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| Titel |
Water savings potentials of irrigation systems: global simulation of processes and linkages |
| VerfasserIn |
J. Jägermeyr, D. Gerten, J. Heinke, S. Schaphoff, M. Kummu, W. Lucht |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 19, no. 7 ; Nr. 19, no. 7 (2015-07-10), S.3073-3091 |
| Datensatznummer |
250120761
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| Publikation (Nr.) |
 copernicus.org/hess-19-3073-2015.pdf |
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| Zusammenfassung |
| Global agricultural production is heavily sustained by irrigation, but
irrigation system efficiencies are often surprisingly low. However, our
knowledge of irrigation efficiencies is mostly confined to rough indicative
estimates for countries or regions that do not account for spatiotemporal
heterogeneity due to climate and other biophysical dependencies. To allow for
refined estimates of global agricultural water use, and of water saving and
water productivity potentials constrained by biophysical processes and also
non-trivial downstream effects, we incorporated a process-based
representation of the three major irrigation systems (surface, sprinkler, and
drip) into a bio- and agrosphere model, LPJmL. Based on this enhanced model
we provide a gridded world map of irrigation efficiencies that are calculated
in direct linkage to differences in system types, crop types, climatic and
hydrologic conditions, and overall crop management. We find pronounced
regional patterns in beneficial irrigation efficiency (a refined irrigation
efficiency indicator accounting for crop-productive water consumption only),
due to differences in these features, with the lowest values (< 30 %) in south
Asia and sub-Saharan Africa and the highest values (> 60 %) in Europe and North
America. We arrive at an estimate of global irrigation water withdrawal of
2469 km3 (2004–2009 average); irrigation water consumption is calculated
to be 1257 km3, of which 608 km3 are non-beneficially consumed,
i.e., lost through evaporation, interception, and conveyance. Replacing surface
systems by sprinkler or drip systems could, on average across the world's
river basins, reduce the non-beneficial consumption at river basin level by
54 and 76 %, respectively, while maintaining the current level of crop
yields. Accordingly, crop water productivity would increase by 9 and 15 %,
respectively, and by much more in specific regions such as in the Indus
basin. This study significantly advances the global quantification of
irrigation systems while providing a framework for assessing potential future
transitions in these systems. In this paper, presented opportunities associated with
irrigation improvements are significant and suggest that they should be
considered an important means on the way to sustainable food security. |
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