United States General Accounting Office 

Washington, DC 20548 

October 28, 2003 

The Honorable Ernest F. Hollings 

Ranking Member 

Committee on Commerce, Science, 

and Transportation 

United States Senate 

The Honorable John F. Kerry 

Ranking Member 

Subcommittee on Oceans, Fisheries, 

and Coast Guard 

Committee on Commerce, Science, 

and Transportation 

United States Senate 

Subject: 	 Climate Change: Trends in Greenhouse Gas Emissions and Emissions 

Intensity in the United States and Other High-Emitting Nations 

In February 2002, the President reaffirmed a previous U.S. commitment to stabilize 

atmospheric concentrations of carbon dioxide and other greenhouse gases at a level 

designed to prevent dangerous human interference with the earth’s climate. At the 

same time, he announced a Global Climate Change Initiative to reduce the rate of 

increase of greenhouse gas emissions in the United States between 2002 and 2012. 

Specifically, he established the goal of reducing the “emissions intensity” of the U.S. 

economy by 18 percent, a reduction 4 percentage points greater than would be 

expected absent any new policy. 

Emissions intensity is a ratio calculated by dividing emissions in a given year by 

economic output for that year. For example, in 2000, U.S. greenhouse gas emissions 

were 1,909 million metric tons of carbon equivalent,1

 and U.S. economic output was 

$9,216 billion;2

 dividing these numbers yields an emissions intensity of 207 tons of 

emissions per million dollars of economic output. Changes in emissions intensity 

depend on the relative rate of change in emissions and economic output. For 

example, if emissions and economic output increase (or decrease) at the same rate, 

intensity remains constant. However, if emissions increase faster than economic 

1

To allow for comparisons among greenhouse gases, which differ in terms of their effects on the 

atmosphere and their expected lifetimes, emissions are typically measured in million metric tons of 

carbon equivalent, which we refer to as million metric tons. 

2

Economic output (gross domestic product, or GDP) is expressed in billions of 1996 dollars, as 

reported in the Economic Report of the President, 2002. 

GAO-04-146R Greenhouse Gas Emissions Intensity 
output, intensity increases. Conversely, if economic output rises faster than 

emissions, intensity decreases. 

You asked us to describe how U.S. emissions and emissions intensity compare to the 

world’s other highest emitters. Specifically, as agreed with your offices, this report 

focuses on (1) how greenhouse gas emissions and the emissions intensity of the 

United States and the nine nations with the next-highest emissions changed from 

1980 to 2000, (2) how such emissions and the emissions intensities of the same 

nations are expected to change between 2001 and 2025, and (3) how meeting the 

administration’s goal of reducing emissions intensity by 18 percent would affect 

cumulative U.S. emissions between 2002 and 2012. 

To accomplish these objectives, we analyzed data from the Energy Information 

Administration (EIA), an independent statistical and analytical agency within the U.S. 

Department of Energy. After the United States, the next nine nations (excluding 

Russia3

) with the highest 2001 emissions, in declining order, are China, Japan, India, 

Germany, Canada, the United Kingdom, Italy, South Korea, and France. With the 

United States, these nations accounted for 59 percent of the world’s energy-related 

carbon emissions in 2001 and are projected to account for the same percentage in 

2025. For the first two objectives, we used data on emissions of energy-related 

carbon dioxide (generally, emissions from the consumption of fossil fuels) because 

we did not find data on the other greenhouse gas emissions for these high-emitting 

nations. (Energy-related carbon dioxide accounts for an estimated 85 percent of 

world greenhouse gas emissions, according to the International Energy Agency.4

) For 

the third objective, we used data on U.S. emissions of all greenhouse gases. We also 

analyzed the administration’s February 2002 Global Climate Change Initiative and 

supporting documentation. 

Results in Brief 

Between 1980 and 2000, energy-related carbon dioxide emissions increased in the 

United States and six of the other nine highest-emitting nations. Emissions increased 

22.5 percent in the United States, while the largest increase occurred in South Korea 

(231.4 percent). Emissions decreased in the United Kingdom (10.1 percent), France 

(19.9 percent), and Germany (22.3 percent). During the same period, emissions 

intensities fell in the United States (34.7 percent) and the other nations reviewed 

except India. The decrease was the smallest in Italy (19.6 percent) and the greatest in 

China (68.9 percent). In India, emissions intensity increased slightly but was 

essentially stable. 

Between 2001 and 2025, energy-related carbon dioxide emissions are expected to 

increase in all 10 nations. U.S. emissions are projected to rise 43.5 percent, not 

3

Although Russia was the world’s third-largest emitter of energy-related carbon dioxide emissions in 

2001, we did not include Russia in our study because EIA did not project emissions intensity for Russia 

for 2025. 

4

The International Energy Agency is the energy forum for the 26 member nations of the 

Organization for Economic Cooperation and Development. 

Page 2 GAO-04-416R Greenhouse Gas Emissions Intensity 
counting any reductions from the administration’s initiative. The smallest increase is 

expected in Germany (15.2 percent), and the largest increase is expected in China 

(121.6 percent). During the same period, emissions intensities are expected to 

decrease in all 10 nations. In the United States, the expected decrease is 30.1 percent. 

Decreases in intensities are expected to be smallest in Japan (20.8 percent) and 

largest in China (47.6 percent). 

If the administration’s goal of reducing U.S. emissions intensity by 18 percent 

between 2002 and 2012 is met, cumulative emissions for that 11-year period would be 

about 500 million metric tons of carbon equivalent lower than the 23,162 million 

metric tons that would otherwise be expected, according to an EIA projection. 

Specifically, achieving the administration’s goal would limit emissions to no more 

than 22,662 million metric tons—2 percent below the level that would otherwise be 

expected over the period. 

In commenting on a draft of this report, a senior EIA official concurred without 

further comment, and a senior staff economist at the Council of Economic Advisers, 

part of the Executive Office of the President, provided technical comments, which we 

incorporated where appropriate. 

Background 

Carbon dioxide and certain other gases trap some of the sun’s heat in the earth’s 

atmosphere and prevent it from returning to space. The trapped heat warms the 

earth’s climate, much like the process that occurs in a greenhouse. Hence, the gases 

that cause this effect are often referred to as greenhouse gases. The most prevalent 

of these gases is carbon dioxide, which results from the combustion of coal and other 

fossil fuels in power plants, the burning of gasoline in vehicles, and other sources. In 

recent decades, concentrations of these gases have built up in the atmosphere, giving 

rise to concerns that continuing increases might interfere with the planet’s climate, 

for example, by increasing temperatures or changing precipitation patterns. 

In 1992, the United States ratified the United Nations Framework Convention on 

Climate Change, which was intended to stabilize the buildup of greenhouse gases in 

the earth’s atmosphere, but did not impose specific goals or timetables for limiting 

emissions. In 1997 the United States participated in drafting the Kyoto Protocol, an 

international agreement to specifically limit greenhouse gas emissions, and in 1998 it 

signed the protocol. However, the previous administration did not submit the 

protocol to the Senate for advice and consent, which are necessary for ratification. 

In March 2001, the President announced that he opposed the protocol. 

Nearly a year later, in February 2002, the President announced his Global Climate 

Change Initiative, which focuses on reducing emissions intensity compared to what 

would otherwise be expected, but not necessarily on reducing the level of emissions. 

EIA projects that, in the absence of new policies, U.S. greenhouse gas emissions 

intensity will decrease from 183 metric tons of emissions per million dollars of GDP 

in 2002 to 158 metric tons in 2012, a decrease of 14 percent. The administration’s goal 

is to reduce emissions intensity to 151 metric tons per million dollars of GDP—a 

Page 3 GAO-04-416R Greenhouse Gas Emissions Intensity 
further reduction of 4 percentage points, bringing the total reduction to 18 percent by 

2012. 

According to EIA, reductions in emissions intensity can have various causes. For 

example, in the last half-century the U.S. energy supply has come to rely less on fuels 

with a high carbon content as nuclear energy, hydropower, and natural gas have been 

increasingly substituted for coal and oil in power generation. The use of renewable 

energy sources, such as ethanol, has also increased in the United States. In nations 

such as China and India, lower emissions intensities result primarily from rapid 

economic growth, rather than from a switch to less carbon-intensive fuels. 

Emissions Increased, While Intensities 

Decreased, in Most of the 10 Nations 

between 1980 and 2000 

Energy-related carbon emissions increased in the United States and six of the other 

nine highest emitters between 1980 and 2000. In the United States, emissions 

increased 22.5 percent. The increases were relatively small in Italy (17.5 percent) and 

Japan (18.8 percent) and relatively large in India (203.7 percent) and South Korea 

(231.4 percent). Emissions decreased in the United Kingdom (10.1 percent), France 

(19.9 percent), and Germany (22.3 percent). (See table 1.) 

Table 1: Emissions in 10 Nations, 1980 and 2000 (ranked by 2000 emissions levels) 

Nation 

Emissions (million metric tons) Percent change 

1980 2000 Cumulative 

Average 

annual rate 

United States 1,288 1,578 22.5 1.0 

China 394 780 98 3.4 

Japan 261 310 18.8 0.9 

India 82 249 203.7 5.6 

Germany 291 226 –22.3 –1.3 

Canada 125 158 26.4 1.2 

United Kingdom 168 151 –10.1 –0.5 

Italy 103 121 17.5 0.8 

South Korea 35 116 231.4 6.0 

France 136 109 –19.9 –1.1 

Sources: EIA (data); GAO (calculations). 

Emissions intensity decreased 34.7 percent in the United States and also decreased in 

eight of the other nine nations between 1980 and 2000. The decreases were the 

smallest in Italy (19.6 percent) and South Korea (20.8 percent) and the largest in 

France (47.2 percent) and China (68.9 percent). In contrast, intensity increased 1.3 

percent in India. (See table 2.) 

Page 4 GAO-04-416R Greenhouse Gas Emissions Intensity 
Table 2: Emissions Intensities in 10 Nations, 1980 and 2000 (ranked by 2000 emissions levels) 

Nation 

Emissions intensity (metric tons of 

carbon equivalent per million dollars of 

economic output) Percent change 

1980 2000 Cumulative 

Average 

annual rate 

United States 269 176 –34.7 –2.1 

China 2,407 749 –68.9 –5.8 

Japan 79 55 –30.5 –1.8 

India 514 520 1.3 0.1 

Germanya 108 84 –22.0 –2.8 

Canada 308 226 –26.7 –1.5 

United Kingdom 210 116 –44.9 –3.0 

Italy 125 100 –19.6 –1.1 

South Korea 236 187 –20.8 –1.2 

France 116 61 –47.2 –3.2 

Sources: EIA (data); GAO (calculations). 

a

Intensity data are for 1991 (the first year for which an intensity figure is available for all the territory comprising 

unified Germany) and 2000; the percentage changes are calculated accordingly. 

Emissions Are Projected to Increase and 

Intensities to Decrease in All 10 Nations 

between 2001 and 2025 

Energy-related carbon dioxide emissions levels of the United States and the nine 

other high-emitting nations are projected to increase through 2025, while their 

emissions intensities are expected to decrease over the same period, according to 

EIA.5 U.S. emissions are projected to increase 43.5 percent.6 Smaller increases are 

expected in Germany (15.2 percent) and the United Kingdom (19 percent). Larger 

increases are expected in India (102.4 percent) and China (121.6 percent). (See table 

3.) 

5

EIA cautions that its projections present plausible paths or trends for the future based on current laws 

and regulations; do not anticipate volatile social, political, or economic events; and are not intended as 

precise predictions of future events. In its most recent International Energy Outlook, EIA reported on 

the accuracy of its past projections; see the Scope and Methodology section for additional details. 

6

This projection for the United States does not include the administration’s initiative. 

Page 5 GAO-04-416R Greenhouse Gas Emissions Intensity 
Table 3: Projected Emissions in 10 Nations, 2001 and 2025 (ranked by 2025 level of emissions) 

Nation 

Emissions (million metric tons) Percent change 

2001 2025 Cumulative 

Average 

annual rate 

United States 1,559 2,237 43.5 1.5 

China 832 1,844 121.6 3.3 

India 250 506 102.4 2.9 

Japan 316 382 20.9 0.8 

Germany 223 257 15.2 0.6 

Canada 155 206 32.9 1.2 

South Korea 121 206 70.2 2.2 

United Kingdom 153 182 19 0.7 

Italy 121 146 20.7 0.8 

France 108 135 25 0.9 

Sources: EIA (data); GAO (calculations). 

During the same time period, emissions intensities are projected to decrease in all 10 

nations. The decrease in the United States is projected to be 30.1 percent. The 

smallest decreases are expected in Japan (20.8 percent) and France (29.4 percent), 

and the largest decreases are expected in India (40.6 percent) and China (47.6 

percent). (See table 4.) 

Table 4: Projected Emissions Intensities in 10 Nations, 2001 and 2025 (ranked by 2025 level of 

emissions) 

Nation 

Emissions intensities (metric tons of 

carbon equivalent per million dollars of 

economic output Percent change 

2001 2025 Cumulative 

Average 

annual rate 

United States 166 116 –30.1 –1.5 

China 693 363 –47.6 –2.7 

India 480 285 –40.6 –2.1 

Japan 72 57 –20.8 –1.0 

Germany 98 67 –31.6 –1.5 

Canada 209 146 –30.1 –1.5 

South Korea 217 137 –36.9 –1.9 

United Kingdom 104 73 –29.8 –1.5 

Italy 96 67 –30.2 –1.5 

France 68 48 –29.4 –1.4 

Sources: EIA (data); GAO (calculations). 

Administration’s Initiative Would Reduce 

Cumulative U.S. Emissions 2 Percent below 

the Otherwise Expected Level 

If the administration’s goal is met, cumulative emissions for 2002 through 2012 would 

be about 500 million metric tons lower than otherwise expected. EIA projected that, 

in the absence of any policy change, cumulative U.S. emissions from 2002 through 

2012 would be 23,162 million metric tons. The administration projected that the 

initiative would reduce that total to no more than 22,662 million metric tons. The 

Page 6 GAO-04-416R Greenhouse Gas Emissions Intensity 
reduction in emissions attributed to the initiative is expected to increase each year 

through 2012, reaching 106 million metric tons in that year, which would represent a 

5 percent decrease from the level otherwise expected. Cumulatively, for 2002 

through 2012, the initiative is projected to reduce emissions by 500 million metric 

tons, or 2 percent below the otherwise expected level. 

Observations 

Emissions increased in 7 out of the 10 highest-emitting nations from 1980 through 

2000 and are projected to increase in all 10 through 2025. Emissions intensity 

decreased in all but one of the nations from 1980 through 2000 and is projected to 

decrease in all 10 highest-emitting nations through 2025. 

Agency Comments 

We provided a draft of this report for review and comment to the Secretary of Energy 

and to the Chairman of the Council of Economic Advisers, a part of the Executive 

Office of the President. The Director of EIA’s Office of Integrated Analysis and 

Forecasting concurred with the report without further comment. A Senior Staff 

Economist at the Council of Economic Advisers provided technical comments, which 

we incorporated where appropriate. 

Scope and Methodology 

To answer our objectives, we analyzed EIA data and the administration’s February 

2002 Global Climate Change Initiative and supporting documentation. For our 

analysis of emissions from 1980 through 2000 and from 2001 through 2025, we used 

data on energy-related carbon dioxide emissions (generally, emissions from the 

consumption of fossil fuels).7

 For our analysis of emissions intensity from 1980 

through 2000, we used intensity data calculated using 1995 U.S. dollars and carbon 

dioxide emissions from the consumption and flaring of fossil fuels. For the analysis 

of emissions intensity from 2001 through 2025, we used intensity data calculated 

using 1997 U.S. dollars and carbon dioxide emissions. For the discussion of the 

initiative, we used Environmental Protection Agency data for all greenhouse gas 

emissions. 

We did not independently assess the reliability of EIA data nor the validity of EIA 

models used in this report. In its most recent International Energy Outlook, EIA 

reported on the accuracy of certain of its projections of energy consumption and 

other measures. For example, it noted that its 1997 projections of 2000 energy 

consumption were accurate for North America (which includes Canada and the 

United States), 4 percent too high for Western Europe (which includes France, 

Germany, Italy, and the United Kingdom), and 11 percent too high for developing 

nations in Asia (which includes China and India), a region affected by a severe 

recession in the late 1990s.8

 We performed our work between April and October 2003 

7

These emissions data do not include carbon dioxide emitted from natural gas flaring. 

8

See EIA’s International Energy Outlook 2003, DOE/EIA-0484 (2003). 

Page 7 GAO-04-416R Greenhouse Gas Emissions Intensity 
- - - - 

in accordance with generally accepted government auditing standards, except as 

noted. 

As arranged with your offices, unless you publicly announce the contents of this 

report earlier, we plan no further distribution until 10 days from the report date. At 

that time, we will send copies to the appropriate congressional committees; the 

Secretary of Energy; and the Chairman, Council of Economic Advisers. In addition, 

the report will be available at no charge on the GAO Web site at http//:www.gao.gov. 

Should you or your staff need further information, please contact me or David 

Marwick at (202) 512-3841. Anne K. Johnson and Kevin Tarmann made key 

contributions to this report. John Delicath and Cynthia Norris also made important 

contributions. 

John B. Stephenson 

Director, Natural Resources 

and Environment 

(360316) 


Page 8 GAO-04-416R Greenhouse Gas Emissions Intensity