The European Space Agency (ESA) Climate Change Initiative - Agricultural Water Use (CCI-AWU) is a precursor project that aims to provide a long-term time series (e.g., 20 years) of Anthropogenic Water Use (AWU). AWU focuses mainly on agricultural irrigation, as this is the human activity that consumes by far the most water on a global scale (around 70% of water consumption worldwide). Long-term time series of AWU, declared as an Essential Climate Variable (ECV), are essential to better understand anthropogenic perturbations of land-atmosphere interaction processes, provide information to water managers at regional and national scales, and close water balance on a regional or global scale.

These AWU time series will be generated in four highly irrigated pilot regions (USA, India, Spain, Australia) for which irrigation data are available for validation. Four different irrigation retrieval algorithms will be used, using coarse-scale remote sensing products (soil moisture and total water storage from the GRACE satellite). This project will assess the ability of coarse-scale satellite data to retrieve irrigation and develop tools and techniques to characterize better the uncertainties associated with retrieved irrigation. To this end, cross-comparisons between the four AWU datasets will be carried out.