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| Titel |
The effects of country-level population policy for enhancing adaptation to climate change |
| VerfasserIn |
N. K. Gunasekara, S. Kazama, D. Yamazaki, T. Oki |
| 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 ; 17, no. 11 ; Nr. 17, no. 11 (2013-11-12), S.4429-4440 |
| Datensatznummer |
250085989
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| Publikation (Nr.) |
 copernicus.org/hess-17-4429-2013.pdf |
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| Zusammenfassung |
The effectiveness of population policy in reducing the combined impacts of
population change and climate change on water resources is explored. One
no-policy scenario and two scenarios with population policy assumptions are
employed in combination with water availability under the SRES scenarios
A1b, B1 and A2 for the impact analysis. The population data used are from the
World Bank. The river discharges per grid of horizontal resolution
0.5° are obtained from the Total Runoff Integrating Pathways
(TRIP) of the University of Tokyo, Japan. Unlike the population scenarios
utilized in the SRES emission scenarios and the newest representative
concentration pathways, the scenarios employed in this research are based,
even after 2050, on country-level rather than regional-level growth assumptions.
Our analysis implies that the heterogeneous pattern of population changes
across the world is the dominant driver of water stress, irrespective of
future greenhouse gas emissions, with highest impacts occurring in the
already water-stressed low latitudes. In 2100, Africa, Middle East and parts
of Asia are under extreme water stress under all scenarios. The sensitivity
analysis reveals that a small reduction in populations over the region could
relieve a large number of people from high water stress, while a further
increase in population from the assumed levels (SC1) might not increase the
number of people under high water stress considerably. Most of the
population increase towards 2100 occurs in the already water-stressed lower
latitudes. Therefore, population reduction policies are recommended for this
region as a method of adaptation to the future water stress conditions.
Population reduction policies will facilitate more control over their future
development pathways, even if these countries were not able to
contribute significantly to greenhouse gas (GHG) emission cuts due to economic constraints.
However, for the European region, the population living in water-stressed
regions is almost 20 times lower than that in the lower latitudes.
For countries with high population momentum, the population policy scenario
with fertility-reduction assumptions gained a maximum of 6.1 times the water
availability in Niger and 5.3 times that in Uganda compared with the
no-policy scenario. Most of these countries are in sub-Saharan Africa. These
countries represent 24.5% of the global population in the no-policy
scenario, and the scenario with fertility-reduction assumptions reduces it
to 8.7% by 2100. This scenario is also effective in reducing the area
under extreme water stress in these countries. However, the policy scenario
with assumptions of population stabilization at the replacement fertility
rate increases the water stress in high-latitude countries. Nevertheless,
the impact is low due to the high per capita water availability in the
region. This research is expected to widen the understanding of the combined
impacts of climate change in the future and of the strategies needed to
enhance the space for adaptation. |
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