Climate Change has been a controversial topic for decades.  If you're still on the fence, or have doubts, read this article about 3 important numbers.  http://www.rollingstone.com/politics/news/global-warmings-terrifying-new-math-20120719?print=true  I've supplied the printer friendly link, so the article isn't split between ad-laden pages.

It all comes down to the math. 2 Degrees Celsius is the most we can afford to let the Earth heat up.  565 Gigatons of CO2 released into the atmosphere will do exactly that.  2795 Gigatons of CO2 are currently in the pipeline for fossil fuel companies to burn.  That's 5 times the most we can handle in even the best case scenarios.  As it is, the actual results of Climate Change have so far been worse than predicted for the 0.8 degrees we've warmed up already.

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Alone among businesses, the fossil-fuel industry is allowed to dump its main waste, carbon dioxide, for free. Nobody else gets that break – if you own a restaurant, you have to pay someone to cart away your trash, since piling it in the street would breed rats. But the fossil-fuel industry is different, and for sound historical reasons: Until a quarter-century ago, almost no one knew that CO2 was dangerous. But now that we understand that carbon is heating the planet and acidifying the oceans, its price becomes the central issue.

Not depressed enough by that last article?  Read this one: http://io9.com/5945658/what-the-hell-is-happening-to-the-arctic-sea-ice