Climate vulnerability of ecosystems and landscapes on Alaska’s North Slope

Kittel, T.G.F.; Baker, Brett; Higgins, Jonathan; Haney, J. Christopher

doi:10.1007/s10113-010-0180-y

Cited by 37 publications

(43 citation statements)

References 83 publications

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“…The timing of this high diurnal variation period of melt refreeze (when the snow is fully saturated and the snowpack isothermal) affects the progression of meltwater through a basin, as its timing is closely followed by the snow off date (which is usually a few days to weeks later depending on maximum snow accumulation), freshet timing, and peak snowmelt runoff, and is closely linked to green-up and growing season start (Cayan et al, 2001;Schwartz et al, 2006;Wang et al, 2011). Further, shifts in the timing of melt refreeze and freeze-thaw processes may have nonlinear effects on ecosystems once thresholds are surpassed (Kittel et al, 2011). Some shifts are already being identified such as spring snowmelt in northern Alaska advancing since the 1960s due to warmer temperatures and diminished snowfall, of importance to the surface radiation budget due to the resulting changes in albedo (Stone et al, 2002).…”

Section: K a Semmens And J M Ramage: Recent Changes In Spring Snomentioning

confidence: 99%

“…Arctic air temperature has increased at roughly double the global rate for the past several decades with more recent warming appearing strongest in winter and spring, critical seasons for snow accumulation and melt, ice breakup, and first leaf/bloom (IPCC, 2007;Schwartz et al, 2006;Kittel et al, 2011). Higher latitudes are especially sensitive to climatic change due to various positive feedbacks such as from snow-albedo and sea ice interactions resulting in Arctic amplification (Kittel et al, 2011;Overland et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

“…Higher latitudes are especially sensitive to climatic change due to various positive feedbacks such as from snow-albedo and sea ice interactions resulting in Arctic amplification (Kittel et al, 2011;Overland et al, 2011). Climate models project increases in average air temperatures of 3 • C for the Arctic by 2040, increases in precipitation in mid to high latitudes leading to overall deeper arctic snow cover, and increases in snowmelt and runoff for cold regions (Adam et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

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Recent changes in spring snowmelt timing in the Yukon River basin detected by passive microwave satellite data

Semmens

Ramage

2013

The Cryosphere

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Abstract. Spring melt is a significant feature of high latitude snowmelt dominated drainage basins influencing hydrological and ecological processes such as snowmelt runoff and green-up. Melt duration, defined as the transition period from snowmelt onset until the end of the melt refreeze, is characterized by high diurnal amplitude variations (DAV) where the snowpack is melting during the day and refreezing at night, after which the snowpack melts constantly until depletion. Determining trends for this critical period is necessary for understanding how the Arctic is changing with rising temperatures and provides a baseline from which to assess future change. To study this dynamic period, brightness temperature (T b ) data from the Special Sensor Microwave Imager (SSM/I) 37 V-GHz frequency from 1988 to 2010 were used to assess snowmelt timing trends for the Yukon River basin, Alaska/Canada. Annual T b and DAV for 1434 Equal-Area Scalable Earth (EASE)-Grid pixels (25 km resolution) were processed to determine melt onset and melt refreeze dates from T b and DAV thresholds previously established in the region. Temporal and spatial trends in the timing of melt onset and melt refreeze, and the duration of melt were analyzed for the 13 sub-basins of the Yukon River basin with three different time interval approaches. Results show a lengthening of the melt period for the majority of the sub-basins with a significant trend toward later end of melt refreeze after which the snowpack melts day and night leading to snow clearance, peak discharge, and green-up. Earlier melt onset trends were also found in the higher elevations and northernmost subbasins (Porcupine, Chandalar, and Koyukuk rivers). Latitude and elevation displayed the dominant controls on melt timing variability and spring solar flux was highly correlated with melt timing in middle (∼ 600-1600 m) elevations.

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Section: K a Semmens And J M Ramage: Recent Changes In Spring Snomentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Recent changes in spring snowmelt timing in the Yukon River basin detected by passive microwave satellite data

Semmens

Ramage

2013

The Cryosphere

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“…Kittel et al (2010) provide an insight into the profound changes in the Alaskan landscape and ecosystems that have been observed in the past 50 years, including by the Inuit people, driven by warming, permafrost thaw and sea-ice thinning and that are projected to accelerate the future. Whilst legally unclear in the context of the UNFCCC, the impacts of climate change on indigenous people and communities, particularly in polar and mountain regions was recognized as a key vulnerability in the IPCC AR4 assessment.…”

Section: Preventing Dangerous Anthropogenic Interference With the CLImentioning

confidence: 99%

Climate hotspots: key vulnerable regions, climate change and limits to warming

et al. 2011

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Defining and operationalizing Article 2 of the UNFCCC remains a challenge. The question of what is dangerous climate change is not a purely scientific one, as danger necessarily has a subjective dimension and its definition requires judgment and precaution. The papers in this special issue of Regional Environmental Change attempt to navigate this problem, by offering an overview of the latest scientific findings in the context of risks and uncertainties, and assess some key vulnerabilities that might lead to dangerous climate change. This synthesis provides an overview of the papers in this issue and looks at four areas of possible dangerous climate changeadverse declines in regional food and water security, loss of arctic sea ice with projected extinction of species, largescale sea-level rise and loss of coral reef systems. These issues affect a number of different regions including Africa, South Asia, and Small Island Developing States. Significant risks to vulnerable regions and systems at warming levels of 1.5-2°C above pre-industrial are identified. The direct effects of CO 2 concentration increases in terms of ocean acidification are identified as relevant to Article 2 because of the risks posed to coral reefs. Ultimate CO 2 stabilization levels that allow for the long-term viability of coral reefs likely are below 350 ppm. The paper concludes by arguing that the emission reduction pledges made by countries under the Copenhagen Accord will not suffice to prevent dangerous climate change.

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“…Along the approximately 800 km-long Arctic Coastal Plain of Alaska (ACP), a rapid rise in air temperatures over the last half century has been associated with a decreasing ice pack, thawing of the permafrost, and a significant shift in the productivity and species composition of plant communities [1][2][3]. These dynamic environmental changes complicate predictions of the future abundance and distributions of coastal plant communities as some may be lost to sea level rise and erosion, whereas others may be transformed from freshwater to halophytic species through saltwater intrusion [4,5].…”

Section: Introductionmentioning

confidence: 99%

Normalized Difference Vegetation Index as an Estimator for Abundance and Quality of Avian Herbivore Forage in Arctic Alaska

et al. 2017

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Tools that can monitor biomass and nutritional quality of forage plants are needed to understand how arctic herbivores may respond to the rapidly changing environment at high latitudes. The Normalized Difference Vegetation Index (NDVI) has been widely used to assess changes in abundance and distribution of terrestrial vegetative communities. However, the efficacy of NDVI to measure seasonal changes in biomass and nutritional quality of forage plants in the Arctic remains largely un-evaluated at landscape and fine-scale levels. We modeled the relationships between NDVI and seasonal changes in aboveground biomass and nitrogen concentration in halophytic graminoids, a key food source for arctic-nesting geese. The model was calibrated based on data collected at one site and validated using data from another site. Effects of spatial scale on model accuracy were determined by comparing model predictions between NDVI derived from moderate resolution (250 × 250 m pixels) satellite data and high resolution (20 cm diameter area) handheld spectrometer data. NDVI derived from the handheld spectrometer was a superior estimator (R 2 ≥ 0.67) of seasonal changes in aboveground biomass compared to satellite-derived NDVI (R 2 ≤ 0.40). The addition of temperature and precipitation variables to the model for biomass improved fit, but provided minor gains in predictive power beyond that of the NDVI-only model. This model, however, was only a moderately accurate estimator of biomass in an ecologically-similar halophytic graminoid wetland located 100 km away, indicating the necessity for site-specific validation. In contrast to assessments of biomass, satellite-derived NDVI was a better estimator for the timing of peak percent of nitrogen than NDVI derived from the handheld spectrometer. We confirmed that the date when NDVI reached 50% of its seasonal maximum was a reasonable approximation of the period of peak spring vegetative green-up and peak percent nitrogen. This study demonstrates the importance of matching the scale of NDVI measurements to the vegetation properties of biomass and nitrogen phenology.

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Climate vulnerability of ecosystems and landscapes on Alaska’s North Slope

Cited by 37 publications

References 83 publications

Recent changes in spring snowmelt timing in the Yukon River basin detected by passive microwave satellite data

Recent changes in spring snowmelt timing in the Yukon River basin detected by passive microwave satellite data

Climate hotspots: key vulnerable regions, climate change and limits to warming

Normalized Difference Vegetation Index as an Estimator for Abundance and Quality of Avian Herbivore Forage in Arctic Alaska

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