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Titel |
Assessing water resources adaptive capacity to climate change impacts in the Pacific Northwest Region of North America |
VerfasserIn |
A. F. Hamlet |
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. 5 ; Nr. 15, no. 5 (2011-05-06), S.1427-1443 |
Datensatznummer |
250012779
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Publikation (Nr.) |
copernicus.org/hess-15-1427-2011.pdf |
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Zusammenfassung |
Climate change impacts in Pacific Northwest Region of North America (PNW)
are projected to include increasing temperatures and changes in the
seasonality of precipitation (increasing precipitation in winter, decreasing
precipitation in summer). Changes in precipitation are also spatially
varying, with the northwestern parts of the region generally experiencing
greater increases in cool season precipitation than the southeastern parts.
These changes in climate are projected to cause loss of snowpack and
associated streamflow timing shifts which will increase cool season
(October–March) flows and decrease warm season (April–September) flows and water
availability. Hydrologic extremes such as the 100 yr flood and extreme low
flows are also expected to change, although these impacts are not spatially
homogeneous and vary with mid-winter temperatures and other factors. These
changes have important implications for natural ecosystems affected by
water, and for human systems.
The PNW is endowed with extensive water resources infrastructure and
well-established and well-funded management agencies responsible for
ensuring that water resources objectives (such as water supply, water
quality, flood control, hydropower production, environmental services, etc.)
are met. Likewise, access to observed hydrological, meteorological, and
climatic data and forecasts is in general exceptionally good in the United
States and Canada, and is often supported by federally funded programs that
ensure that these resources are freely available to water resources
practitioners, policy makers, and the general public.
Access to these extensive resources support the argument that at a technical
level the PNW has high capacity to deal with the potential impacts of natural
climate variability on water resources. To the extent that climate change
will manifest itself as moderate changes in variability or
extremes, we argue that existing water resources infrastructure and
institutional arrangements provide a reasonably solid foundation for coping
with climate change impacts, and that the mandates of existing water
resources policy and water resources management institutions are at least
consistent with the fundamental objectives of climate change adaptation. A
deeper inquiry into the underlying nature of PNW water resources systems,
however, reveals significant and persistent obstacles to climate change
adaptation, which will need to be overcome if effective use of the region's
extensive water resources management capacity can be brought to bear on this
problem. Primary obstacles include assumptions of stationarity as the
fundamental basis of water resources system design, entrenched use of
historical records as the sole basis for planning, problems related to the
relatively short time scale of planning, lack of familiarity with climate
science and models, downscaling procedures, and hydrologic models, limited
access to climate change scenarios and hydrologic products for specific water
systems, and rigid water allocation and water resources operating rules that
effectively block adaptive response. Institutional barriers include
systematic loss of technical capacity in many water resources agencies
following the dam building era, jurisdictional fragmentation affecting
response to drought, disconnections between water policy and practice, and
entrenched bureaucratic resistance to change in many water management
agencies. These factors, combined with a federal agenda to block climate
change policy in the US during the Bush administration have (with some
exceptions) contributed to widespread institutional
"gridlock" in the PNW over the last decade or so despite a
growing awareness of climate change as a significant threat to water
management. In the last several years, however, significant progress has
been made in surmounting some of these obstacles, and the region's water
resources agencies at all levels of governance are making progress in
addressing the fundamental challenges inherent in adapting to climate
change. |
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