Remote Sensing of Basin Evapotranspiration Under Interacting Climate Change and Human Activities: From Estimates to Verifiable Evidence for Water Management

Remote sensing-based evapotranspiration (ET) provides spatially continuous information on basin water consumption, but its use in water resources management requires careful consideration of scale, attribution assumptions, and uncertainty. This narrative review synthesizes ET models and products, climatic and human controls, attribution approaches, and hydrological evaluation. Product performance varies across regions and scales, and agreement among products sharing inputs cannot replace independent evaluation. Statistical associations, model-conditioned contributions, and intervention effects answer different questions; climate–human interactions require explicit reference states and decomposition rules. We propose three checks for ET-change claims: whether the uncertainty interval supports a defined decision threshold, whether the attribution method supports the intended interpretation, and whether independent hydrological evidence constrains the conclusion. A workflow links these checks to irrigation, water-rights, groundwater, drought-restriction, and ecological-restoration applications. In a worked example from a Kansas groundwater management area, a published pumping-reduction interval meets the program threshold, and a hypothetical calculation shows that error correlation between periods can change whether an ET-based indicator meets a threshold. The framework offers a transparent basis for screening and conditional assessment, while accounting and causal claims require evidence matched to the quantity, domain, and period.