Arctic permafrost landscapes in transition: towards an integrated Earth system approach

Abstract

Permafrost science and engineering are of vital importance for northern development and climate adaptation given that buildings, roads and other infrastructure in many parts of the Arctic depend on permafrost stability. Permafrost also has wide-ranging effects on other features of the Arctic environment including geomorphology, biogeochemical fluxes, tundra plant and animal ecology, and the functioning of lake, river and coastal marine ecosystems. This review presents an Earth system perspective on permafrost landscapes as an approach towards integration across disciplines. The permafrost system can be described by a three-layer conceptual model, with an upper buffer layer that contains vegetation or infrastructure. Snow and liquid water strongly affect the thermal properties and stability of these layers and their associated interfaces, resulting in critical times and places for accelerated degradation of permafrost and for exchanges of mass and heat with the hydrosphere and atmosphere. Northern permafrost landscapes are now in rapid transition as a result of climate warming and socioeconomic development, which is affecting their ability to provide geosystem and ecosystem services. The Earth system approach provides a framework for identifying linkages, thresholds and feedbacks among system components, including human systems, and for the development of management strategies to cope with permafrost change.

New insights into the environmental factors controlling the ground thermal regime across the Northern Hemisphere: a comparison between permafrost and non-permafrost areas

“…Permafrost temperature and the depth of the overlying seasonally thawed layer, i.e. active layer, are key components of the ground thermal regime that govern various geomorphological and ecological processes (Frauenfeld et al, 2007;, as well as human activity, in permafrost regions (Callaghan et al, 2011;Vincent et al, 2017;Hjort et al, 2018). Outside the permafrost domain, extensive regions undergo seasonal freezing, which in itself affects many aspects of natural and human activities (e.g.…”

Remote sensing evaluation of High Arctic wetland depletion following permafrost disturbance by thermo-erosion gullying processes

“…Their sustainability relies on the integrity of perennially frozen ground that provides permanent or seasonal water supply and prevents vertical percolation (Woo 2012;Natali et al 2015). However, observations over the last decades indicate that permafrost thawing and active layer deepening, closely related to the ratio of ground ice content and ground thermal conditions (Burn and Kokelj 2009;Kanevskiy et al 2013;Rudy et al 2017), have intensified with increasing temperatures (Romanovsky et al 2010;Rowland et al 2010;Liljedahl et al 2016;Vincent et al 2017). The resulting changes in hydrological conditions can have profound consequences for biochemical cycles and ecological communities (see Wrona et al 2016 for a review).…”

Periphytic diatom community structure in thermokarst ecosystems of Nunavik (Québec, Canada)

“…The impacts of recent climate warming on northern circumpolar landscapes have already included shrub expansion and permafrost degradation through thawing and erosion (e.g., Romanovsky et al 2010;Myers-Smith et al 2011). Changes in permafrost distribution and stability can also affect northern communities by modifying infrastructure durability as well as water quantity and quality through the ecosystem services provided by freshwater landscapes (Rowland et al 2010;Vincent et al 2017).…”

“…The degradation of palsas and lithalsas results in the formation of thermokarst (thaw) ponds and lakes (hereafter referred to as lakes), which are among the most abundant aquatic ecosystems in circumpolar regions ). These thermokarst ecosystems are critical places of rapid changes in energy and matter fluxes (Vonk et al 2015;Vincent et al 2017 and references therein) that transfer large quantities of organic carbon to the atmosphere in the form of greenhouse gases such as CO 2 and CH 4 (Walter et al 2006;Laurion et al 2010), although this may be offset by bacterial consumption processes (Crevecoeur et al 2015). As climate is the main driver of vegetation and aquatic ecosystem dynamics in these systems, increasing air temperatures can have a strong impact on lake spatiotemporal evolution and vegetation densification (Fallu and Pienitz 1999;Bouchard et al 2014;Beck et al 2015).…”