Post Carbon Fellow Bill McKibben wrote a follow up to his article “Global Warming’s Terrifying New Math.” from four years ago in the New Republic.

From the article:

The future of humanity depends on math. And the numbers in a new study released Thursday are the most ominous yet.

Those numbers spell out, in simple arithmetic, how much of the fossil fuel in the world’s existing coal mines and oil wells we can burn if we want to prevent global warming from cooking the planet. In other words, if our goal is to keep the Earth’s temperature from rising more than two degrees Celsius—the upper limit identified by the nations of the world—how much more new digging and drilling can we do?

Here’s the answer: zero.