DB1013 (Last revised March 1996) Global and Latitudinal Estimates of del 13C from Fossil-Fuel Consumption and Cement Manufacture Robert J. Andres Institute of Northern Engineering University of Alaska-Fairbanks Fairbanks, Alaska 99775-5900 Gregg Marland Environmental Sciences Division Oak Ridge National Laboratory Oak Ridge, Tennessee 37831-6335 Steve Bischof Connecticut College New London, Connecticut 06320 DOI: 10.3334/CDIAC/ffe.db1013 INTRODUCTION This database contains estimates of the annual mean value of del 13C of CO2 emissions from fossil-fuel consumption and cement manufacture for 1860-1992. It also contains estimates of the value of del 13C for one degree bands for the years 1950, 1960, 1970, 1980, 1990, 1991, and 1992. These estimates of the carbon isotopic signature account for the changing mix of coal, petroleum, and natural gas being consumed and for the changing mix of petroleum from various producing areas with characteristic isotopic signatures. This time series of fossil-fuel del 13C signature provides an additional constraint for balancing the sources and sinks of the global carbon cycle and complements the atmospheric del 13C measurements that are used to partition the uptake of fossil carbon emissions among the ocean, atmosphere, and terrestrial biosphere reservoirs. For the period 1860-1949, these estimates are based on estimates of global total CO2 emissions from combustion of coal, petroleum, and natural gas (Keeling 1973). For the period 1950-92, the estimates are based on national fuel consumption data from the United Nations Statistics Office (see Boden et al. 1995) and use discrete values for the isotopic signature of the petroleum produced in 17 of the primary oil-producing countries. The following values of del 13C were used for all global and national CO2-emissions estimates: -24.1 per mil for coal, -44 per mil for natural gas, -40 per mil for gas flaring, and 0 per mil for cement production. The modal value for petroleum, -26.5 per mil, was used for all petroleum before 1950 and, beginning in 1950, for all except the 17 countries for which unique values were derived. For 15 countries (listed below and discussed in Andres et al. 1996a) a characteristic value for del 13C of oil produced was derived. For two other countries, the U.S. and the former U.S.S.R., petroleum production has shifted over the years among oil fields with distinctive isotopic signatures and estimates are provided for how the mean isotopic value has changed with time. The del 13C values used for the U.S. decrease linearly from 1950 to 1992, whereas the del 13C values for the former U.S.S.R. decreased in two linear segments: from 1965 to 1975 and from 1975 to 1980 (see table below). Greater detail about the global time series of del 13C is provided in Andres et al. (1996b). The 17 countries assigned discrete values for del 13C were responsible for over 93% of world petroleum production in 1950 and over 85% of world petroleum production in 1990. Estimates of the del 13C of CO2 emissions as a function of latitude require several assumptions. Using United Nations data on world petroleum trade, it is possible to track much of world petroleum from the country of production to the country where final consumption occurs. It is not possible to continue to track the fuel within a country. The isotope calculation is thus based on the national CO2 emissions estimates of Boden et al. (1995). The estimates assume that the isotopic signature of CO2 from fuel combustion is uniform within a country and that the total of national CO2 emissions is distributed within the country in the same way as population. One-degree latitude by one-degree longitude maps containing political units and human population density, compiled by Inez Fung and others at the Goddard Institute for Space Studies, were used to distribute CO2 emissions within countries. It does not seem useful to illustrate the isotopic signatures thus derived on a 1 degree by 1 degree grid, but when summed along latitude bands, they should provide a useful indication of how the isotopic signature of emissions changes with latitude. Greater detail about the gridded CO2 emissions is given in Andres et al. (1996a). More details on the latitudinal distribution of del 13C are given in Andres et al. (1996b). FORMAT AND CONTENTS OF DATA FILES This database contains three files: this descriptive file (named "db1013.des"); a file containing the global annual estimates of del 13C for anthropogenic CO2 fossil-fuel emissions for 1860-1992 ("isoglob.dat"); and a file containing 1 degree latitudinal means of del 13C from fossil-fuel CO2 emissions for 1950, 1960, 1970, 1980, 1990, 1991, and 1992 ("isolat.dat"). The file "isoglob.dat" contains 157 records. The first 24 lines contain source, file name, revision date, and column identification information. The remaining 133 records contain the globally-averaged, annual del 13C values covering 1860 to 1992. Each data line contains the year and globally-averaged del 13C value, expressed as a per mil deviation from the PDB (PeeDee belemnite limestone) reference scale. The basis of this scale is PDB-CO2, that is, CO2 derived from CaCO3 from the rostrum of a Cretaceous belemnite (Belemnitella americana) collected in the PeeDee River formation of South Carolina, U.S.A. The file "isolat.dat" contains 206 records. The first 26 lines contain source, file name, revision date, and column identification information, and the remaining 180 records contain the 1 degree latitudinal del 13C values. Each data record contains a latitude band (180 - 179 represents 90 - 89 degrees N, and 1 - 0 represents 89-90 degrees S) and seven del 13C values for 1950, 1960, 1970, 1980, 1990, 1991, and 1992, respectively. The data are arranged by descending latitude, and all del 13C signatures are expressed in per mil units relative to the PDB scale. REFERENCES Andres, R. J., G. Marland, I. Fung, and E. Matthews. 1996a. A one degree by one degree distribution of carbon dioxide emissions from fossil fuel consumption and cement manufacture, 1950-1990. Global Biogeochemical Cycles (submitted) Andres, R. J., G. Marland, T. Boden, and S. Bischof. 1996b. Carbon dioxide emissions from fossil fuel consumption and cement manufacture 1751-1991; and an estimate of their isotopic composition and latitudinal distribution. In T. Wigley and D. Schimel (eds.), Global Change Institute, Aspen, Colorado, Cambridge University Press (in press). Boden, T. A., G. Marland, and R. J. Andres. 1995. Estimates of global, regional, and national annual CO2 emissions from fossil-fuel burning, hydraulic cement production, and gas flaring: 1950-1992. ORNL/CDIAC-90, NDP030/R6. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee, U.S.A. Keeling, C. D. 1973. Industrial production of carbon dioxide from fossil fuels and limestone. Tellus 2:174-98. ------------------------------------------------------------------------------------ del 13C values of CO2 emissions from crude oils for large oil-producing countries Oil-producing country del 13C (per mil ) --------------------- ----------------- Canada -29.9 China -29.3 Egypt -28.5 Indonesia -27.7 Iran -26.8 Iraq -27.1 Kuwait -27.3 Libya -28.2 Mexico -26.5 Nigeria -26.6 Norway -28.9 Saudi Arabia -26.4 United Arab Emirates -27.0 United Kingdom -29.6 Venezuela -26.1 Former Soviet Union 1950-1965 -28.0 1966-1975, 0.1 per mil steps -28.1 to -29.0 1976-1979, 0.2 per mil steps -29.2 to -29.8 1980-present -30.0 United States* 1950-1992, 0.025 per mil steps -26.5 to -27.525 -------------------------------------------------------------------------------------- * does not have specific imports associated with this production _______________________________ This descriptive file was created by Tom Boden (Carbon Dioxide Information Analysis Center, Environmental Sciences Division, Oak Ridge National Laboratory) and reviewed by the authors. This file is Environmental Sciences Division publication number 4541. Oak Ridge National Laboratory is managed by Lockheed Martin Energy Research Corp. for the U.S. Department of Energy under contract number DE-AC05-96OR22464.