Is it possible to heat the planet to dangerous levels and then cool it down later? Economic models charting the world’s path to net zero emissions say yes. However, this bet on future large-scale carbon removal risks becoming a “get out of jail free” clause that allows high emissions to continue inflaming the climate crisis. A new study by leading scientists has criticised the overconfidence of policymakers and climate modellers – even the authors of the 2015 Paris agreement – for making this gamble. Their research highlights the pitfalls of assuming temperature thresholds can be safely exceeded and then reinstated. They’re right – and the problem runs even deeper. The challenge of implementing carbon removal at the scale required isn’t simply a matter of the technology being available and cost effective to deploy. Large-scale CO₂ removal depends on there being vast amounts of land to store carbon in trees and soil.