A leaky endeavor Considerable amounts of the greenhouse gas methane leak from the U.S. oil and natural gas supply chain. Alvarez et al. reassessed the magnitude of this leakage and found that in 2015, supply chain emissions were ∼60% higher than the U.S. Environmental Protection Agency inventory estimate. They suggest that this discrepancy exists because current inventory methods miss emissions that occur during abnormal operating conditions. These data, and the methodology used to obtain them, could improve and verify international inventories of greenhouse gases and provide a better understanding of mitigation efforts outlined by the Paris Agreement. Science, this issue p. 186 Methane leakage from the U.S. oil and natural gas supply chain is much greater than previously estimated. Methane emissions from the U.S. oil and natural gas supply chain were estimated by using ground-based, facility-scale measurements and validated with aircraft observations in areas accounting for ~30% of U.S. gas production. When scaled up nationally, our facility-based estimate of 2015 supply chain emissions is 13 ± 2 teragrams per year, equivalent to 2.3% of gross U.S. gas production. This value is ~60% higher than the U.S. Environmental Protection Agency inventory estimate, likely because existing inventory methods miss emissions released during abnormal operating conditions. Methane emissions of this magnitude, per unit of natural gas consumed, produce radiative forcing over a 20-year time horizon comparable to the CO2 from natural gas combustion. Substantial emission reductions are feasible through rapid detection of the root causes of high emissions and deployment of less failure-prone systems.

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美国石油和天然气供应链的甲烷排放评估

泄漏的努力 大量温室气体甲烷从美国石油和天然气供应链泄漏。阿尔瓦雷斯等人。重新评估了这种泄漏的严重程度，发现 2015 年，供应链排放量比美国环境保护署的清单估计高出约 60%。他们认为存在这种差异是因为当前的清单方法错过了异常操作条件下发生的排放。这些数据以及用于获取它们的方法可以改进和验证国际温室气体清单，并更好地了解《巴黎协定》概述的缓解工作。科学，这个问题 p。186 美国石油和天然气供应链的甲烷泄漏比之前估计的要大得多。美国的甲烷排放量 石油和天然气供应链是通过使用地面、设施规模的测量来估计的，并在占美国天然气产量约 30% 的地区通过飞机观测进行验证。在全国范围内扩大规模时，我们基于设施的 2015 年供应链排放估计为每年 13 ± 2 太克，相当于美国天然气总产量的 2.3%。该值比美国环境保护署的清单估计值高约 60%，可能是因为现有的清单方法错过了异常操作条件下释放的排放。如此数量级的甲烷排放，每单位消耗的天然气，在 20 年的时间范围内产生的辐射强迫与天然气燃烧产生的 CO2 相当。