The status and stability of permafrost carbon on the Tibetan Plateau

verfasst von

Cuicui Mu, Benjamin W. Abbott, Adam J. Norris, Mei Mu, Chenyan Fan, Xu Chen, Lin Jia, Ruimin Yang, Tingjun Zhang, Kang Wang, Xiaoqing Peng, Qingbai Wu, Georg Guggenberger, Xiaodong Wu

Abstract

Permafrost regions at high latitudes and altitudes store about half of the Earth's soil organic carbon (SOC). These areas are also some of the most intensely affected by anthropogenic climate change. The Tibetan Plateau or Third Pole (TP) contains most of the world's alpine permafrost, yet there remains substantial uncertainty about the role of this region in regulating the overall permafrost climate feedback. Here, we review the thermal and biogeochemical status of permafrost on the TP, with a particular focus on SOC stocks and vulnerability in the face of climate warming. SOC storage in permafrost-affected regions of the TP is estimated to be 19.0±6.6 Pg to a depth of 2 m. The distribution of this SOC on the TP is strongly associated with active layer thickness, soil moisture, soil texture, topographic position, and thickness of weathered parent material. The mean temperature sensitivity coefficient (Q₁₀) of SOC decomposition is 9.2±7.1 across different soil depths and under different land-cover types, suggesting that carbon on the TP is very vulnerable to climate change. While the TP ecosystem currently is a net carbon sink, climate change will likely increase ecosystem respiration and may weaken or reverse the sink function of this region in the future. Although the TP has less ground ice than high latitude permafrost regions, the rugged topography makes it vulnerable to widespread permafrost collapse and thermo-erosion (thermokarst), which accelerates carbon losses. To reduce uncertainty about SOC quantities and sensitivity to warming, future studies are needed that explain variation in Q₁₀ (e.g. based on SOC source or depositional position) and quantify the role of nutrient availability in regulating SOC dynamics and ecosystem recovery following disturbance. Additionally, as for the high latitude permafrost region, soil moisture and thermokarst formation remain major challenges to predicting the permafrost climate feedback on the TP. We present a conceptual model for of greenhouse gas release from the TP and outline the empirical observations and modeling approaches needed to test it.

Organisationseinheit(en)

Institut für Bodenkunde
AG Bodenchemie

Externe Organisation(en)

Lanzhou University
Chinese Academy of Sciences (CAS)
Southern Marine Science and Engineering Guangdong Laboratory
Brigham Young University
East China Normal University
Graduate University of Chinese Academy of Sciences

Typ

Artikel

Journal

Earth-Science Reviews

Band

211

ISSN

0012-8252

Publikationsdatum

12.2020

Publikationsstatus

Veröffentlicht

ASJC Scopus Sachgebiete

Allgemeine Erdkunde und Planetologie

Ziele für nachhaltige Entwicklung

SDG 13 – Klimaschutzmaßnahmen, SDG 15 – Lebensraum Land

Elektronische Version(en)

https://doi.org/10.1016/j.earscirev.2020.103433 (Zugang: Geschlossen)