192 major Chinese cities where groundwater accounts for more than 10% of total water supply during 2001–2020, covering major hydrogeological settings, including the North China Plain aquifer system, alluvial aquifers of the Yangtze River Basin, and karst aquifers in southwestern China. This study develops an emergy-based assessment framework to quantify ecological compensation requirements associated with groundwater extraction. The framework integrates time-dependent allocation of environmental losses with the conversion of water conservation potential to evaluate the environmental costs of groundwater overexploitation and support sustainable groundwater management at the urban scale. Groundwater extraction induces substantial hydrological and ecological impacts, including land subsidence, groundwater pollution, vegetation deterioration, seawater intrusion, and surface runoff reduction. Emergy-based assessment reveals that cumulative environmental losses reached 9.75 × 10 23 sej between 2001 and 2020, with land subsidence accounting for the dominant share (6.41 × 10 23 sej). The results reveal pronounced spatial heterogeneity in ecosystem losses across hydrogeological settings, reflecting differences in geological sensitivity and groundwater exploitation intensity. Futhermore, the analysis captures the temporal evolution of groundwater-related environmental pressures and indicates that ecological compensation policies, combined with water-saving measures such as winter fallowing, crop structure optimization, and improved irrigation efficiency, could reduce groundwater extraction by approximately 2.43 × 10 11 m 3 over a 20-year period. • Emergy-based model quantifies impacts of groundwater extraction. • Emergy loss reached 9.75 × 10 23 sej (2001–2020), dominated by land subsidence. • Ecological compensation estimated at 1.79 × 10 11 USD with regional variation. • Compensation policy could reduce groundwater extraction by 2.43 × 10 11 m 3 .
Ji et al. (Mon,) studied this question.