 I wrote about three numbers in a piece last summer for Rolling Stone. It was the issue with Justin Bieber on the cover. The next day, I got a call from the editor saying, your piece has gotten ten times more likes on Facebook than Justin Bieber's. Some of that is doubtless the result of my sort of soulful stare. But mostly it's because we managed to just kind of lay out this math in a very straightforward way that people needed to understand. Shall we work through the numbers? They're three and they're easy. The first one's two degrees. That's how much the world has said it would be safe to let the planet warm. In political terms, it's the only thing that anybody's agreed to. Some of you may remember that climate summit in Copenhagen. There was only one number in the final two-page voluntary accord that people signed. There was only one number in it, two degrees. Every signatory pledged to make sure the temperature wouldn't rise above that. The EU, Japan, Russia, China, countries that make their money selling oil like the United Arab Emirates, the most conservative, recalcitrant, reluctant countries on Earth, even the United States. If the world officially believes anything about climate change, it's that two degrees is too much. The second number, scientists have calculated how much carbon we could pour into the atmosphere and have a reasonable chance of staying below two degrees. They say about 565 more gigatons. A gigaton is a billion tons. That's not a perfect chance. That's worse odds than Russian roulette, you know. It sounds like it should be a lot. It is a lot. 565 billion tons of CO2. The problem is we pour 30 billion tons a year in now and it goes up 3% a year due to the math and it's about 15 years before we go past that threshold. So that's sobering news. But the scary number is the third number. The third number was the important one and the new one. And it came from a team of financial analysts in the United Kingdom. And what they did was sit down with all the annual reports and SEC filings and things and figure out how much carbon the world's fossil fuel industry, how much they had already in their reserves. And that number turned out to be 2,795 gigatons worth of carbon. Five times as much as the most conservative governments on earth think would be safe to pour into the atmosphere. It's not even close. I mean, it's five times more. And once you know that number, then you understand the essence of this problem.