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| Titel |
Integrated assessment of global water scarcity over the 21st century under multiple climate change mitigation policies |
| VerfasserIn |
M. I. Hejazi, J. Edmonds, L. Clarke, P. Kyle, E. Davies, V. Chaturvedi, M. Wise, P. Patel, J. Eom, K. Calvin |
| 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. 8 ; Nr. 18, no. 8 (2014-08-06), S.2859-2883 |
| Datensatznummer |
250120425
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| Publikation (Nr.) |
 copernicus.org/hess-18-2859-2014.pdf |
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| Zusammenfassung |
| Water scarcity conditions over the 21st century both globally and regionally
are assessed in the context of climate change and climate mitigation
policies, by estimating both water availability and water demand within the
Global Change Assessment Model (GCAM), a leading community-integrated
assessment model of energy, agriculture, climate, and water. To quantify
changes in future water availability, a new gridded water-balance global
hydrologic model – namely, the Global Water Availability Model (GWAM) – is
developed and evaluated. Global water demands for six major demand sectors
(irrigation, livestock, domestic, electricity generation, primary energy
production, and manufacturing) are modeled in GCAM at the regional scale (14
geopolitical regions, 151 sub-regions) and then spatially downscaled to
0.5° × 0.5° resolution to match the scale of GWAM.
Using a baseline scenario (i.e., no climate change mitigation policy) with
radiative forcing reaching 8.8 W m−2 (equivalent to the SRES A1Fi
emission scenario) and three climate policy scenarios with increasing
mitigation stringency of 7.7, 5.5, and 4.2 W m−2 (equivalent to the
SRES A2, B2, and B1 emission scenarios, respectively), we investigate the
effects of emission mitigation policies on water scarcity. Two carbon tax
regimes (a universal carbon tax (UCT) which includes land use change
emissions, and a fossil fuel and industrial emissions carbon tax (FFICT)
which excludes land use change emissions) are analyzed. The baseline scenario
results in more than half of the world population living under extreme water
scarcity by the end of the 21st century. Additionally, in years 2050 and
2095, 36% (28%) and 44% (39%) of the global population,
respectively, is projected to live in grid cells (in basins) that will
experience greater water demands than the amount of available water in a year
(i.e., the water scarcity index (WSI) > 1.0). When comparing the climate
policy scenarios to the baseline scenario while maintaining the same baseline
socioeconomic assumptions, water scarcity declines under a UCT mitigation
policy but increases with a FFICT mitigation scenario by the year 2095,
particularly with more stringent climate mitigation targets. Under the FFICT
scenario, water scarcity is projected to increase, driven by higher water
demands for bio-energy crops. |
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