Predicted Vulnerability of Carbon in Permafrost Peatlands With Future Climate Change and Permafrost Thaw in Western Canada
Predicted Vulnerability of Carbon in Permafrost Peatlands With Future Climate Change and Permafrost Thaw in Western Canada
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DOI：
10.1029/2020jg005872
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发表时间：
2021-04
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影响因子：
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通讯作者：
C. Treat;Miriam C. Jones;J. Alder;A. Sannel;P. Camill;S. Frolking
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作者：
C. Treat;Miriam C. Jones;J. Alder;A. Sannel;P. Camill;S. Frolking
高纬度地区的气候变暖正在融化富含碳的永久冻土，这可能会向大气释放碳，从而加剧气候变暖。利用一个长期泥炭地动态耦合模型（全新世泥炭模型，HPM‐Arctic），我们量化了未来气候变暖对加拿大西北部六个具有不同气候和永久冻土历史的地点的潜在碳损失。我们比较了在RCP8.5作为高端约束条件下，2100年由新生产力、活动层分解和新融化的永久冻土泥炭造成的净碳平衡。在2015年至2100年期间，模拟的净碳损失范围为- 3.0 kg cm - 2（净损失）至+0.1 kg cm - 2（净增加）。新融化的永久冻土泥炭的损失占“旧”碳损失的0.2%-25%（中位数：1.6%），这与泥炭在被纳入永久冻土之前在活动层的停留时间、泥炭温度和永久冻土的存在有关。最大的碳损失来自无永久冻土区，而不是永久冻土区。在深度0.2 ~ 1.0 m处碳损失最大。2015年至2100年期间，通过净初级生产力增加到剖面上的新碳抵消了整个站点上旧碳损失的40%至100%。模拟活动层加深和多年冻土融化后的洪水之间的差异导致到2100年净碳损失的差异非常小，说明了当前条件和多年冻土退化历史在控制净碳损失方面的重要作用。
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.