Why is the research valuable?

Addressing persistent global undernutrition remains a challenge, particularly among children. Irrigation is commonly promoted as a strategy to enhance food production, reduce poverty, and improve nutrition. However, the realities on the ground often complicate this. With our work, we aimed to assess whether irrigation expansion directly translates to better diets for children and how this interacts with local water availability. Understanding these dynamics is essential for developing sound policies to simultaneously tackle hunger and maintain water sustainability.

The story behind our research

Our team was initially driven by curiosity: how well do global irrigation efforts align with local nutritional improvements? Early discussions revealed an intriguing paradox—regions most in need of nutritional gains often lack sufficient water to sustainably support irrigation. In an earlier paper, we mapped global irrigation expansion, which laid the groundwork for this study linking irrigation expansion to nutritional outcomes at a global scale for the first time.

The project involved synthesizing global datasets and extensive geospatial analysis, examining over 70,000 households across 26 low- and medium-income countries across the globe. As we merged household-level nutritional data with global irrigation maps, we encountered unexpected complexities: irrigation was indeed boosting dietary diversity, but predominantly in regions where water resources were already under severe pressure. Meanwhile, water-abundant regions were mostly shifting to cash crops for export, limiting local nutritional gains.

What did the researchers find?

Our analysis revealed a clear positive link between irrigation expansion and improved child dietary diversity—particularly in water-stressed regions. Surprisingly, regions with ample water availability often directed new irrigation efforts toward export-oriented cash crops rather than local nutritional staples. Consequently, these areas saw limited nutritional improvements locally.

This pattern underscores a critical tension: the most pronounced nutritional benefits were often achieved at the cost of sustainability, raising serious concerns about long-term water resource management. Our findings suggest that merely expanding irrigation without considering crop choices and water sustainability risks missing broader development goals.

Broader Implications and Next Steps

The broader implications of our findings are significant. They challenge policymakers and development agencies to rethink irrigation expansion strategies. A key takeaway from our research is the importance of incorporating nutrition-sensitive policies—prioritizing locally consumed, nutrient-dense crops—to maximize the dietary benefits of irrigation.

Moving forward, critical questions remain: how can we integrate local food security objectives into irrigation planning more effectively? What role can technology play in enhancing irrigation efficiency, especially in water-stressed regions? Our ongoing work continues to delve deeper into these questions, aiming to provide actionable insights for sustainable development practices worldwide.

Article Link

Read the full paper in Nature Sustainability

Read link

Please feel free to reach out if you'd like a copy of the paper.

References

• Mehta, P., Muller, M., Niles, M. T., & Davis, K. F. (2025). Evidence of tradeoffs between child diet diversity and water-stressed irrigation expansion in the Global South. Nature Sustainability. https://doi.org/10.1038/s41893-025-01584-y
• Mehta, P., Siebert, S., Kummu, M., Deng, Q., Ali, T., Marston, L., Xie, W. and Davis, K.F., 2024. Half of twenty-first century global irrigation expansion has been in water-stressed regions. Nature Water, 2(3), pp.254-261. https://doi.org/10.1038/s44221-024-00206-9
• Niles, M.T., Emery, B.F., Wiltshire, S., Brown, M.E., Fisher, B. and Ricketts, T.H., 2021. Climate impacts associated with reduced diet diversity in children across nineteen countries. Environmental Research Letters, 16(1), p.015010.. https://doi.org/10.1088/1748-9326/abd0ab
• Müller, M.F., Penny, G., Niles, M.T., Ricciardi, V., Chiarelli, D.D., Davis, K.F., Dell’Angelo, J., D’Odorico, P., Rosa, L., Rulli, M.C. and Mueller, N.D., 2021. Impact of transnational land acquisitions on local food security and dietary diversity. Proceedings of the National Academy of Sciences, 118(4), p.e2020535118. https://doi.org/10.1073/pnas.2020535118
• Muller, M., Mehta, P., Niles, M. T., Madani, K., & Davis, K. F. (2025). Expanding Irrigation Could Enhance Child Nutrition but Risks Unsustainable Water Use. United Nations University Institute for Water, Environment and Health (UNU INWEH).  http://dx.doi.org/10.53328/INR25MMU005