This appendix presents estimates of U.S. carbon dioxide emissions for the period 1949-1997. The data were developed originally at the request of the President's Council of Economic Advisors, for inclusion in a graphic that appeared in the 1997 Economic Report of the  President.⁽²⁰⁷⁾ U.S. energy data have undergone a number of shifts over the years, and the estimates can be divided into three periods:

• 1980-1997. The emissions estimates for this period were developed using the methods and sources described in this report. The energy data on which the emissions estimates are based are from the Energy Information Administration (EIA) data series published in the State Energy Data Report.⁽²⁰⁸⁾

• 1960-1979. Before 1980, the EIA did not maintain a detailed accounting of carbon sequestration due to nonfuel use of fossil fuels. Hence, the data for industrial sector petroleum use, particularly in the category "other petroleum," are not as reliable as those for subsequent years. The EIA has also not attempted to develop annual emissions coefficients for fuels in use before 1980, and the estimates do not reflect any changes in fuel quality. The energy data for this period are also drawn from the database of the State Energy Data Report.

• 1949-1959. The EIA has made no attempt to distinguish between residential and commercial energy consumption for historical data earlier than 1960. To provide consistent estimates for this appendix, the combined data for residential and commercial energy consumption have been prorated by fuel according to the ratio of consumption in 1960. Composite sectoral petroleum emissions factors are used for this period, based on 1960-weighted petroleum products emissions. The energy data for this period are drawn from the Annual Energy Review.⁽²⁰⁹⁾

In future years, EIA hopes to be able to create annual emissions factors for electric utility coal for the period 1949-1979, to extend the estimates to cover U.S. territories and non-energy carbon dioxide, to estimate sequestration from nonfuel use in somewhat more detail for the period 1974-1979, and to use historical data on consumption of petroleum products by product and sector for the 1949-1959 period, rather than the 1960-based sectoral averages.

• Table E1. Energy-Related Carbon Dioxide Emissions from the Residential and Commercial Sectors, 1949-1997

• Table E2. Energy-Related Carbon Dioxide Emissions from the Industrial and Transportation Sectors, 1949-1997