The social cost of methane (SC-CH₄) measures the economic loss of welfare caused by emitting one tonne of methane into the atmosphere. This valuation may in turn be used in cost–benefit analyses or to inform climate policies^1,2,3. However, current SC-CH₄ estimates have not included key scientific findings and observational constraints. Here we estimate the SC-CH₄ by incorporating the recent upward revision of 25 per cent to calculations of the radiative forcing of methane⁴, combined with calibrated reduced-form global climate models and an ensemble of integrated assessment models (IAMs). Our multi-model mean estimate for the SC-CH₄ is US$933 per tonne of CH₄ (5–95 per cent range, US$471–1,570 per tonne of CH₄) under a high-emissions scenario (Representative Concentration Pathway (RCP) 8.5), a 22 per cent decrease compared to estimates based on the climate uncertainty framework used by the US federal government⁵. Our ninety-fifth percentile estimate is 51 per cent lower than the corresponding figure from the US framework. Under a low-emissions scenario (RCP 2.6), our multi-model mean decreases to US$710 per tonne of CH₄. Tightened equilibrium climate sensitivity estimates paired with the effect of previously neglected relationships between uncertain parameters of the climate model lower these estimates. We also show that our SC-CH₄ estimates are sensitive to model combinations; for example, within one IAM, different methane cycle sub-models can induce variations of approximately 20 per cent in the estimated SC-CH₄. But switching IAMs can more than double the estimated SC-CH₄. Extending our results to account for societal concerns about equity produces SC-CH₄ estimates that differ by more than an order of magnitude between low- and high-income regions. Our central equity-weighted estimate for the USA increases to US$8,290 per tonne of CH₄ whereas our estimate for sub-Saharan Africa decreases to US$134 per tonne of CH₄.

甲烷的社会成本 (SC-CH ₄ ) 衡量的是向大气排放一吨甲烷所造成的福利经济损失。该估值可反过来用于成本效益分析或为气候政策提供信息^1,2,3。然而，目前的 SC-CH ₄估计值并未包括关键的科学发现和观测限制。在这里，我们通过将最近向上修正的 25% 与甲烷⁴辐射强迫的计算结合起来，结合校准的简化形式的全球气候模型和综合评估模型 (IAM)来估计 SC-CH _{4 。我们对 SC-CH 4}的多模型平均估计为每吨 CH ₄ 933 美元_{（5-95% 的范围，每吨 CH 4} 471-1,570 美元）在高排放情景（代表性浓度路径 (RCP) 8.5）下，与基于气候不确定性框架使用的估算值相比下降了 22%美国联邦政府⁵．我们对百分之九十五的估计比美国框架中的相应数字低 51%。_{在低排放情景 (RCP 2.6) 下，我们的多模型平均值降至每吨 CH 4} 710 美元。收紧的平衡气候敏感性估计与先前被忽视的气候模型不确定参数之间的关系的影响相结合，降低了这些估计。我们还表明我们的 SC-CH ₄估计对模型组合很敏感；_{例如，在一个 IAM 中，不同的甲烷循环子模型可以在估计的 SC-CH 4}中引起大约 20% 的变化。_{但是切换 IAM 可以使估计的 SC-CH 4}增加一倍以上。将我们的结果扩展到考虑社会对公平的担忧，得出的 SC-CH ₄估计值在低收入和高收入地区之间的差异超过一个数量级。_{我们对美国的中央股票加权估值上升至每吨 CH 4} 8,290 美元，而我们对撒哈拉以南非洲地区的估值下降至每吨 CH ₄ 134 美元。