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| Titel |
A global and high-resolution assessment of the green, blue and grey water footprint of wheat |
| VerfasserIn |
M. M. Mekonnen, A. Y. Hoekstra |
| 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 ; 14, no. 7 ; Nr. 14, no. 7 (2010-07-15), S.1259-1276 |
| Datensatznummer |
250012368
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| Publikation (Nr.) |
 copernicus.org/hess-14-1259-2010.pdf |
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| Zusammenfassung |
The aim of this study is to estimate the green, blue and grey water
footprint of wheat in a spatially-explicit way, both from a production and
consumption perspective. The assessment is global and improves upon earlier
research by taking a high-resolution approach, estimating the water
footprint of the crop at a 5 by 5 arc minute grid. We have used a grid-based
dynamic water balance model to calculate crop water use over time, with a
time step of one day. The model takes into account the daily soil water
balance and climatic conditions for each grid cell. In addition, the water
pollution associated with the use of nitrogen fertilizer in wheat production
is estimated for each grid cell. We have used the water footprint and
virtual water flow assessment framework as in the guideline of the Water
Footprint Network.
The global wheat production in the period 1996–2005 required about 108
billion cubic meters of water per year. The major portion of this water
(70%) comes from green water, about 19% comes from blue water, and the
remaining 11% is grey water. The global average water footprint of wheat
per ton of crop was 1830 m3/ton. About 18% of the water footprint
related to the production of wheat is meant not for domestic consumption but
for export. About 55% of the virtual water export comes from the USA,
Canada and Australia alone. For the period 1996–2005, the global average
water saving from international trade in wheat products was 65 Gm3/yr.
A relatively large total blue water footprint as a result of wheat
production is observed in the Ganges and Indus river basins, which are known
for their water stress problems. The two basins alone account for about
47% of the blue water footprint related to global wheat production. About
93% of the water footprint of wheat consumption in Japan lies in other
countries, particularly the USA, Australia and Canada. In Italy, with an
average wheat consumption of 150 kg/yr per person, more than two times the
word average, about 44% of the total water footprint related to this
wheat consumption lies outside Italy. The major part of this external water
footprint of Italy lies in France and the USA. |
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