Exploring differences in FFCO 2 emissions in the United States: comparison of the Vulcan data product and the EPA national GHG inventory

作者：Anna Kato, K. R. Gurney, Geoffrey Roest, P. Dass · 发表于：Environmental Research Letters · 年份：2023 · DOI：10.1088/1748-9326/ad0b22 · 被引用次数：6 · 研究领域：Atmospheric and Environmental Gas Dynamics、Atmospheric Ozone and Climate、Atmospheric chemistry and aerosols

Abstract Quantitative assessment of greenhouse gas emissions is an essential step to plan, track, and verify emission reductions. Multiple approaches have been taken to quantify U.S. CO 2 emissions from fossil fuel combustion (FFCO 2 ), the primary driver of global climate change. A 2020 study analyzing atmospheric 14 CO 2 observations (a key check on bottom-up estimates) and multiple inventories found significant differences in the U.S. total FFCO 2 emissions. The specific reasons for the differences were left for future work. Here, we take up this task and explore the differences between two widely used U.S. FFCO 2 inventories, the Vulcan FFCO 2 emissions data product and the Environmental Protection Agency (EPA) GHG inventory, developed using mostly independent data sources. Where possible, we isolate definitions and data sources to quantify/understand discrepancies. We find that the initial 2011 emissions difference (104 MtC yr −1 ; RD = 10.7%) can be reduced by aligning the two estimates to account for differing definitions of emission categories or system boundaries. Out of the remaining 90.6 MtC yr −1 gap (RD = 6.2%), we find that differences can be largely explained by data completeness, emission factors, and fuel heating values. The remaining difference, 45.4 MtC yr −1 (3.2%), is difficult to isolate due to limited EPA documentation and disaggregation of emissions by sector/fuel categories. Furthermore, the final net difference obscures countervailing gross differenc...