Presence of rapidly degrading permafrost plateaus  in south-central Alaska

Jones, Benjamin M.; Baughman, Carson A.; Romanovsky, V. E.; Parsekian, Andrew D.; Babcock, Esther; Stephani, E.; Jones, Miriam C.; Grosse, Guido; Berg, Edward E.

doi:10.5194/tc-10-2673-2016

Cited by 42 publications

(38 citation statements)

References 73 publications

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“…A similar trend was also found previously in northern Sweden (Gałka et al, ). Chronologically, this habitat change corresponds to extensive permafrost degradation reported for the last approximately 50 years (Jones et al, ; Kokfelt et al, ). A multiple linear regression between these environmental variables and ACAR data suggest that summer temperature ( β = 22.53, p = 0.002), WTD ( β = 6.28, p = 0.018) and UOM ( β = −0.40, p = 0.017) are significant explanatory variables explaining overall ACAR patterns (Table S4).…”

Section: Discussionmentioning

confidence: 82%

Inconsistent Response of Arctic Permafrost Peatland Carbon Accumulation to Warm Climate Phases

Zhang

Gallego‐Sala

Amesbury

et al. 2018

Global Biogeochemical Cycles

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Northern peatlands have accumulated large carbon (C) stocks since the last deglaciation and during past millennia they have acted as important atmospheric C sinks. However, it is still poorly understood how northern peatlands in general and Arctic permafrost peatlands in particular will respond to future climate change. In this study, we present C accumulation reconstructions derived from 14 peat cores from four permafrost peatlands in northeast European Russia and Finnish Lapland. The main focus is on warm climate phases. We used regression analyses to test the importance of different environmental variables such as summer temperature, hydrology, and vegetation as drivers for nonautogenic C accumulation. We used modeling approaches to simulate potential decomposition patterns. The data show that our study sites have been persistent mid‐ to late‐Holocene C sinks with an average accumulation rate of 10.80–32.40 g C m−2 year−1. The warmer climate phase during the Holocene Thermal Maximum stimulated faster apparent C accumulation rates while the Medieval Climate Anomaly did not. Moreover, during the Little Ice Age, apparent C accumulation rates were controlled more by other factors than by cold climate per se. Although we could not identify any significant environmental factor that drove C accumulation, our data show that recent warming has increased C accumulation in some permafrost peatland sites. However, the synchronous slight decrease of C accumulation in other sites may be an alternative response of these peatlands to warming in the future. This would lead to a decrease in the C sequestration ability of permafrost peatlands overall.

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Section: Discussionmentioning

confidence: 82%

Inconsistent Response of Arctic Permafrost Peatland Carbon Accumulation to Warm Climate Phases

Zhang

Gallego‐Sala

Amesbury

et al. 2018

Global Biogeochemical Cycles

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“…Trends in growing season remotely sensed vegetation productivity and wetness indices (i.e., Normalized Difference Vegetation Index, NDVI; Normalized Difference Water Index, NDWI) were analyzed with respect to ecological and geomorphological change (or no change), identified from time series of high‐resolution imagery of surface water (Jones et al., ), coastal areas (Arp, Jones, Schmutz, Urban, & Jorgenson, ; Jones et al., ), thermokarst (Jones et al., ; Swanson, ), glacial areas (Loso, A. Arendt, & J. Rich, ), and geomorphic and vegetation change studies discussed in the previous section.…”

Section: Methodsmentioning

confidence: 99%

Spatiotemporal remote sensing of ecosystem change and causation across Alaska

Pastick

Jorgenson²,

Goetz

et al. 2018

Global Change Biology

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Contemporary climate change in Alaska has resulted in amplified rates of press and pulse disturbances that drive ecosystem change with significant consequences for socio-environmental systems. Despite the vulnerability of Arctic and boreal landscapes to change, little has been done to characterize landscape change and associated drivers across northern high-latitude ecosystems. Here we characterize the historical sensitivity of Alaska's ecosystems to environmental change and anthropogenic disturbances using expert knowledge, remote sensing data, and spatiotemporal analyses and modeling. Time-series analysis of moderate-and high-resolution imagery was used to characterize land- and water-surface dynamics across Alaska. Some 430,000 interpretations of ecological and geomorphological change were made using historical air photos and satellite imagery, and corroborate land-surface greening, browning, and wetness/moisture trend parameters derived from peak-growing season Landsat imagery acquired from 1984 to 2015. The time series of change metrics, together with climatic data and maps of landscape characteristics, were incorporated into a modeling framework for mapping and understanding of drivers of change throughout Alaska. According to our analysis, approximately 13% (~174,000 ± 8700 km ) of Alaska has experienced directional change in the last 32 years (±95% confidence intervals). At the ecoregions level, substantial increases in remotely sensed vegetation productivity were most pronounced in western and northern foothills of Alaska, which is explained by vegetation growth associated with increasing air temperatures. Significant browning trends were largely the result of recent wildfires in interior Alaska, but browning trends are also driven by increases in evaporative demand and surface-water gains that have predominately occurred over warming permafrost landscapes. Increased rates of photosynthetic activity are associated with stabilization and recovery processes following wildfire, timber harvesting, insect damage, thermokarst, glacial retreat, and lake infilling and drainage events. Our results fill a critical gap in the understanding of historical and potential future trajectories of change in northern high-latitude regions.

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“…Because most permafrost peatlands are located in the southern parts of the permafrost region they are already near thawing and very sensitive to future warmer conditions . Extensive landscape changes have already started to take place in subarctic peatlands in recent decades as a result of permafrost thaw . As long as the ground stays frozen, these environments are net carbon sinks through uptake of carbon dioxide (CO 2 ) by plants and peat accumulation.…”

Section: Introductionmentioning

confidence: 99%

Ground temperature and snow depth variability within a subarctic peat plateau landscape

Sannel

2020

Permafrost & Periglacial

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Subarctic permafrost peatlands cover extensive areas and store large amounts of soil organic carbon that can be remobilized as active layer deepening and thermokarst formation increase in a future warmer climate. Better knowledge of ground thermal variability within these ecosystems is important for understanding future landscape development and permafrost carbon feedbacks. In a peat plateau complex in Tavvavuoma, northern Sweden, ground temperatures and snow depth have been monitored in six different landscape units: on a peat plateau, in a depression within a peat plateau, along a peat plateau edge (close to a thermokarst lake), at a thermokarst lake shoreline, in a thermokarst lake and in a fen. Permafrost is present in all three peat plateau landscape units, and mean annual ground temperature (MAGT) in the central parts of the peat plateau is −0.3 C at 2 m depth. In the three low-lying wetter or saturated landscape units (along the thermokarst lake shoreline, in the lake and the fen) taliks are present and MAGT at 1 m depth is 1.0-2.7 C. Topographical differences between the elevated and low-lying units affect both local snow depth and soil moisture, and are important for ground thermal patterns in this landscape. Permafrost exists in landscape units with a shallow mean December-April snow depth (<20 cm) whereas snow depths >40 cm mostly result in absence of permafrost. K E Y W O R D Slandscape unit, peatland, permafrost, small-scale morphology, subarctic, temperature regime

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Presence of rapidly degrading permafrost plateaus in south-central Alaska

Cited by 42 publications

References 73 publications

Inconsistent Response of Arctic Permafrost Peatland Carbon Accumulation to Warm Climate Phases

Inconsistent Response of Arctic Permafrost Peatland Carbon Accumulation to Warm Climate Phases

Spatiotemporal remote sensing of ecosystem change and causation across Alaska

Ground temperature and snow depth variability within a subarctic peat plateau landscape

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