Weathering of huge amounts of tiny rocks could be a means to reduce greenhouse gases in the atmosphere. While this is normally a slow, natural process during which minerals chemically bind CO2, technological upscaling could make this relevant for so-called negative emissions to help limit climate risks. Yet, the CO2 reduction potential is limited and would require strong CO2 pricing to become economically feasible, according to the first comprehensive assessment of costs and possibilities now published in the journal Environmental Research Letters.