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Titel |
Hydrological responses to climate change conditioned by historic alterations of land-use and water-use |
VerfasserIn |
J. Jarsjö, S. M. Asokan, C. Prieto, A. Bring, G. Destouni |
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 ; 16, no. 5 ; Nr. 16, no. 5 (2012-05-09), S.1335-1347 |
Datensatznummer |
250013291
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Publikation (Nr.) |
copernicus.org/hess-16-1335-2012.pdf |
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Zusammenfassung |
This paper quantifies and conditions expected hydrological responses in the
Aral Sea Drainage Basin (ASDB; occupying 1.3% of the earth's land
surface), Central Asia, to multi-model projections of climate change in the
region from 20 general circulation models (GCMs). The aim is to investigate
how uncertainties of future climate change interact with the effects of
historic human re-distributions of water for land irrigation to influence
future water fluxes and water resources. So far, historic irrigation changes
have greatly amplified water losses by evapotranspiration (ET) in the ASDB,
whereas 20th century climate change has not much affected the
regional net water loss to the atmosphere. Results show that errors in
temperature (T) and precipitation (P) from single GCMs have large influence
on projected change trends (for the period 2010–2039) of river runoff (R),
even though the ASDB is spatially well resolved by current GCMs. By
contrast, observed biases in GCM ensemble mean results have relatively small
influence on projected R change trends. Ensemble mean results show that
projected future climate change will considerably increase the net water
loss to the atmosphere. Furthermore, the ET response strength to any future
T change will be further increased by maintained (or increased) irrigation
practices, which shows how climate change and water use change can interact
in modifying ET (and R). With maintained irrigation practices, R is likely
to decrease to near-total depletion, with risk for cascading ecological
regime shifts in aquatic ecosystems downstream of irrigated land areas.
Without irrigation, the agricultural areas of the principal Syr Darya river
basin could sustain a 50% higher T increase (of 2.3 °C instead of the
projected 1.5 °C until 2010–2039) before yielding the same consumptive ET
increase and associated R decrease as with the present irrigation practices. |
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