner, more efficient technologies, a cleaner environment, and the knowledge that we don't have to pollute the planet to prosper. That, to me, is well worth the effort. If scientists are correct, we'll have gained all of those things PLUS done our best to address a problem that could have dire implications for millions if not billions of our fellow citizens.
Addendum: I should also add that modern, market-driven economies put remarkable power in the hands of individual consumers. To quote Tim Flannery, the author of The Weather Makers that I mentioned above, "if enough of us buy green power, solar panels, solar hot water systems, and hybrid vehicles, the cost of these items will plummet" (306). Not to mention energy-efficient appliances, recycled building materials, better home insulation, etc. As costs plummet, sales will grow, not just in California, Maine, or Quebec, but also in China, India, and other developing nations where affordable, sustainable energy is a pressing need. So global warming isn't just about doomsday pronouncements (thanks again, Miguel, for bringing that into focus) -- it's about an opportunity for us to make important changes in our own personal lives whose ramifications are potentially global in scope.