Significant feedbacks of wetland methane release on climate change and the causes of their uncertainty
Significant feedbacks of wetland methane release on climate change and the causes of their uncertainty
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DOI：
10.1088/1748-9326/ab2726
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发表时间：
2019-08-01
影响因子：
6.7
通讯作者：
Wiltshire, A.
中科院分区：
文献类型：
--
作者：
Gedney, N.;Huntingford, C.;Wiltshire, A.
来自湿地的排放是大气温室气体（GHG）甲烷（CH 4）的单一最大来源。这可能会在气候变暖时增加，导致对气候变化的积极反馈。这是第一次，我们扩大了互动湿地甲烷排放计划，包括最近量化的，重要的过程中，通过热带树木的甲烷转移。我们约束的参数化使用多站点通量研究，地球化学和反演模型。这为当代大规模湿地排放及其对温度的响应提供了一个估计和不确定性范围。为了评估未来湿地CH 4排放对气候反馈的潜力，这些计划被迫使用“模式缩放”系统模拟气候变化，该系统将改变大气辐射强迫与气象变化联系起来。我们对34个地球系统模型在不同的人为温室气体排放情景（RCP）下进行了多个模拟。我们对预测湿地CH 4-气候反馈的不确定性原因进行了详细评估。尽管应用的限制，湿地甲烷排放量建模的不确定性更大，从预测的气候蔓延（在一个给定的RCP）。有限的知识，当代全球湿地排放量限制模型校准，湿地参数化的不确定性产生的最大的个人原因。湿地反馈在21世纪导致额外的温度增加0.6%至5.5%，对气候的反馈范围为0.01至0.11 Wm（-2）K（-1）。在一个模拟中，湿地CH 4排放放大了大气CH 4的增加，最多可达25.4%，并减少了剩余的允许人为排放，以维持RCP2.6温度阈值的平均8.0%。
Emissions from wetlands are the single largest source of the atmospheric greenhouse gas (GHG) methane (CH4). This may increase in a warming climate, leading to a positive feedback on climate change. For the first time, we extend interactive wetland CH4 emissions schemes to include the recently quantified, significant process of CH4 transfer through tropical trees. We constrain the parameterisations using a multi-site flux study, and biogeochemical and inversion models. This provides an estimate and uncertainty range in contemporary, large-scale wetland emissions and their response to temperature. To assess the potential for future wetland CH4 emissions to feedback on climate, the schemes are forced with simulated climate change using a 'pattern-scaling' system, which links altered atmospheric radiative forcing to meteorology changes. We perform multiple simulations emulating 34 Earth System Models over different anthropogenic GHG emissions scenarios (RCPs). We provide a detailed assessment of the causes of uncertainty in predicting wetland CH4-climate feedback. Despite the constraints applied, uncertainty from wetland CH4 emission modelling is greater that from projected climate spread (under a given RCP). Limited knowledge of contemporary global wetland emissions restricts model calibration, producing the largest individual cause of wetland parameterisation uncertainty. Wetland feedback causes an additional temperature increase between 0.6% and 5.5% over the 21st century, with a feedback on climate ranging from 0.01 to 0.11 Wm(-2)K(-1). Wetland CH4 emissions amplify atmospheric CH4 increases by up to a further possible 25.4% in one simulation, and reduce remaining allowed anthropogenic emissions to maintain the RCP2.6 temperature threshold by 8.0% on average.