Climate warming in high‐latitude regions is thawing carbon‐rich permafrost soils, which can release carbon to the atmosphere and enhance climate warming. Using a coupled model of long‐term peatland dynamics (Holocene Peat Model, HPM‐Arctic), we quantify the potential loss of carbon with future climate warming for six sites with differing climates and permafrost histories in Northwestern Canada. We compared the net carbon balance at 2100 CE resulting from new productivity and the decomposition of active layer and newly thawed permafrost peats under RCP8.5 as a high‐end constraint. Modeled net carbon losses ranged from −3.0 kg C m⁻² (net loss) to +0.1 kg C m⁻² (net gain) between 2015 and 2100. Losses of newly thawed permafrost peat comprised 0.2%–25% (median: 1.6%) of “old” C loss, which were related to the residence time of peat in the active layer before being incorporated into the permafrost, peat temperature, and presence of permafrost. The largest C loss was from the permafrost‐free site, not from permafrost sites. C losses were greatest from depths of 0.2–1.0 m. New C added to the profile through net primary productivity between 2015 and 2100 offset ∼40% to >100% of old C losses across the sites. Differences between modeled active layer deepening and flooding following permafrost thaw resulted in very small differences in net C loss by 2100, illustrating the important role of present‐day conditions and permafrost aggradation history in controlling net C loss.

中文翻译：

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未来气候变化和加拿大西部多年冻土融化对永久冻土泥炭地碳脆弱性的预测

高纬度地区的气候变暖正在解冻富含碳的多年冻土，这些土壤可以将碳释放到大气中并增强气候变暖。使用长期泥炭地动力学的耦合模型（全新世泥炭模型，HPM-Arctic），我们对加拿大西北部六个具有不同气候和多年冻土历史的地点的未来气候变暖，量化了潜在的碳损失。我们比较了RCP8.5作为高端约束条件下新生产力，活性层分解和新解冻的永久冻土泥炭导致的2100 CE的净碳平衡。建模的净碳损失范围为-3.0 kg C m ^-2（净损失）至+0.1 kg C m ^-2（净收益）在2015年至2100年之间。新融化的永久冻土泥炭的损失占“旧” C损失的0.2％–25％（中位数：1.6％），这与泥炭在掺入之前在活性层中的停留时间有关。进入永久冻土，泥炭温度和永久冻土的存在。最大的碳损失来自无多年冻土的地点，而不是来自永冻土的地点。在0.2–1.0 m的深度，C损失最大。通过2015年至2100年之间的净初级生产力，新碳增加了分布，抵消了各地旧碳损失的40％至100％以上。到2100年，模拟的活动层加深和多年冻土融化后的洪水之间的差异导致净碳损失的差异很小，这说明了当前条件和多年冻土凝集历史在控制净碳损失中的重要作用。