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

Intergovernmental Panel on Climate Change (IPCCd) in 2001 reported that the Earth air temperature would rise by 1.4-5.8 degrees C and 2.5 degrees 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 degrees 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 56 and 100 years under the two climatic warming scenarios, i.e. 0.02 degrees C/a, the lower value of IPCC's estimation, and 0.052 degrees C/a, the higher value predicted by Qin et al. Simulation results show that (i) in the case of 0.02 degrees 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 degrees C may turn into seasonal frozen soils. In the next 100 years, permafrost with MAGT higher than -0.5 degrees C will disappear and the permafrost area will shrink up to 13.4%. (ii) In the case of 0.052 degrees 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 degrees C will turn into seasonal frozen soils and even unfrozen soils.