The changing thermal state of permafrost

Smith, Sharon L.; O'Neill, H B; Isaksen, Ketil; Nötzli, Jeannette; Romanovsky, V. E.

doi:10.1038/s43017-021-00240-1

Cited by 271 publications

(226 citation statements)

References 147 publications

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“…html). The regional average ALT increased slightly at a rate of 0.2 cm a −1 (range: −0.1-0.5 cm a −1 ) and 0.1 cm a −1 (range: −1.5-2.5 cm a −1 ) in the Alaska North Slope regions and the Antarctica, respectively, while the increasing rate is 0.9 cm a −1 (range: 0.2-0.7 cm a −1 ) in the Alaska interior regions (Smith et al 2022). The active layers have deepened by 0.82-1.74 cm a −1 in the western northwest territories of Canada during last 25 years (Mamet et al 2017).…”

Section: Alt Dynamicsmentioning

confidence: 86%

“…The active layers have deepened by 0.82-1.74 cm a −1 in the western northwest territories of Canada during last 25 years (Mamet et al 2017). In western Russia and central Siberia, the active layers are deepening with an average rate of 1.3 cm a −1 (Vasiliev et al 2020, Smith et al 2022. These comparisons suggest that the QTP is experiencing the most drastic permafrost degradation and active layer thickening (1.77 cm a −1 ) over the globe and thus calls for more attention and protective measures.…”

Section: Alt Dynamicsmentioning

confidence: 99%

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How does soil water content influence permafrost evolution on the Qinghai-Tibet Plateau under climate warming?

Fan

Kuang

et al. 2022

Environ. Res. Lett.

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The active layer thickness (ALT) in permafrost regions regulates hydrological cycles, water sustainability, and ecosystem functions in the cryosphere and is extremely sensitive to climate change. Previous studies often focused on the impacts of rising temperature on the ALT, while the roles of soil water content and soil granularity have rarely been investigated. Here, we incorporate alterations of soil water contents in soil thermal properties across various soil granularities and assess spatiotemporal ALT dynamics on the Qinghai-Tibet Plateau (QTP). The regional average ALT on the QTP is projected to be nearly 4 m by 2100. Our results indicate that soil wetting decelerates the active layer thickening in response to warming, while latent heat exerts stronger control on ALTs than thermal conductivity does. Under similar warming conditions, active layers thicken faster in coarse soils than in fine soils. An important ramification of this study is that neglecting soil wetting may cause overestimations of active layer thickening on the QTP.

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Section: Alt Dynamicsmentioning

confidence: 86%

Section: Alt Dynamicsmentioning

confidence: 99%

How does soil water content influence permafrost evolution on the Qinghai-Tibet Plateau under climate warming?

Fan

Kuang

et al. 2022

Environ. Res. Lett.

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“…Of its total length of 1937 km, 528.5 km is over continuous permafrost terrain [1]. Due to global warming, the permafrost table on the QTP has fallen significantly [2][3][4], and the presence of the QTH has modified the water and heat exchange conditions of the original soil on the QTP. This has created a surface temperature difference between the black asphalt pavement and the natural ground surface, which has accelerated the permafrost thaw under the highway embankment [5][6][7][8][9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Damage Properties of the Block-Stone Embankment in the Qinghai–Tibet Highway Using Ground-Penetrating Radar Imagery

Chen

et al. 2022

Remote Sensing

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The block-stone embankment is a special type of embankment widely used to protect the stability of the underlying warm and ice-rich permafrost. Under the influence of multiple factors, certain damages will still occur in the block-stone embankment after a period of operation, which may weaken or destroy its cooling function, introducing more serious damages to the Qinghai–Tibet Highway (QTH). Ground-penetrating radar (GPR), a nondestructive testing technique, was adopted to investigate the damage properties of the damaged block-stone embankment. GPR imagery, together with the other data and methods (structural characteristics, field survey data, GPR parameters, etc.), indicated four categories of damage: (i) loosening of the upper sand-gravel layer; (ii) loosening of the block-stone layer; (iii) settlement of the block-stone layer; and (iv) dense filling of the block-stones layer. The first two conditions were widely distributed, whereas the settlement and dense filling of the block-stone layer were less so, and the other combined damages also occurred frequently. The close correlation between the different damages indicated a causal relationship. A preliminary discussion of these observations about the influences on the formation of the damage of the block-stone embankment is included. The findings provide some points of reference for the future construction and maintenance of block-stone embankments in permafrost regions.

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“…Seasonal or degradational thawing of excess ground ice (ice that exceeds the unfrozen pore volume) is typically accompanied by ground surface disturbance or subsidence, which affects the landscape and sustainability of permafrost as an engineering substrate (de Grandpré et al 2012;Lamoureux et al 2015). Smith et al (2022) document evidence of decadal permafrost warming in terms of increases in ground temperature at a global scale and specific to Canada's Arctic. Romanovsky et al (2019) and Smith et al (2022) report long-term increases in active layer thickness (maximum summer thaw depth) for a number of Arctic sites.…”

Section: Introductionmentioning

confidence: 99%

“…Smith et al (2022) document evidence of decadal permafrost warming in terms of increases in ground temperature at a global scale and specific to Canada's Arctic. Romanovsky et al (2019) and Smith et al (2022) report long-term increases in active layer thickness (maximum summer thaw depth) for a number of Arctic sites. In this context of a warming climate and warming permafrost, knowledge of thaw sensitivitythe susceptibility of permafrost terrain to thawrelated subsidenceis important for understanding permafrost conditions and the evolution of permafrost landscapes.…”

Section: Introductionmentioning

confidence: 99%

Permafrost thaw sensitivity prediction using surficial geology, topography, and remote-sensing imagery: a data-driven neural network approach

2022

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Seasonal or degradational thaw subsidence of permafrost terrain affects the landscape, hydrology, and sustainability of permafrost as an engineering substrate. We perform permafrost thaw sensitivity prediction via supervised classification of a feature set consisting of geological, topographic, and multi-spectral variables over continuous permafrost near Rankin Inlet, Nunavut, Canada. We build a reference classification of thaw sensitivity using process-based categorization of seasonal subsidence as measured from differential interferometric synthetic aperture radar whereby categories of thaw sensitivity are reflective of ground ice conditions. Classification is performed using a neural network trained on both dispersed and parcel-based reference data. For Low, Medium, High, and Very High thaw sensitivity categories, generalized classification accuracy is 70.8% for 20.6 km2 of dispersed training data. In all cases, the majority classes of Low and Medium thaw sensitivity are predicted with higher accuracy and more certainty, while the minority classes of High and Very High thaw sensitivity are under-predicted. Minority classes can be combined to improve accuracy at the expense of a reduced level of discrimination. The two-class problem can be classified with an accuracy of 81.8%, thereby effectively distinguishing between stable and unstable ground. The method is applicable to similar low-Arctic permafrost terrain with geological and topographical controls on thaw sensitivity. However, generalized accuracy is reduced for parcel-based training, indicating that reference samples are not totally representative for inference beyond the parcel, and any deployment of the network to other geographical regions would benefit from full or partial re-training with local data.

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The changing thermal state of permafrost

Cited by 271 publications

References 147 publications

How does soil water content influence permafrost evolution on the Qinghai-Tibet Plateau under climate warming?

How does soil water content influence permafrost evolution on the Qinghai-Tibet Plateau under climate warming?

Damage Properties of the Block-Stone Embankment in the Qinghai–Tibet Highway Using Ground-Penetrating Radar Imagery

Permafrost thaw sensitivity prediction using surficial geology, topography, and remote-sensing imagery: a data-driven neural network approach

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