Hydrology and Land Surface Studies
Global irrigation water demand: Variability and uncertainties arising from agricultural and climate data sets
Article first published online: 31 DEC 2008
Copyright 2008 by the American Geophysical Union.
Geophysical Research Letters
Volume 35, Issue 24, December 2008
How to Cite
2008), Global irrigation water demand: Variability and uncertainties arising from agricultural and climate data sets, Geophys. Res. Lett., 35, L24408, doi:10.1029/2008GL035296., , , , , and (
- Issue published online: 31 DEC 2008
- Article first published online: 31 DEC 2008
- Manuscript Accepted: 5 NOV 2008
- Manuscript Revised: 1 OCT 2008
- Manuscript Received: 9 JUL 2008
 Agricultural water use accounts for around 70% of the total water that is withdrawn from surface water and groundwater. We use a new, gridded, global-scale water balance model to estimate interannual variability in global irrigation water demand arising from climate data sets and uncertainties arising from agricultural and climate data sets. We used contemporary maps of irrigation and crop distribution, and so do not account for variability or trends in irrigation area or cropping. We used two different global maps of irrigation and two different reconstructions of daily weather 1963–2002. Simulated global irrigation water demand varied by ∼30%, depending on irrigation map or weather data. The combined effect of irrigation map and weather data generated a global irrigation water use range of 2200 to 3800 km3 a−1. Weather driven variability in global irrigation was generally less than ±300 km3 a−1, globally (<∼10%), but could be as large as ±70% at the national scale.