Impact of climate warming on permafrost changes in the Qinghai-Tibet Plateau

Evaluating the changes in permafrost in the Qinghai-Tibet Plateau (QTP) is important for environmental researches and engineering applications, particularly under climate warming. In this study, the temperature at the top of permafrost (TTOP) and modified Stefan models were employed to explore the spatiotemporal changes in permafrost distribution, permafrost thermal stability, and active layer thickness (ALT) in the historical (1980-2000), current (2001-2020), and future (2021-2100) periods. The average warming trend from the historical to current period was 0.25 degrees C/10 a, and the average permafrost area declined by 8.84% since the historical period. Data from four shared socio-economic pathways (SSP), namely SSP126, SSP245, SSP370, and SSP585, were applied to evaluate future changes. Overall, permafrost would continue to degrade, with approximately 18.80%, 40.81%, 56.96% and 63.28% of permafrost in 2020 disappearing by the end of 21st century under the SSP126, SSP245, SSP370, and SSP585 scenarios, respectively. In addition, permafrost thermal stability would decrease, and under the SSP585 scenario, the percentage of unstable permafrost would increase to 25.58% by the end of the 21st century. Moreover, under the SSP585 scenario, more than half of permafrost region would be covered by an active layer with the thickness exceeding 4 m by the end of the 21st century. The present results can provide a reference basis for environmental protection and engineering risk management.