TY - JOUR

T1 - The status and stability of permafrost carbon on the Tibetan Plateau

AU - Mu, Cuicui

AU - Abbott, Benjamin W.

AU - Norris, Adam J.

AU - Mu, Mei

AU - Fan, Chenyan

AU - Chen, Xu

AU - Jia, Lin

AU - Yang, Ruimin

AU - Zhang, Tingjun

AU - Wang, Kang

AU - Peng, Xiaoqing

AU - Wu, Qingbai

AU - Guggenberger, Georg

AU - Wu, Xiaodong

N1 - Funding Information: This work was supported by the second Tibetan Plateau Scientific Expedition and Research Program (STEP) ( 2019QZKK0605 ), the foundation of State Key Laboratory of Cryospheric Science ( SKLCS-ZZ-2020 ), the National Natural Science Foundation of China ( 41721091 , 41941015 , 41871050 ), the National Key Research and Development Program of China ( 2019YFA0607003 , 2019YFC1509104 ), and the Open Foundations of the State Key Laboratory of Frozen Soil Engineering (Grant No. SKLFSE201705 ). B.W. Abbott and A.J. Norris were supported by the U.S. National Science Foundation award number 1916565 , and G. Guggenberger acknowledges support by the German Research Foundation (DFG) ( GRK 2309/1 ).

PY - 2020/12

Y1 - 2020/12

N2 - 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.

AB - 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.

KW - greenhouse gas

KW - permafrost

KW - Soil organic carbon

KW - temperature sensitivity

KW - thaw slumps, thermokarst lakes

KW - Tibetan Plateau

UR - http://www.scopus.com/inward/record.url?scp=85096183926&partnerID=8YFLogxK

U2 - 10.1016/j.earscirev.2020.103433

DO - 10.1016/j.earscirev.2020.103433

M3 - Article

AN - SCOPUS:85096183926

VL - 211

JO - Earth-Science Reviews

JF - Earth-Science Reviews

SN - 0012-8252

M1 - 103433

ER -