Recent research published in Nature Food shows that global crop water use has increased by 9% within the past decade (from 2010 to 2020), indicating growing pressure on water and food systems worldwide. This is largely the result of expanding harvested areas to meet increasing needs for food, feed and biofuels. The paper also includes an open-source model that can be used by anyone with basic modelling skills to make additional analyses.
Agriculture is the largest water user worldwide, in terms of both blue and green water — blue water being the water in rivers, lakes and groundwater — and green soil water formed by precipitation and available to plants.
With global demand for food and feed growing, the agricultural demand for water will continue to increase. Concurrently, water demands for towns and cities, energy, industries, livestock, mining and ecosystems need to be met.
There is, however, a persistent lack of reliable water data, especially sectoral water demand data. To address this gap, the International Water Management Institute (IWMI) collaborated with the IHE Delft Institute for Water Education and the University of Alabama to provide a detailed crop water use baseline for researchers, along with a global database and an easy-to-use model.
Our new robust yet easy-to-use Python code model — CropGBWater — calculated global blue and green water consumption of 46 crops in a resolution of 10 kilometers for the year 2020
Our new robust yet easy-to-use Python code model — CropGBWater — calculated global blue and green water consumption of 46 crops in a resolution of 10 kilometers for the year 2020. The crops with high water use include rice, maize, wheat, sugarcane, cotton, soybean and oil palm.
We developed CropGBWater as an open-access assessment model for global gridded water consumption. The model provides an unprecedented level of detail covering individual crops. It has been designed for use by any stakeholder with basic modelling skills, and, with its easy accessibility and open-source input data, is of significant value to users in the Global South who often lack the funds for data or software acquisition. In combination with high-resolution open datasets, it makes global crop WC estimates reproducible, transparent, and reusable for research, planning and decision-making.
We used the new Spatial Production Allocation Model (SPAM) crop database of the International Food Policy Research Institute (IFPRI) for the years 2020 and 2010, to calculate the daily water consumption for each crop and aggregated the results to monthly and annual levels. We found that global water consumption for crops has increased by 9% between 2010 and 2020. The water used to cultivate several of the world’s most planted crops has risen significantly, with cassava using 82% more water, soybeans 60% more and maize 45% more.
The rise in water use increases pressure on key water stressed basins, including the Indus, Ganges, Yellow River and Nile basins. This threatens local ecosystems and food security in areas that already face water-related challenges due to population growth, dietary shifts, climate change, and other factors. Solutions to increasing crop water use worldwide include producing more food with less water, cultivating less water demanding crops in water stressed river basins, shifting to more plant-based diets among affluent populations and reducing food losses and waste along the supply chain.
The new model and its resulting global crop water consumption database are valuable for informed and smart decision-making in the water and agricultural sectors, particularly in the Global South. By providing all results open access, we help close the water data gap, a widespread constraint on water management in the Global South.