An economic study calculates the effectiveness of a novel policy instrument: The underlying idea is that you are allowed to release the climate gas CO₂ into the atmosphere—but only if you promise to "clean up" later through carbon removal. The market forces activated by clean-up certificates can greatly strengthen the fight against global heating without placing an extra burden on the economy. The study was conducted by the Potsdam Institute for Climate Impact Research (PIK) and released in the...