The delusive accuracy of global irrigation water withdrawal estimates

Serious flaws in the estimations of global water needs are putting agriculture and communities around the world at risk, according to recent research from an international team of researchers, including some from OPSIS at the University of Oxford.

According to the research, the Irrigation Water Withdrawal estimates produced by large-scale hydrological models are unreliable. They disregard uncertainties in key parameters and exclude legitimate conceptions of irrigation that do not easily fit within the normative agronomist or engineering mindset, such as that of local and traditional irrigators. This can lead to policy misjudgements and cause social and environmental harm on a vast scale.

Dr Razi Sheikholeslami, a co-author and researcher from Oxford’s Programme for Sustainable Infrastructure Systems, says, “We discuss the dangers of relying on spuriously accurate models for policymaking [in the research paper]… and offer corrective measures to ensure that uncertainties are properly accounted for and quantified.”

“We are significantly in the dark and pretending we are not… global hydrological models are often used to inform the Sustainable Development Goals (SGDs) in the water-food interface and high-level policies.”

“This becomes more critical considering the ongoing transition from smallholder farming to large-scale industrial agriculture… as we showed in our study, current models misguide us under an accuracy mirage, and it is impossible to know whether we are underestimating or overestimating the impact of irrigation agriculture in the water cycle.”

The report outlines suggest three corrective measures and concludes that ‘large-scale hydrological models should recognize and embrace uncertainties lest they become irrelevant tools for future water management.’

You can read the full report here.