I've done a blog post for Science Progress about the competing goals at Copenhagen, as industrial powers say holding temperature rise to 2 degrees Celsius will by 2100 will be enough, but developing nations and some scientists say we need to be much more precautionary, and shoot for more like 1.5 degrees C. It may sound like a small difference, but once you convert it into parts per million of carbon dioxide in the atmosphere, you're looking at a gap between 450 and 350--with the later being a threshold we've already crossed. So the question is, can Copenhagen really succeed, where succeed means to avert any serious chance of climate disaster? My answer is that, barring some radical last minute deal, it may not be able to do so. And that's scary. Read the full analysis here.