The "Oh Shit" Era of Environmental Awareness

If you haven't read it yet, this essay by Bill McKibben, author of "The End of Nature," is a good overview of levels of awareness in the climate change debate:

The worst thing about the "Oh shit" era is we don't know for sure exactly what will happen.

Most of the changes I've been listing -- nastier storms, rising sea levels -- are pretty much linear extrapolations. If you make it hotter, they'll just keep getting worse. But researchers suspect that the world also has some trapdoors -- mechanisms that don't work in straightforward fashion, but instead trigger a nasty chain reaction.

Melt enough of that Arctic ice, for instance, and you may alter the salinity of the North Atlantic enough to shut down the Gulf Stream. All of a sudden the rest of the world would be heating up, while northwestern Europe would be getting very cold.

"Climate is an angry beast," Wallace Broecker, dean of the planet's climate scientists, said a few years ago. "And we are poking at it with sticks."