Today in the Independent Johann Hari has a pretty good article on the climate change issue leading up to Copenhagen. There isn’t anything alarmist or sensationalist about it, and most of the examples he gives are not predictions - they’ve already happened.
I recommend reading the article.
But don’t read the comments. Please don’t read the comments. Not unless you want to feel like you immersed in a nauseating slime that will never wash off. The Independent which normally appeals to a readership which doesn’t drag its knuckles along the ground, but you’d never know it here. The (sadly typical) display of ignorance and denial fueled by petty greed and bigotry is more than enough to make me feel that wiping out the human species, by and large, will be a very positive step for the Universe.