チベット高原の永久凍土融解と炭素フィードバックの定量的評価に成功（Study Provides Key Evidence of Permafrost Carbon Feedback on Qinghai-Tibet Plateau）

2025-12-17 中国科学院（CAS）

＜関連情報＞

• https://english.cas.cn/newsroom/cas_media/202512/t20251217_1137777.shtml
• https://www.nature.com/articles/s41467-025-66869-4

雪解けの急激な減少がチベット高原の高山草原の生態系の炭素収支に変化をもたらす Thaw slumps alter ecosystem carbon budget in alpine grassland on the Tibetan Plateau

Guanli Jiang,Xinyu Men,Ziteng Fu,Lili Zeng,Weigang Hu,Siru Gao,Luyang Wang,Wenyan Du,Bo Elberling,Yuanhe Yang,Yuzhong Yang & Qingbai Wu
Nature Communications  Published:29 November 2025
DOI:https://doi.org/10.1038/s41467-025-66869-4　An unedited version

Abstract

Retrogressive thaw slumps are an increasingly prevalent form of abrupt permafrost thaw that can reshape ecosystem carbon exchange, yet their impacts remain poorly quantified. Here we show, using chamber measurements of fluxes at five young slumps during the 2024 growing season and a complementary August 2025 survey at five young and two older slumps, that thaw slumps shift alpine grasslands on the interior Tibetan Plateau from a carbon sink toward a carbon source. Exposed, vegetation-free surfaces halve respiration but reduce gross primary productivity by approximately four-fifths, producing a large increase in net CO₂ release relative to undisturbed ground. CH₄ uptake occurs but is too small to offset these losses. Cross-age comparisons show that the CO₂ anomaly diminishes with time, with net exchange trending toward undisturbed levels. Together these results support a single-peak trajectory: expansion of exposed areas drives a source state, followed by partial recovery as vegetation re-establishes. These findings highlight the critical role of thaw slumps in reshaping alpine grassland carbon dynamics and underscore the need to incorporate abrupt thaw and its age dependence into carbon–climate models under ongoing permafrost degradation.