Anthropogenic emissions of methane in the United States
Anthropogenic emissions of methane in the United States
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DOI：
10.1073/pnas.1314392110
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发表时间：
2013-12-10
影响因子：
11.1
通讯作者：
Sweeney, Colm
中科院分区：
文献类型：
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作者：
Miller, Scot M.;Wofsy, Steven C.;Sweeney, Colm
本研究通过结合全面的大气甲烷观测、广泛的空间数据集和高分辨率大气传输模型，定量估计了美国人为甲烷源的空间分布。结果显示，美国环境保护署 (EPA) 和全球大气研究排放数据库的当前清单分别低估了全国甲烷排放量，分别为 1.5 倍和 1.7 倍。我们的研究表明，反刍动物和粪便造成的排放量高达现有清单的两倍。此外，甲烷来源估计的差异在美国中南部尤其明显，我们发现那里的总排放量大约是大多数清单中的 2.7 倍，占全国排放量的 24 +/- 3%。我们的排放通量的空间模式和观察到的甲烷-丙烷相关性表明，化石燃料的开采和精炼是美国中南部的主要贡献者 (45 +/- 13%)。这一结果表明，化石燃料开采和加工造成的区域甲烷排放量可能比 EDGAR（最全面的全球甲烷清单）高 4.9 +/- 2.6 倍。这些结果使人对美国环保署最近将全国天然气排放量预估下调 25-30% 的决定产生了怀疑。总体而言，我们得出的结论是，与畜牧业和化石燃料行业相关的甲烷排放对温室气体的影响比现有清单显示的要大。
This study quantitatively estimates the spatial distribution of anthropogenic methane sources in the United States by combining comprehensive atmospheric methane observations, extensive spatial datasets, and a high-resolution atmospheric transport model. Results show that current inventories from the US Environmental Protection Agency (EPA) and the Emissions Database for Global Atmospheric Research underestimate methane emissions nationally by a factor of similar to 1.5 and similar to 1.7, respectively. Our study indicates that emissions due to ruminants and manure are up to twice the magnitude of existing inventories. In addition, the discrepancy in methane source estimates is particularly pronounced in the south-central United States, where we find total emissions are similar to 2.7 times greater than in most inventories and account for 24 +/- 3% of national emissions. The spatial patterns of our emission fluxes and observed methane-propane correlations indicate that fossil fuel extraction and refining are major contributors (45 +/- 13%) in the south-central United States. This result suggests that regional methane emissions due to fossil fuel extraction and processing could be 4.9 +/- 2.6 times larger than in EDGAR, the most comprehensive global methane inventory. These results cast doubt on the US EPA's recent decision to downscale its estimate of national natural gas emissions by 25-30%. Overall, we conclude that methane emissions associated with both the animal husbandry and fossil fuel industries have larger greenhouse gas impacts than indicated by existing inventories.