Prediction of permafrost distribution on the Qinghai-Tibet Plateau in the next 50 and 100 years

Intergovernmental Panel on Climate Change (IPCC) in 2001 reported that the Earth air temperature would rise by 1.4–5.8°C and 2.5°C on average by the year 2100. China regional climate model results also showed that the air temperature on the Qinghai-Tibet Plateau (QTP) would increase by 2.2–2.6°C in the next 50 years. A numerical permafrost model was developed to predict the changes of permafrost distribution on the QTP over the next 50 and 100 years under the two climatic warming scenarios, i.e. 0.02°C/a, the lower value of IPCC’s estimation, and 0.052°C/a, the higher value predicted by Qin et al. Simulation results show that (i) in the case of 0.02°C/a air-temperature rise, permafrost area on the QTP will shrink about 8.8% in the next 50 years, and high temperature permafrost with mean annual ground temperature (MAGT) higher than-0.11°C may turn into seasonal frozen soils. In the next 100 years, permafrost with MAGT higher than-0.5°C will disappear and the permafrost area will shrink up to 13.4%. (ii) In the case of 0.052°C/a air-temperature rise, permafrost area on the QTP will reduce about 13.5% after 50 years. More remarkable degradation will take place after 100 years, and permafrost area will reduce about 46%. Permafrost with MAGT higher than-2°C will turn into seasonal frozen soils and even unfrozen soils.