 |
| Titel |
Internal and external green-blue agricultural water footprints of nations, and related water and land savings through trade |
| VerfasserIn |
M. Fader, D. Gerten, M. Thammer, J. Heinke, H. Lotze-Campen, W. Lucht, W. Cramer |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1027-5606
|
| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 15, no. 5 ; Nr. 15, no. 5 (2011-05-27), S.1641-1660 |
| Datensatznummer |
250012794
|
| Publikation (Nr.) |
 copernicus.org/hess-15-1641-2011.pdf |
|
|
|
|
|
| Zusammenfassung |
| The need to increase food production for a growing world population makes an
assessment of global agricultural water productivities and virtual water
flows important. Using the hydrology and agro-biosphere model LPJmL, we
quantify at 0.5° resolution the amount of blue and green water
(irrigation and precipitation water) needed to produce one unit of crop
yield, for 11 of the world's major crop types. Based on these, we also
quantify the agricultural water footprints (WFP) of all countries, for the
period 1998–2002, distinguishing internal and external WFP (virtual water
imported from other countries) and their blue and green components,
respectively. Moreover, we calculate water savings and losses, and for the
first time also land savings and losses, through international trade with
these products. The consistent separation of blue and green water flows and
footprints shows that green water globally dominates both the internal and
external WFP (84 % of the global WFP and 94 % of the external WFP rely
on green water). While no country ranks among the top ten with respect to
all water footprints calculated here, Pakistan and Iran demonstrate high
absolute and per capita blue WFP, and the US and India demonstrate high
absolute green and blue WFPs. The external WFPs are relatively small (6 % of
the total global blue WFP, 16 % of the total global green WFP).
Nevertheless, current trade of the products considered here saves
significant water volumes and land areas (~263 km3 and ~41
Mha, respectively, equivalent to 5 % of the sowing area of the considered
crops and 3.5 % of the annual precipitation on this area). Relating the
proportions of external to internal blue/green WFP to the per capita WFPs
allows recognizing that only a few countries consume more water from abroad
than from their own territory and have at the same time above-average WFPs.
Thus, countries with high per capita water consumption affect mainly the
water availability in their own country. Finally, this study finds that
flows/savings of both virtual water and virtual land need to be analysed
together, since they are intrinsically related. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|