Widely cited global irrigation statistics lack empirical support

A prevailing notion in sustainability science is that irrigated agriculture underpins global food and water security because it accounts for 40% of crop production and 70% of freshwater withdrawals. Through a network citation analysis of 3,500 documents, we reveal that this belief has spread through the literature with minimal empirical support: 60-80% of all citation paths lead to sources that lack supporting data or that do not even contain the 40 or 70% numbers. We also demonstrate that these figures mask a much more uncertain contribution of irrigation to global crop production and water withdrawals, which can lie anywhere between 18-50 and 45-90%, respectively. These ranges should be understood as lower bounds on the true uncertainty. Our findings underscore the need to rigorously evaluate foundational claims in sustainability science and embrace ambiguity to produce robust research and policy-making.