I'm not unworried about it, I'm just more worried about other things. There's a chapter in Superfreakonomics on global warming that changed my thinking on it. Warming can be halted. Doing so requires interventions that would have unanticipated consequences--throwing sulfur into the stratosphere, seeding clouds over the oceans. But if disaster were at our door, we could do these things within a few years and halt the problem until we figured out a more permanent solution. The people who want us to worry about global warming don't just want to solve the problem; they want to use it as an excuse to solve other, more difficult environmental problems that some people don't agree are problems at all.

Man, the rule that we have to pay karma to reply to down-voted comments is not just stupid--on a blog that is specifically about rationality, it's hard for me to believe it isn't a deliberate attempt to enforce groupthink.

ADDED: I'm going to add further discussion into this comment, instead of paying 5 karma each time I reply.

It's odd to talk about possible irreparable harm to ecosystems, when we've already pretty much destroyed most ecosystems on Earth. 12% of the US is national Forest, but most of that is either mountains or desert. Everything between the Mississippi and the Rocky Mountains is gone. Oceans around the world are fished nearly empty, etc. That train has left the station.