Global Climate Change: U.S. Greenhouse Gas Emissions - Status, Trends, and Projections

Global Climate Change: U.S. Greenhouse Gas Emissions - Status, Trends, and Projections

Order Code 98-235 ENR
CRS Report for Congress
Received through the CRS Web
Global Climate Change:
U.S. Greenhouse Gas Emissions —
Status, Trends, and Projections
Updated August 15, 2003
John Blodgett and Larry Parker
Resources, Science, and Industry Division
Congressional Research Service ˜ The Library of Congress

Global Climate Change:
U.S. Greenhouse Gas Emissions —
Status, Trends, and Projections
Summary
This report reviews U.S. emissions of greenhouse gases in the contexts both of
domestic policy and of international obligations and proposals. On October 15,
1992, the United States ratified the United Nations Framework Convention on
Climate Change (UNFCCC), which entered into force on March 21, 1994. This
committed the United States to “national policies” to limit “its anthropogenic
emissions of greenhouse gases,” with a voluntary goal of returning “emissions of
carbon dioxide [CO ] and other greenhouse gases [methane (CH ), nitrous oxide
2
4
(N O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride
2
(SF )]” at the “end of the decade” to “their 1990 levels.”
6
Subsequently, in the 1997 Kyoto Protocol to the UNFCCC, the United States
participated in negotiations that ended with agreement on further reductions that
could become legally binding. The United States signed the Kyoto Protocol in 1998,
but President Clinton did not send it to the Senate for advice and consent. President
Bush has said that he rejects the Protocol, and former U.S. Environmental Protection
Agency Administrator Christine Todd Whitman told reporters that the
Administration would not be pursuing the UNFCCC commitment either. Instead,
President Bush has proposed to shift the nation’s climate change program from a goal
of reducing emissions per se to a goal of reducing energy intensity — the amount of
greenhouse gases emitted per unit of economic productivity. Under the proposal, the
intensity, which has been declining for a number of years, would decline 18%
between 2002 and 2012, as opposed to a 14% projected “business as usual” decline.
Meanwhile, the UNFCCC “end of the decade” deadline has passed and U.S.
greenhouse gas emissions continue on an upward trend, though with dips in 1991 and
in 2001, attributed mostly to economic slowdowns. Based on historical data, 2001
emissions were about 13% in excess of the UNFCCC goal. Overall, from 1990 to
2001, U.S. greenhouse gas emissions (weighted by global warming potential) have
increased an average of about 1.1% per year. Projections suggest that U.S. emissions
will continue to rise for at least the next decade. Reversing the upward trend in
greenhouse gas emissions would represent an extraordinary technical and political
challenge to U.S. energy and environmental policy.
This report will be updated as necessary.

Contents
U.S. Greenhouse Gas Emissions and Baselines . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Emissions Projections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
The Climate Action Report Projection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Effect on Projections of Varying Assumptions . . . . . . . . . . . . . . . . . . . . . . . 9
Status of Emissions Relative to Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Additional Considerations in Assessing Possible Reductions . . . . . . . . . . . . . . 14
Carbon Sequestration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Emissions Trading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
List of Figures
Figure 1. U.S. Emissions of CO : Historical and Projected (2005, 2010) . . . . . . . 7
2
Figure 2. U.S. Emissions of CH , N 0, and HFCs, PFCs, and SF :
4
2
6
Historical and Projected (2005, 2010) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Figure 3. U.S. Aggregate Gross Emissions of Six Greenhouse Gases:
Historical and Projected (2005, 2010) (MMTCE) . . . . . . . . . . . . . . . . . . . . 10
Figure 4. Greenhouse Gas Intensity: President’s Initiative . . . . . . . . . . . . . . . . . 14
List of Tables
Table 1. U.S. Greenhouse Gas Emissions (MMTCE), 1990-2001 . . . . . . . . . . . . 3
Table 2. U.S. Baseline Year Greenhouse Gas Emissions . . . . . . . . . . . . . . . . . . . 4
Table 3. U.S. Greenhouse Gas Intensity (1990-2001) . . . . . . . . . . . . . . . . . . . . . 6
Table 4. Impact of Economic Assumptions on Projections of CO Emissions . 11
2
Table 5. Impact of Technology/Efficiency Assumptions on Projections of
CO Emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2

Global Climate Change:
U.S. Greenhouse Gas Emissions —
Status, Trends, and Projections
This report reviews U.S. emissions of greenhouse gases in the contexts both of
domestic policy and of international obligations and proposals. On October 15,
1992, the United States ratified the United Nations Framework Convention on
Climate Change (UNFCCC), which entered into force on March 21, 1994. By this
action, the nation made a legally non-binding commitment to “national policies” to
limit “its anthropogenic emissions of greenhouse gases,” which are believed to pose
a risk of global climate change.1 The goal was to return “these anthropogenic
emissions of carbon dioxide and other greenhouse gases” at the “end of the decade”
to “their 1990 levels.” This goal was voluntary, to “demonstrate that developed
countries are taking the lead in modifying longer-term trends in anthropogenic
emissions consistent with the objective of the Convention.”2 The Convention
established standards for inventorying and reporting greenhouse gas emissions.
Subsequently, the United States participated in negotiating the Kyoto Protocol
to the UNFCCC.3 Under the Kyoto Protocol, the United States would have made a
legally binding agreement that for the 5-year period 2008-2012, it would reduce its
average annual aggregate carbon-equivalent emissions of six gases by 7% below
specified baseline years.4 However, while President Clinton signed the Protocol in
1998, he did not send it to the Senate for its advice and consent; and President
George W. Bush has said that he has no intention of pursuing the Kyoto Protocol —
that it is “fatally flawed.”5
Nonetheless, other nations continue efforts to implement the Kyoto Protocol,
and the United States remains obligated under the UNFCCC to inventory its
emissions of greenhouse gases and to pursue voluntary reductions.
However, as
1 This report does not address the underlying debate over global climate change and the
potential role of humans in contributing to it. On the science and policy of global climate
change, see CRS Issue Brief IB89005, Global Climate Change.
2 UNFCCC, Article 4, Commitments, sections 2(a) and (b).
3On the agreement, see CRS Report RS30692, Global Climate Change Treaty: The Kyoto
Protocol.
4Technically, the net carbon-equivalent emissions of the six greenhouse gases for the 5-year
period 2008-2012 are not to exceed 5 times 93% of the baseline emissions. Kyoto Protocol,
Article 3(1). This is equivalent to the average annual emission load during the 5-year
period being 7% below the baseline.
5White House, Office of the Press Secretary, “President Bush Discusses Global Climate
Change,” June 11, 2001.

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described below, President Bush has announced a voluntary program to reduce the
intensity of U.S. greenhouse gas emissions per unit of economic productivity.6 Based
on this initiative, according to former Environmental Protection Agency
Administrator Christine Todd Whitman, “the Bush Administration does not intend
to pursue emissions cuts it committed to” in the UNFCCC.7
It is in this context, then, that this report sets out the baseline emissions that the
United States has established and portrays trends in emissions over the past decade;8
notes the current status of U.S. emissions as compared to the UNFCCC goals; and
reviews projections and, as a point of reference, compares them to the Kyoto Protocol
emissions commitments. (Assessing that prospective commitment does not imply
that the United States should reduce emissions, only what would be required if it
were to join that agreement to reduce emissions.)
In what follows, figures for emissions are point estimates9 and rounded to
millions of metric tons of carbon equivalents (MMTCE10). As will be discussed, the
data are of varying robustness and may be subject to adjustments. The data for CO ,
2
which accounts for over 80% of domestic greenhouse gas emissions, are the most
robust, being largely based on comprehensive fuel use data. Subsumed estimates and
uncertainties in projected emissions have greater effect the further into the future one
looks. But even allowing for these imprecisions, the trendline of aggregate U.S.
emissions of greenhouse gases is clear: over the decade of the 1990s emissions
trended upward, and they are projected to continue to rise in the future.
U.S. Greenhouse Gas Emissions and Baselines
Pursuant to the United Nations Framework Convention on Climate Change, the
United States has published “national inventories of anthropogenic emissions by
sources and removals by sinks of all greenhouse gases not controlled by the Montreal
Protocol, using comparable methodologies ... agreed upon by the Conference of the
Parties.”11 (See Table 1.)
6 For documents on the Administration plan, see [http://www.whitehouse.gov/news/releases/
2002/02/climatechange.html].
7“Bush Emissions Plan Seen Replacing Regs,” Platts Inside Energy (Feb. 25, 2002), p. 9.
8Environmental Protection Agency, Inventory of U.S. Greenhouse Gas Emissions and Sinks:
1990-2001 (April 2003), EPA 430R03004.
9 Although emissions data are typically presented as individual figures for each year, this
single number (point estimate) actually represents a range bounded by potential errors
arising from assumptions underlying the data.
10MMTCE figures combine the variable greenhouse effects of the different gases by
calculating and summing their equivalent effects, with carbon dioxide serving as the
reference gas. Global warming potential figures have an uncertainty of + or - 35%; a recent
recalculation is not included in the current figures (see discussion in EPA, Inventory of U.S.
Greenhouse Gas Emissions and Sinks: 1990-2001 (April 2003), EPA 430R03004. pp. 6-9).
11 UNFCCC, Article 4, section 1(a) and Article 12, section 1(a).

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Table 1. U.S. Greenhouse Gas Emissions (MMTCE), 1990-2001
Gas
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
CO
1,365
1,354
1,381
1,412
1,438
1,455
1,504
1,526
1,531
1,549
1,604
1,580
2
CO (sinks)a
(293)
(289)
(291)
(291)
(292)
(290)
(289)
(229)
(226)
(229)
(228)
(229)
2
CH
176
176
176
174
176
177
174
172
170
168
167
165
4
N O
108
110
113
113
120
118
120
120
119
117
117
116
2
HFCs, PFCs, SF
26
24
25
26
26
27
31
32
35
33
33
30
6
Total emissions
1,675
1,664
1,694
1,726
1,760
1,777
1,829
1,850
1,855
1,867
1,921
1,892
Net emissions
1,382
1,375
1,403
1,435
1,468
1,487
1,540
1,621
1,629
1,638
1,693
1,663
Source: Environmental Protection Agency, Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2001 (April 2003), EPA 430R03004. (Data for 1991-
1994 provided by EPA.) Following international convention, EPA presents the data in teragrams of CO equivalent; CRS has converted the figures to million metric
2
tons of carbon equivalent (MMTCE), a metric that is more familiar to most U.S. policymakers.
aLand-use changes and forestry sinks that sequester carbon; included in net emissions total only.

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The Environmental Protection Agency (EPA) publishes the official emissions
data annually.12 The United States also from time to time reports on emissions and
explains its climate change programs in the Climate Action Report (CAR) to the
United Nations; the third CAR was published in 2002.13
The U.S. baselines for the UNFCCC and the Kyoto Protocol are shown in Table
2.
For the UNFCCC commitment, the baseline is 1990 emissions, or 1,675
MMTCE; if the United States had acceded to the Kyoto targets, the baseline would
have been 1,676 MMTCE, a negligible difference. By definition, sinks are not
included in calculating the baselines.
Table 2. U.S. Baseline Year Greenhouse Gas Emissions
Greenhouse Gas
Baseline Year
Emissions (MMTCE)
Carbon dioxide (CO )
1990
1,365
2
Methane (CH )
1990
176
4
Nitrous oxide (N O)
1990
108
2
Hydrofluorocarbons (HFCs)
1990
1995
26
27
Perfluorocarbons (PFCs)
UNFCC
Kyoto
UNFCC
Kyoto
Sulfur hexafluoride (SF )
6
Total
1,675
1,676
Source: EPA, Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990 - 2001) April
2003, EPA 430R03004.
The emissions baselines shown in Table 2 are not immutable. Each annual
report includes updated estimates based on methodological and data revisions,
although such changes are usually small. Revisions are discussed at some length in
each report. The criteria for calculating emissions agreed upon by the Conference of
Parties hinge on both current technical knowledge and policy judgments. New
technical information can change factors, for example concerning calculation of
greenhouse gas equivalents; and policy judgments can be adjusted, for example
concerning the time frame for calculating effects. In addition, a few technical issues
remain unresolved, for example in assigning emissions from fuels burned in
international travel. However, any changes tend to be modest, seldom affecting totals
12EPA, Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990 - 2001, April 2003,
EPA 430R03004, available at [http://yosemite.epa.gov/OAR/globalwarming.nsf/content/
ResourceCenterPublicationsGHGEmissionsUSEmissionsInventory2003].
13The Climate Action Reports, submitted by the United States of America under the United
Nations Framework Convention on Climate Change, appeared in October 1994, July 1997,
and May 2002; for the third report, see U.S. Department of State, U.S. Climate Action
Report (May 2002), available at [http://yosemite.epa.gov/oar/globalwarming.nsf/content/
ResourceCenterPublicationsUSClimateActionReport.html].

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much more than plus or minus 1%, except for sequestration figures, which have been
subject to larger changes.14
Besides actual quantities of emissions, an alternative measure of a nation’s
contribution to global warming is “greenhouse gas intensity of the economy” — that
is, emissions per unit of gross domestic product (GDP). In effect, this measure
focuses on the efficiency of the economy in terms of greenhouse gas emissions: the
more efficient, the fewer emissions per dollar of economic output and thus the lower
the “greenhouse gas intensity.” For the United States, greenhouse gas intensity has
been declining since at least the 1980s; for the 1990s, the decline in intensity was
about 10%, based on net emissions15 (see Table 3).
Emissions Projections
Projecting greenhouse gas emissions involves modeling the nation’s economic
growth and activity, with special attention to variables affecting fossil fuel
combustion. The modeling also depends on assumptions about energy policy
directions. If reducing emissions becomes a goal, then projections become subject
to the outcome of unresolved issues in how the emissions reductions goals might be
met.
For example, the major source of CO emissions, fossil fuel combustion, is
2
influenced by overall economic activity and growth as well as by energy policy
decisions such as development of non-carbon based substitutes, the rate of adoption
of energy efficient technologies, and the retirement rate of nuclear facilities, among
others. These policy factors are difficult to predict in the absence of a concrete
climate change policy.16 The climate change plan proposed by President Bush in
February 2002 provides some new policy directions, but many elements depend on
congressional action (e.g., for funding) or voluntary private sector initiatives, making
projections of their impact problematic.
14 See “Changes in This Year’s Inventory Report,” EPA, Inventory of U.S. Greenhouse Gas
Emissions and Sinks: 1990-2001, pp. Changes-1 - Changes-13.
15 Following the Administration’s practice, discussions in this report of greenhouse gas
intensity are based on net emissions per unit of economic activity.
16 On current federal policies, see CRS Report RL31921, Climate Change: Federal Laws
and Policies Related to Greenhouse Gas Reductions.

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Table 3. U.S. Greenhouse Gas Intensity (1990-2001)
GDP (billions of chained
Greenhouse Gas Intensity (metric
(1996) dollars)
tons carbon equivalent per million
$ GDP)
Total Emissions
Net Emissions
1990
6,708
250
206
1991
6,677
249
206
1992
6,880
246
204
1993
7,063
244
203
1994
7,348
240
200
1995
7,544
236
197
1996
7,813
234
197
1997
8,160
227
199
1998
8,509
218
184
1999
8,859
211
185
2000
9,191
209
184
2001
9,214
205
180
Source: Table 1; Economic Report of the President, February 2003, Table B-2; CRS
calculations.
The Climate Action Report Projection
The third U.S. Climate Action Report (CAR 2002) projects greenhouse gas
emissions at 5-year intervals through 2020. For this report, the projections are
followed only to 2010 (see Figures 1 and 2), because of the difficulties in projecting
into the more distant future. Also, 2010 provides a basis for evaluating a relationship
to the Kyoto Protocol targets.

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Figure 1. U.S. Emissions of CO : Historical and Projected (2005, 2010)
2
1800
1600
1400
1200
CE
1000
MMT
800
600
400
200
0
1990
1992
1994
1996
1998
2000
2002
2004
2006
2008
2010
CO2
CO2 (sinks)
Net CO2
Sources: Historical data (through 2001): EPA, Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990 - 2001, April 2003, EPA 430R03004, pp. ES-2 - ES-4. Projections (to
2010): U.S. Department of State, Climate Action Report 2002, May 2002. [Data converted to MMTCE by CRS.]

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Figure 2. U.S. Emissions of CH , N 0, and HFCs, PFCs, and SF : Historical and Projected (2005, 2010)
4
2
6
175
150
125
100
CE
MMT
75
50
25
0
1990
1992
1994
1996
1998
2000
2002
2004
2006
2008
2010
CH4
N20
HFCs, PFCs, SF6
Sources: Historical data (through 2001): EPA, Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990 - 2001, April 2003, EPA 430R03004, pp. ES-2 - ES-4. Projections (to
2010): U.S. Department of State, Climate Action Report 2002, May 2002. [Data converted to MMTCE by CRS.]

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The CAR 2002 estimate for aggregate gross greenhouse emissions17 in 2010 is
2,213 MMTCE (see Figure 3). The President’s 2002 initiative to reduce greenhouse
gas intensity proposes a series of policy initiatives that it estimates “will achieve 100
million tons of reduced emissions in 2012.”18 Extrapolating between the CAR 2002
projections from 2010 to 2015 (a 1.9% annual growth rate), the 2012 projected
emission level would be 2,298 MMTCE. The President’s initiative suggesting a
decline in emissions of 100 million tons in 2012 would reduce this to 2,198
MMTCE, representing a reduction of about 4.4% from “business as usual” gross
greenhouse emissions in that year.
In addition, largely separate from federal
activities, a number of state and local governmental initiatives, as well as a variety
of private sector activities, are underway to address greenhouse gas emissions.
Effect on Projections of Varying Assumptions
CAR 2002 only makes point estimates, but some sense of the implications of
varying assumptions that affect the estimates can be gleaned from examining an
alternative source of CO emissions data, the Energy Information Agency’s (EIA’s)
2
Annual Energy Outlook series.19 (Because of minor differences in data calculation
and presentation, EIA’s annual emissions figures differ slightly from EPA’s.)
The EIA report’s projections of CO emissions include sensitivity analyses to
2
various changes in assumptions, and since CO from fuel combustion accounts for
2
about 80% of U.S. greenhouse gas emissions, the analysis is a reasonable test of the
projections. The assumptions EIA examines include economic growth, technological
innovation, oil prices, electricity demand, and others. The first two, economic
growth and technological innovation, have the greatest effect on variance in
projections of CO emissions (see Table 4). For 2010, compared to EIA’s “reference
2
case” (which is equivalent to a “business as usual” case), low economic growth
would reduce projected emissions by about 2%,20 while high economic growth would
increase projected emissions by about 3%. Compared to the reference case that
assumes anticipated technological developments, static technology would result in
emissions rising about 2%, while a “high-technology” case is projected to reduce
emissions about 2%.
The point reference case — CAR’s point estimate —
effectively assumes the several variances affecting emissions cancel out. But if all the
variances increasing emissions prove true and cumulative, then projected emissions
for 2010 could be 5% or more higher than the point estimate; conversely, if all the
variances decreasing emissions prove true and cumulative, emissions could be 5%
or more lower.
17 CAR 2002, Table 5-2, p. 74; this excludes “Sequestration Removals” and includes
“Adjustments.”
18
White House, Global Climate Change Policy Book, “Executive Summary,” at
[http://www.whitehouse.gov/news/releases/2002/02/climatechange.html].
19 EIA, Annual Energy Outlook 2003 (Jan. 2003), DOE/EIA-0383(2003).
20 The impact of economic activity can be seen (Table 1) in the fact that gross emissions
declined in both 1991 and 2001, in tandem with economic downturns.

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Figure 3. U.S. Aggregate Gross Emissions of Six Greenhouse Gases:
Historical and Projected (2005, 2010) (MMTCE)
2400
2350
2300
2250
2200
2150
2100
2050
2000
1950
1900
1850
1800
1750
1700
1650
1600
1550
1500
1450
1400
1350
1300
1990
1992
1994
1996
1998
2000
2002
2004
2006
2008
2010
2012
Gross Emissions
Upper Bound
Lower Bound
President's Initiative
Sources: Historical data (through 2001): EPA, Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990 - 2001, April 2003, EPA 430R03004, pp. ES-2 - ES-4. Projections (to
2010): U.S. Department of State, Climate Action Report 2002, May 2002. [Data converted to MMTCE by CRS.] Upper and lower bound equal + 5% and - 5%, as discussed in text.
President’s initiative is from documents on the Administration plan at [http://www.whitehouse.gov/news/releases/2002/02/climatechange.html].

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Table 4. Impact of Economic Assumptions on Projections of
CO Emissions
2
Change in CO Emissions from Fuel Use,
2
Case Comparisons
2010
Low
Reference
High
economic
case
economic
growth
growth
MMTCE (%)
MMTCE
MMTCE (%)
Economic Growth
1,759 (-2%)
1,800
1,852 (+3%)
2003
Reference
High
Technology
Case
Technology
Integrated Technology
1,831 (+2%)
1,800
1,759 (-2%)
Source: EIA, Annual Energy Outlook 2003 (January 2003) DOE/EIA-0383(2003), pp. 174, 218.
Some studies suggest that even greater variance in projections is possible — for
example, that new energy-efficient technologies could be deployed more quickly than
generally assumed if appropriate policies were instituted. A November 2000 DOE
study, commonly called the “New 5-Lab Study,” shows that energy efficiency gains
in the transportation, industry, commercial, and residential sectors could reduce
emissions from the “business as usual” scenario.21 The “business as usual” scenario
in this study is very similar to EIA’s reference case, though it projects somewhat
smaller emissions in 2010 (1,769 MMTCE from fossil fuel combustion, compared
to EIA’s most recent projection of 1,800). The study compares “moderate” and
“advanced” scenarios “that are defined by policies that are consistent with increasing
levels of public commitment and political resolve to solving the nation’s energy-
related challenges.”
Policies examined include “fiscal incentives, voluntary
programs, regulations, and research and development.”22
Under the “moderate scenario,” energy efficiency is improved through such
policies as expanded labeling, new efficiency standards, tax credits, and cost-shared
R&D; renewable energy grows more rapidly than in the “business as usual” scenario,
and a higher proportion of nuclear power is retained. Under the “advanced scenario,”
which has more aggressive demand- and supply-side policies and a doubling of
R&D, a federally sponsored carbon trading system is announced in 2002 and
21
DOE, Interlaboratory Working Group, Scenarios for a Clean Energy Future,
ORNL/CON-476, LBNL-44029, and NREL-TP-620-29379 (Oak Ridge, TN: Oak Ridge
National Laboratory; Berkeley, CA: Lawrence Berkeley National Laboratory; Golden, CO:
National Renewable Energy Laboratory, November 2000), at [http://www.ornl.gov/ORNL/
Energy_Eff/CEF.htm].
22 Ibid., p. 1.4.

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implemented in 2005 with a clearing equilibrium price of $50 per ton of carbon.23
The results of this analysis are shown in Table 5.
Table 5. Impact of Technology/Efficiency Assumptions on
Projections of CO Emissions
2
Total CO Emissions from Fuel Use, 2010
2
Case Comparisons
(MMTCE)
“Business as Usual” (BAU)
1,769
Moderate Scenario
1,684 (-5% from BAU)
Advanced Scenario
1,467 (-17% from BAU)
Source: DOE, Interlaboratory Working Group, Scenarios for a Clean Energy Future,
ORNL/CON-476 and LBNL-44029 (Oak Ridge, TN: Oak Ridge National Laboratory; Berkeley, CA:
Lawrence Berkeley National Laboratory, 2000), Table 1.8, p. 1.18.
This “New 5-Lab Study” thus suggests that if specified policies were adopted,
emissions could be considerably lower than even EIA’s high-technology scenario
indicates, by as much as 17% compared to EIA’s high-technology reduction in
emissions of about 2%. EPA and the Department of Energy (DOE) have underway
a number of programs to foster the development and deployment of energy-efficient
technologies.24
The President’s greenhouse gas intensity reduction initiative is a new variable
affecting projections. It would have the effect of reducing anticipated emissions
below “business as usual” levels in the future (see Figure 3); however, the initiative
does not reflect the level of aggressiveness assumed by the “New 5-Lab Study” for
policy interventions to achieve its “advanced scenario” for rapid penetration of
energy-efficient technologies.
Status of Emissions Relative to Goals
Under the UNFCCC, the United States committed to the voluntary goal of
holding greenhouse gas emissions at the end of the 1990s to their 1990 levels. If the
United States had met this goal, its greenhouse gas emissions for 2000 would have
been 1,675 MMTCE. However, U.S. emissions in 2000 were 1,921 MMTCE (not
23 Ibid., pp. 1.6-1.7. Note that the carbon trading assumption has been effectively mooted
since it was not implemented in 2002 as assumed in the study.
24 See the Climate Action Report, Chapter 4; EIA, Analysis of the Climate Change
Technology Initiative, SR/OIAF/99-1, available at [http://www.eia.doe.gov/oiaf/climate99/
climaterpt.html]; and EIA, Analysis of the Climate Change Technology Initiative: Fiscal
Year 2001, SR/OIAF/2000-01, April 2000, available at [http://www.eia.doe.gov/oiaf/
climate/index.html].

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counting sinks). These figures indicate that in 2000, the nation was exceeding its
UNFCCC greenhouse gas emissions commitment by 246 MMTCE, or nearly 15%.
If the United States had acceded to the Kyoto Protocol, its greenhouse gases
emissions target for the period 2008-2012 would have been 5 times 93% of the 1,676
MMTCE baseline, or 1,559 MMTCE on average per year for the period. This
hypothetical goal would imply reductions equal to the difference between the goal
and what would be “business as usual emissions” for the period 2008-2012. Based
on the CAR projection that emissions will be 2,213 MMTCE in 2010, the average
annual reduction that would be necessary for the United States to meet the Kyoto
target of 1,559 MMTCE per year for 2008-2012 would be 654 MMTCE per year, or
about 30% below the estimated level of “business as usual” emissions. Higher than
base case economic growth or lower penetration of energy-efficient technologies
would mean that emissions would be even higher (and reductions necessary to meet
a goal like Kyoto greater). Slower economic growth, or faster penetration of energy-
efficient technologies as suggested by the 5-Lab Study, would decrease emissions
(and hence reductions to meet a goal).
The President’s greenhouse gas initiative has the goal of reducing, through
voluntary activities, the intensity of net greenhouse gas emissions per unit of
economic activity by 18% over the next 10 years; this compares to a projected
“business as usual” decline in intensity of 14% for the period — compared to a
decline during the 1990s of about 10% (see Table 3). According to the White House
announcement, this goal means that the current (2002) intensity of 183 metric tons
of carbon emissions per million dollars of GDP would fall to 151 MMTCE per
million dollars of GDP in 2012 (see Figure 4).25 At the anticipated increased rate of
intensity decline, total emissions would decline 100 MMTCE below “business as
usual” emissions (although the absolute amount of emissions would continue to rise).
It is too early to assess progress toward the Administration’s goal of diminishing
greenhouse gas intensity.
25 Current data suggests that the 2002 carbon intensity baseline may have dropped below 180
MMTCE (see Table 3).

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Figure 4. Greenhouse Gas Intensity:
President’s Initiative
Source: White House, Global Climate Change Policy Book, Feb. 14, 2002, at [http://www.epa.gov/
globalwarming/publications/actions/us_position/bush_gccp_021402.pdf].
These projected emissions levels (and any implied reductions) are gross
estimates and do not take sinks into account (except for the intensity projection). As
previously noted, the baseline could be revised, at least slightly. More important,
such projections depend on assumptions about economic trends as well as about
policy actions at the local, domestic, and international levels. However, whatever the
assumptions, the trend in total emissions experienced over the past decade and
projected for the next decade is clearly upward, while the UNFCCC goal was for
stabilization and the Kyoto Protocol calls for emissions levels of developed nations
to decline.
Additional Considerations in
Assessing Possible Reductions
If one is concerned about assessing the implications of possible reduction
requirements in the future, two further factors must be considered.
One is
sequestration, which removes CO from the atmosphere, thereby reducing gross
2
emissions. The second is a series of proposed trading mechanisms that could allow
a country to take credit for reductions it sponsors in other countries. The United
States was a strong supporter of including both these variables in the Kyoto Protocol.
Sequestration could directly diminish a country’s reduction requirement; trading does
not change a reduction requirement, but it could affect costs and who would actually
achieve the reductions.
Carbon Sequestration. Atmospheric greenhouse gas levels are affected not
only by emissions, but also by carbon sinks — processes that remove and sequester
carbon from the atmosphere. Activities that affect sequestration include farming and
forestry practices. For example, a positive net growth of trees removes carbon from
the atmosphere; clearing forests typically releases carbon.
Table 1, “U.S.

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Greenhouse Gas Emissions, 1990 -2001,” includes figures for carbon sequestration
from land-use activities and forestry, which are the difference between “total
emissions” and “net emissions.”
The UNFCCC states that signatory nations shall commit to “promote sustainable
management, and promote and cooperate in the conservation and enhancement, as
appropriate, of sinks and reservoirs of all greenhouse gases ... , including biomass,
forests and oceans as well as other terrestrial, coastal and marine ecosystems”
(Article 4(1)(d)).
The Kyoto Protocol also would provide that sinks can be taken into account in
calculating a nation’s emissions and its reduction obligation. “The net changes in
greenhouse gas emissions from sources and removals by sinks resulting from direct
human-induced land-use change and forestry activities, limited to afforestation,
reforestation, and deforestation since 1990, measured as verifiable changes in stocks
... shall be used to meet” the 2008-2012 commitments (Article 3(3)). In general,
then, a net increase in human-induced carbon sequestration from forestry practices
between 1990 and 2008-2012 would be subtracted from emissions during the period,
thereby reducing the amount of actual emissions that will have to be curtailed.
Conversely, net negative sequestration from forestry practices would be added to the
emissions that will have to be reduced.
Just how this calculation would be done is not prescribed in the Protocol, and
disagreements on how much carbon sequestration could be counted toward a nation’s
reduction obligations were debated through several subsequent conferences. In July
2001, the Sixth Conference of Parties in Bonn (COP6) agreed to limits on
sequestration activities that could be credited against the Protocol’s reduction
requirements.
Although the United States chose not to participate in these
proceedings, the Conference stated in a footnote26 that under the methodology agreed
upon, the United States could take credit for net increases of sequestration of up to
28 million metric tons per year.
Emissions Trading. Emissions trading, strongly supported by the United
States in the Kyoto negotiations, derives from the principle of economic efficiency
— that reductions, if necessary, should be achieved at the lowest cost. Trading
mechanisms thus are designed to allow low-cost reductions to substitute for higher-
cost ones. The idea is that a country could achieve its reduction goal not only by
reducing its domestic emissions, but also by reducing emissions elsewhere. Trading
does not actually reduce a nation’s reduction requirement, but it does allow it to
contract for and to count reductions elsewhere that are cheaper to achieve than
domestic ones.
The Kyoto Protocol provides for emissions trading mechanisms27 that can be
used to “supplement” domestic reductions; this offers the possibility that actual
26“Draft Decision on Implementation of the Kyoto Protocol on Climate Change,” adopted
in Bonn, Germany, July 23, 2001, footnote to Appendix Z.
27Kyoto Protocol, articles 4, 6, and 12; see also CRS Issue Brief IB97057, Global Climate
Change: Market-Based Strategies to Reduce Greenhouse Gases.

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domestic greenhouse gas reductions achieved by a party to the Kyoto Protocol will
be less than the party’s actual commitment.
Some portion of the reduction
requirement could be shifted elsewhere. The Clinton Administration argued that
emission trading would be critical to U.S. compliance with Kyoto;28 a Clinton
Administration economic analysis suggested that U.S. compliance costs would drop
from $193 per ton with no international emissions trading to $23 per ton with global
trading.29 COP6 agreed that there would be no quantitative limit on the amount of
credit a country could receive from trading, but that domestic action must constitute
a significant part of a nation’s reduction efforts.30 With no quantitative limit on
trading, any estimate of actual domestic reduction required to comply with the Kyoto
Protocol, or of the costs involved, remains problematic — and is moot as long as the
United States declines to participate in the Kyoto process.
Conclusion
The precise numerical projections of greenhouse gas emissions (or of proposed
reductions) should be viewed as indicative (see Figure 3). They are less accurate
than they appear, given the potential for revisions in data and the uncertainties of
projections. But in assessing the status of U.S. greenhouse gas emissions, the
trendline for aggregate greenhouse gas emissions is clear: for the United States, the
overall trend is up. None of the reviewed scenarios using assumptions that diminish
emissions — low economic growth, putting off retirement of nuclear facilities,
accelerated fostering of energy-efficient technologies, the President’s voluntary
program to reduce greenhouse gas intensity — reverses the upward trend in aggregate
greenhouse gas emissions by 2010.31
Historical data show that the United States failed to meet its voluntary
commitment under the UNFCCC for returning aggregate emissions at the end of the
1990s decade to the 1990 level. Any goal to reduce emissions to or below 1990
levels would require the continuing upward trend to turn down. Even with the
potential for sequestration and emissions trading to reduce domestic reduction
efforts, a goal to reverse greenhouse gas emissions trends would represent an
extraordinary technical and political challenge for U.S. energy and environmental
policy.
28Statement of Janet Yellen, Chair, President’s Council of Economic Advisors, House
Committee on Commerce, Subcommittee on Energy and Power, March 4, 1998.
29For a discussion of the impact of emissions trading on costs, see CRS Report RL30285,
Global Climate Change: Lowering Cost Estimates through Emissions Trading — Some
Dynamics and Pitfalls, by Larry Parker.
30“Draft Decision on Implementation of the Kyoto Protocol on Climate Change,” adopted
in Bonn, Germany, July 23, 2001.
31The “advanced” scenario of the “New 5-Lab Study” projects the trend turning downward
after 2020.