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Global irrigation water demand: Variability and uncertainties arising from agricultural and climate data sets
Author(s) -
Wisser Dominik,
Frolking Steve,
Douglas Ellen M.,
Fekete Balazs M.,
Vörösmarty Charles J.,
Schumann Andreas H.
Publication year - 2008
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2008gl035296
Subject(s) - environmental science , irrigation , irrigation statistics , water balance , cropping , farm water , agriculture , water use , climate change , water resource management , hydrology (agriculture) , water resources , water conservation , geography , agronomy , geology , ecology , oceanography , archaeology , biology , geotechnical engineering
Agricultural water use accounts for around 70% of the total water that is withdrawn from surface water and groundwater.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 km 3 a −1 . Weather driven variability in global irrigation was generally less than ±300 km 3 a −1 , globally (<∼10%), but could be as large as ±70% at the national scale.