Department of Geosciences, University of Oslo, Oslo, Norway.
Department of Biological and Environmental Sciences, University of Gothenburg, Gothenburg, Sweden.
Glob Chang Biol. 2020 Jul;26(7):4119-4133. doi: 10.1111/gcb.15099. Epub 2020 May 5.
The majority of northern peatlands were initiated during the Holocene. Owing to their mass imbalance, they have sequestered huge amounts of carbon in terrestrial ecosystems. Although recent syntheses have filled some knowledge gaps, the extent and remoteness of many peatlands pose challenges to developing reliable regional carbon accumulation estimates from observations. In this work, we employed an individual- and patch-based dynamic global vegetation model (LPJ-GUESS) with peatland and permafrost functionality to quantify long-term carbon accumulation rates in northern peatlands and to assess the effects of historical and projected future climate change on peatland carbon balance. We combined published datasets of peat basal age to form an up-to-date peat inception surface for the pan-Arctic region which we then used to constrain the model. We divided our analysis into two parts, with a focus both on the carbon accumulation changes detected within the observed peatland boundary and at pan-Arctic scale under two contrasting warming scenarios (representative concentration pathway-RCP8.5 and RCP2.6). We found that peatlands continue to act as carbon sinks under both warming scenarios, but their sink capacity will be substantially reduced under the high-warming (RCP8.5) scenario after 2050. Areas where peat production was initially hampered by permafrost and low productivity were found to accumulate more carbon because of the initial warming and moisture-rich environment due to permafrost thaw, higher precipitation and elevated CO levels. On the other hand, we project that areas which will experience reduced precipitation rates and those without permafrost will lose more carbon in the near future, particularly peatlands located in the European region and between 45 and 55°N latitude. Overall, we found that rapid global warming could reduce the carbon sink capacity of the northern peatlands in the coming decades.
大多数北方泥炭地是在全新世形成的。由于它们的质量不平衡，它们在地 球生态系统中封存了大量的碳。尽管最近的综合研究填补了一些知识空白，但许多泥炭地的范围和偏远性给从观测中得出可靠的区域碳积累估计带来了挑战。在这项工作中，我们使用了一个具有泥炭地和永冻层功能的基于个体和斑块的动态全球植被模型（LPJ-GUESS），来量化北方泥炭地的长期碳积累速率，并评估历史和未来气候变 化对泥炭地碳平衡的影响。我们结合了已发表的泥炭基年龄数据集，形成了一个最新的北极地区泥炭形成表面，然后用它来约束模型。我们将分析分为两部分，重点关注在观测到的泥炭地边界内检测到的碳积累变化，以及在两种对比的变暖情景（代表性浓度路径-RCP8.5 和 RCP2.6）下的泛北极尺度上的碳积累变化。我们发现，在两种变暖情景下，泥炭地仍然是碳汇，但在 2050 年后，在高变暖（RCP8.5）情景下，它们的汇能力将大幅减少。由于初始变暖和富水环境（由于永冻层融化、增加的降水和升高的 CO2 水平），最初受到永冻层和低生产力阻碍的泥炭生产地区积累了更多的碳。另一方面，我们预计降水减少的地区和没有永冻层的地区将在不久的将来失去更多的碳，特别是位于欧洲地区和北纬 45 度至 55 度之间的泥炭地。总的来说，我们发现快速的全球变暖可能会降低未来几十年北方泥炭地的碳汇能力。
