New Study Questions Validity of Irrigation Statistics in Food Security

A recent study from the University of Birmingham has raised significant concerns about the reliability of widely cited irrigation statistics that have influenced global food security policies for decades. The research, published on November 11, 2025, in the journal PNAS Nexus, reveals that claims stating irrigation contributes to 40% of global crop production and accounts for 70% of freshwater withdrawals lack robust empirical support.

For over 50 years, these figures have been referenced in more than 3,500 documents, spanning academic research and policy discussions. However, the origins and validity of these statistics remain largely unverified. The research team found that only 1.5% of the cited documents provided original data, with many either failing to mention the figures or lacking sufficient evidence to support their claims.

Questioning Established Data

Dr. Arnald Puy, associate professor and lead author of the study, emphasized that the propagation of these statistics appears to stem from hearsay. He noted that their emotional impact and simplicity have made them appealing to policymakers, despite the complex realities surrounding food and water security. Dr. Puy stated, “As we approach COP30 in Brazil, the time is ripe for us to critically analyze the quality of water use data at the heart of the policy debate on food security.”

The study highlights that the role of irrigation in food and water security is far from straightforward. Current data indicates that irrigation’s contribution could range anywhere from 18% to 50% of global food production, while its share of freshwater withdrawals varies dramatically between 45% and 90%. This variability underlines the challenges in establishing a clear understanding of irrigation’s impact.

Implications for Policy and Practice

Co-author Seth N. Linga, a Ph.D. researcher, pointed out that the inconsistent data creates a dichotomy in perceptions of irrigation’s importance. “Irrigation can be viewed either as a minor player in global food production or as a crucial component,” he explained. This duality extends to its efficiency in water use, with available data supporting both highly inefficient and remarkably effective interpretations.

Ph.D. student Carmen Aguiló-Rivera, another co-author, suggested that future policies should focus on collaboration with local stakeholders. “Our research indicates that designing resilient food and water policies should not depend solely on the precise quantification of global resources. Engaging communities can lead to enhanced crop production and water conservation, irrespective of benchmark calculations,” she asserted.

The findings of this study serve as a critical reminder of the importance of verifying data that influences global policy decisions. As discussions for the upcoming COP30 gain momentum, the need for accurate and reliable statistics in shaping food security strategies becomes increasingly vital.

For more information, refer to the study titled “Widely cited global irrigation statistics lack empirical support” published in PNAS Nexus. The DOI for the study is 10.1093/pnasnexus/pgaf323.