Liu Mengmeng, Prentice Iain Colin, Menviel Laurie, Harrison Sandy P
Department of Life Sciences, Imperial College London, London, UK.
Department of Biological Sciences, Macquarie University, North Ryde, NSW Australia.
Commun Earth Environ. 2022;3(1):196. doi: 10.1038/s43247-022-00536-0. Epub 2022 Aug 30.
There are large uncertainties in the estimation of greenhouse-gas climate feedback. Recent observations do not provide strong constraints because they are short and complicated by human interventions, while model-based estimates differ considerably. Rapid climate changes during the last glacial period (Dansgaard-Oeschger events), observed near-globally, were comparable in both rate and magnitude to current and projected 21st century climate warming and therefore provide a relevant constraint on feedback strength. Here we use these events to quantify the centennial-scale feedback strength of CO, CH and NO by relating global mean temperature changes, simulated by an appropriately forced low-resolution climate model, to the radiative forcing of these greenhouse gases derived from their concentration changes in ice-core records. We derive feedback estimates (95% CI) of 0.155 ± 0.035 W m K for CO, 0.114 ± 0.013 W m K for CH and 0.106 ± 0.026 W m K for NO. This indicates that much lower or higher estimates, particularly some previously published values for CO, are unrealistic.
在温室气体气候反馈的估算中存在很大的不确定性。近期的观测结果并未提供有力的约束，因为观测时间较短且受到人类活动干预的影响而变得复杂，同时基于模型的估算结果差异很大。在全球范围内观测到的末次冰期（丹斯加德-奥施格事件）期间的快速气候变化，其速率和幅度与当前及预计的21世纪气候变暖相当，因此为反馈强度提供了一个相关的约束条件。在这里，我们通过将一个适当强迫的低分辨率气候模型模拟的全球平均温度变化与从冰芯记录中的浓度变化得出的这些温室气体的辐射强迫联系起来，利用这些事件来量化二氧化碳、甲烷和一氧化二氮的百年尺度反馈强度。我们得出的反馈估算值（95%置信区间）为：二氧化碳0.155±0.035W·m⁻²·K⁻¹，甲烷0.114±0.013W·m⁻²·K⁻¹，一氧化二氮0.106±0.026W·m⁻²·K⁻¹。这表明低得多或高得多的估算值，特别是一些先前公布的二氧化碳估算值，是不现实的。
