Kyle Manley, Tristan Salles Dietmar Müller Since roughly 1880 the Earth has warmed by 1 deg C, many times faster than any warming episode in the past 65 million years of Earth’s geological history. We will need to remove hundreds of gigatons of carbon dioxide (CO2) from the atmosphere by the end of the twenty-first century to keep global warming below 2°C within the constraints of the global carbon budget.