Qinghai‐Tibet Plateau Permafrost at Risk in the Late 21st Century

• Published in: Earth's future Vol. 10; no. 6
• Main Authors: Zhang, Guofei, Nan, Zhuotong, Hu, Na, Yin, Ziyun, Zhao, Lin, Cheng, Guodong, Mu, Cuicui
• Format: Journal Article
• Language: English
• Published: Bognor Regis John Wiley & Sons, Inc 01.06.2022
• Subjects: 21st century; Active layer; Alpine climates; Atmosphere; Carbon budget; Climate change; CMIP6; Datasets; Frozen ground; future prediction; Global warming; Hydrologic processes; Hydrology; Ice; Land surface models; numerical simulation; Permafrost; Permafrost distribution; Qinghai‐Tibet Plateau; Radiation; Soil degradation; Temperature; Thickness; Three Rivers Source region; China
• ISSN: 2328-4277; 2328-4277
• DOI: 10.1029/2022EF002652

Global warming has led to permafrost degradation worldwide. The Qinghai‐Tibet Plateau (QTP) hosts most of the world's alpine permafrost, yet its impending changes remain largely unclear, thereby affecting regional hydrological and ecological processes and the global carbon budget. By employing a land surface model adapted to simulate frozen ground, and using state‐of‐the‐art multi‐model and multi‐scenario data from the Coupled Model Intercomparison Project Phase 6, changes in permafrost distribution and its thermal regimes on the QTP are systematically predicted under various shared socioeconomic pathways (SSPs). Projections for SSP2‐4.5, SSP3‐7.0, and SSP5‐8.5 show that most of the continuous permafrost region of the QTP will persist through 2050. Much of the permafrost is likely to degrade in the late 21st century, with projected area losses of 44 ± 4%, 59 ± 5%, and 71 ± 7%, respectively, by 2100. In particular, the Three Rivers Source region in the central eastern part of the QTP is a key area of permafrost degradation, where permafrost is most vulnerable and degradation occurs earliest. The mean annual ground temperature of QTP permafrost will increase by 0.8 ± 0.2°C, 2.0 ± 0.3°C, and 2.6 ± 0.3°C under SSP2‐4.5, SSP3‐7.0, and SSP5‐8.5, respectively, and the active layer thickness will increase by 0.7 ± 0.1 m, 1.5 ± 0.3 m, and 3.0 ± 1.0 m, respectively. The surviving permafrost under SSP3‐7.0 and SSP5‐8.5 will be thermally unstable, which is a clear warning sign of complete disappearance. The analysis of permafrost sensitivity to climate change signifies that alpine permafrost on the QTP has low resilience to climate change, in contrast to permafrost in pan‐Artic high latitudes. Plain Language Summary The Qinghai‐Tibet Plateau (QTP) contains the largest area of alpine permafrost on Earth. It has been observed that permafrost on the QTP has been substantially degraded due to drastic climate warming. Existing prediction studies have consistently concluded that QTP permafrost will degrade with climate warming, but there is no consensus on the extent of degradation. To date, there have been no studies employing land surface models to predict future changes in QTP permafrost based on the latest Coupled Model Intercomparison Project Phase 6 data. Here, based on climate outputs from multi‐model projections under the Shared Socioeconomic Pathways, we used a land surface model adapted to frozen ground modeling to simulate future changes in permafrost distribution and its thermal regimes on the QTP, and evaluated permafrost responses to various scenarios of future climate change. The results show that much of the QTP permafrost will degrade in the late 21st century, and the Three Rivers Source region is a key area of future permafrost degradation, where permafrost is most vulnerable and degradation will occur earliest. Our results will help improve understanding of future changes in QTP permafrost as the climate warms and provide scientific support for climate change adaptation policies and sustainable regional development. Key Points By 2100, permafrost area will shrink by 44 ± 4%, 59 ± 5%, and 71 ± 7% for SSP2‐4.5, SSP3‐7.0 and SSP5‐8.5, respectively Permafrost in the Three Rivers Source region is the most vulnerable and begins to degrade the earliest Under SSP3‐7.0 and SSP5‐8.5, the surviving permafrost becomes unstable and is on the verge of disappearing by 2100