Illustration by Neil Webb

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.

That’s right: If we’re serious about preventing catastrophic warming, the new study shows, we can’t dig any new coal mines, drill any new fields, build any more pipelines. Not a single one. We’re done expanding the fossil fuel frontier. Our only hope is a swift, managed decline in the production of all carbon-based energy from the fields we’ve already put in production.

The new numbers are startling. Only four years ago, I wrote an essay called “Global Warming’s Terrifying New Math.” In the piece, I drew on research from a London-based think tank, the Carbon Tracker Initiative. The research showed that the untapped reserves of coal, oil, and gas identified by the world’s fossil fuel industry contained five times more carbon than we can burn if we want to keep from raising the planet’s temperature by more than two degrees Celsius. That is, if energy companies eventually dug up and burned everything they’d laid claim to, the planet would cook five times over. That math kicked off a widespread campaign of divestment from fossil fuel stocks by universities, churches, and foundations. And it’s since become the conventional wisdom: Many central bankers and world leaders now agree that we need to keep the bulk of fossil fuel reserves underground.