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| Titel |
Modelling global water stress of the recent past: on the relative importance of trends in water demand and climate variability |
| VerfasserIn |
Y. Wada, L. P. H. Beek, M. F. P. Bierkens |
| 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 ; 15, no. 12 ; Nr. 15, no. 12 (2011-12-20), S.3785-3808 |
| Datensatznummer |
250013057
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| Publikation (Nr.) |
 copernicus.org/hess-15-3785-2011.pdf |
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| Zusammenfassung |
| During the past decades, human water use has more than doubled, yet available
freshwater resources are finite. As a result, water scarcity has been
prevalent in various regions of the world. Here, we present the first global
assessment of past development of water stress considering not only climate
variability but also growing water demand, desalinated water use and
non-renewable groundwater abstraction over the period 1960–2001 at a spatial
resolution of 0.5°. Agricultural water demand is estimated based on
past extents of irrigated areas and livestock densities. We approximate past
economic development based on GDP, energy and household consumption and
electricity production, which are subsequently used together with population
numbers to estimate industrial and domestic water demand. Climate variability
is expressed by simulated blue water availability defined by freshwater in
rivers, lakes, wetlands and reservoirs by means of the global hydrological
model PCR-GLOBWB. We thus define blue water stress by comparing blue water
availability with corresponding net total blue water demand by means of the
commonly used, Water Scarcity Index. The results show a drastic increase in
the global population living under water-stressed conditions (i.e. moderate
to high water stress) due to growing water demand, primarily for irrigation,
which has more than doubled from 1708/818 to 3708/1832 km3 yr−1
(gross/net) over the period 1960–2000. We estimate that 800 million people
or 27% of the global population were living under water-stressed
conditions for 1960. This number is eventually increased to 2.6 billion or
43% for 2000. Our results indicate that increased water demand is a
decisive factor for heightened water stress in various regions such as India
and North China, enhancing the intensity of water stress up to 200%, while
climate variability is often a main determinant of extreme events. However,
our results also suggest that in several emerging and developing economies
(e.g. India, Turkey, Romania and Cuba) some of past extreme events were
anthropogenically driven due to increased water demand rather than being
climate-induced. |
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