Frozen ground is an important element of the global cryosphere and is the largest terrestrial organic carbon pool to a long term. Triggered by climate warming, permafrost degradation may decrease soil organic carbon stability and induce massive carbon loss, thus leading to positive carbon–climate feedback.  

The Third Pole regions are also one of the most sensitive areas responding to the global climate change, and would be turned into a net carbon source under future climate. However, the data regarding the spatial distribution of soil organic carbon (SOC) in the Third Pole regions are still scarce and uncertain. 

By way of integrating the field investigated data and all available information from the studies on SOC stocks in the Third Pole regions published since 2000, Prof. WU Tonghua and his research group from the Northwest Institute of Eco-Environment and Resources (NIEER) of the Chinese Academy of Sciences (CAS), applied machine learning methods to simulate the spatial pattern of the SOC stocks at a 1–km resolution over the Third Pole region, and systematically estimated the SOC storage at a depth interval of 0–3 m in the Third Pole regions. 

The results are of higher resolution and more accurate than previous studies. The estimated SOC storage in the upper 3 m of the soil profile approximates to 46.18 Pg for an area of 3.27 × 10⁶ km2, which included 21.69 Pg and 24.49 Pg for areas of permafrost and seasonally frozen ground, respectively. The datasets provide basic data for Earth system modeling, and reference methods for soil mapping under complex terrain. 

The research has been accepted to publish in Earth System Science Data as an article entitled A 1-km resolution soil organic carbon dataset for frozen ground in the Third Pole. This work was financially supported by the State Key Laboratory of Cryospheric Science (SKLCS–ZZ–2020), the National Natural Science Foundations of China (41690142, 41721091, 41771076, 41961144021, 41671070), and the CAS "Light of West China" Program. 

Contact: 

WU Tonghua 

E-mail: thuawu@lzb.ac.cn 

State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resource, Chinese Academy of Sciences, Lanzhou, China.