Assessing virtual water flows from small-scale and large-scale agriculture in global trade

Non-technical Summary
Water is a shared global resource, yet its movement is often invisible. When a country imports products, it also imports ‘virtual water’, the water used to produce those products. While agriculture accounts for 85% of global water transfers, we have lacked a clear understanding of who is actually moving this water: large industrial farms or small-scale farmers? Our study shows that small-scale agriculture plays a disproportionately large role in global virtual water flows, compared to its volume of crop production involved in trade.

Technical Summary
Most global virtual water flows come from agri-food sectors, describing how commodity demand in one country drives water use in others. Despite their significance, virtual water flow assessments have largely overlooked the distinct roles of small-scale versus large-scale agriculture, hindering the development of targeted water and food security policies in both producing and consuming
countries. To address this gap, we estimate the contributions of small-scale and large-scale agriculture to crop production and virtual water embedded in trade (export) using detailed hybrid multi-regional input-output tables spanning 55 countries. We reveal that, although small-scale agriculture accounts for only 17% of the total crop production involved in trade (in tonnes), its role in virtual water flows is disproportionately large, accounting for 22% of blue and 30% of green virtual water flows. In 13 of the 55 countries, small-scale agriculture accounts for more than 50% of green virtual water exports. Furthermore, virtual water exports from small-scale agriculture exhibit distinct spatial patterns and are driven primarily by demand for labor-intensive crops rather than animal-sourced human food and non-food products. Our results suggest that explicitly accounting for farmers’ roles in virtual water flows is critical for the design of context-specific, effective, and equitable policy interventions.

Social Media Summary
Check out the unique role of small-scale agriculture in global crop trade and virtual water flows.