Degradation and stabilization of ice wedges: Implications for assessing risk of thermokarst in northern Alaska

Kanevskiy, Mikhail; Shur, Y.; Jorgenson, T.; Brown, Dana R. N.; Москаленко, Н. Г.; Brown, Jerry; Walker, Donald A.; Raynolds, Martha K.; Buchhorn, Marcel

doi:10.1016/j.geomorph.2017.09.001

Cited by 100 publications

(214 citation statements)

References 59 publications

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“…Thus, the historical perspective we provide in this study corroborates observational records and conceptual frameworks articulated by previous authors [19], and indicates that the potential for large-scale landscape collapse and persistent increases in surface water extent after ice-wedge degradation are unlikely. Nonetheless, even though the mapped extent of flooded thaw pits was generally small compared to the total extent of residual deposits at most study sites, the microtopographic changes associated with differential thaw subsidence dramatically alters landscape hydrologic connectivity and the soil moisture regime far beyond the footprints of the thaw pits themselves.…”

Section: Implications For North Slope Ecosystemssupporting

confidence: 89%

“…The recent onset of ice-wedge degradation that we observed at most of the Beaufort and foothills sites was contemporaneous with that observed by others farther east near the Colville River Delta and Deadhorse, where field studies provide strong evidence that thawing was initiated by extremely warm summers during the 1990s and early 2000s [12][13][14]19]. These warm summers are prominent in instrumental records from stations across the North Slope (Figure 6), suggesting that ice-wedge degradation at most of the Beaufort and foothills sites probably began by the same mechanism.…”

Section: Mechanisms For Asynchronous Onsetsupporting

confidence: 84%

“…The three western study areas on the Chukchi coastal plain all had abundant thaw pits by the mid-20th century, and changes since then generally reflect a shift from open surface water to increased cover of hydrophytic vegetation. This is consistent with successional sequences observed in polygonal landscapes elsewhere on the North Slope [18,19]. Although the areal extent of individual thaw features is small, the cumulative area of these features is large enough that vegetation mortality and ponding in early stages, and vegetation succession and reduction in surface wetness in later stages could influence landscape "greenness" observed by satellites in the form of the Normalized Difference Vegetation Index (NDVI) [48].…”

Section: Implications For North Slope Ecosystemssupporting

confidence: 78%

“…Secondary impacts can affect large areas because pitting creates new hydrologic flowpaths that alter soil hydrology and the distribution of surface water [14]. Over time, most pits become colonized by wetland vegetation and surface water extent declines due to the development of an organic mat [18,19].…”

Section: Introductionmentioning

confidence: 99%

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Regional Patterns and Asynchronous Onset of Ice-Wedge Degradation since the Mid-20th Century in Arctic Alaska

Frost

Christopherson

Jorgenson³

et al. 2018

Remote Sensing

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Ice-wedge polygons are widespread and conspicuous surficial expressions of ground-ice in permafrost landscapes. Thawing of ice wedges triggers differential ground subsidence, local ponding, and persistent changes to vegetation and hydrologic connectivity across the landscape. Here we characterize spatio-temporal patterns of ice-wedge degradation since circa 1950 across environmental gradients on Alaska's North Slope. We used a spectral thresholding approach validated by field observations to map flooded thaw pits in high-resolution images from circa 1950, 1982, and 2012 for 11 study areas (1577-4460 ha). The total area of flooded pits increased since 1950 at 8 of 11 study areas (median change +3.6 ha; 130.3%). There were strong regional differences in the timing and extent of degradation; flooded pits were already extensive by 1950 on the Chukchi coastal plain (alluvial-marine deposits) and subsequent changes there indicate pit stabilization. Degradation began more recently on the central Beaufort coastal plain (eolian sand) and Arctic foothills (yedoma). Our results indicate that ice-wedge degradation in northern Alaska cannot be explained by late-20th century warmth alone. Likely mechanisms for asynchronous onset include landscape-scale differences in surficial materials and ground-ice content, regional climate gradients from west (maritime) to east (continental), and regional differences in the timing and magnitude of extreme warm summers after the Little Ice Age.

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Section: Implications For North Slope Ecosystemssupporting

confidence: 89%

Section: Mechanisms For Asynchronous Onsetsupporting

confidence: 84%

Section: Implications For North Slope Ecosystemssupporting

confidence: 78%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Regional Patterns and Asynchronous Onset of Ice-Wedge Degradation since the Mid-20th Century in Arctic Alaska

Frost

Christopherson

Jorgenson³

et al. 2018

Remote Sensing

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“…Stable isotope analysis of ice‐wedge ice has been successfully used to reconstruct climate across much of Beringia . In Siberia, oxygen isotope values have become progressively enriched over the past 9–10 ka BP, with the highest rates of enrichment occurring during the last century .…”

Section: Introductionmentioning

confidence: 99%

Isotopic evidence for Holocene January air temperature variability on the East Chukotka Peninsula

Vasil'chuk

Budantseva

Farquharson

et al. 2018

Permafrost & Periglacial

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Ice‐wedge ice can provide a valuable record of past winter climate variability at high latitudes yet to date this proxy has been applied only sparsely across the Chukotka region of Siberia. Here we present data from eight ice‐wedges at four sites across a 600‐km transect in Eastern Chukotka which we use to reconstruct regional Holocene winter paleotemperature. The Holocene age of ice‐wedges was established by radiocarbon dating of peat surrounding individual ice‐wedges. Our suite of radiocarbon ages suggests that the studied ice‐wedges formed between 12.9–11.8 and 3–2.5 cal ka BP. δ18O and δ2H values from ice‐wedge ice indicate that in coastal areas of Eastern Chukotka mean January air temperatures in the first half of the Holocene were on average 2–3°С lower than modern values, a finding that corresponds well with winter climate reconstructions for the other areas of Beringia. The variability of reconstructed mean January air temperatures in the study area did not exceed 2–4°C during the early to mid‐Holocene.

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Landscape impacts of 3D‐seismic surveys in the Arctic National Wildlife Refuge, Alaska

Raynolds

Jorgenson

Jorgenson³

et al. 2020

Ecological Applications

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Although three-dimensional (3D) seismic surveys have improved the success rate of exploratory drilling for oil and gas, the impacts have received little scientific scrutiny, despite affecting more area than any other oil and gas activity. To aid policy-makers and scientists, we reviewed studies of the landscape impacts of 3D-seismic surveys in the Arctic. We analyzed a proposed 3D-seismic program in northeast Alaska, in the northern Arctic National Wildlife Refuge, which includes a grid 63,000 km of seismic trails and additional camp-move trails. Current regulations are not adequate to eliminate impacts from these activities. We address issues related to the high-density of 3D trails compared to 2D methods, with larger crews, more camps, and more vehicles. We focus on consequences to the hilly landscapes, including microtopography, snow, vegetation, hydrology, active layers, and permafrost. Based on studies of 2D-seismic trails created in 1984-1985 in the same area by similar types of vehicles, under similar regulations, approximately 122 km 2 would likely sustain direct medium-to high-level disturbance from the proposed exploration, with possibly expanded impacts through permafrost degradation and hydrological connectivity. Strong winds are common, and snow cover necessary to minimize impacts from vehicles is windblown and inadequate to protect much of the area. Studies of 2D-seismic impacts have shown that moist vegetation types, which dominate the area, sustain longer-lasting damage than wet or dry types, and that the heavy vehicles used for mobile camps caused the most damage. The permafrost is ice rich, which combined with the hilly topography, makes it especially susceptible to thermokarst and erosion triggered by winter vehicle traffic. The effects of climate warming will exacerbate the impacts of winter travel due to warmer permafrost and a shift of precipitation from snow to rain. The cumulative impacts of 3D-seismic traffic in tundra areas need to be better assessed, together with the effects of climate change and the industrial development that would likely follow. Current data needs include studies of the impacts of 3D-seismic exploration, better climate records for the Arctic National Wildlife Refuge, especially for wind and snow; and high-resolution maps of topography, ground ice, hydrology, and vegetation.

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Degradation and stabilization of ice wedges: Implications for assessing risk of thermokarst in northern Alaska

Cited by 100 publications

References 59 publications

Regional Patterns and Asynchronous Onset of Ice-Wedge Degradation since the Mid-20th Century in Arctic Alaska

Regional Patterns and Asynchronous Onset of Ice-Wedge Degradation since the Mid-20th Century in Arctic Alaska

Isotopic evidence for Holocene January air temperature variability on the East Chukotka Peninsula

Landscape impacts of 3D‐seismic surveys in the Arctic National Wildlife Refuge, Alaska

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