Water Footprint Assessment in Agricultural Systems

Water footprint assessment provides a comprehensive metric for quantifying the volumes of freshwater—divided into green (soil moisture), blue (surface and groundwater) and grey (pollution dilution)—required to produce agricultural goods. Originating from life cycle thinking, this approach integrates crop water use, pollutant loads and trade flows to reveal spatial patterns of water consumption and stress. In agricultural systems, it underpins evaluation of irrigation efficiency, crop selection, pollutant management and supply-chain impacts, offering a unifying framework for farmers, policymakers and corporations. By mapping virtual water trade, researchers can trace how consumption in one region externalises water demands in another, with implications for water-scarce basins. The method has evolved to include basin-level assessments, scenario analysis for future demand and detailed process models linking evapotranspiration, yield responses and management practices. Ultimately, water footprint assessment supports the optimisation of water resources, guides sustainable agricultural intensification and informs trade policy to balance food security with freshwater conservation on a global scale.

Research from Nature Portfolio

Recent studies have quantified how displaced populations alter agricultural water demands by embedding global refugee movements into food-production networks. Modelling annual data from 2005 to 2016, researchers demonstrated that refugee-driven food consumption amplified water stress in vulnerable countries by up to 75 percentage points, emphasising the role of trade realignment and aid planning in mitigating water shortages. Another investigation employed a multi-model framework to assess the land and water footprints of European Union food consumption, revealing that livestock grazing alone accounted for a significant share of total water demand. This work highlighted discrepancies among existing footprint methods and called for consistent protocols to monitor reduction targets under regional sustainability strategies.

Water Footprint Assessment in Agricultural Systems publication trend

The graph below shows the total number of articles in water footprint assessment in agricultural systems across all publications each year (not limited to Nature Index journals).

Technical terms

Water footprint: Total volume of freshwater (green, blue and grey) consumed and polluted per unit of agricultural output.

Green water footprint: Rainwater stored in the soil and used by crops through evapotranspiration.

Blue water footprint: Surface and groundwater withdrawn for irrigation and not returned to the catchment.

Grey water footprint: Volume of freshwater required to assimilate pollutants (e.g. fertilisers, pesticides) to meet water quality standards.

Virtual water trade: Water embedded in traded agricultural products, indicating how consumption in one region relies on water resources elsewhere.

References

1. Food demand displaced by global refugee migration influences water use in already water stressed countries. Nature Communications (2023).
2. Multi-model assessment identifies livestock grazing as a major contributor to variation in European Union land and water footprints. Nature Food (2023).
3. Spatial and temporal grey water footprints of agricultural pesticide use: Improved pesticide use options to decrease water pollution in China. Energy Nexus (2024).
4. Green and blue water footprint reduction in irrigated agriculture: effect of irrigation techniques, irrigation strategies and mulching. Hydrology and Earth System Sciences (2015).
5. The green, blue and grey water footprint of crops and derived crop products. Hydrology and Earth System Sciences (2011).
6. Assessing water footprint at river basin level: a case study for the Heihe River Basin in northwest China. Hydrology and Earth System Sciences (2012).
7. Water footprint scenarios for 2050: A global analysis. Environment International (2013).
8. Improvements in crop water productivity increase water sustainability and food security—a global analysis. Environmental Research Letters (2013).
9. Water Footprint Assessment: Evolvement of a New Research Field. Water Resources Management (2017).