Permafrost_carbon_Supplementary_Data.xlsx

The datasets presented are primarily data syntheses from the literature of carbon stocks and fluxes from the northern permafrost region from the Last Glacial Maximum (LGM; 21,000 years before present) to present. Deglacial carbon stocks were estimated from the northern permafrost zone by subtracting estimates of carbon losses from LGM values of different systems (e.g., shelf/subsea, thermokarst lakes, peatland, yedoma, subglacial) reported in the literature. Values reported for present day were compiled from the literature. Carbon losses from permafrost thaw are reported as petagrams CO₂-C (fraction of carbon from CO₂) per degree Celsius (Pg CO₂-C ºC^-1), petagrams CH₄-C (fraction of carbon from CH4) per degree Celsius, and total petagrams carbon per degree Celsius (Pg CH4-C ºC^-1) where possible. Where values were not reported as Pg C ºC^-1 in the literature, fluxes were divided by the change in temperature for the time period using deglacial temperature changes from the literature.

本次发布的数据集主要整合了末次冰盛期（Last Glacial Maximum，LGM；距今21000年）至今北半球永久冻土区域的碳储量与碳通量相关文献综合数据。冰消期碳储量的估算方法为：从文献报道的不同系统（陆架/海底、热喀斯特湖、泥炭地、冰楔砂质冻土（yedoma）、冰下环境）的末次冰盛期碳储量数值中，扣除对应碳损失估算值，进而得到北半球永久冻土带的冰消期碳储量。当前碳储量数值则通过整理相关文献汇编得到。永久冻土融化引发的碳损失采用以下单位报道：每摄氏度对应的二氧化碳结合态碳拍克数（Pg CO₂-C ·℃⁻¹，即碳组分中来自CO₂的占比）、每摄氏度对应的甲烷结合态碳拍克数（Pg CH₄-C ·℃⁻¹，即碳组分中来自CH₄的占比），条件允许时还会报道每摄氏度对应的总碳拍克数。若文献中未以Pg C ·℃⁻¹为单位报道相关数值，则采用文献中给出的冰消期温度变化数据，将碳通量除以对应时段的温度变化量进行单位换算。