Peatland rewetting has been proposed as a vital climate change mitigation tool to reduce greenhouse gas emissions and to generate suitable conditions for the return of carbon (C) sequestration. In this study, we present annual C balances for a 5-year period at a rewetted peatland in Ireland (rewetted at the start of the study) and compare the results with an adjacent drained area (represents business-as-usual). Hydrological modelling of the 230-hectare site was carried out to determine the likely ecotopes (vegetation communities) that will develop post-rewetting and was used to inform a radiative forcing modelling exercise to determine the climate impacts of rewetting this peatland under five high-priority scenarios (SSP1-1.9, SS1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5). The drained area (marginal ecotope) was a net C source throughout the study and emitted 157 ± 25.5 g C m⁻² year⁻¹. In contrast, the rewetted area (sub-central ecotope) was a net C sink of 78.0 ± 37.6 g C m⁻² year⁻¹, despite relatively large annual methane emissions post-rewetting (average 19.3 ± 5.2 g C m⁻² year⁻¹). Hydrological modelling predicted the development of three key ecotopes at the site, with the sub-central ecotope predicted to cover 24% of the site, the sub-marginal predicted to cover 59% and the marginal predicted to cover 16%. Using these areal estimates, our radiative forcing modelling projects that under the SSP1-1.9 scenario, the site will have a warming effect on the climate until 2085 but will then have a strong cooling impact. In contrast, our modelling exercise shows that the site will never have a cooling impact under the SSP5-8.5 scenario. Our results confirm the importance of rapid rewetting of drained peatland sites to (a) achieve strong C emissions reductions, (b) establish optimal conditions for C sequestration and (c) set the site on a climate cooling trajectory.

中文翻译：

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重新润湿爱尔兰高地沼泽的碳和气候影响

泥炭地再润湿已被提议作为一种重要的气候变化缓解工具，以减少温室气体排放并为碳 (C) 封存的返回创造合适的条件。在本研究中，我们展示了爱尔兰再湿润泥炭地（在研究开始时再湿润）5 年期间的年度碳平衡，并将结果与​​邻近的排水区（代表一切照旧）进行比较。对占地 230 公顷的场地进行了水文建模，以确定可能会在再湿润后发展的生态区（植被群落），并用于为辐射强迫模拟活动提供信息，以确定在五个高优先级下再湿润该泥炭地的气候影响场景（SSP1-1.9、SS1-2.6、SSP2-4.5、SSP3-7.0 和 SSP5-8.5）。⁻² 年⁻¹。相比之下，再湿润区（次中央生态区）的净碳汇为 78.0 ± 37.6 g C m ⁻² 年⁻¹，尽管再湿润后的年甲烷排放量相对较大（平均 19.3 ± 5.2 g C m ⁻² 年） ⁻¹). 水文模型预测了该地点三个关键生态区的发展情况，次中心生态区预计将覆盖该地点的 24%，次边缘预计将覆盖 59%，边缘预计将覆盖 16%。使用这些区域估计，我们的辐射强迫模型预测，在 SSP1-1.9 情景下，该地点将对气候产生变暖影响，直到 2085 年，但随后将产生强烈的降温影响。相比之下，我们的建模练习表明，在 SSP5-8.5 情景下，该站点永远不会产生冷却影响。我们的结果证实了排水泥炭地快速再湿润对于 (a) 实现强劲的 C 排放减少，(b) 建立 C 封存的最佳条件和 (c) 将场地设置在气候冷却轨道上的重要性。