While the climate policy world is littered with numbers, three of them have dominated recent discourse: 2, 1000, and 66. At the 2015 U.N. climate summit in Paris , world leaders agreed to limit global warming below 2°C to avoid catastrophic impacts of human-caused climate change. The science consequently dictates that, for a 50% chance of staying below 2°C, around 1,000 billion tonnes of carbon dioxide (or 300 billion tonnes of carbon) can be emitted between now and 2050, and close to zero thereafter. We’re currently emitting 36 billion tonnes of carbon dioxide per year. However, the potential greenhouse gas emissions contained in known, extractable fossil fuel reserves are around three times higher than this carbon budget, meaning that 66% must be kept in the ground. Sign up to the Green Light email to get the planet’s most important stories The debate du jour thus centers on which emissions […]