Commentary: The impact of climate change on landslides in southeastern of high-latitude permafrost regions of China

Citation: Matano F (2016) Commentary: The impact of climate change on landslides in southeastern of high-latitude permafrost regions of China. Front. Earth Sci. 4:22. Permafrost is defined as " ground remaining at or below 0 • C for at least two consecutive years " (van Everdingen, 2005). The definition itself stresses that the permafrost should not be considered as a permanent thermal state, because it is extremely vulnerable to natural and man-induced climatic and environmental changes on different spatial and temporal scales. More in detail, the process of degradation, i.e., the fall in permafrost temperature within it (Dobinski, 2011), may entail several effects on permafrost (lowering of the table, raising of the base, thickening of the active layer) with a resulting reduction of its areal extent up to the complete disappearance with severe consequences on the stability of slopes and infrastructures. In the high-latitude permafrost regions of northern hemisphere, permafrost degradation is occurring under current climate warming (Osterkamp, 2005; Anisimov and Reneva, 2006). One of the most important effects of climate changes in these regions is the progressive modification of the permafrost thermal regime, and hence its physical properties and distribution, beyond the range of variability documented in historical archives (Harris et al., 2009). The mode of permafrost degradation is highly variable, and its consequences on geomorphological conditions and engineering infrastructures depend on the interaction of slope position and aspect, soil and ground type, vegetation cover, hydrology, and ice content (Nelson et al., 2001). Some future projections (Lawrence and Slater, 2005) predict a severe permafrost degradation during twenty-first century with a reduction up to about 90% of the near-surface permafrost total area, excluding ice sheets, in circum-Arctic regions of Eurasia and North America. In the high-latitude permafrost regions of China, climate change is leading to permafrost degradation at a greater extent, as testified by the occurrences of shrinking areas of permafrost, increasing depth of the active layer, rising of lower latitudinal limit of permafrost, and thinning of the seasonal frost (Li et al., 2008; He et al., 2009). Due to the combined influence of climatic warming and increasing anthropogenic activities, further substantial retreat of permafrost is specifically expected on the Qinghai–Tibetan Plateau and in northeastern China during the twenty-first century (Jin et al., 2000). Therefore, permafrost degradation has and will have great influence on engineering construction, water resources and environments in the cold regions of China.