Abstract
Accurately assessing green and blue water requirements from croplands is fundamental to promote sustainable water management. In the last decade, global hydrological models have provided important insights into global patterns of water requirements for crop production. As important as these models are, they do not provide monthly crop-specific and year-specific data of green and blue water requirements. Gridded crop-specific products are therefore needed to better understand the spatial and temporal evolution of water demand. Here, we present a global gridded database of monthly crop-specific green (rain-fed) and blue (irrigated) water requirements for 23 main crops and 3 crop groups obtained using our WATNEEDS model. For the time periods in which our dataset matched, these estimates are validated against existing global products and satellite based datasets of evapotranspiration. The data are publicly available and can be used by practitioners in the water-energy-food nexus to assess the water sustainability of our food and energy systems at multiple spatial (local to global) and temporal (seasonal to multi-year) scales.
Highlights
Background & SummaryWater plays a central role in supporting agriculture, with food production responsible for ~90% of humanity’s consumptive water footprint[1,2]
A better understanding of agricultural water needs could be used to identify those places where water demand and its variability could potentially compromise the reliability of food production, and for formulating solutions to promote sustainable water management
Some studies have provided estimates of annual trends in water demand from croplands[5,6] while others have progressed to finer temporal resolutions that consider multiple individual crops[4,7]. The latter crop-specific studies have been typically centred on the year 2000, offering an important snapshot of the global distribution of water demand and insight into the importance of certain crops in driving water demands in different regions. All of these products have helped to advance the science of food security and water sustainability and to identify those places where chronic or seasonal water stress is occurring because of agricultural water demand
Summary
Water plays a central role in supporting agriculture, with food production responsible for ~90% of humanity’s consumptive water footprint[1,2]. These values are typically multiplied by a crop’s annual harvested area in a particular country to determine the total water demand for that crop in that year While such analyses provide important information related to broad trends of water use for crop production, such an approach does not permit temporal examinations that are spatially explicit and intra-annually disaggregated or that account for different crop growing periods. Where temporal and spatial overlap permits, the model outputs generated by this study are compared to other existing global model outputs and satellite-derived products this model will be used to develop a continuous global time series for better understanding the spatial and temporal heterogeneity and variability of freshwater demand for food production as well as how water demand has evolved through time relative to water availability Such historical examinations can provide insights for more accurate predictions of future water demand and availability
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