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Emission Statistics
In 1998, greenhouse gas (GHG) emissions in the US were nearly 10% higher
than 1990 levels, and could rise 47% above 1990 levels by 2020,
according to two new reports from the US Department of Energy's
Energy Information Administration (EIA) . GHG emissions in 1998 totaled 1,803
million metric tons of carbon equivalent (MtCe), with CO2 representing
about 83% of the total, according to Emissions of Greenhouse Gases in
the United States 1998. Emissions rose only slightly (0.2%) from 1997 to
1998, the lowest annual growth rate since 1991, when emissions actually
fell slightly owing to economic recession.
Warmer winter weather (13% warmer than in 1997) reduced consumption of winter heating fuels; however, this was offset by warmer summer weather (14% warmer than average and 22% warmer than in 1997) that led to greater use of air- conditioning and thus higher electrical production. Low oil prices also led to "large-scale" fuel switching from natural gas to oil for electrical generation -- increasing oil consumption in this sector by 42%. Transportation emissions grew by 2.4% from 1997 to 1998, primarily owing to an increase in gasoline consumption. Overall, CO2 emissions climbed 0.3% from 1997 to 1998, and are now 11% higher than 1990 levels.
Meanwhile, methane emissions dropped 1.4% between 1997 and 1998, and are now nearly 5% lower than in 1990. EIA attributes the decline to increased capture of methane from landfills, mandated by EPA regulations but spurred on by operators trying to meet a deadline to receive tax credits for landfill gas recovery projects. Emissions of HFCs, perfluorocarbons, and sulfur hexafluoride -- accounting for just over 2% of total GHG emissions on a carbon equivalent basis -- grew by 5% between 1997 and 1998, and are now some 82% higher than in 1990.
Finally, EIA estimates that forest regrowth in the US currently sequesters some 209 MtC annually -- about 14% of US CO2 emissions. However, the report notes that this rate of sequestration is slowing as these regenerating forests reach maturity.
Despite the low emissions growth rate from 1997 to 1998, EIA does not expect this trend to continue, according to the reference case forecasts in its Annual Energy Outlook 2000. This analysis projects that carbon emissions from energy use will increase an average of 1.3% annually, growing to 33% above 1990 levels in 2010 and 47% above 1990 levels in 2020. The forecast for 2020 is slightly higher than projected in last year's Outlook, owing to higher projected economic growth, travel, and electricity generation.
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