Open AccessLarge variations in global irrigation withdrawals caused by uncertain irrigation efficiencies
Author(s) -
Arnald Puy,
Bruce Lankford,
Jonas Meier,
Saskia van der Kooij,
Andrea Saltelli
Publication year - 2022
Publication title -
environmental research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.37
H-Index - 124
ISSN - 1748-9326
DOI - 10.1088/1748-9326/ac5768
Subject(s) - irrigation , environmental science , irrigation management , water resource management , agriculture , agricultural engineering , irrigation district , irrigation statistics , deficit irrigation , water cycle , water resources , surface irrigation , hydrology (agriculture) , agronomy , geography , ecology , biology , geotechnical engineering , archaeology , engineering
An assessment of the human impact on the global water cycle requires estimating the volume of water withdrawn for irrigated agriculture. A key parameter in this calculation is the irrigation efficiency, which corrects for the fraction of water lost between irrigation withdrawals and the crop due to management, distribution or conveyance losses. Here we show that the irrigation efficiency used in global irrigation models is flawed for it overlooks key ambiguities in partial efficiencies, irrigation technologies, the definition of ‘large-scale’ irrigated areas or managerial factors. Once accounted for, these uncertainties can make irrigation withdrawal estimates fluctuate by more than one order of magnitude at the country level. Such variability is larger and leads to more extreme values than that caused by the uncertainties related with climate change. Our results highlight the need to embrace deep uncertainties in irrigation efficiency to prevent the design of shortsighted policies at the river basin-water-agricultural interface.