n 2012, the writer and activist Bill McKibben published a heart-stopping essay in Rolling Stone titled “Global Warming’s Terrifying New Math.” I’ve read hundreds of thousands of words about climate change over the last decade, but that essay haunts me the most.
The piece walks through a fairly straightforward bit of arithmetic that goes as follows. The scientific consensus is that human civilization cannot survive in any recognizable form a temperature increase this century more than 2 degrees Celsius (3.6 degrees Fahrenheit). Given that we’ve already warmed the earth about 0.8 degrees Celsius, that means we have 1.2 degrees left—and some of that warming is already in motion. Given the relationship between carbon emissions and global average temperatures, that means we can release about 565 gigatons of carbon into the atmosphere by mid-century. Total. That’s all we get to emit if we hope to keep inhabiting the planet in a manner that resembles current conditions.
Now here’s the terrifying part. The Carbon Tracker Initiative, a consortium of financial analysts and environmentalists, set out to tally the amount of carbon contained in the proven fossil fuel reserves of the world’s energy companies and major fossil fuel–producing countries. That is, the total amount of carbon we know is in the ground that we can, with present technology, extract, burn and put into the atmosphere. The number that the Carbon Tracker Initiative came up with is… 2,795 gigatons. Which means the total amount of known, proven extractable fossil fuel in the ground at this very moment is almost five times the amount we can safely burn.
Proceeding from this fact, McKibben leads us inexorably to the staggering conclusion that the work of the climate movement is to find a way to force the powers that be, from the government of Saudi Arabia to the board and shareholders of ExxonMobil, to leave 80 percent of the carbon they have claims on in the ground. That stuff you own, that property you’re counting on and pricing into your stocks? You can’t have it.