As with all proposed carbon dioxide removal strategies, scale-up would need to start small with rigorous tests to ensure it is effective, safe and socially acceptable, before proceeding to the next stage in coming decades.  Our research indicates that the best places to begin rolling it out would be croplands of the three countries that are currently the highest fossil fuel emitters: China, USA and India.  Croplands of some European countries may also be especially suitable.  These are ideal initial target areas because crop production in warm climates tends to be high and both factors accelerate the breakdown of rock grains.  Scaling up enhanced weathering on existing agricultural land (or with forestry land) means that no land would need to be diverted from other uses. Increasing the productivity on existing land also reduces pressure for converting forested land to agriculture.