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![Thermokarst lakes formation [36]](profile/Sahar-Palangi/publication/318672969/figure/fig9/AS:519932455473153@1500972965582/Thermokarst-lakes-formation-36.png)
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![Figure 5. Projections of global average potential surface warming [17]](profile/Sahar-Palangi/publication/318672969/figure/fig5/AS:519932454633472@1500972965162/Projections-of-global-average-potential-surface-warming-17_Q320.jpg)
Permafrost is perennially frozen ground remaining at or below 0°C for at least two consecutive years. Any location with annual average air temperatures below freezing can potentially form permafrost. Most of the current permafrost formed during or since the last ice age and can extend down to depths of more than 700 meters. Arctic and alpine air te...
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... and methane are not frozen in the permafrost; rather, the thaw of permafrost triggers decay, which converts the organic material into CO2 and methane. Thermokarst lakes are especially effective in inducing rapid thaw of permafrost, with subsequent release of substantial amounts of methane ( figure 9). The release of CO2 and methane from thawing permafrost will amplify the rate of global warming due to anthropogenic greenhouse gas emissions and further accelerate permafrost degradation. ...
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About a quarter of the land area of the northern hemisphere is underlain by permafrost. But the frozen ground is increasingly warming and thawing due to global warming, which is particularly pronounced in arctic and subarctic regions. Local activities of residents also contribute to disturbing the thermal equilibrium of permafrost. What significanc...
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... Any location with annual average year temperatures below freezing can potentially form permafrost. Permafrost includes the content of the ground before it was frozen such as bedrock, gravel, silt and organic material. Permafrost often contains large lenses, layers and wedges of pure ice that grow over many years as a result of annual freezing and thawing of the surface soil layer [11]. It is present extensively in polar, high plateau, alpine and mountainous regions with the model estimated total extent of permafrost regions at 22.79 million square kilometers [3,5]. ...
... Very shall permafrost with depth from a few to 20 m formed during the Little Ice Age in the 16th and 19th century along the southern permafrost boundary in sporadic and discontinuous permafrost zones. Subsea permafrost in the east Siberian sea and elsewhere along the Arctic coastline was formed when these regions were above sea level but were inundated after the last ice age ended more than 15,000 years ago [11,12]. About a quarter of the entire Northern hemisphere is permafrost where the ground is frozen year round. ...
... Figure shows the vertical structure of permafrost as determined by the soil temperature. The depth of zero annual amplitude varies from a few meters in discontinuous permafrost to 20 meters or more in continuous or in bedrock [11,13]. Temperatures at the depth of zero annual amplitude reflect climate conditions at the end of 20th century but temperatures at 400 to 800 M depth reflect the climatic conditions at the Holocene optimum around 8000 years ago, just after the end of the last ice age [11]. ...
Permafrost, the permanently frozen ground is defined as any type of ground-from soil to sediment to rock- that remains at or below 0° C for at least two consecutive years. At present, permafrost occurs on one quarter of the exposed land surfaces of the earth, but the permafrost extent and its estimate have been changing rapidly. Under warming climate permafrost has been degrading extensively, persistently and rapidly. This degradation of permafrost has resulted in profound hydrological, ecological and socio-economic consequences. To sustainably develop resources in the cold regions while prudently protect the permafrost environment under constantly changing climate, we need to design and manage our environmental and engineering projects by creative and innovative thinking and with rapidly improving technologies. The paper mainly focuses on understanding the meaning and the extent of permafrost, the changing permafrost environment, the impacts of thawing permafrost and proactively adapting to and effective management of these rapidly changing cold regions environment with the latest technologies.
