Groundwater Depletion Under Irrigated Agriculture: Evidence and Governance

Abstract

Groundwater carried the green revolution. It is now being spent faster than it is replaced across most of the world's intensively irrigated plains. This review synthesises 37 peer-reviewed studies on the measurement, drivers, consequences and governance of agricultural groundwater depletion, with north-west India treated as the principal case. Satellite gravimetry made the problem visible: Rodell and colleagues reported a loss of about 109 cubic kilometres from the aquifers of north-west India over roughly six years and Tiwari and colleagues put the northern Indian rate near 54 cubic kilometres a year . Global estimates remain far apart, from 283 down to 113 cubic kilometres a year depending on method and at least one reanalysis argues that satellite-based Indian figures were too high. We make three arguments. Depletion is a governance failure with an energy price at its centre, not a hydrological accident. Efficiency measures alone do not conserve the resource, because saved water is usually reinvested in more irrigated area . And the consequences now reach beyond the farm, into river baseflow, national emissions and the food trade of other countries . Measurement disagreement is itself a governance problem, since a resource nobody can measure consistently is hard to allocate.