A New Method of Diagnosing the Historical and Projected Changes in Permafrost on the Tibetan Plateau

Abstract The Tibetan Plateau (TP) is the largest permafrost distribution zone at high‐altitude in the mid‐latitude region. Climate change has caused significant permafrost degradation on the TP, which has important impacts for the eco‐hydrological processes. In this study, the frost number is utiliz...

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Bibliographic Details
Published in:Earth's Future
Main Authors: Hu Li, Xiaoduo Pan, Rana Muhammad Ali Washakh, Xiaowei Nie
Format: Article in Journal/Newspaper
Language:English
Published: Wiley 2024
Subjects:
Tibetan Plateau
permafrost
CMIP6
frost number model
future scenario
climate change
Environmental sciences
GE1-350
Ecology
QH540-549.5
Online Access:https://doi.org/10.1029/2023EF003897
https://doaj.org/article/1350c14d5aa3414e8b74d8296b820824
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Summary:Abstract The Tibetan Plateau (TP) is the largest permafrost distribution zone at high‐altitude in the mid‐latitude region. Climate change has caused significant permafrost degradation on the TP, which has important impacts for the eco‐hydrological processes. In this study, the frost number is utilized to calculate the frost number (F) based on the air freezing/thawing index obtained from the downscaled Coupled Model Intercomparison Project Phase 6 (CMIP6) data sets. A novel method is proposed to determine the frost number threshold (Ft) for diagnosing permafrost distribution. Then the simulated permafrost distribution maps are compared with the existing permafrost distribution map, employing the Kappa coefficient as the measure of classification accuracy to identify the optimal Ft. Finally, the permafrost distribution on the TP under different Shared Socio‐economic Pathways (SSP) scenarios are diagnosed with the optimal Ft. Simulation results demonstrate that across all scenarios, the rates of permafrost degradation during the mid‐future period (2040–2060) remain comparable to those observed in the baseline period (2000), ranging from 33% ± 3% to 53% ± 4%. Conversely, during the far‐future (2080–2099), the permafrost degradation rates display significant variation across different scenarios, ranging from 37% ± 4% to 96% ± 3%. The profound impacts of permafrost degradation on the TP are reflected in decreasing trends in soil moisture and runoff, as well as a slower increasing trend in Normalized Difference Vegetation Index (NDVI) compared to other regions, indicating negative impacts on vegetation growth.

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