Article

The effect of climate change on glacier ablation and baseflow support in the Nooksack River basin and implications on Pacific salmonid species protection and recovery

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Abstract

The Nooksack Indian Tribe (Tribe) inhabits the area around Deming, Washington, in the northwest corner of the state. The Tribe is dependent on various species of Pacific salmonids that inhabit the Nooksack River for ceremonial, commercial, and subsistence purposes. Of particular importance to the Tribe are spring Chinook salmon. Since European arrival, the numbers of fish that return to spawn have greatly diminished because of substantial loss of habitat primarily due to human-caused alteration of the watershed. Although direct counts are not available, it is estimated that native salmonid runs are less than 8 % of the runs in the late 1800’s. In addition, climate change has caused and will continue to cause an increase in winter flows, earlier snowmelt, decrease in summer baseflows, and an increase in water temperatures that exceed the tolerance levels, and in some cases lethal levels, of several Pacific salmonid species. The headwaters of the Nooksack River originate from glaciers on Mount Baker that have experienced significant changes over the last century due to climate change. Melt from the glaciers is a major source of runoff during the low-flow critical summer season, and climate change will have a direct effect on the magnitude and timing of stream flow in the Nooksack River. Understanding these changes is necessary to protect the Pacific salmonid species from the harmful effects of climate change. All nine salmonid species that inhabit the Nooksack River will be adversely affected by reduced summer flows and increased temperatures. The most important task ahead is the planning for, and implementation of, habitat restoration prior to climate change becoming more threatening to the survival of these important fish species. The Tribe has been collaboratively working with government agencies and scientists on the effects of climate change on the hydrology of the Nooksack River. The extinction of salmonids from the Nooksack River is unacceptable to the Tribe since it is dependent on these species and the Tribe is place-based and cannot relocate to areas where salmon will survive.

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... An important impact of changing glacier runoff in the Nooksack River is the stress of warming stream temperatures on salmon populations [13,14]. Temperature thresholds for changes in fish communities in the Fraser River region of British Columbia were noted as 12 • C and 19 • C [14]. ...
... An important impact of changing glacier runoff in the Nooksack River is the stress of warming stream temperatures on salmon populations [13,14]. Temperature thresholds for changes in fish communities in the Fraser River region of British Columbia were noted as 12 • C and 19 • C [14]. The reduction of the glacial melt component augmenting summer low flows is already resulting in more low-flow days in the North Cascade region as has occurred other alpine regions with small glaciers [12,15]. ...
... In the Skykomish River from 1950-2013, there were 230 days during the summer melt season with discharge below 10% of mean annual flow (14 m 3 s −1 ); of these, 99% (228 days) had occurred since 1985 [12]. Of great concern for aquatic life is the occurrence of extended periods of low flow [14] that have increased in frequency. ...
Article
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The thirty-eight-year record (1984–2021) of glacier mass balance measurement indicates a significant glacier response to climate change in the North Cascades, Washington that has led to declining glacier runoff in the Nooksack Basin. Glacier runoff in the Nooksack Basin is a major source of streamflow during the summer low-flow season and mitigates both low flow and warm water temperatures; this is particularly true during summer heat waves. Synchronous observations of glacier ablation and stream discharge immediately below Sholes Glacier from 2013–2017, independently identify daily discharge during the ablation season. The identified ablation rate is applied to glaciers across the North Fork Nooksack watershed, providing daily glacier runoff discharge to the North Fork Nooksack River. This is compared to observed daily discharge and temperature data of the North Fork Nooksack River and the unglaciated South Fork Nooksack River from the USGS. The ameliorating role of glacier runoff on discharge and water temperature is examined during 24 late summer heat wave events from 2010–2021. The primary response to these events is increased discharge in the heavily glaciated North Fork, and increased stream temperature in the unglaciated South Fork. During the 24 heat events, the discharge increased an average of +24% (±17%) in the North Fork and decreased an average of 20% (±8%) in the South Fork. For water temperature the mean increase was 0.7 °C (±0.4 °C) in the North Fork and 2.1 °C (±1.2 °C) in the South Fork. For the North Fork glacier runoff production was equivalent to 34% of the total discharge during the 24 events. Ongoing climate change will likely cause further decreases in summer baseflow and summer baseflow, along with an increase in water temperature potentially exceeding tolerance levels of several Pacific salmonid species that would further stress this population.
... The shadberry (or serviceberry) is a well-known commodity among the Wabanaki people. In early spring, the blossoming of the shadbush coincided with the arrival of the spring migration of the shad fish and acted as a signal for the people to move to the low lands (Frink and Dow 2005). Berry plants are also extremely important for Wabanaki women. ...
... The Fond du Lac are now building dams at ditch flow points to keep water levels stable and prevent extreme changes in water level that would negatively affect wild rice harvests (Hoene 2010). Climate change is thought to be posing significant threats to salmon (Mote et al. 2003, Dittmer 2013; Grah and Beaulieu 2013; Beechie et al. 2012). Salmon is central to the lives of many indigenous peoples, providing spiritual, physical and cultural well-being (Dittmer 2013). ...
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American Indian and Alaska Native tribes are uniquely affected by climate change. Indigenous peoples have depended on a wide variety of native fungi, plant and animal species for food, medicine, ceremonies, community and economic health for countless generations. Climate change stands to impact the species and ecosystems that constitute tribal traditional foods that are vital to tribal culture, economy and traditional ways of life. This paper examines the impacts of climate change on tribal traditional foods by providing cultural context for the importance of traditional foods to tribal culture, recognizing that tribal access to traditional food resources is strongly influenced by the legal and regulatory relationship with the federal government, and examining the multi-faceted relationship that tribes have with places, ecological processes and species. Tribal participation in local, regional and national climate change adaption strategies, with a focus on food-based resources, can inform and strengthen the ability of both tribes and other governmental resource managers to address and adapt to climate change impacts.
... The Nooksack Indian Tribe in the Pacific Northwest of North America is concerned that glacier retreat will change salmon habitat in ways requiring them to alter the social, cultural and economic ties to salmon dating to time immemorial (Campbell and De Melker 2012;Grah and Beaulieu 2013). The Tlicho First Nation communities in the Arctic are experiencing shifts of Caribou populations away from them and to the north, which means they will have to adapt complex cultural connections to the species and land (Jacobsen 2011). ...
Article
Indigenous peoples must adapt to a number of losses and damages from climate change impacts that threaten to harm their cultural and political self-determination. Industrial settler states, such as the U.S. or Canada, have responsibilities to indigenous peoples to address loss and damage that flow from how their industrial activities have factored into anthropogenic climate change. This essay describes two kinds of responsibility, impending and pending. Impending responsibility requires settler states to live up to the ramifications of developmental paths that they continue to pursue and that are at odds with indigenous cultural and political self- determination. Yet concepts of impending responsibility can tend to propose solutions that remain silent on the underlying political relations between indigenous peoples and settler states that threaten the viability of such solutions. Pending responsibility demands that settler states acknowledge that today’s political relations with indigenous peoples descend from structures of settler colonialism designed to limit indigenous adaptation to environmental change. Pending responsibility requires settler states to engage in a long needed process of political reconciliation with indigenous peoples that would radically restructure such political relations in ways that are flexible enough to facilitate styles of indigenous adaptation that accord with indigenous cultural and political self-determination.
... Pelto (2011) noted a substantial increase in the number of very low flow days in the glacier/snowmelt dominated Skykomish River Basin. Many Washington Cascade basins are fed by summer glacial melt, which is in decline due to warming temperatures (Grah and Beaulieu 2013). CIG (2009) used the IPCC A1B and B emissions scenarios to show that Washington snowmelt basins could become transient and transient basins could become rainfalldominant by 2020, 2040, and 2080. ...
Article
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Over the last 100 years, linear trends of tributary streamflow have changed on Columbia River Basin tribal reservations and historical lands ceded by tribes in treaties with the United States. Analysis of independent flow measures (Seasonal Flow Fraction, Center Timing, Spring Flow Onset, High Flow, Low Flow) using the Student t test and Mann-Kendall trend test suggests evidence for climate change trends for many of the 32 study basins. The trends exist despite interannual climate variability driven by the El Niño–Southern Oscillation and Pacific Decadal Oscillation. The average April—July flow volume declined by 16 %. The median runoff volume date has moved earlier by 5.8 days. The Spring Flow Onset date has shifted earlier by 5.7 days. The trend of the flow standard deviation (i.e., weather variability) increased 3 % to 11 %. The 100-year November floods increased 49 %. The mid-Columbia 7Q10 low flows have decreased by 5 % to 38 %. Continuation of these climatic and hydrological trends may seriously challenge the future of salmon, their critical habitats, and the tribal peoples who depend upon these resources for their traditional livelihood, subsistence, and ceremonial purposes.
... Large populations living downstream of glacierized catchments primarily rely on snow and glacier meltwater for drinking and irrigation needs (Kriegel et al., 2013). Meltwater also plays an important role in the aquatic ecology of downstream reaches, because it regulates summer stream temperatures, maintaining high-quality habitat for fish and cold-water communities (Grah and Beaulieu, 2013). From a hydrological perspective, snowmelt and glacier melt are important because they moderate inter-annual variability in streamflow (Stewart, 2009), and can maintain elevated discharge during the dry season or relatively dry years (Milner et al., 2009) when water demand is highest. ...
Conference Paper
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Water budget of high elevation catchments is dominated by snow and glacier runoff contributions. However, climate change is rapidly affecting such processes and many areas are experiencing an increasing human pressure on water resources. Therefore, it is crucial to develop reliable methods to quantify the partitioning of rainfall, snow and ice melt contribution to runoff. This study focuses on the identification of the sources of stream runoff in a glacierized catchment in the Eastern Italian Alps by means of isotopic (δ18O) and electrical conductivity data. The information is then used for the parameterization of the distributed hydrological model GEOtop 1.2, applied implementing different model scenarios. Field work and modelling activities were carried out for the Saldur basin (South Tyrol, 62 km2 drainage area). Catchment elevations range between 900 and 3700 m a.s.l., and the main glacier is located between 2700 and 3700 m a.s.l. (3.3 km2 glacier extent). Water stage was continuously recorded at two cross sections at 2150 m a.s.l. (20 km2 drainage area) and at 2350 m a.s.l. (11 km2 drainage area). Additionally, discharge measurements (by salt dilution method) were carried out to build up the flow rating curves. From late spring to early fall 2011, two sampling approaches were adopted to measure the spatial and temporal variability of tracer concentration: (1) monthly or twice a month water samples were manually taken in the Saldur stream and in its tributaries at different sections ranging from 1800 m to 2400 m a.s.l., and also in some spring sources considered as possible end-members. (2) hourly water samples over 24 hours were taken simultaneously at different stream sections, tributaries and spring sources during two glacier melt- and snowmelt-induced flood events in mid-July and mid-August. Tracer results confirm a great contribution of snow and ice melt to runoff during warmer days, while the influence of groundwater increased during colder days. Isotope data for two daily melting cycles in mid-July and mid-August 2011 highlight different snow and ice melt contributions to river runoff, reflecting the reduced extent of snow cover in the basin during the later period. Based on this information, for both sub-catchments, GEOtop model was run. Input data contained a digital elevation model, land cover data, and the current glacier extent. Meteorological data was provided by a weather station managed by the European Academy of Bozen/Bolzano (EURAC). In order to isolate the contribution of snow- versus ice-related runoff, model scenarios were prepared with different initial model conditions (i.e. snow cover and ice cover extent). Model results thus provided an independent estimation of the different water sources and offered a conceptual framework for isotopic observations.
... Global warming is causing glacial retreat and thinning, resulting in an altered glacial meltwater contribution to stream flow in glacierised catchments (Sorg et al., 2012;Grah & Beaulieu, 2013;Rabatel et al., 2013). The reduction in ice volume should yield a significant increase in annual glacial runoff in the early stages of glacial retreat Orsay Cedex, France. ...
Article
As glacier shrinkage is accelerating due to climate change, it is important to understand the effect of changes in glacier runoff on downstream aquatic communities. The overall goal of this study was to test the relevance of recently developed wavelet-based metrics of flow variations caused by glacial melting cycles to deepen our knowledge about the relationship between glacial influence and aquatic biodiversity.In an equatorial glacierised catchment, we selected 15 stream sites covering a gradient of direct contribution from glacial runoff. At each site, we recorded water level time series for 10 months and sampled benthic macroinvertebrates. Wavelet analyses on the water level time series were used to calculate three indices: glacial flood intensity, frequency and temporal clustering. We then examined how these three indices were related to macroinvertebrate community composition using generalised additive models.While macroinvertebrate density decreased significantly with glacial flood intensity, we found a significant hump-shaped relationship between local taxon richness and glacial flood intensity, a pattern that was not produced simply by overlapping broad taxon distributions from either end of the environmental gradient. These results suggest that glacial meltwater contribution creates local peaks in macroinvertebrate richness and enhances regional diversity in the catchment.The significant relationships between faunal metrics and the new glacial influence indices suggest the latter are valuable for assessing the effects of altered meltwater contributions on aquatic communities of glacier-fed rivers. Relationships differed depending on the feature of the glacial disturbance considered (glacial flood intensity, frequency, temporal clustering). We anticipate that these distinctions may help disentangle the mechanisms driving aquatic biodiversity in glacierised catchments, especially in terms of identifying resistance and/or resilience as key processes in glacial macroinvertebrate communities.
... Today, as in the past, many indigenous peoples are planning for how to adapt to current and future climate change scenarios (McLean, Ramos-Castillo, and Rubis 2011;Voggesser 2010;Abate and Kronk 2013;Maldonado, Pandya, and Colombi 2013;Krakoff 2008;Nakashima et al. 2012). The Nooksack Indian Tribe in the Pacific Northwest of North America is concerned that glacier retreat will change salmon habitat in ways requiring them to alter the social, cultural and economic ties to salmon dating to time immemorial (Campbell and De Melker 2012;Grah and Beaulieu 2013). The Tlicho First Nation communities in the Arctic are experiencing shifts of Caribou populations away from them and to the north, which means they will have to adapt complex cultural connections to the species and land (Jacobsen 2011). ...
Article
Full-text available
Indigenous peoples must adapt to a number of climate change impacts that threaten to harm their cultural and political self determination. Industrial settler states, such as the U.S. or Canada, have responsibilities to indigenous peoples that flow from how their industrial activities have factored into anthropogenic climate change. This essay describes two kinds of responsibility, impending and pending. Impending responsibility requires settler states to live up to the ramifications of developmental paths that they continue to pursue and that are at odds with indigenous cultural and political self-determination. Yet concepts of impending responsibility can tend to propose solutions that remain silent on the underlying political relations between indigenous peoples and settler states that threaten the viability of such solutions. Pending responsibility demands that settler states acknowledge that today’s political relations with indigenous peoples descend from structures of settler colonialism designed to limit indigenous adaptation to environmental change So it is no surprise that these political relations are morally and practically problematic today for adaptation. Pending responsibility requires settler states to engage in a long needed process of political reconciliation with indigenous peoples that would radically restructure such political relations in ways that are flexible enough to facilitate styles of indigenous adaptation that accord with indigenous cultural and political self-determination.
... Large populations living downstream of glacierized catchments primarily rely on snow and glacier meltwater for drinking and irrigation needs (Kriegel et al., 2013). Meltwater also plays an important role in the aquatic ecology of downstream reaches, because it regulates summer stream temperatures, maintaining high-quality habitat for fish and cold-water communities (Grah and Beaulieu, 2013). From a hydrological perspective, snowmelt and glacier melt are important because they moderate inter-annual variability in streamflow (Stewart, 2009), and can maintain elevated discharge during the dry season or relatively dry years (Milner et al., 2009) when water demand is highest. ...
Article
Full-text available
Snow-dominated and glacierized catchments are important sources of fresh water for biological communities and for populations living in mountain valleys. Gaining a better understanding of the runoff origin and of the hydrological interactions between meltwater, streamflow and groundwater is critical for natural risk assessment and mitigation as well as for effective water resource management in mountain regions. This study is based on the use of stable isotopes of water and electrical conductivity as tracers to identify the water sources for runoff and groundwater and their seasonal variability in a glacierized catchment in the Italian Alps. Samples were collected from rainfall, snow, snowmelt, ice melt, spring and stream water (from the main stream at different locations and from selected tributaries) in 2011, 2012 and 2013. The tracer-based mixing analysis revealed that, overall, snowmelt and glacier melt were the most important end-members for stream runoff during late spring, summer and early fall. The temporal variability of the tracer concentration suggested that stream water was dominated by snowmelt at the beginning of the melting season (May–June), by a mixture of snowmelt and glacier melt during mid-summer (July–early August), and by glacier melt during the end of the summer (end of August–September). The same seasonal pattern observed in streamflow was also evident for groundwater, with the highest electrical conductivity and least negative isotopic values found during cold or relatively less warm periods, when the melt of snowpack and ice was limited. Particularly, the application of a two-component mixing model to data from different springs showed that the snowmelt contribution to groundwater recharge varied between 21% (±3%) and 93% (±1%) over the season, and the overall contribution during the three study years ranged between 58% (±24%) and 72% (±19%). These results provided new insights into the isotopic characterization of the study catchment presenting further understanding of the spatio-temporal variability of the main water sources contributing to runoff.
... Global warming is causing glacial retreat and thinning, resulting in an altered glacial meltwater contribution to stream flow in glacierised catchments Grah & Beaulieu, 2013;. The reduction in ice volume should yield a significant increase in annual glacial runoff in the early stages of glacial retreat , but after a critical threshold (depending on the glacier size), annual glacial runoff should decrease until the complete disappearance of the glacier when glacial influence on outflow will be nonexistent (Rees & Collins, 2006;. ...
Article
Full-text available
In mountainous glacierized catchments, stream biodiversity is strongly influenced by physicochemical habitat heterogeneity linked to the spatio-temporal dynamics of water source contributions from snowmelt, ice-melt and groundwater. One impact of climate change is the rapid shrinking of glaciers, resulting in a reduction in glacial meltwater contribution to river flow in glacierized catchments. These modifications in water regimes are expected to affect the aquatic biodiversity. Thus it is of critical importance to understand the effect of glacial influence on aquatic communities in glacierized catchments to be able to predict the impact of glacier retreat on the aquatic biodiversity. In this study, we investigated the effects of the glacial influence on aquatic macroinvertebrates. The study was conducted in 51 stream sites in a glacierized catchment in the equatorial Andes (Antisana, Ecuador), where glacial floods occur all year round due to the lack of thermal seasonality. Our main objectives were to determine the glacial influence at each stream site; to characterize the impact of the glacial influence on the macroinvertebrate communities; and to anticipate the aquatic macroinvertebrates response to glacier retreat. In order to meet these objectives, we quantified the glacial influence using different methods and test its effects on macroinvertebrates at different scales from the stream reach to the entire catchment. These analyses allowed us to better understand the mechanisms governing macroinvertebrates distribution, and to determine the potential risk of species loss with the diminution of glacial meltwater contribution.
... Three different fi sh species in the Nooksack River system have been listed as Threatened under the Endangered Species Act (ESA). These include: chinook salmon, steelhead and bull trout (Grah and Beaulieu 2013 ). ...
Book
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This book presents the impact of climate change on Mount Baker glaciers, USA, and the rivers surrounding them. Glaciers are natural reservoirs that yield their resource primarily on warm dry summer days when other sources are at their lowest yield. This natural tempering of drought conditions will be reduced as they retreat. Mount Baker, a volcano in the Cascades of Washington, is currently host to 12 principal glaciers with an area of 36.8 km2. The glaciers yield 125 million cubic meters of water each summer that is a resource for salmon, irrigation and hydropower to the Nooksack River and Baker River watersheds. Recent rapid retreat of all 22 glaciers is altering the runoff from the glaciers, impacting both the discharge and temperature of the Nooksack and Baker River. Over the last 30 years we have spent 270 nights camped on the mountain conducting 10,500 observations of snow depth and melt rate on Mount Baker. This data combined with observations of terminus change, area change and glacier runoff over the same 30 years allow an unusually comprehensive story to be told of the effects of climate change to Mount Baker Glaciers and the rivers that drain them.
... Three different fi sh species in the Nooksack River system have been listed as Threatened under the Endangered Species Act (ESA). These include: chinook salmon, steelhead and bull trout (Grah and Beaulieu 2013 ). ...
Chapter
The headwaters of the North Fork and Middle Fork Nooksack River are the glaciers of Mount Baker, the South Fork Nooksack River lacks glacier cover. The glaciers are a critical source of runoff for the North Fork contributing 30–40 % of the total runoff during late summer. In the last 30 years glacier retreat and climate change is altering the timing and magnitude of glacier runoff. For 31 years the North Cascade Glacier Climate Project has been examining glaciers at the headwaters of this system.
... Pelto clearly demonstrates his experience and knowledge base for the locality, although some material is distilled to a brevity that perhaps leaves some segments a little weaker, dependent on inference, or subtly lacking in scientific clarity or elaboration. The more specialist reader might expect to consult the references cited, or turn to recent scientific publications in similar topic fields for the region Grah and Beaulieu 2013;Cowie et al 2014;O'Neal et al 2015). One further frustrating element is the variability in quality and formatting of the significant volume of illustrative material, along with other subtle stylistic concerns-an observation that was surprising and tarnishes the clarity of the core messages being presented to a wide audience. ...
Article
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Reviewed: Climate Driven Retreat of Mount Baker Glaciers and Changing Water Resources By Mauri Pelto. Cham, Switzerland: Springer, 2015. x + 107 pp. Softcover: US$ 54.99, ISBN 978-3-319-22604-0. E-book: US$ 39.99, ISBN 978-3-319-22605-7.
... Water quality is also of critical importance to human livelihoods in glacier-fed watersheds. Glacier retreat can warm downstream water (Mantua, Tohver, and Hamlet 2010;Pelto 2011), with potential implications for fish populations that societies depend on for food security, fishing markets, and cultural aspects (Lackey 2000;Grah and Beaulieu 2013). Mining (Bury 2015) and changes in sediment load resulting from increased glacier melting (Riedel et al. 2015) can both affect water quality, which could be exacerbated by glacier shrinkage and declining runoff. ...
Article
Full-text available
Glacierized mountains are often referred to as our world's water towers because glaciers both store water over time and regulate seasonal stream flow, releasing runoff during dry seasons when societies most need water. Ice loss thus has the potential to affect human societies in diverse ways, including irrigation, agriculture, hydropower, potable water, livelihoods, recreation, spirituality, and demography. Unfortunately, research focusing on the human impacts of glacier runoff variability in mountain regions remains limited, and studies often rely on assumptions rather than concrete evidence about the effects of shrinking glaciers on mountain hydrology and societies. This article provides a systematic review of international research on human impacts of glacier meltwater variability in mountain ranges worldwide, including the Andes, Alps, greater Himalayan region, Cascades, and Alaska. It identifies four main areas of existing research: (1) socioeconomic impacts; (2) hydropower; (3) agriculture, irrigation, and food security; and (4) cultural impacts. The article also suggests paths forward for social sciences, humanities, and natural sciences research that could more accurately detect and attribute glacier runoff and human impacts, grapple with complex and intersecting spatial and temporal scales, and implement transdisciplinary research approaches to study glacier runoff. The objective is ultimately to redefine and reorient the glacier-water problem around human societies rather than simply around ice and climate. By systematically evaluating human impacts in different mountain regions, the article strives to stimulate cross-regional thinking and inspire new studies on glaciers, hydrology, risk, adaptation, and human–environment interactions in mountain regions.
... Large populations living downstream of glacierized catchments primary rely on snow and glacier meltwater for drinking and 5 irrigation needs (Kriegel et al., 2013). Meltwater plays also an important role in the aquatic ecology of downstream reaches, because it regulates summer stream temperatures, maintaining high-quality habitat for fish and cold-water communities (Grah and Beaulieu, 2013). From a hydrological perspective, snowmelt and glacier melt are important because moderate inter-annual variability in streamflow (Stewart, 2009) and 10 can maintain elevated discharge during the dry season or relatively dry years (Milner et al., 2009) when water demand is highest. ...
Article
Full-text available
Snow-dominated and glacierized catchments are important sources of fresh water for biological communities and for population living in mountain valleys. Gaining a better understanding of the runoff origin and of the hydrological interactions between meltwater and streamflow is critical for natural risk assessment and mitigation as well as for effective water resources management in mountain regions. This study is based on the use of stable isotopes of water and electrical conductivity as tracers to identify the water sources for runoff and their seasonal variability in a glacierized catchment in the Italian Alps. Samples were collected from rainfall, snow, snowmelt, ice melt and stream water (from the main stream at different locations and from selected tributaries) in 2011, 2012 and 2013. The tracer-based mixing analysis revealed that, overall, snowmelt and glacier melt were the most important end-members for stream runoff during late spring, summer and early fall. The temporal variability of the tracer concentration suggested that stream water was dominated by snowmelt at the beginning of the melting season (May–June), by a mixture of snowmelt and glacier melt during mid-summer (July–early August), and by glacier melt during the end of the summer (end of August–September). The same seasonal pattern observed in streamflow was also evident for groundwater, with the highest electrical conductivity and least negative isotopic values found during periods of limited melting. Particularly, the application of a two-component mixing model to data from different springs showed that the overall snowmelt contribution to groundwater recharge during the three study years ranged between 58% (±15%) and 72% (±15%). These results provided new insights on the isotopic characterization of the study catchment and the presented approach could offer further understanding of the spatio-temporal variability of the main water sources contributing to runoff in other snow-dominated and glacierized Alpine catchments.
... Global warming is causing glacial retreat and thinning, resulting in an altered glacial meltwater contribution to stream flow in glacierised catchments (Sorg et al., 2012;Grah & Beaulieu, 2013;Rabatel et al., 2013). The reduction in ice volume should yield a significant increase in annual glacial runoff in the early stages of glacial retreat Orsay Cedex, France. ...
... Although the landscape may not completely revert to more typical arid conditions seen in the Andes, the Aymaran and scientists are anticipating greater losses to occur, which will impact tangible and intangible cultural heritage and ILK knowledge. Another example of the impact of glacier loss comes from a study by Grah and Beaulieu (2014) on the Nooksack River Basin in Washington State, USA. The authors noted the material dependence and spiritual connection of the many societies of that region with nine salmon species. ...
Article
Anthropogenic climate change is leading to widespread losses around the world. While the focus of research over the last decade has largely been on economic or tangible losses, researchers have begun to shift their focus to understanding the non-economic or intangible dimensions of loss more deeply. Loss of life, biodiversity and social cohesion are some of the losses that are beginning to be explored, along with Indigenous and local knowledge (ILK) and cultural heritage. These latter two form the basis of this systematic review of 100 studies to take stock of what we know about climate-driven losses to ILK and cultural heritage, how such losses manifest and how they are overcome, revealing gaps in our knowledge and carving a path for future research.
... Changes in temperature and the type, timing, and amount of precipitation are driving declines in snowpack and altering associated hydrological dynamics in the region (i.e., the timing and intensity of flood events and warm season flow levels) (Adam, Hamlet, & Lettenmaier, 2009;Mote, Hamlet, Clark, & Lettenmaier, 2005). Although warming in the winter and spring may benefit the freshwater life-cycle stage of some salmon, overall reproductive success for salmon is expected to decline in Washington State (Grah & Beaulieu, 2014) as a result of increased winter flows and scour events, earlier snowmelt, decreased base-flows in summer, and increasing water temperatures (Mantua, Tohver, & Hamlet, 2010). ...
Article
1.Climate change influences apex predators in complex ways, due to their important trophic position, capacity for resource plasticity, and sensitivity to numerous anthropogenic stressors. Bald eagles, an ecologically and culturally significant apex predator, congregate seasonally in high densities on salmon spawning rivers across the Pacific Northwest. One of the largest eagle concentrations is in the Skagit River watershed, which connects the montane wilderness of North Cascades National Park to the Puget Sound. 2.Using multiple long‐term datasets, we evaluated local bald eagle abundance in relation to chum and coho salmon availability; salmon phenology; and the number and timing of flood events in the Skagit. We analysed changes over time as a reflection of climate change impacts, as well as differences between managed and unmanaged portions of the river. 3.We found that peaks in chum salmon and bald eagle presence have advanced at remarkably similar rates (~0.45 days/year), suggesting synchronous phenological responses within this trophic relationship. 4.Yet the temporal relationship between chum salmon spawning and flood events, which remove salmon carcasses from the system, has not remained constant. This has resulted in a paradigm shift whereby the peak of chum spawning now occurs before the first flood event of the season rather than after. 5.The interval between peak chum and first flood event was a significant predictor of bald eagle presence: as this interval grew over time (by nearly one day per year), bald eagle counts declined, with a steady decrease in bald eagle observations since 2002. River section was also an important factor, with fewer flood events and more eagle observations occurring in the river section experiencing direct hydroelectric flow management. 6.Synthesis and applications. The effects of climate change and hydroelectric management contribute to a complex human footprint in the North Cascades National Park, an otherwise largely natural ecosystem. By accounting for the differential phenological impacts of climate change on bald eagles, salmon, and flood events, Park managers and the operators of the hydroelectric system can more effectively ensure the resilience of the eagle‐salmon relationship along the Skagit River. This article is protected by copyright. All rights reserved.
... The depletion of sea ice and earlier snowmelt has been reported to have an impact both on native communities and ecosystems. Due to these recent cryosphere changes, native communities are experiencing negative effects in subsistence activities (fishing and hunting; e.g., Grah & Beaulieu, 2013), while high-trophic predators are adapting their foraging behavior and dietary preferences (e.g., Brown et al., 2016;Grémillet et al., 2015;Laidre et al., 2008;Lydersen et al., 2017;Pagano et al., 2018). ...
Article
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This article is composed of two independent commentaries about the state of Integrated, Coordinated, Open, Networked (ICON) principles (Goldman et al., 2021, https://doi.org/10.1002/essoar.10508554.1) in cryosphere science and discussion on the opportunities and challenges of adopting them. Each commentary focuses on a different topic: (Section 2) observational and modeling data research and application in cryosphere sciences and (Section 3) expanding undergraduate research experiences in cryosphere science. We found that many cryosphere‐related research projects and data sharing initiatives engage in ICON research. These efforts should be continued and improved. Specifically, we recommend standardizing methodologies and data, and removing existing barriers to data access and participation in our field. We acknowledge that such ICON‐Findable, Accessible, Interoperable, Reusable‐aligned efforts are cost‐ and labor‐intensive. They require leadership and accountability but they also have the potential to increase the diversity and knowledge of the cryosphere research community in the future.
... This study looks primarily at the natural characteristics, including the area, shape, length and average elevation of the basin, average annual rainfall, watershed slope, river network, lake density, forest coverage, main channel length, and soil and geological characteristics. Glaciers can also affect local hydrological cycles by influencing the changes in runoff and baseflow (Grah and Beaulieu, 2013). Temperature and precipitation are the main factors influencing the amount of melting from glaciers. ...
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The increasing shortage in water resources is a key factor affecting sustainable socio-economic development in the arid region of Northwest China (ARNC). Water shortages also affect the stability of the region’s oasis ecosystem. This paper summarizes the hydrological processes and water cycle of inland river basins in the ARNC, focusing on the following aspects: the spatial-temporal features of water resources (including air water vapor resources, runoff, and glacial meltwater) and their driving forces; the characteristics of streamflow composition in the inland river basins; the characteristics and main controlling factors of baseflow in the inland rivers; and anticipated future changes in hydrological processes and water resources. The results indicate that: (1) although the runoff in most inland rivers in the ARNC showed a significant increasing trend, both the glaciated area and glacial ice reserves have been reduced in the mountains; (2) snow melt and glacier melt are extremely important hydrological processes in the ARNC, especially in the Kunlun and Tianshan mountains; (3) baseflow in the inland rivers of the ARNC is the result of climate change and human activities, with the main driving factors being the reduction in forest area and the over-exploitation and utilization of groundwater in the river basins; and (4) the contradictions among water resources, ecology and economy will further increase in the future. The findings of this study might also help strengthen the ecological, economic and social sustainable development in the study region.
... Water quality is also of critical importance to human livelihoods in glacier-fed watersheds. Glacier retreat can warm downstream water (Mantua, Tohver, and Hamlet 2010;Pelto 2011), with potential implications for fish populations that societies depend on for food security, fishing markets, and cultural aspects (Lackey 2000;Grah and Beaulieu 2013). Mining (Bury 2015) and changes in sediment load resulting from increased glacier melting (Riedel et al. 2015) can both affect water quality, which could be exacerbated by glacier shrinkage and declining runoff. ...
... Global warming is causing glacial retreat and thinning, resulting in an altered glacial meltwater contribution to stream flow in glacierised catchments (Sorg et al., 2012;Grah & Beaulieu, 2013;Rabatel et al., 2013). The reduction in ice volume should yield a significant increase in annual glacial runoff in the early stages of glacial retreat Orsay Cedex, France. ...
... Additionally, the Tribe visits the monitoring site weekly to measure stream velocity with a Xylem Flowprobe which was integrated over the cross-sectional area to determine discharge. A discharge rating curve was then developed for each creek in order to model continuous discharge over the field season from late July through mid-September (Grah and Beaulieu, 2013). ...
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The glaciers of the North Cascades have experienced mass loss and terminus retreat due to climate change. The meltwater from these glaciers provides a flux of cold glacier meltwater into the river systems, which supports salmon spawning during the late summer dry season. The Nooksack Indian Tribe monitors the outlet flow of the Sholes Glacier within the North Cascades range with the goal of understanding the health of the glacier and the ability of the Tribe to continue to harvest sustainable populations of salmon. This study compares the UAV derived glacier ablation with the discharge data collected by the Tribe. We surveyed the Sholes Glacier twice throughout the 2020 melt season and, using Structure-from-Motion technology, generated high resolution multispectral orthomosaics and Digital Elevation Models (DEMs) of the glacier on each of the survey dates. The DEMs were differenced to reveal the surface height change of the glacier. The spectral data of the orthomosaics were used to conduct IsoData unsupervised classification. This process divided the survey area into Snow, Ice, and Rock classes that were then used to attribute the surface height changes of the DEMs to either snow or ice melt. The analysis revealed the glacier lost an average thickness of −0.132 m per day (m d ⁻¹ ) with snow and ice losing thickness at similar rates, −0.130 m d ⁻¹ and −0.132 m d ⁻¹ respectively. DEM differencing reveals that a total of −550,161 ± 45,206 m ³ water equivalent (w.e.) was discharged into Wells Creek between the survey dates whereas the stream gauge station measured a total discharge of 350,023 m ³ . This study demonstrates the ability to spectrally classify the UAV data and derive discharge measurements while evaluating the small-scale spatial variability of glacier melt. Assessing ablation in small alpine glaciers is of great importance to downstream communities, like the Nooksack Indian Tribe who seek to understand the magnitude and timing of glacier melt in order to better protect their salmon populations. With this paper, we provide a baseline for future glacier monitoring and the potential to connect the snow surface properties with the rate of snow melt into a warming future.
... Groundwater is a component of the water balance in many glacier-and snow-dominated basins (Grah and Beaulieu, 2013) and can comprise a sizeable portion of the runoff budget in glaciated catchments (Gan et al., 2015). Contributions to river flow in several basins in Nepal were delayed by ∼45 days as a result of flows through fractured aquifers (Andermann et al., 2012), and subsurface storage of glacier meltwater was found to be important to river flows in the Langtang basin (Wilson et al., 2016). ...
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Climate-influenced changes in hydrology affect water-food-energy security that may impact up to two billion people downstream of the High Mountain Asia (HMA) region. Changes in water supply affect energy, industry, transportation, and ecosystems (agriculture, fisheries) and as a result, also affect the region's social, environmental, and economic fabrics. Sustaining the highly interconnected food-energy-water nexus (FEWN) will be a fundamental and increasing challenge under a changing climate regime. High variability in topography and distribution of glaciated and snow-covered areas in the HMA region, and scarcity of high resolution (in-situ) data make it difficult to model and project climate change impacts on individual watersheds. We lack basic understanding of the spatial and temporal variations in climate, surface impurities in snow and ice such as black carbon and dust that alter surface albedo, and glacier mass balance and dynamics. These knowledge gaps create challenges in predicting where and when the impact of changes in river flow will be the most significant economically and ecologically. In response to these challenges, the United States National Aeronautics and Space Administration (NASA) established the High Mountain Asia Team (HiMAT) in 2016 to conduct research to address knowledge gaps. This paper summarizes some of the advances HiMAT made over the past 5 years, highlights the scientific challenges in improving our understanding of the hydrology of the HMA region, and introduces an integrated assessment framework to assess the impacts of climate changes on the FEWN for the HMA region. The framework, developed under a NASA HMA project, links climate models, hydrology, hydropower, fish biology, and economic analysis. The framework could be applied to develop scientific understanding of spatio-temporal variability in water availability and the resultant downstream impacts on the FEWN to support water resource management under a changing climate regime.
... Continued glacier retreat is inevitable; 75% of the North Cascade glaciers that we observed are in disequilibrium and will melt away during this century with the current climate [36]. The loss of glacier area will lead to further declines in summer runoff in glacier fed rivers, as the glacier area available for melting in the summer declines [37,38]. This will impact salmon in streams such as the Nooksack River [39]. ...
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In 1983, the North Cascade Glacier Climate Project (NCGCP) began the annual monitoring of the mass balance on 10 glaciers throughout the range, in order to identify their response to climate change. Annual mass balance (Ba) measurements have continued on seven original glaciers, with an additional two glaciers being added in 1990. The measurements were discontinued on two glaciers that had disappeared and one was that had separated into several sections. This comparatively long record from nine glaciers in one region, using the same methods, offers some useful comparative data in order to place the impact of the regional climate warmth of 2015 in perspective. The mean annual balance of the NCGCP glaciers is reported to the World Glacier Monitoring Service (WGMS), with two glaciers, Columbia and Rainbow Glacier, being reference glaciers. The mean Ba of the NCGCP glaciers from 1984 to 2015, was −0.54 m w.e.a−1 (water equivalent per year), ranging from −0.44 to −0.67 m w.e.a−1 for individual glaciers. In 2015, the mean Ba of nine North Cascade glaciers was −3.10 m w.e., the most negative result in the 32-year record. The correlation coefficient of Ba was above 0.80 between all North Cascade glaciers, indicating that the response was regional and not controlled by local factors. The probability of achieving the observed 2015 Ba of −3.10 is 0.34%.
... The transition from a nivo-glacial to a more pluvial river regime in response to warming would change the timing and magnitude of floods, leading to altered patterns of erosion and sediment deposition and impacting biodiversity and water quality downstream (Déry et al., 40 2009;Huss et al., 2017). The impacts of the progressive loss of ice and snow surfaces and resulting alterations of the hydrological cycle can reach well beyond the glacierized catchments, affecting agriculture (Barnett et al., 2005;Comeau et al., 2009;Milner et al., 2017;Schindler and Donahue, 2006), fisheries (Dittmer, 2013;Grah and Beaulieu, 2013;Huss et al., 2017), hydropower and general ecological integrity (Huss et al., 2017). Glaciers and ice caps (GIC) mass loss have also contributed to sea level rise over the last decades, with recent estimates of 0.48 ± 0.1 mm a -1 between 1992 and 2016 for GIC excluding 45 ...
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Glacier mass balance models are needed at sites with scarce long-term observations to reconstruct past glacier mass balance and assess its sensitivity to future climate change. In this study North American Regional Reanalysis (NARR) data are used to force a physically-based, distributed glacier mass balance model of Saskatchewan Glacier for the historical period 1979–2016 and assess it sensitivity to climate change. A two-year record (2014–2016) from an on-glacier automatic weather station (AWS) and a homogenized historical precipitation record from nearby permanent weather stations were used to downscale air temperature, relative humidity, wind speed, incoming solar radiation and precipitation from the nearest NARR gridpoint to the glacier AWS site. The model was run with fixed (1979, 2010) and time-varying (dynamic) geometry using a multi-temporal digital elevation model (DEM) dataset. The model showed a good performance against recent (2012–2016) direct glaciological mass balance observations as well as with cumulative geodetic mass balance estimates. The simulated mass balance showed a large sensitivity to the biases in NARR precipitation and solar radiation, as well as to the prescribed precipitation lapse rate and ice aerodynamic roughness lengths, showing the importance of constraining these parameters with ancillary data. The difference between the static (1979) and dynamic simulations showed small differences (mean = 0.06 m w.e. a−1 or 1.5 m w.e. over 37 yrs), indicating minor effects of elevation changes on the glacier specific mass balance. The static mass balance sensitivity to climate was assessed for prescribed changes in regional mean air temperature between 0 to 7 °C and precipitation between −20 to +20 %, which comprise the spread of ensemble IPCC representative concentration pathways climate scenarios for the mid (2041–2070) and late (2071–2100) 21st century. The climate sensitivity experiments showed that future changes in precipitation would have a small impact on glacier mass-balance, while the temperature sensitivity increases with warming, from −0.65 to −0.93 m w.e. °C−1. Increased melting accounted for 90 % of the temperature sensitivity while precipitation phase feedbacks accounted for only 10 %. Roughly half of the melt response to warming was driven by a positive albedo feedback, in which glacier albedo decreases as the snow cover on the glacier thins and recedes earlier in response to warming, increasing net solar radiation fluxes. About one quarter of the melt response to warming was driven by latent heat energy gains (positive humidity feedback). Our study underlines the key role of albedo and air humidity in modulating the response of winter-accumulation type mountain glaciers and upland icefield-outlet glacier settings to climate.
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Federally-recognized tribes must adapt to many ecological challenges arising from climate change, from the effects of glacier retreat on the habitats of culturally significant species to how sea leave rise forces human communities to relocate. The governmental and social institutions supporting tribes in adapting to climate change are often constrained by political obstructions, raising concerns about justice. Beyond typical uses of justice, which call attention to violations of formal rights or to considerations about the degree to which some populations may have caused anthropogenic climate change, a justice framework should guide how leaders, scientists and professionals of all heritages and who work with or for federally-recognized tribes understand what actions are morally essential for supporting tribes’ adaptation efforts. This paper motivates a shift to a forward-looking framework of justice. The framework situates justice within the systems of responsibilities that matter to tribes and many others, which range from webs of inter-species relationships to government-to-government partnerships. Justice is achieved when these systems of responsibilities operate in ways that support the continued flourishing of tribal communities.
Technical Report
Bennett, T. M. B., N. G. Maynard, P. Cochran, R. Gough, K. Lynn, J. Maldonado, G. Voggesser, S. Wotkyns, and K. Cozzetto, 2014: Ch. 12: Indigenous Peoples, Lands, and Resources. Climate Change Impacts in the United States: The Third National Climate Assessment, J. M. Melillo, Terese (T.C.) Richmond, and G. W. Yohe, Eds., U.S. Global Change Research Program, 297- 317.
Thesis
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Climate change is one of the current threats that are impacting the world, and its consequences are greater when it comes to vulnerable communities. Despite its vast areas covered by untouched forest and plenty of natural resources, British Columbia, with a myriad of First Nations and other Indigenous peoples, is not the exception. First Nations culture and knowledge are based on natural resources; therefore, trying to understand what are the major impacts of a changing climate becomes paramount. Through this research, I sought to examine and characterize potential climate changes impacts in the lands covered by the Nisga’a Nation (Northern BC), and how these impacts are affecting traditional forest practices of the Nisga’a people. The method I used to gather the stories of participants in this study was participatory interviews. For the knowledge interpretation and analysis, I integrated individual research stories and thematic coding. I also conducted a community presentation during which the results were presented to the Wilp Wilxo’oskwhl Nisga’a Institute Board of Directors, enabling the findings to be validated. The Nisga’a People are very concerned about the consequences that climate change could have on fish, not only because of the warmer temperatures, but also because of the flooding and the high level of the Nass River. Forests and the river are intimately connected, so any impacts on forests would have implications on the river, and consequently on fish. For instance, flooding and pests pose great risk to forests. Flooding affects the regeneration of forests species, and pests affect growth, even killing important cultural species for the Nisga’a people (e.g. western redcedar). Thus, by improving the forest’s resilience, the conditions that fish are facing during the spawning seasons would be also improved. To improve current conditions, the findings suggest that it is an imperative to revitalize a more traditional Nisga’a-oriented approach to resource management by adopting an integrative approach, where the management is undertaken from a resilience point of view, allowing the Nisga’a forests to return to their past non-degraded status (i.e. before logging started), and thus able to absorb the expected and unexpected impacts deriving from climate change.
Chapter
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Climate change will have complex and profound effects on tribal resources, cultures, and economies. Indigenous peoples have lived in the region for thousands of years, developing cultural and social customs that revolve around traditional foods and materials and a spiritual tradition that is inseparable from the environment. Projected changes in temperature, precipitation, sea level, hydrology, and ocean chemistry threaten not only the lands, resources, and economies of tribes, but also tribal homelands, ceremonial sites, burial sites, tribal traditions, and cultural practices that have relied on native plant and animal species since time immemorial (Williams and Hardison 2005, 2006, 2007, 2012).
Research
Calls for for public comments closed today on Washington State’s Salmon Recovery Strategy. In an effort to promote cutting-edge management practices in an issue that is very important to me and the Southern Resident killer whales that I also advocate for, I drafted a concise letter highlighting important strategy considerations as the latest research suggests. Below is a copy of the text of that letter for matter of public record and general interest. I wrote it as a researcher, though I must confess, also out of a sense of love and connection for the region’s ecology. I applaud and greatly appreciate the efforts of the agencies, staff, and leadership that make challenging participatory efforts such as these happen!
Research
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Purpose of the Guidelines These guidelines are intended to meet multiple goals. First and foremost, these guidelines are intended to be provisional. They are intended to: 1) Increase understanding of the role of and protections for TKs in climate initiatives: • Provide foundational information to federal agencies on intergovernmental relationships and science when engaging tribal and indigenous peoples in federal climate change initiatives; and • Provide foundational information on the role of traditional knowledges (TKs) in federal climate change initiatives. 2) Provide provisional guidance to those engaging in efforts that encompass TKs: • Establish principles of engagement with tribes on issues related to TKs; and • Establish processes and protocols that govern the sharing and protection of TKs. 3) Increase mutually beneficial and ethical interactions between tribes and non-tribal partners: • Examine the significance of TKs in relation to climate change and the potential risks to indigenous peoples in the U.S. for sharing TKs in federal and other non-indigenous climate change initiatives; • Guide the motivation, character, and intent of collaborative climate initiatives undertaken between government agencies, research scientists, tribal communities and TKs holders; • Provide specific measures that federal agencies, researchers, tribes, and TKs holders can follow in conceptualizing, developing, and implementing climate change initiatives involving TKs; and, • Promote the use of TKs in climate change initiatives in such a way as to benefit indigenous peoples and promote greater collaboration between federal agencies and tribes and increase tribal representation in federal climate initiatives.
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Within the cryosphere, glacier-fed streams exhibit distinctive thermal regimes due to glacier melt influences; accordingly, these streams host a unique coldwater ecosystem. The role of water temperature as a driver of various intra-ecosystem processes is particularly significant in glacierized basins due to the strong coupling and high sensitivity between atmospheric and in-stream processes. In this paper, we review studies of the temperature characteristics in glacier-fed river streams, the influencing factors, and the response in aquatic ecosystems. Previous analyses have shown that glacial rivers are characterized by low temperatures and remarkable spatiotemporal temperature variations. Influencing factors in glacial rivers can be summarized in four major categories: heat transfer at the air-water interface, heat transfer at the water-channel interface, runoff components, and climate change and human activity. The response of a glacial river thermal regime to its physicochemical properties results in changes to the river water quality and thermo-hydrological fluxes. While the response of the aquatic ecosystem changes the distribution and structure of aquatic system with changing glacial stream temperature, once a certain threshold is exceeded, the change will be irreversible.
Thesis
In the last decade, Indigenous peoples of the United States have begun a concerted effort to formalize climate adaptation plans. As communities that are among the earliest to experience negative impacts of climate change and the most vulnerable to its effects, tribal communities are keenly aware of the urgency of undertaking an adaptation planning process. Assessing and adapting to the threats posed by climate change are not new concepts for indigenous peoples, who view their societies as always having had to constantly adapt to shifting environmental conditions since time immemorial. The principles and practices by which tribes plan for and design their communities to withstand change are centered on the seven generations model, which is predicated on long-term, sustained patterns of collective ownership and decision making that is guided by an ethical framework. In contrast, Western planning centers on regulation of land use, and adaptation planning decisions are largely guided by cost-benefit analyses that depend on economic valuations of quantified ecosystem services. Using directed content analysis of the 24 adaptation plans that have been published by tribal entities in the United States as of August 2015, this thesis explores the climate change-induced issues faced by tribal communities, how they are addressing them, and how their perspectives, knowledge, and approaches can inform community-based climate change adaptation efforts of other indigenous groups as well as in non-indigenous contexts.
Chapter
Glacier runoff is a major source of streamflow during the summer low-flow season and mitigates both low flow and high water temperatures. Measurement of ablation and discharge immediately below Sholes Glacier quantifies the volume of glacier runoff to the North Fork Nooksack River, which provided more than 40 % of total river runoff on 21 days in August and September, 2014, peaking at 80 % of total flow on Sept. 15th. The ameliorating role of glacier runoff on discharge and water temperature will be reduced as glacier area declines.
Chapter
A 31 year record (1984–2014) of glacier mass balance and areal extent indicate a significant glacier response to climate change in the North Cascades of Washington state. Glacier runoff is a major source of streamflow during the summer low-flow season and mitigates both low flow and high water temperatures. Measurement of ablation and discharge immediately below Sholes Glacier quantifies the volume of glacier runoff to the North Fork Nooksack River, which provided more than 40 % of total river runoff for 21 days in August and September, 2014, peaking at 80 % of total flow on Sept. 15th. The ameliorating role of glacier runoff on discharge and water temperature has been observed during 12 late summer warm weather events from 2009 to 2013 in the Nooksack Basin. The primary response to these events is increased discharge in the heavily glaciated North Fork, and increased stream temperature in the unglaciated South Fork. During the 12 warm weather events a +15 % increase in discharge was observed during 11 events in the North Fork, and zero in the South Fork. For water temperature all 12 events caused a 2 °C rise in water temperature in the South Fork, but just two events caused this rise in the North Fork.
Chapter
The North Cascades, Washington, are host to more glaciers than any other region of the United States outside of Alaska. The glaciers are small and occupy a temperate maritime climate setting, making them particularly sensitive to climate. Glacier retreat and changes in summer runoff have been pronounced in the Skykomish River Basin, North Cascades, Washington from 1950 to 2009. Mount Baker, a stratovolcano, is the highest mountain in the North Cascade Range at 3286 m. Deming Glacier is the headwaters of the Middle Fork Nooksack River. The glacier descends the southwest flank of Mount Baker beneath the Black Buttes. Glacier runoff discharge records below Sholes Glacier are compared with the observed discharge at the USGS station on the North Fork Nooksack to determine the percent of runoff generated by glaciers in 2014. The percent glacier contribution peaked on September 15 and 16 at over 80% of total stream discharge.
Chapter
Glacier fluctuations in terminus position, mass balance, and area are recognized as one of the most reliable indicators of climate change. The recognition of glacier sensitivity to climate led to the development of a global reporting system for glacier terminus change and glacier mass balance during the International Geophysical Year (IGY). Observations of alpine glaciers most commonly focus on changes in terminus behavior, to identify glacier response to climate changes. In addition, the advent of frequent high-resolution satellite imagery has allowed for the completion of global mountain glacier inventories led by the Global Land Ice Measurements from Space (GLIMS) and the Randolph Glacier Inventory (RGI). Mountain glaciers are important as water resources for agriculture, hydropower, aquatic life, and basic water supply. Glaciers act as natural reservoirs storing water in a frozen state instead of behind a dam. Glacier runoff is the product of glacier area and glacier melt rate.
Article
Glacier mass balance models are needed at sites with scarce long-term observations to reconstruct past glacier mass balance and assess its sensitivity to future climate change. In this study, North American Regional Reanalysis (NARR) data were used to force a physically based, distributed glacier mass balance model of Saskatchewan Glacier for the historical period 1979–2016 and assess its sensitivity to climate change. A 2-year record (2014–2016) from an on-glacier automatic weather station (AWS) and historical precipitation records from nearby permanent weather stations were used to downscale air temperature, relative humidity, wind speed, incoming solar radiation and precipitation from the NARR to the station sites. The model was run with fixed (1979, 2010) and time-varying (dynamic) geometry using a multitemporal digital elevation model dataset. The model showed a good performance against recent (2012–2016) direct glaciological mass balance observations as well as with cumulative geodetic mass balance estimates. The simulated mass balance was not very sensitive to the NARR spatial interpolation method, as long as station data were used for bias correction. The simulated mass balance was however sensitive to the biases in NARR precipitation and air temperature, as well as to the prescribed precipitation lapse rate and ice aerodynamic roughness lengths, showing the importance of constraining these two parameters with ancillary data. The glacier-wide simulated energy balance regime showed a large contribution (57 %) of turbulent (sensible and latent) heat fluxes to melting in summer, higher than typical mid-latitude glaciers in continental climates, which reflects the local humid “icefield weather” of the Columbia Icefield. The static mass balance sensitivity to climate was assessed for prescribed changes in regional mean air temperature between 0 and 7 ∘C and precipitation between −20 % and +20 %, which comprise the spread of ensemble Representative Concentration Pathway (RCP) climate scenarios for the mid (2041–2070) and late (2071–2100) 21st century. The climate sensitivity experiments showed that future changes in precipitation would have a small impact on glacier mass balance, while the temperature sensitivity increases with warming, from −0.65 to −0.93 m w.e. a−1 ∘C−1. The mass balance response to warming was driven by a positive albedo feedback (44 %), followed by direct atmospheric warming impacts (24 %), a positive air humidity feedback (22 %) and a positive precipitation phase feedback (10 %). Our study underlines the key role of albedo and air humidity in modulating the response of winter-accumulation type mountain glaciers and upland icefield-outlet glacier settings to climate.
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Projections of changes in climate extremes are critical to assessing the potential impacts of climate change on human and natural systems. Modeling advances now provide the opportunity of utilizing global general circulation models (GCMs) for projections of extreme temperature and precipitation indicators. We analyze historical and future simulations of ten such indicators as derived from an ensemble of 9 GCMs contributing to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC-AR4), under a range of emissions scenarios. Our focus is on the consensus from the GCM ensemble, in terms of direction and significance of the changes, at the global average and geographical scale. The climate extremes described by the ten indices range from heat-wave frequency to frost-day occurrence, from dry-spell length to heavy rainfall amounts. Historical trends generally agree with previous observational studies, providing a basic sense of reliability for the GCM simulations. Individual model projections for the 21st century across the three scenarios examined are in agreement in showing greater temperature extremes consistent with a warmer climate. For any specific temperature index, minor differences appear in the spatial distribution of the changes across models and across scenarios, while substantial differences appear in the relative magnitude of the trends under different emissions rates. Depictions of a wetter world and greater precipitation intensity emerge unequivocally in the global averages of most of the precipitation indices. However, consensus and significance are less strong when regional patterns are considered. This analysis provides a first overview of projected changes in climate extremes from the IPCC-AR4 model ensemble, and has significant implications with regard to climate projections for impact assessments.
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Over the last 100 years, linear trends of tributary streamflow have changed on Columbia River Basin tribal reservations and historical lands ceded by tribes in treaties with the United States. Analysis of independent flow measures (Seasonal Flow Fraction, Center Timing, Spring Flow Onset, High Flow, Low Flow) using the Student t test and Mann-Kendall trend test suggests evidence for climate change trends for many of the 32 study basins. The trends exist despite interannual climate variability driven by the El Niño–Southern Oscillation and Pacific Decadal Oscillation. The average April—July flow volume declined by 16 %. The median runoff volume date has moved earlier by 5.8 days. The Spring Flow Onset date has shifted earlier by 5.7 days. The trend of the flow standard deviation (i.e., weather variability) increased 3 % to 11 %. The 100-year November floods increased 49 %. The mid-Columbia 7Q10 low flows have decreased by 5 % to 38 %. Continuation of these climatic and hydrological trends may seriously challenge the future of salmon, their critical habitats, and the tribal peoples who depend upon these resources for their traditional livelihood, subsistence, and ceremonial purposes.
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Recent studies have shown substantial declines in snow water equivalent (SWE) over much of the western United States in the last half century, as well as trends toward earlier spring snowmelt and peak spring streamflows. These trends are influenced both by interannual and decadal-scale climate variability, and also by temperature trends at longer time scales that are generally consistent with observations of global warming over the twentieth century. In this study, the linear trends in 1 April SWE over the western United States are examined, as simulated by the Variable Infiltration Capacity hydrologic model implemented at 1/8° latitude longitude spatial resolution, and driven by a carefully quality controlled gridded daily precipitation and temperature dataset for the period 1915 2003. The long simulations of snowpack are used as surrogates for observations and are the basis for an analysis of regional trends in snowpack over the western United States and southern British Columbia, Canada. By isolating the trends due to temperature and precipitation in separate simulations, the influence of temperature and precipitation variability on the overall trends in SWE is evaluated. Downward trends in 1 April SWE over the western United States from 1916 to 2003 and 1947 to 2003, and for a time series constructed using two warm Pacific decadal oscillation (PDO) epochs concatenated together, are shown to be primarily due to widespread warming. These temperature-related trends are not well explained by decadal climate variability associated with the PDO. Trends in SWE associated with precipitation trends, however, are very different in different time periods and are apparently largely controlled by decadal variability rather than longer-term trends in climate.
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Analysis of key components of the alpine North Cascade hydrologic system indicate significant changes in glacier mass balance, terminus behavior, alpine snowpack, and alpine streamflow from 1950 to 2005. North Cascade glacier retreat is rapid and ubiquitous. All 47 monitored glaciers are currently undergoing a significant retreat and four of them have disappeared. Annual mass balance measured on ten glaciers, averaging 30–50 m in thickness, yields a mean cumulative annual balance for the 1984–2006 period of −12.4 m water equivalent (m we), a net loss of 14 m in glacier thickness and 20–40% loss of their total volume in two decades. The data indicate broad regional continuity in North Cascades glacial response to climate. The substantial negative annual balances have accompanied significant thinning in the accumulation zone of 75% of North Cascade glaciers monitored. This is indicative of glacier disequilibrium; a glacier in disequilibrium will not survive the current warmer climate trend. Alpine snowpack snow water equivalent (SWE) on April 1 has declined 25% since 1946 at five USDA Snow Course sites. This decline has occurred in spite of a slight increase in winter precipitation. The combination of a decline in winter snowpack and a 0.6° increase in ablation season temperature, during the 1946–2005 period in the North Cascades, has altered alpine streamflow in six North Cascade basins. Observed changes in streamflow are: increased winter streamflow, slightly declining spring streamflow and a 27% decline in summer streamflow. Only in the heavily glaciated Thunder Creek Basin (> 10% glaciated) has summer streamflow declined less than 10%; this is attributable to enhanced glacier melting.
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Controls on the sensitivity of mountain snowpack accumulation to climate warming (lambda(S)) are investigated. This is accomplished using two idealized, physically based models of mountain snowfall to simulate snowpack accumulation for the Cascade Mountains under current and warmed climates. Both models are forced from sounding observations. The first model uses the linear theory (LT) model of orographic precipitation to predict precipitation as a function of the incoming flow characteristics and uses the sounding temperatures to estimate the elevation of the rain-snow boundary, called the melting level (ML). The second "ML model'' uses only the ML from the sounding and assumptions of uniform and constant precipitation. Both models simulate increases in precipitation intensity and elevated storm MLs under climate warming. The LT model predicts a 14.8%-18.1% loss of Cascade snowfall per degree of warming, depending on the vertical structure of the warming. The loss of snowfall is significantly greater, 19.4%-22.6%, if precipitation increases are neglected. Comparing the two models shows that the predominant control on lS is the relationship between the distribution of storm MLs and the distribution of topographic area with elevation. Although increases in precipitation due to warming may act to moderate lambda(S), the loss of snow accumulation area profoundly limits the ability of precipitation increases to maintain the snowpack under substantial climate warming (beyond 1 degrees-2 degrees C). Circulation changes may act to moderate or exacerbate the loss of mountain snowpack under climate change via impacts on orographic precipitation enhancement.
Article
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The decrease in mountain snowpack associated with global warming is difficult to estimate in the presence of the large year-to-year natural variability in observations of snow-water equivalent (SWE). A more robust approach for inferring the impacts of global warming is to estimate the temperature sensitivity (λ) of spring snowpack and multiply it by putative past and future temperature rises observed across the Northern Hemisphere. Estimates of λ can be obtained from (i) simple geometric considerations based on the notion that as the seasonal-mean temperature rises by the amount δT, the freezing level and the entire snowpack should rise by the increment δT/Γ, where Γ is the mean lapse rate; (ii) the regression of 1 April SWE measurements upon mean winter temperatures; (iii) a hydrological model forced by daily temperature and precipitation observations; and (iv) the use of inferred accumulated snowfall derived from daily temperature and precipitation data as a proxy for SWE. All four methods yield an estimated sensitivity of 20% of spring snowpack lost per degree Celsius temperature rise. The increase of precipitation accompanying a 1°C warming can be expected to decrease the sensitivity to 16%. Considering observations of temperature rise over the Northern Hemisphere, it is estimated that spring snow-water equivalent in the Cascades portion of the Puget Sound drainage basin should have declined by 8%–16% over the past 30 yr resulting from global warming, and it can be expected to decline by another 11%–21% by 2050. These losses would be statistically undetectable from a trend analysis of the region’s snowpack over the past 30 yr.
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In western North America, snow provides crucial storage of winter precipitation, effectively transferring water from the relatively wet winter season to the typically dry summers. Manual and telemetered measurements of spring snow-pack, corroborated by a physically based hydrologic model, are examined here for climate-driven fluctuations and trends during the period of 1916-2002. Much of the mountain West has experienced declines in spring snowpack, especially since midcentury, despite increases in winter precipitation in many places. Analysis and modeling show that climatic trends are the dominant factor, not changes in land use, forest canopy, or other factors. The largest decreases have occurred where winter temperatures are mild, especially in the Cascade Mountains and northern California. In most mountain ranges, relative declines grow from minimal at ridgetop to substantial at snow line. Taken together, these results emphasize that the West's snow resources are already declining as earth's climate warms. Joint Institute for the Study of the Atmosphere and the Ocean Contribution Number 1073.
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The spatial characteristics for all glaciers in the North Cascades National Park Complex, USA, were estimated in 1958 and again in 1998. The total glacier area in 1958 was 117.3 ± 1.1 km2; by 1998 the glacier area had decreased to 109.1 ± 1.1 km2, a reduction of 8.2 ± 0.1 km2 (7%). Estimated volume loss during the 40 year period was 0.8 ± 0.1 km3 of ice. This volume loss contributes up to 6% of the August-September stream-flow and equals 16% of the August-September precipitation. No significant correlations were found between magnitude of glacier shrinkage and topographic characteristics of elevation, aspect or slope. However, the smaller glaciers lost proportionally more area than the larger glaciers and had a greater variability in fractional change than larger glaciers. Most of the well-studied alpine glaciers are much larger than the population median, so global estimates of glacier shrinkage, based on these well-studied glaciers, probably underestimate the true magnitude of regional glacier change.
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An important question for salmon restoration efforts in the western USA is 'How should habitat restoration plans be altered to accommodate climate change effects on stream flow and temperature?' We developed a decision support process for adapting salmon recovery plans that incorporates (1) local habitat factors limiting salmon recovery, (2) scenarios of climate change effects on stream flow and temperature, (3) the ability of restoration actions to ameliorate climate change effects, and (4) the ability of restoration actions to increase habitat diversity and salmon population resilience. To facilitate the use of this decision support framework, we mapped scenarios of future stream flow and temperature in the Pacific Northwest region and reviewed literature on habitat restoration actions to determine whether they ameliorate a climate change effect or increase life history diversity and salmon resilience. Under the climate change scenarios considered here, summer low flows decrease by 35–75% west of the Cascade Mountains, maximum monthly flows increase by 10–60% across most of the region, and stream temperatures increase between 2 and 6 C by 2070–2099. On the basis of our literature review, we found that restoring floodplain connectivity, restoring stream flow regimes, and re-aggrading incised channels are most likely to ameliorate stream flow and temperature changes and increase habitat diversity and population resilience. By contrast, most restoration actions focused on in-stream rehabilitation are unlikely to ameliorate climate change effects. Finally, we illustrate how the decision support process can be used to evaluate whether climate change should alter the types or priority of restoration actions in a salmon habitat restoration plan.
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Glacier retreat and changes in summer runoff have been pronounced in the Skykomish River Basin, North Cascades, Washington from 1950 to 2009. An analysis comparing USGS streamflow records for the 1950–1985 to the 1985–2009 period indicates that during the recent period the Skykomish River summer streamflow (July–September) has declined 26% in the watershed, spring runoff (April–June) has declined 6%, while winter runoff (November–March) has increased 10%. The minimum mean monthly August discharge from 1928 to 2010 occurred in 2003 and 2005 when streamflow was 15·1 and 15·2 m3s−1, respectively. From 1929 to 1985, streamflow was less than 14 m3s−1 during the glacier melt season on a single day in 1951. From 1986 to 2007 there were 217 days with discharge below 14 m3s−1 with 9 periods lasting for 10 consecutive days. In the Skykomish River watershed from 1958 to 2009, glacier area declined from 3·8 to 2·1 km2. Columbia, Foss, Hinman and Lynch Glacier, the primary glaciers in the basin, declined in area by 10, 60, 90 and 35%, respectively, since 1958. Annual mass balance measurements completed from 1984 to 2009 on Columbia, Foss and Lynch Glacier indicate a mass loss of 13·1 m w.e. Despite 15% higher ablation rates during the 1985–2009 period, the 45% reduction in glacier area led to a 38% reduction in glacier runoff between 1958 and 2009. The 38% reduction in glacier runoff did not lead to a significant decline in the percentage summer runoff contributed by glaciers under average conditions; the contribution has remained in the range of 1–3% from July to September. The glacier runoff decline impacted river discharge only during low flow periods in August and September. In August 2003 and 2005, glacier ablation contributed 1·5–1·6 m3s−1 to total discharge, or 10–11% of August discharge. While declining glacier area in the region has and will lead to reduced glacier runoff and reduced late summer streamflow, it has limited impact on the Skykomish River except during periods of critically low flow, below 14 m3s−1 when glaciers currently contribute more than 10% of the streamflow. Copyright © 2011 John Wiley & Sons, Ltd.
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1] While the impacts of long‐term climate change trends on glacier hydrology have received much attention, little has been done to quantify direct glacier runoff contributions to streamflow. This paper presents an approach for determining glacier runoff contributions to streamflow and estimating the effects of increased temperature and decreased glacier area on future runoff. We focus on late summer streamflow (when flow is lowest and nonglacier contributions to flow are minimal) of a small glacierized watershed on the flanks of Mount Hood, Oregon, United States. Field and lab measurements and satellite imagery were used in conjunction with a temperature‐index model of glacier runoff to simulate potential effects of increased temperature and reduction in glacier area on late summer runoff in the watershed. Discharge and stable isotope data show that 41–73% of late summer streamflow is presently derived directly from glacier melt. Model simulations indicate that while increased temperature leads to rapid glacier melt and therefore increased streamflow, the consequences of glacier recession overcomes this effect, ultimately leading to substantial declines in streamflow. Model sensitivity analyses show that simulation results are most sensitive to degree day factor and less sensitive to uncertainties in debris‐covered area and accumulation area ratio. This case study demonstrates that the effects of glacier recession on streamflow are a concern for water resource management at the local scale. This approach could also be extended to larger scales such as the upper Columbia River basin where glacier contributions to late summer flows are also thought to be substantial.
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1] Recent global climate model simulations for the IPCC Fourth Assessment report show a realistic North Pacific storm track and Aleutian Low for present-day climate conditions. Under climate change, the storm track and Aleutian Low move northward and intensify. These changes shift precipitation northward along the Pacific coast of North America. In particular, precipitation is intensified over the Pacific Northwest. Results from a statistical downscaling model suggest that precipitation may become more intense both due to the increased frequency of large-scale storms and due to changes in the interaction of these storms with the local terrain. Citation: Salathé, E. P., Jr. (2006), Influences of a shift in North Pacific storm tracks on western North American precipitation under global warming, Geophys. Res. Lett., 33, L19820, doi:10.1029/2006GL026882.
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Three lines of evidence indicate that North Cascade (Washington, USA) glaciers are currently in a state of disequilibrium. First, annual balance measured on nine glaciers yields a mean cumulative balance for the 1984–2004 period of −8·58 m water equivalent (w.e.), a net loss of ice thickness exceeding 9·5 m. This is a significant loss for glaciers that average 30–50 m in thickness, representing 18–32% of their entire volume. Second, longitudinal profiles completed in 1984 and 2002 on 12 North Cascade glaciers confirm this volume change indicating a loss of −5·7 to −6·3 m in thickness (5·0–5·6 m w.e.) between 1984 and 2002, agreeing well with the measured cumulative balance of −5·52 m w.e. for the same period. The change in thickness on several glaciers has been equally substantial in the accumulation zone and the ablation zone, indicating that there is no point to which the glacier can retreat to achieve equilibrium. Substantial thinning along the entire length of a glacier is the key indicator that a glacier is in disequilibrium. Third, North Cascade glacier retreat is rapid and ubiquitous. All 47 glaciers monitored are currently undergoing significant retreat or, in the case of four, have disappeared. Two of the glaciers where mass balance observations were begun, Spider Glacier and Lewis Glacier, have disappeared. The retreat since 1984 of eight Mount Baker glaciers that were all advancing in 1975 has averaged 297 m. These observations indicate broad regional continuity in glacial response to climate. Copyright
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Thermal regimes in rivers and streams are fundamentally important to aquatic ecosystems and are expected to change in response to climate forcing as the Earth’s temperature warms. Description and attribution of stream temperature changes are key to understanding how these ecosystems may be affected by climate change, but difficult given the rarity of long-term monitoring data. We assembled 18 temperature time-series from sites on regulated and unregulated streams in the northwest U.S. to describe historical trends from 1980–2009 and assess thermal consistency between these stream categories. Statistically significant temperature trends were detected across seven sites on unregulated streams during all seasons of the year, with a cooling trend apparent during the spring and warming trends during the summer, fall, and winter. The amount of warming more than compensated for spring cooling to cause a net temperature increase, and rates of warming were highest during the summer (raw trend = 0.17°C/decade; reconstructed trend = 0.22°C/decade). Air temperature was the dominant factor explaining long-term stream temperature trends (82–94% of trends) and inter-annual variability (48–86% of variability), except during the summer when discharge accounted for approximately half (52%) of the inter-annual variation in stream temperatures. Seasonal temperature trends at eleven sites on regulated streams were qualitatively similar to those at unregulated sites if two sites managed to reduce summer and fall temperatures were excluded from the analysis. However, these trends were never statistically significant due to greater variation among sites that resulted from local water management policies and effects of upstream reservoirs. Despite serious deficiencies in the stream temperature monitoring record, our results suggest many streams in the northwest U.S. are exhibiting a regionally coherent response to climate forcing. More extensive monitoring efforts are needed as are techniques for short-term sensitivity analysis and reconstructing historical temperature trends so that spatial and temporal patterns of warming can be better understood. Continuation of warming trends this century will increasingly stress important regional salmon and trout resources and hamper efforts to recover these species, so comprehensive vulnerability assessments are needed to provide strategic frameworks for prioritizing conservation efforts.
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The design of stormwater infrastructure is based on an underlying assumption that the probability distribution of precipitation extremes is statistically stationary. This assumption is called into question by climate change, resulting in uncertainty about the future performance of systems constructed under this paradigm. We therefore examined both historical precipitation records and simulations of future rainfall to evaluate past and prospective changes in the probability distributions of precipitation extremes across Washington State. Our historical analyses were based on hourly precipitation records for the time period 1949–2007 from weather stations in and near the state’s three major metropolitan areas: the Puget Sound region, Vancouver (WA), and Spokane. Changes in future precipitation were evaluated using two runs of the Weather Research and Forecast (WRF) regional climate model (RCM) for the time periods 1970–2000 and 2020–2050, dynamically downscaled from the ECHAM5 and CCSM3 global climate models. Bias-corrected and statistically downscaled hourly precipitation sequences were then used as input to the HSPF hydrologic model to simulate streamflow in two urban watersheds in central Puget Sound. Few statistically significant changes were observed in the historical records, with the possible exception of the Puget Sound region. Although RCM simulations generally predict increases in extreme rainfall magnitudes, the range of these projections is too large at present to provide a basis for engineering design, and can only be narrowed through consideration of a larger sample of simulated climate data. Nonetheless, the evidence suggests that drainage infrastructure designed using mid-20th century rainfall records may be subject to a future rainfall regime that differs from current design standards.
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Pacific Northwest (PNW) hydrology is particularly sensitive to changes in climate because snowmelt dominates seasonal runoff, and temperature changes impact the rain/snow balance. Based on results from the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR4), we updated previous studies of implications of climate change on PNW hydrology. PNW 21st century hydrology was simulated using 20 Global Climate Models (GCMs) and 2 greenhouse gas emissions scenarios over Washington and the greater Columbia River watershed, with additional focus on the Yakima River watershed and the Puget Sound which are particularly sensitive to climate change. We evaluated projected changes in snow water equivalent (SWE), soil moisture, runoff, and streamflow for A1B and B1 emissions scenarios for the 2020s, 2040s, and 2080s. April 1 SWE is projected to decrease by approximately 38–46% by the 2040s (compared with the mean over water years 1917–2006), based on composite scenarios of B1 and A1B, respectively, which represent average effects of all climate models. In three relatively warm transient watersheds west of the Cascade crest, April 1 SWE is projected to almost completely disappear by the 2080s. By the 2080s, seasonal streamflow timing will shift significantly in both snowmelt dominant and rain–snow mixed watersheds. Annual runoff across the State is projected to increase by 2–3% by the 2040s; these changes are mainly driven by projected increases in winter precipitation.
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Climate models used in the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4) on the whole reproduce the observed seasonal cycle and twentieth century warming trend of 0.8°C (1.5°F) in the Pacific Northwest, and point to much greater warming for the next century. These models project increases in annual temperature of, on average, 1.1°C (2.0°F) by the 2020s, 1.8°C (3.2°F) by the 2040s, and 3.0°C (5.3°F) by the 2080s, compared with the average from 1970 to 1999, averaged across all climate models. Rates of warming range from 0.1°C to 0.6°C (0.2°F to 1.0°F) per decade. Projected changes in annual precipitation, averaged over all models, are small (+1% to +2%), but some models project an enhanced seasonal cycle with changes toward wetter autumns and winters and drier summers. Changes in nearshore sea surface temperatures, though smaller than on land, are likely to substantially exceed interannual variability, but coastal upwelling changes little. Rates of twenty-first century sea level rise will depend on poorly known factors like ice sheet instability in Greenland and Antarctica, and could be as low as twentieth century values (20cm, 8″) or as large as 1.3m (50″).
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Global climate models do not have sufficient spatial resolution to represent the atmospheric and land surface processes that determine the unique regional climate of the State of Washington. Regional climate models explicitly simulate the interactions between the large-scale weather patterns simulated by a global model and the local terrain. We have performed two 100-year regional climate simulations using the Weather Research and Forecasting (WRF) model developed at the National Center for Atmospheric Research (NCAR). One simulation is forced by the NCAR Community Climate System Model version 3 (CCSM3) and the second is forced by a simulation of the Max Plank Institute, Hamburg, global model (ECHAM5). The mesoscale simulations produce regional changes in snow cover, cloudiness, and circulation patterns associated with interactions between the large-scale climate change and the regional topography and land-water contrasts. These changes substantially alter the temperature and precipitation trends over the region relative to the global model result or statistical downscaling. To illustrate this effect, we analyze the changes from the current climate (1970–1999) to the mid twenty-first century (2030–2059). Changes in seasonal-mean temperature, precipitation, and snowpack are presented. Several climatological indices of extreme daily weather are also presented: precipitation intensity, fraction of precipitation occurring in extreme daily events, heat wave frequency, growing season length, and frequency of warm nights. Despite somewhat different changes in seasonal precipitation and temperature from the two regional simulations, consistent results for changes in snowpack and extreme precipitation are found in both simulations.
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This study evaluates the sensitivity of Washington State’s freshwater habitat of Pacific Salmon (Oncorhynchus spp.) to climate change. Our analysis focuses on summertime stream temperatures, seasonal low flows, and changes in peak and base flows because these physical factors are likely to be key pressure points for many of Washington’s salmon populations. Weekly summertime water temperatures and extreme daily high and low streamflows are evaluated under multimodel composites for A1B and B1 greenhouse gas emissions scenarios. Simulations predict rising water temperatures will thermally stress salmon throughout Washington’s watersheds, becoming increasingly severe later in the twenty-first century. Streamflow simulations predict that basins strongly influenced by transient runoff (a mix of direct runoff from cool-season rainfall and springtime snowmelt) are most sensitive to climate change. By the 2080s, hydrologic simulations predict a complete loss of Washington’s snowmelt dominant basins, and only about ten transient basins remaining in the north Cascades. Historically transient runoff watersheds will shift towards rainfall dominant behavior, undergoing more severe summer low flow periods and more frequent days with intense winter flooding. While cool-season stream temperature changes and impacts on salmon are not assessed in this study, it is possible that climate-induced warming in winter and spring will benefit parts of the freshwater life-cycle of some salmon populations enough to increase their reproductive success (or overall fitness). However, the combined effects of warming summertime stream temperatures and altered streamflows will likely reduce the reproductive success for many Washington salmon populations, with impacts varying for different life history-types and watershed-types. Diminishing streamflows and higher stream temperatures in summer will be stressful for stream-type salmon populations that have freshwater rearing periods in summer. Increased winter flooding in transient runoff watersheds will likely reduce the egg-to-fry survival rates for ocean-type and stream-type salmon.
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Temperate alpine glacier survival is dependent on the consistent presence of an accumulation zone. Frequent low accumulation area ratio values, below 30%, indicate the lack of a consistent accumulation zone, which leads to substantial thinning of the glacier in the accumulation zone. This thinning is often evident from substantial marginal recession, emergence of new rock outcrops and surface elevation decline in the accumulation zone. In the North Cascades 9 of the 12 examined glaciers exhibit characteristics of substantial accumulation zone thinning; marginal recession or emergent bedrock areas in the accumulation zone. The longitudinal profile thinning factor, f, which is a measure of the ratio of thinning in the accumulation zone to that at the terminus, is above 0.6 for all glaciers exhibiting accumulation zone thinning characteristics. The ratio of accumulation zone thinning to cumulative mass balance is above 0.5 for glacier experiencing substantial accumulation zone thinning. Without a consistent accumulation zone these glaciers are forecast not to survive the current climate or future additional warming. The results vary considerably with adjacent glaciers having a different survival forecast. This emphasizes the danger of extrapolating survival from one glacier to the next.
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Documenting long-term trends or persistent shifts in temperature and precipitation is important for understanding present and future changes in flora and fauna. Carefully adjusted datasets for climate records in the USA and Canada are combined and used here to describe the spatial and seasonal variation in trends in the maritime, central, and Rocky Mountain climatic zones of the Pacific Northwest. Trends during the 20th century in annually averaged temperature (0.7degreesC-0.9degreesC) and precipitation (13%-38%) exceed the global averages. Largest warming rates occurred in the maritime zone and in winter and at lower elevations in all zones, and smallest warming rates occurred in autumn and in the Rockies. Largest increases in precipitation (upwards of 60% per century) were observed in the dry areas in northeast Washington and south central British Columbia. Increases in precipitation were largest in spring, but were also large in summer in the central and Rocky Mountain climatic zones. These trends have already had profound impacts on streamflow and on certain plant species in the region (Cayan et al. 2001), and other important impacts remain to be discovered. The warming observed in winter and spring can be attributed partially to climatic variations over the Pacific Ocean, and the buildup of greenhouse gases probably also plays an important role.
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As part of the National Assessment of Climate Change, the implications of future climate predictions derived from four global climate models (GCMs) were used to evaluate possible future changes to Pacific Northwest climate, the surface water response of the Columbia River basin, and the ability of the Columbia River reservoir system to meet regional water resources objectives. Two representative GCM simulations from the Hadley Centre (HC) and Max Planck Institute (MPI) were selected from a group of GCM simulations made available via the National Assessment for climate change. From these simulations, quasi-stationary, decadal mean temperature and precipitation changes were used to perturb historical records of precipitation and temperature data to create inferred conditions for 2025, 2045, and 2095. These perturbed records, which represent future climate in the experiments, were used to drive a macro-scale hydrology model of the Columbia River at 1/8 degree resolution. The altered streamflows simulated for each scenario were, in turn, used to drive a reservoir model, from which the ability of the system to meet water resources objectives was determined relative to a simulated hydrologic base case (current climate). Although the two GCM simulations showed somewhat different seasonal patterns for temperature change, in general the simulations show reasonably consistent basin average increases in temperature of about 1.8-2.1°C for 2025, and about 2.32.9°C for 2045. The HC simulations predict an annual average temperature increase of about 4.5°C for 2095. Changes in basin averaged winter precipitation range from -1 percent to +20 percent for the HC and MPI scenarios, and summer precipitation is also variously affected. These changes in climate result in significant increases in winter runoff volumes due to increased winter precipitation and warmer winter temperatures, with resulting reductions in snowpack. Average March 1 basin average snow water equivalents are 75 to 85 percent of the base case for 2025, and 55 to 65 percent of the base case by 2045. By 2045 the reduced snowpack and earlier snow melt, coupled with higher evapotranspiration in early summer, would lead to earlier spring peak flows and reduced runoff volumes from April-September ranging from about 75 percent to 90 percent of the base case. Annual runoff volumes range from 85 percent to 110 percent of the base case in the simulations for 2045. These changes in streamflow create increased competition for water during the spring, summer, and early fall between nonfirm energy production, irrigation, instream flow, and recreation. Flood control effectiveness is moderately reduced for most of the scenarios examined, and desirable navigation conditions on the Snake are generally enhanced or unchanged. Current levels of winter-dominated firm energy production are only significantly impacted for the MPI 2045 simulations.
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The terminus positions of six glaciers located on Mount Baker, Washington, were mapped by photogrammetric techniques at 2- to 7-yr intervals for the period 1940-1990. Although the timing varied slightly, each of the glaciers experienced a similar fluctuation sequence consisting of three phases: (1) rapid retreat, beginning prior to 1940 and lasting through the late 1940s to early 1950s; (2) approximately 30 yr of advance, ending in the late 1970s to early 1980s; (3) retreat though 1990. Terminus positions changed by up to 750 m during phases, with the advance phase increasing the lengths of glaciers by 13 to 24%. These fluctuations are well explained by variations in a smoothed time-series of accumulation-season precipitation and ablation-season mean temperature. The study glaciers appear to respond to interannual scale changes in climate within 20 yr or less. The glaciers on Mount Baker have a maritime location and a large percentage of area at high elevation, which may make their termini undergo greater fluctuations in response to climatic changes, especially precipitation variations, than most other glaciers in the North Cascades region.
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The Nooksack River has its headwaters in the North Cascade Mountains and drains an approximately 2000 km2 watershed in northwestern Washington State. The timing and magnitude of streamflow in a snowpack-dominated drainage basin such as the Nooksack River basin are strongly influenced by temperature and precipitation. Projections of future climate made by general circulation models (GCMs) indicate increases in temperature and variable changes in precipitation for the Nooksack River basin. Understanding the response of the river to climate change is crucial for regional water resources planning because municipalities, tribes, and industry depend on the river for water use and for fish habitat. We combine three different climate scenarios downscaled from GCMs and the Distributed-Hydrology-Soil-Vegetation Model to simulate future changes to timing and magnitude of streamflow in the higher elevations of the Nooksack River. Simulations of future streamflow and snowpack in the basin project a range of magnitudes, which reflects the variable meteorological changes indicated by the three GCM scenarios and the local natural variability employed in the modeling. Simulation results project increased winter flows, decreased summer flows, decreased snowpack, and a shift in timing of the spring melt peak and maximum snow water equivalent. These results are consistent with previous regional studies, but the magnitude of increased winter flows and total annual runoff is higher. Increases in temperature dominate snowpack declines and changes to spring and summer streamflow, whereas a combination of increases in temperature and precipitation control increased winter streamflow. Copyright © 2013 John Wiley & Sons, Ltd.
Article
Mount Baker, North Cascades, WA, has a current glacierized area of 38.6 km2. From 1984 to 2010, the North Cascade Glacier Climate Project has monitored the annual mass balance (Ba), accumulation area ratio (AAR), terminus behaviour and longitudinal profiles of Mount Baker glaciers. The Ba on Rainbow, Easton and Sholes Glaciers from 1990 to 2010 averaged −0.52 m w.e. a−1(m a−1). Terminus observations on nine principal Mount Baker glaciers, 1984–2009, indicate retreat ranging from 240 to 520 m, with a mean of 370 m or 14 m a−1. AAR observations on Rainbow, Sholes and Easton Glaciers for 1990–2010 indicate a mean AAR of 0.55 and a steady state AAR of 0.65.A comparison of Ba and AAR on these three glaciers yields a relationship that is used in combination with AAR observations made on all Mount Baker glaciers during 7 years to assess Mount Baker glacier mass balance. Utilizing the AAR–Ba relationship for the three glaciers yields a mean Ba of −0.55 m a−1 for the 1990–2010 period, 0.03 m a−1 higher than the measured mean Ba. The mean Ba based on the AAR–Ba relationship for the entire mountain from 1990 to 2010 is −0.57 m a−1. The product of the mean observed mass balance gradient determined from 11 000 surface mass balance measurements and glacier area in each 100-m elevation band on Mount Baker yields a Ba of −0.50 m a−1 from 1990–2010 for the entire mountain. The median altitude of the three index glaciers is lower than that of all Mount Baker glaciers. Adjusting the balance gradient for this difference yields a mean Ba of −0.77 m a−1 from 1990 to 2010. All but one estimate converge on a loss of −0.5 m a−1 for Mount Baker from 1990 to 2010. This equates to an 11-m loss in glacier thickness, 12–20% of the entire 1990 volume of glaciers on Mount Baker. Copyright © 2012 John Wiley & Sons, Ltd.
Article
Comparison of historic maps and aerial and ground-based photographs for the small cirque glaciers and glacierets of Rocky Mountain National Park in the northern Front Range of Colorado, USA, indicates modest change during the 20th century. The glaciers retreated through the first half of the 20th century, advanced slightly from the mid-1940s to the end of the century and have retreated slightly since. High interannual variability in area and temporal gaps in data complicate the trends. Local climate records indicate a lack of systematic change between 1950 and 1975, but significant warming afterwards. Local topographic effects (e.g. wind redistribution of snow and avalanching) are important influences. These small glaciers respond to changes in regional climate; summer temperature alone is a good predictor of the mass balance of Andrews Glacier (r = −0.93). Spring snowfall is also an important factor. That winter precipitation is not statistically significant supports the notion that these small glaciers gain much snow from wind drift and avalanching, making winter snow accumulation almost indifferent to variations in direct snowfall. Less than expected glacier retreat may be due to increased summer cloudiness.
Article
Meltwater contributes to watershed hydrology by increasing summer discharge, delaying the peak spring runoff, and decreasing variability in runoff. High-elevation snowshed meltwater, including glacier-derived input, provides an estimated 26.9 percent of summer streamflow (ranging annually from 16 to 40 percent) in the Nooksack River Basin above the town of Deming, Washington, in the North Cascades Range. The Nooksack is a major spawning river for salmon and once was important for commercial, recreational, and tribal fishing, and in the past its flow met the demands of both human and aquatic ecosystems. But the river is already legally overallocated, and demand is rising in response to the rapidly growing human population. Variability in snowshed contributions to the watershed is considerable but has increased from an average of 25.2 percent in the 1940s to an average of 30.8 percent in the 1990s. Overall stream discharge shows no significant increase, suggesting that the glaciers are melting, and/or precipitation levels (or other hydrologic factors) are decreasing at about the same rate. If glaciers continue to recede, they may disappear permanently from the Cascades. If that occurs, their summer contribution to surface-water supplies will cease, and water-management policies will need drastic revision.
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As part of the National Assessment of Climate Change, the implications of future climate predictions derived from four global climate models (GCMs) were used to evaluate possible future changes to Pacific Northwest climate, the surface water response of the Columbia River basin, and the ability of the Columbia River reservoir system to meet regional water resources objectives. Two representative GCM simulations from the Hadley Centre (HC) and Max Planck Institute (MPI) were selected from a group of GCM simulations made available via the National Assessment for climate change. From these simulations, quasi-stationary, decadal mean temperature and precipitation changes were used to perturb historical records of precipitation and temperature data to create inferred conditions for 2025, 2045, and 2095. These perturbed records, which represent future climate in the experiments, were used to drive a macro-scale hydrology model of the Columbia River at 1/8 degree resolution. The altered streamflows simulated for each scenario were, in turn, used to drive a reservoir model, from which the ability of the system to meet water resources objectives was determined relative to a simulated hydrologic base case (current climate). Although the two GCM simulations showed somewhat different seasonal patterns for temperature change, in general the simulations show reasonably consistent basin average increases in temperature of about 1.8–2.1°C for 2025, and about 2.3–2.9°C for 2045. The HC simulations predict an annual average temperature increase of about 4.5°C for 2095. Changes in basin averaged winter precipitation range from -1 percent to + 20 percent for the HC and MPI scenarios, and summer precipitation is also variously affected. These changes in climate result in significant increases in winter runoff volumes due to increased winter precipitation and warmer winter temperatures, with resulting reductions in snowpack. Average March 1 basin average snow water equivalents are 75 to 85 percent of the base case for 2025, and 55 to 65 percent of the base case by 2045. By 2045 the reduced snowpack and earlier snow melt, coupled with higher evapotranspiration in early summer, would lead to earlier spring peak flows and reduced runoff volumes from April-September ranging from about 75 percent to 90 percent of the base case. Annual runoff volumes range from 85 percent to 110 percent of the base case in the simulations for 2045. These changes in streamflow create increased competition for water during the spring, summer, and early fall between non-firm energy production, irrigation, instream flow, and recreation. Flood control effectiveness is moderately reduced for most of the scenarios examined, and desirable navigation conditions on the Snake are generally enhanced or unchanged. Current levels of winter-dominated firm energy production are only significantly impacted for the MPI 2045 simulations.
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Mountain snowpack and spring runoff are key components of surface water resources, and serve as important, regionally integrated indicators of climate variability and change. This study examines whether mountain snowpack and snowmelt have manifested a consistent hydrologic response to global climatic changes over the past several decades. Prior findings are compared to identify spatial and temporal patterns of trends in the volume, extent, and seasonality of snowpack and melt for key mountain regions. Evidence suggests that both temperature and precipitation increases to date have impacted mountain snowpacks simultaneously on the global scale; however, the nature of the impact is, among other factors, strongly dependent on geographic location, latitude, and elevation. Warmer temperatures at mid-elevations have decreased snowpack and resulted in earlier melt in spite of precipitation increases, while they have not affected high-elevation regions that remain well below freezing during winter. At high elevations, precipitation increases have resulted in increased snowpack. Not all local responses are consistent with the general findings, possibly because of local climatic trends, atmospheric circulation patterns, record lengths, or data quality issues. With continued warming, increasingly higher elevations are projected to experience declines in snowpack accumulation and melt that can no longer be offset by winter precipitation increases. There is a continued research need for hydroclimatic trend detection and attribution in mountains owing to the length, quality, and sparseness of available data from monitoring stations not directly impacted by human activity. Copyright © 2008 John Wiley & Sons, Ltd.
Article
As part of the National Assessment of Climate Change, the implications of future climate predictions derived from four global climate models (GCMs) were used to evaluate possible future changes to Pacific Northwest climate, the surface water response of the Columbia River basin, and the ability of the Columbia River reservoir system to meet regional water resources objectives. Two representative GCM simulations from the Hadley Centre (HC) and Max Planck Institute (MPI) were selected from a group of GCM simulations made available via the National Assessment for climate change. From these simulations, quasi-stationary, decadal mean temperature and precipitation changes were used to perturb historical records of precipitation and temperature data to create inferred conditions for 2025, 2045, and 2095. These perturbed records, which represent future climate in the experiments, were used to drive a macro-scale hydrology model of the Columbia River at 1/8 degree resolution. The altered streamflows simulated for each scenario were, in turn, used to drive a reservoir model, from which the ability of the system to meet water resources objectives was determined relative to a simulated hydrologic base case (current climate). Although the two GCM simulations showed somewhat different seasonal patterns for temperature change, in general the simulations show reasonably consistent basin average increases in temperature of about 1.820132.1�C for 2025, and about 2.320132.9�C for 2045. The HC simulations predict an annual average temperature increase of about 4.5�C for 2095. Changes in basin averaged winter precipitation range from -1 percent to + 20 percent for the HC and MPI scenarios, and summer precipitation is also variously affected. These changes in climate result in significant increases in winter runoff volumes due to increased winter precipitation and warmer winter temperatures, with resulting reductions in snowpack. Average March 1 basin average snow water equivalents are 75 to 85 percent of the base case for 2025, and 55 to 65 percent of the base case by 2045. By 2045 the reduced snowpack and earlier snow melt, coupled with higher evapotranspiration in early summer, would lead to earlier spring peak flows and reduced runoff volumes from April-September ranging from about 75 percent to 90 percent of the base case. Annual runoff volumes range from 85 percent to 110 percent of the base case in the simulations for 2045. These changes in streamflow create increased competition for water during the spring, summer, and early fall between non-firm energy production, irrigation, instream flow, and recreation. Flood control effectiveness is moderately reduced for most of the scenarios examined, and desirable navigation conditions on the Snake are generally enhanced or unchanged. Current levels of winter-dominated firm energy production are only significantly impacted for the MPI 2045 simulations.
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