A few weeks ago in my Earth 130 class (Global Warming) Professor Lea asked that we each share the following link to at least one person.
The bright red number in the billions is the estimated tonnes of carbon emitted since the Industrial Revolution. Once we reach 1 trillion tonnes of carbon, there is expected to be a global warming of 2 degrees Celsuis. This site even has the date and time we expect to hit that point, as well as the estimated rate we must reduce our carbon emissions to avoid emitting 1 trillion tonnes of carbon. It's extremely interesting to see these numbers changing at such a fast rate, and the expected time move closer and closer. Definitely check it out. (I also highly recommend Earth 130, Professor Lea is awesome to have discussions with and knows it all, considering climate change is his line of work.)