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| Titel |
Comparing impacts of climate change on streamflow in four large African river basins |
| VerfasserIn |
V. Aich, S. Liersch, T. Vetter, S. Huang, J. Tecklenburg, P. Hoffmann, H. Koch, S. Fournet, V. Krysanova, E. N. Müller, F. F. Hattermann |
| 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 ; 18, no. 4 ; Nr. 18, no. 4 (2014-04-04), S.1305-1321 |
| Datensatznummer |
250120324
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| Publikation (Nr.) |
 copernicus.org/hess-18-1305-2014.pdf |
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| Zusammenfassung |
This study aims to compare impacts of climate change on streamflow in four
large representative African river basins: the Niger, the Upper Blue Nile,
the Oubangui and the Limpopo. We set up the eco-hydrological model SWIM
(Soil and Water Integrated Model) for all four basins individually. The
validation of the models for four basins shows results from adequate to very
good, depending on the quality and availability of input and calibration
data.
For the climate impact assessment, we drive the model with outputs of five
bias corrected Earth system models of Coupled Model Intercomparison Project
Phase 5 (CMIP5) for the representative concentration pathways (RCPs) 2.6 and
8.5. This climate input is put into the context of climate trends of the
whole African continent and compared to a CMIP5 ensemble of 19 models in
order to test their representativeness. Subsequently, we compare the trends
in mean discharges, seasonality and hydrological extremes in the 21st
century. The uncertainty of results for all basins is high. Still, climate
change impact is clearly visible for mean discharges but also for extremes
in high and low flows. The uncertainty of the projections is the lowest in
the Upper Blue Nile, where an increase in streamflow is most likely. In the
Niger and the Limpopo basins, the magnitude of trends in both directions is
high and has a wide range of uncertainty. In the Oubangui, impacts are the
least significant. Our results confirm partly the findings of previous
continental impact analyses for Africa. However, contradictory to these
studies we find a tendency for increased streamflows in three of the four
basins (not for the Oubangui). Guided by these results, we argue for
attention to the possible risks of increasing high flows in the face of the
dominant water scarcity in Africa. In conclusion, the study shows that
impact intercomparisons have added value to the adaptation discussion and
may be used for setting up adaptation plans in the context of a holistic
approach. |
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