Researchers report estimates of fossil fuel CO2 (FF CO2) emissions based on measurements of radiocarbon (14C) in atmospheric CO2. FF CO2 emissions are often tracked using bottom-up inventories of known sources, which are hard to verify independently. Sourish Basu and colleagues report an independent method for estimating FF CO2 based on the isotopic composition of atmospheric CO2. Fossil fuels are depleted in 14C relative to other carbon sources as a result of radioactive decay. Therefore, the relative amount of 14C in atmospheric CO2 provides information on the contribution of FF CO2 to atmospheric CO2. The authors used measurements from the National Oceanographic and Atmospheric Administration's Global Greenhouse Gas Reference Network to estimate US emissions for the year 2010, the earliest year for which sufficient data are available. US FF CO2 emissions for 2010 estimated in this way were approximately 1,653 teragrams of carbon, larger than estimates from the US Environmental Protection Agency and other widely used inventories. The authors' estimated annual emission was comparable to that derived from the high-resolution Vulcan FF CO2 inventory, as were monthly emissions for 9 of 12 months in 2010. The results suggest that atmospheric carbon isotope measurements can be used to independently validate inventory-based estimates of FF CO2 emissions, according to the authors.
Article #19-19032: "Estimating US fossil fuel CO2 emissions from measurements of 14C in atmospheric CO2," by Sourish Basu et al.
MEDIA CONTACT: Sourish Basu, Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD; tel: 301-614-6545, 303-834 5361; e-mail: sourish@umd.edu ; John B. Miller, Global Monitoring Laboratory, National Oceanographic and Atmospheric Administration, Boulder, CO; tel: 303-497-7739; e-mail: john.b.miller@noaa.gov ; Scott Lehman, Institute for Arctic and Alpine Research, University of Colorado Boulder, CO; tel: 303-492-8980; e-mail: scott.lehman@colorado.edu
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Proceedings of the National Academy of Sciences