Thaw Settlement Hazard of Permafrost Related to Climate Warming in Alaska

Abstract

ABSTRACT. Permafrost temperatures have increased in Alaska since the 1960s, and many impacts of climate warming are associated with permafrost thaw. Thaw of permafrost caused by increases in permafrost temperature may result in thaw settlement and significant damage to infrastructure. The goal of this research is to identify regions of Alaska at risk from thaw subsidence related to climate warming and to determine the relative risk of those regions. We developed a Permafrost Settlement Hazard Index (PSHI) by analyzing anticipated climate warming and the ecological characteristics that regulate thaw subsidence. This analysis provides statistical verification that the discontinuous permafrost region is at more risk of thaw settlement than other regions of Alaska. In addition, it estimates future thaw subsidence risk in Alaska in 2050 using future temperature increases projected by published climate models. Results indicate increased thaw subsidence risk in northern Alaska in 2050, with the greatest increase expected in parts of northwest Alaska. However, in the interior and southwest Alaska, projected disappearance of permafrost from the surface will reduce the risk of thaw subsidence.Key words: Permafrost Settlement Hazard Index, permafrost, thaw subsidence, thaw settlement, thaw settlement risk in Alaska, climate warming RÉSUMÉ. Depuis les années 1960, les températures du pergélisol de l'Alaska ont augmenté, et de nombreuses incidences du réchauffement climatique sont liées au dégel du pergélisol. Le dégel du pergélisol découlant de l'augmentation des températures du pergélisol donne lieu au tassement dû au dégel et à d'importants dommages à l'infrastructure. L'objectif de cette recherche consiste à cerner les régions de l'Alaska qui sont à risque d'affaissement attribuable au dégel résultant du réchauffement climatique, ainsi qu'à déterminer le risque relatif qui existe dans ces régions. Nous avons mis au point un indice du danger de tassement du pergélisol (PSHI) en nous appuyant sur l'analyse du réchauffement climatique prévu et sur les caractéristiques écologiques qui régularisent les affaissements résultant du dégel. Cette analyse a permis d'obtenir la vérification statistique selon laquelle les zones à pergélisol discontinu sont plus à risque de subir du tassement dû au dégel que les autres régions de l'Alaska. Par ailleurs, l'analyse permet d'estimer les risques futurs de tassement dû au dégel en Alaska en 2050 en s'appuyant sur les augmentations de température projetées par les modèles climatiques publiés. Les résultats indiquent que le risque d'affaissement attribuable au dégel sera accru dans le nord de l'Alaska en 2050, et que l'augmentation la plus grande devrait se produire dans le nord-ouest de l'Alaska. Cependant, dans l'intérieur et le sud-ouest de l'Alaska, la disparition projetée du pergélisol de la surface réduira le risque d'affaissement attribuable au dégel.Mots clés : indice du danger de tassement du pergélisol, pergélisol, affaissement attribuable au dégel, tassement dû au dégel, risque de...

Climate change damages to Alaska public infrastructure and the economics of proactive adaptation

“…Many previous studies have recognized the risks of permafrost thaw (20,24,25), and our findings indicate extensive damages from this stressor. However, the largest estimated damages in this analysis resulted from flooding caused by increased precipitation.…”

“…Risks to infrastructure associated with climate change in the Arctic have been studied previously for some environmental stressors. Increased near-surface permafrost thaw associated with climate warming has been widely recognized as a cause of increased infrastructure damage (22)(23)(24)(25). This climatedriven thaw can occur concurrent with thaw induced by natural disturbances, such as wildfire (26,27), and human activities (20,23,27,28), including the construction of infrastructure.…”

“…Permafrost thaw and subsequent ground subsidence, particularly where permafrost is ice-rich, negatively impact buildings, roads, railroads, pipelines, and oil and gas infrastructure (19,20,24,29). In Alaska, Hong et al (25) found the greatest near-term risks of thaw settlement in relatively warm permafrost found in the discontinuous permafrost zone in the interior and longer-term risks in the continuous permafrost zone in the northern part of the state ( Fig. 1 shows a map of permafrost distribution).…”

Thaw Subsidence in Undisturbed Tundra Landscapes, Barrow, Alaska, 1962–2015

“…This is an important driver of periglacial geomorphic processes and can significantly impact human infrastructure (e.g. Nelson et al, 2001;Hong et al, 2014). The magnitude of annual frost heave can be substantially larger than simple expansion of soil porewater upon freezing because water migrates to the freezing fronts to form segregation ice.…”

Assessment of climate change impacts on buildings, structures and infrastructure in the Russian regions on permafrost

“…An increase in permafrost temperatures can greatly reduce the ability of frozen ground to carry loads imposed by structures (Instanes and Anisimov 2008). Moreover, the thawing of ice-rich sediments can result in ground subsidence and uneven surface deformations, which can further undermine the stability of engineered structures (Nelson et al 2001, Hong et al 2014. Although disturbances of the natural environment associated with the construction and support of infrastructure has a pronounced effect on thermal-and hence engineering-properties of permafrost, these disturbances are anticipated and frequently accounted for in proper engineering designs.…”