U.S. emissions of greenhouse gases rose in 1997 by 1.4 percent, the sixth yearly increase in a row, according to
the Energy Information Administration's annual report Emissions of Greenhouse Gases in the United States. Emissions in 1997 totaled 1.8 billion metric tons on a carbon-equivalent
basis (see table). Since 1990, U.S. emissions have increased at a compounded annual rate of 1.3 percent, while
population increased 1.1 percent per year, overall energy consumption 1.7 percent per year, and gross domestic
product 2.3 percent per year.
U.S. Emissions of Greenhouse Gases,
1990-1997
(Million Metric Tons
of Carbon or Carbon Equivalent)
|
Gas |
1990 |
1991 |
1992 |
1993 |
1994 |
1995 |
1996 |
P1997 |
| Carbon Dioxide |
1,356 |
1,341 |
1,361 |
1,394 |
1,414 |
1,428 |
1,479 |
1,501 |
| Methane |
173 |
174 |
174 |
170 |
171 |
172 |
167 |
167 |
| Nitrous Oxide |
82 |
83 |
85 |
86 |
91 |
88 |
86 |
85 |
| HFCs, PFCs, and SF6 |
22 |
22 |
23 |
23 |
26 |
31 |
35 |
38 |
|
Total |
1,633 |
1,620 |
1,643 |
1,673 |
1,702 |
1,719 |
1,767 |
1,791 |
P = preliminary data.
Source: Energy Information Administration.
The chief U.S. greenhouse gases
emitted are carbon dioxide, methane, and nitrous oxide, which respectively accounted for 84 percent, 9 percent,
and 5 percent of U.S. total emissions in 1997. A fourth category, which includes hydrofluorocarbons, perfluorocarbons,
and sulfur hexafluoride, accounted for the remaining 2 percent.
Almost all U.S. carbon dioxide emissions result from combustion of fossil fuels. Both emissions per capita and
emissions per kilowatthour of electric power generation increased in recent years. The latter trend is due to the
shutting down of several nuclear power plants and to rising natural gas prices, which have encouraged electric
utilities to use more coal. U.S. methane emissions come mainly from landfills, fossil fuel production and transport,
and livestock and their wastes. Estimates of methane emissions are somewhat uncertain, but emissions appear not
to vary significantly from year to year. Emissions of nitrous oxide seem relatively stable; however, the 1997 estimates
are nearly two and one-half times the previous report's values, due to a change in methodology. Agriculture, especially
nitrogen fertilization, is the main source of nitrous oxide emissions. Engineered gases such as hydrofluorocarbons
are emitted in relatively small quantities but are considerably more potent as greenhouse gases than carbon dioxide.
Emissions have risen rapidly during the 1990s.
In six chapters, the report covers the greenhouse effect and related policy developments; U.S. emissions of carbon
dioxide, methane, nitrous oxide, halocarbons and other gases; and land-use issues. Appendices discuss estimation
methods, carbon coefficients used, sources of uncertainty, and emissions sources excluded.
Contact:
Arthur Rypinski, Office of Integrated Analysis and Forecasting
arthur.rypinski@eia.doe.gov
Phone: (202) 586-8425
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URL: http://www.eia.doe.gov/emeu/plugs/plgge97.html
File last modified: October 30, 1998
