A permafrost warming in a cooling Antarctica?

Abstract

The magnitude and even direction of recent Antarctic climate change is still debated because the paucity of long and complete instrumental data records. While along Antarctic Peninsula a strong warming coupled with large retreat of glaciers occurred, in continental Antarctica a cooling was recently detected. Here, the first existing permafrost data set longer than 10 years recorded in continental Antarctica is presented. Since 1997 summer ground surface temperature showed a strong warming trend (0.31°C per year) although the air temperature was almost stable. The summer ground surface temperature increase seemed to be influenced mainly by the increase of the total summer radiation as confirmed also by the increase of the summer thawing degree days. In the same period the active layer exhibited a thickening trend (1 cm per year) comparable with the thickening rates observed in several Arctic locations where air warming occurred. At all the investigated depths permafrost exhibited an increase of mean annual temperature of approximately 0.1°C per year. The dichotomy between active layer thickness and air temperature trends can produce large unexepected and unmodelled impacts on ecosystems and CO 2 balance.

The origins of Antarctic rock glaciers: periglacial or glacial features?

“…In this area, despite the stability of both mean annual air temperature (MAAT) and summer air temperature, the active layer thickness (ALT) is increasing at a rate up to 1 cm yr -1 (Guglielmin and Cannone, 2012), which is comparable with the higher rates recorded in the Arctic (Callaghan et al, 2010;Christiansen et al, 2010).…”

Response of seasonal soil freeze depth to climate change across China

“…Due to global climate warming, significant efforts have been devoted to permafrost research, such as permafrost variations on the hemispheric-scale permafrost temperature changes (Wu and Zhang, 2008;Guglielmin and Cannone, 2012;Streletskiy et al, 2014;Wu et al, 2015), permafrost degradation (Jorgenson et al, 2006;Ravanel et al, 2010;Sannel and Kuhry, 2011;Streletskiy et al, 2015a;Park et al, 2016), hydrological processes in permafrost regions Wang et al, 2009;Park et al, 2013;Streletskiy et al, 2015b;Ford and Frauenfeld, 2016), feedbacks to climate change (Schuur et al, 2008;Park et al, 2015;Abbott et al, 2016), and other aspects. The increasing thickness of the active layer has been indicated by many observations in permafrost regions at high latitudes and altitudes (Brown et al, 2000;Frauenfeld et al, 2004;Zhang et al, 2005;Fyodorov-Davydov et al, 2008;Wu et al, 2010;Zhao et al, 2010;Callaghan et al, 2011;Liu et al, 2014a, b;Stocker et al, 2014).…”

Advances in permafrost and periglacial research in Antarctica: A review

“…sorting, cryoturbation). Moreover, active layer thickening can occur even in areas where mean annual air temperature is decreasing like Victoria Land (Guglielmin and Cannone, 2011). Finally, climatic change can influence also the sublimation rate, with the consequent increase the thickness of the "dry permafrost" in the most arid parts Antarctica and the potential loss of natural climate terrestrial archives (Swanger and Marchant, 2007).…”

“…Up to now the only dataset with more than 10 years of data of active layer temperatures and thickness is the data set of Boulder Clay (close to the Italian Antartic station, northern Victoria Land) where a strong warming trend of the summer Ground Surface Temperature (GST; 0.31°C per year) was detected between 1997 and 2009 despite the fact that the air temperature was almost stable during the same period (Guglielmin and Cannone, 2011). This discrepancy between GST and air temperature seemed to be due to the increase of the total summer radiation, as confirmed also by the increase of the summer thawing degree days.…”