Response of peat-rich permafrost to a warming climate on the northeast Tibetan Plateau

Abstract

Permafrost degradation leads to the release of organic carbon to the atmosphere, and in turn, affects climate change. The amount of organic carbon released to the atmosphere depends on the thawing rate of peat-rich permafrost. However, the exact mechanism of peat-rich permafrost thawing is still unclear. Here we choose two locations on the northeast Tibetan Plateau: the peat-rich EBoTA (“peatland”) site, and the mineral-rich PT5 (“mineral”) site. We use the Geophysical Institute Permafrost Laboratory model to reveal the response of permafrost to warming climate from 1850 to 2100 applying different shared socioeconomic pathways (SSPs). Monthly soil temperature increased during the historical and future periods at both sites, but a slower trend is evident at the peatland site relative to the mineral site. Seasonally, the warming trend is faster in winter than that in summer at both sites. Active layer deepening at the mineral site is 3–12 times that of the peatland site. In addition, permafrost will persist until 2100 in all but one of the SSPs at the peatland site. At the mineral site, all permafrost will degrade to seasonally frozen ground, with only taliks remaining for all future scenarios. These changes indicated a slower response of peat-rich permafrost to climate change, due to peat's low thermal conductivity and high soil moisture. These results could be useful in permafrost carbon studies.