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 March 12, 2002
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
On 15 October 1992 the United States ratified the United Nations Framework
Convention on Climate Change (UNFCCC), which entered into force 21 March 1994.
This committed the U.S. 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 (N O),
2
4
2
Hydrofluorocarbons (HFCs), Perfluorocarbons (PFCs), and Sulfur Hexafluoride
(SF )]” at the “end of the decade” “to their 1990 levels.”
6
Subsequently, in the 1997 Kyoto Protocol to the UNFCCC, the U.S. 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 U.S. Environmental Protection Agency Administrator
Whitman has told reporters that the Administration will not be pursuing the UNFCCC
commitment either. Instead, President Bush is proposing 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. Based on historical data,
1999 emissions were more than 11% in excess of the UNFCCC goal. Projections
suggest that U.S. emissions will continue to rise for at least the next decade.
Reversing the upward trend in greenhouse gas emissions represents 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 Goals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Emissions Projections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
The Draft Climate Action Report Projection . . . . . . . . . . . . . . . . . . . . . . . 7
Additional Variables Affecting Possible Reductions . . . . . . . . . . . . . . . . . 14
Carbon Sequestration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Emissions Trading . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
List of Figures
Figure 1. U.S. Emissions of CO : Historical (1990s) and Projected (to 2010) . . . 8
2
Figure 2. U.S. Emissions of CH , N O, and HFCs, PFCs, and SF : Historical (1990s)
4
2
6
and Projected (to 2010) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Figure 3. U.S. Aggregate Gross Emissions of Six Greenhouse Gases:
Historical (1990s) and Projected (to 2010) (MMTCE) . . . . . . . . . . . . . . 10
Figure 4: Greenhouse Gas Intensity: President’s Initiative . . . . . . . . . . . . . . . . 13
List of Tables
Table 1: U.S. Greenhouse Gas Emissions, 1990-1999 . . . . . . . . . . . . . . . . . . . . 3
Table 2. U.S. Baseline Year Greenhouse Gas Emissions . . . . . . . . . . . . . . . . . . 4
Table 3: U.S. Greenhouse Gas Intensity (1990-2000) . . . . . . . . . . . . . . . . . . . . 6
Table 4: Impact of Economic Assumptions on Projections of CO Emissions . 12
2
Table 5: Impact of Technology/Efficiency Assumptions on Projections of CO2
Emissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Global Climate Change:
U.S. Greenhouse Gas Emissions —
Status, Trends, and Projections
On 15 October 1992 the United States ratified the United Nations Framework
Convention on Climate Change (UNFCCC), which entered into force 21 March 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.”2 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.”3 The
Convention established standards for inventorying and reporting greenhouse gas
emissions.
Subsequently, the United States participated in negotiating the Kyoto Protocol
to the UNFCCC.4 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 6 gases by 7% below
specified baseline years.5 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.”6
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 by Wayne A. Morrissey and
John R. Justus. See also CRS’s electronic briefing book Global Climate Change at:
[http://www.congress.gov/brbk/html/ebgcc1.shtml].
2 UNFCCC, Article 4, Commitments, sections 2(a) and (b).
3 Ibid., section 2(a).
4On the Agreement, see CRS Report RS30692, Global Climate Change Treaty: The Kyoto
Protocol,
by Susan R. Fletcher.
5Technically, the net carbon-equivalent emissions of the 6 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.
6White House, Office of the Press Secretary, “President Bush Discusses Global Climate
Change,” June 11, 2001.

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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
described below, President Bush has announced a voluntary program to reduce the
intensity of U.S. greenhouse gas emissions per unit of economic productivity. Based
on this initiative, according to Environmental Protection Agency Administrator
Whitman, “the Bush Administration does not intend to pursue emissions cuts it
committed to” in the UNFCCC.7
This report sets out the baseline emissions that the U.S. has established and
portrays trends in emissions over the past decade; 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 the agreement to
reduce emissions.) In what follows, figures for emissions are point estimates and
rounded to millions of metric tons of carbon equivalents (MMTCE8)
. As will be
discussed, even historical data are of varying robustness and may be subject to
adjustments. The data for CO , which accounts for over 80% of domestic greenhouse
2
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
trendlines between baselines and the UNFCCC and Kyoto goals can give a clear
sense of the situation of the United States with respect to those goals.
At this time, the situation is that aggregate U.S. emissions of greenhouse gases
over the decade of the 1990s trended upward and are projected to continue to rise in
the future. In contrast, the UNFCCC called for emissions at the end of the decade to
be at the 1990 level, and the Kyoto Protocol would call for U.S. greenhouse gas
emissions to decrease 7% below the baseline for the period 2008-2012.
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.”9 (See Table 1.)
7“Bush Emissions Plan Seen Replacing Regs,” Platts Inside Energy (Feb. 25, 2002), p. 9.
8MMTCE figures combine the variable greenhouse effects of the different gases by calculating
and summing their equivalent effects. 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.
9 UNFCCC, Article 4, section 1(a) and Article 12, section 1(a).

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Table 1: U.S. Greenhouse Gas Emissions, 1990-1999
Gas
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
CO
1,340
1,326
1,353
1,384
1,410
1,424
1,474
1,494
1,497
1,516
2
CO (sinks)a
(289)
(286)
(272)
(280)
(280)
(278)
(279)
(263)
(268)
(270)
2
CH
176
175
177
174
176
177
174
172
170
169
4
N O
108
110
113
113
121
118
120
121
118
118
2
HFCs, PFCs, SF
23
22
23
23
24
27
31
34
38
37
6
Total emissions
1,647
1,633
1,666
1,694
1,731
1,746
1,799
1,821
1,824
1,840
Net emissions
1,358
1,347
1,394
1,414
1,451
1,468
1,521
1,554
1,556
1,570
aLand-use changes and forestry sinks that sequester carbon; included in net emissions total only.
Source: EPA, Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990 - 1999) April 2001, EPA 236-R-01-001, p. ES-4. [Data
converted to MMTCE by CRS.] Data for 1992-1994 calculated from ibid., Table 1 “Revisions to U.S. Greenhouse Gas Emissions,”
p. xii and EPA, “U.S. Emissions Inventory – 2000,” Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990 – 1998) April 2000,
EPA 236-R-00-001, p. ES-4.

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The Environmental Protection Agency (EPA) publishes the official emissions
data annually,10 and the United States also from time to time reports on emissions and
explains its climate change programs in the Climate Action Report to the United
Nations, the third of which is currently in draft.11
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 1,647 MMTCE;
if the United States had acceded to the Kyoto targets, the baseline would have been
1,651 MMTCE, since the baseline years for HFCs, PFCs, and SF can be 1995. By
6
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
1,340
2
Methane (CH )
1990
176
4
Nitrous Oxide (N O)
1990
108
2
Hydrofluorocarbons (HFCs)
1990
1995
23
27
Perfluorocarbons (PFCs)
UNFCC
Kyoto
UNFCC
Kyoto
Sulfur Hexafluoride (SF )
6
Total
1,647
1,651
Source: EPA, Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990 - 1999) April
2001, EPA 236-R-01-001, p. ES-4. [Data converted to MMTCE by CRS.]
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 the 1990-1999
report, which also converted the figures from MMTCE to teragrams of CO2
equivalent, consistent with international practices.12 (This report maintains the MMTCE
figures, which are more familiar to most U.S. policy makers.) The criteria for calculating
emissions agreed upon by the Conference of Parties hinge on both current technical
10EPA, Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990 - 1999) April 2001,
EPA 236-R-01-001:
[http://www.epa.gov/globalwarming/publications/emissions/us2001/]
11 The first two Climate Action Reports Submitted by the United States of America under the
United National Framework Convention on Climate Change appeared in October 1994 and
July 1997; for the third report, now in draft, see: the Climate Action Report 2001, Draft for
Public Comment, [http://www.epa.gov/globalwarming/publications/natcomm.html]
12 EPA, Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-1999 , xi-xvii.

CRS-5
knowledge and on policy judgments.13 New technical information can change factors,
for example concerning calculation of greenhouse gas equivalents; and policy
judgments can be adjusted, for example concerning the timeframe 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 more than plus or minus 1%.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 (see Table 3), in large part because of the on-
going phase out of chlorofluorocarbons, which deplete stratospheric ozone and which
are not covered by the UNFCCC. For the 1990s, the decline in intensity has been
about 15%.
Emissions Goals
Under the UNFCCC, the U.S. committed to the voluntary goal of holding
greenhouse gas emissions at the end of the 1990s decade to their 1990 levels. If the
U.S. had met this goal, its greenhouse gas emissions for 2000 would have been 1,647
MMTCE. However, U.S. emissions in 1999 were 1,840 MMTCE (not counting
sinks). These figures indicate that in 1999, the U.S. was exceeding its UNFCCC
greenhouse gas emissions commitment by 193 MMTCE, or 11.7%.
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 1,651
MMTCE baseline, or 1,535 MMTCE on average per year for the period. This goal
would imply reductions equal to the difference between the goal and what would be
“business as usual emissions” for the period 2008-2012. Estimating that reduction
requires projecting future emissions.
The present Administration, having rejected the Kyoto Protocol, has proposed
that the United States shift its climate change goal to a reduction in greenhouse gas
intensity of the U.S. economy.15 The President’s initial goal is to reduce that intensity
13The Kyoto Protocol requires that further studies of greenhouse gas emissions and removals
be undertaken and incorporated in any future commitments for reducing greenhouse gases
beyond the 2008-2012 target.
14 See “Table Changes - 1: Revision U.S. Greenhouse Gas Emissions,” EPA, Inventory of
U.S. Greenhouse Gas Emissions and Sinks: 1990-1999
, p. xii. Total 1990 emissions were
revised downward 0.2%; the largest revision was for 1998, down 0.6%. On the other hand,
revisions to sequestration estimates were much greater, from -15.6% to + 31.9%: ibid., p. xiii.
15 For documents on the Administration plan, see
(continued...)

CRS-6
by 18% over the next 10 years through voluntary activities, which means that the
current 183 metric tons of carbon emissions per million dollars of GDP that the
United States is emitting in 2002 would fall to 151 MMTCE per million dollars of
GDP in 2012. To convert that reduction in intensity to a reduction in actual
emissions, so it can be compared to the UNFCCC and Kyoto Protocol goals, requires
projecting future emissions.
Table 3: U.S. Greenhouse Gas Intensity (1990-2000)
GDP (billions of chained
Greenhouse Gas Intensity (metric
(1996) dollars)
tons carbon equivalent per million $
GDP)
1990
6,708
245
1991
6,678
245
1992
6,880
242
1993
7,063
240
1994
7,348
235
1995
7,544
231
1996
7,813
230
1997
8,160
223
1998
8,509
214
1999
8,856
208
2000
9,224
206
Source: Table 1; Economic Report of the President, February 2002, Table B-2; CRS
calculations.
Emissions Projections
Projecting greenhouse gas emissions involves modeling of 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.
15(...continued)
[http://www.whitehouse.gov/news/releases/2002/02/climatechange.html]

CRS-7
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. The policy 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 at best.
The Draft Climate Action Report Projection
The third U.S. Climate Action Report (CAR), prepared as an obligation under
the UNFCCC,16 projects greenhouse gas emissions for the years 2000, 2005, 2010,
and 2020. For this draft 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.
The CAR estimate for aggregate gross greenhouse emissions 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.” Ignoring the 2-year difference between
2010 and 2012, the estimate based on the President’s initiative suggests a decline in
emissions of about 4.5% from the CAR “business as usual” projection for 2010, or
gross greenhouse emissions in 2010 (2012) of approximately 2,113 MMTCE.
CAR 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) Annual
2
Energy Outlook series.17 (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
16 [EPA,] Climate Action Report 2001, The United States of America’s Third National
Communication Under the United Nations Framework Convention on Climate Change
[DRAFT FOR PUBLIC COMMENT ]
[http://www.epa.gov/globalwarming/publications/natcomm.html]
17 EIA, Annual Energy Outlook 2001 (Dec. 2001), DOE/EIA-0383(2002).

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Figure 1. U.S. Emissions of CO : Historical (1990s) and Projected (to 2010)
2
1800
1600
1400
1200
1000
MMTCE
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 1999): EPA, Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990 - 1999, April 2001, EPA 236-R-01-
001, p. ES-4. Data for 1992-1994 calculated from ibid., Table 1 "Revisions to U.S. Greenhouse Gas Emissions," p. xii and EPA, "U.S. Emissions
Inventory – 2000," Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990 – 1998, April 2000, EPA 236-R-00-001, p. ES-4. Year 2000
(preliminary) and projections (to 2010): [EPA,] Climate Action Report 2001, The United States of America's Third National Communication
Under the United Nations Framework Convention on Climate Change [DRAFT FOR PUBLIC COMMENT]
[http://www.epa.gov/globalwarming/publications/natcomm.html] [Data converted to MMTCE by CRS.]

CRS-9
Figure 2. U.S. Emissions of CH , N O, and HFCs, PFCs, and SF : Historical (1990s) and Projected (to 2010)
4
2
6
175
150
125
100
MMTCE
75
50
25
0
1990
1992
1994
1996
1998
2000
2002
2004
2006
2008
2010
CH4
N20
HFCs, PFCs, SF6
Sources: Historical data (through 1999): EPA, Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990 - 1999, April 2001, EPA 236-R-01-
001, p. ES-4. Data for 1992-1994 calculated from ibid., Table 1 "Revisions to U.S. Greenhouse Gas Emissions," p. xii and EPA, "U.S. Emissions
Inventory – 2000," Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990 – 1998, April 2000, EPA 236-R-00-001, p. ES-4. Year 2000
(preliminary) and projections (to 2010): [EPA,] Climate Action Report 2001, The United States of America's Third National Communication
Under the United Nations Framework Convention on Climate Change [DRAFT FOR PUBLIC COMMENT]
[http://www.epa.gov/globalwarming/publications/natcomm.html] [Data converted to MMTCE by CRS.]

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Figure 3. U.S. Aggregate Gross Emissions of Six Greenhouse Gases:
Historical (1990s) and Projected (to 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 1999): EPA, Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990 - 1999, April 2001, EPA 236-R-01-001, p. ES-4.
Data for 1992-1994 calculated from ibid., Table 1 "Revisions to U.S. Greenhouse Gas Emissions," p. xii and EPA, "U.S. Emissions Inventory – 2000," Inventory
of U.S. Greenhouse Gas Emissions and Sinks: 1990 – 1998
, April 2000, EPA 236-R-00-001, p. ES-4. Year 2000 (preliminary) and projections (to 2010): [EPA,]
Climate Action Report 2001, The United States of America's Third National Communication Under the United Nations Framework Convention on Climate
Change [DRAFT FOR PUBLIC COMMENT] [http://www.epa.gov/globalwarming/publications/natcomm.html] [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]

CRS-11
innovation, have the greatest effect on variance in projections of CO emissions. For
2
2010, compared to EIA’s “reference case” (which is equivalent to a “business as
usual” case), low economic growth would reduce projected emissions by about 2%,
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 faster-than-
expected technological development is projected to reduce emissions about 3%.
Overall, if those variances that increase emissions prove true and cumulative, then
projected emissions for 2010 could be higher than the point reference case – or CAR’s
point estimate – by at least 5%; conversely, if those variances that decrease emissions
prove true and cumulative, then projected emissions for 2010 could be at least 5%
lower than projected.

Some studies suggest that even greater variance in projections is possible – for
example, that new energy efficient technologies are available and 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.18 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 1,835). 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.”19
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 federal-sponsored carbon trading system is announced in 2002 and implemented in
2005 with a clearing equilibrium price of $50 per ton of carbon.20 The results of this
analysis are shown in Table 4.
This “New 5-Lab Study,” 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 3%. EPA and the Department of Energy (DOE) have underway
18 DOE, Interlaboratory Working Group, Scenarios for a Clean Energy Future (Oak Ridge,
TN; Oak Ridge National Laboratory and Berkeley, CA; Lawrence Berkeley National
Laboratory; November, 2000) (ORNL/CON-476 and LBNL-44029).
[http://www.ornl.gov/ORNL/Energy_Eff/CEF.htm]
19 Ibid., p. 1.4.
20 Ibid., pp. 1.6-1.7.

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Table 4: Impact of Economic Assumptions on Projections of
CO Emissions
2
Change in CO Emissions from Fuel Use, 2010
2
Case Comparisons
Low
Reference
High
economic
case
economic
growth
growth
MMTCE (%)
MMTCE
MMTCE (%)
Economic Growth
1,794 (-2%)
1,835
1,888 (+3%)
2002
Reference
High
Technology
Case
Technology
Integrated Technology
1,868 (+2%)
1,835
1,782 (-3%)
Source: EIA, Annual Energy Outlook 2002 (December 2001) DOE/EIA-0383(2002), pp.
177, 218.
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 (Oak
Ridge, TN; Oak Ridge National Laboratory and Berkeley, CA; Lawrence Berkeley National
Laboratory, 2000) (ORNL/CON-476 and LBNL-44029), Table 1.8, p. 1.18.
a number of programs to foster the development and deployment of energy efficient
technologies.21 However, even the President’s greenhouse gas intensity reduction
initiative does not reflect the level of aggressiveness assumed by the “New 5-Labs
Study” for policy interventions to achieve its “advanced scenario” for rapid
penetration of energy efficient technologies. Based on the CAR projection that
emissions will be 2,213 MMTCE in 2010, the average annual reduction that would
21 See the Climate Action Report, Chapter 4, and EIA, Analysis of the Climate Change
Technology Initiative
(SR/OIAF/99-1) [www.eia.doe.gov/oiaf/climate99/climaterpt.html] and
EIA, Analysis of the Climate Change Technology Initiative: Fiscal Year 2001
(SR/OIAF/2000-01 (Washington, D.C.: April 2000)
[www.eia.doe.gov/oiaf/climate/index.html]


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be necessary for the United States to meet the Kyoto target of 1,535 MMTCE per
year for 2008-2012 would be 668 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).
If successful, the President’s greenhouse gas reduced intensity initiative would
mean that emissions would be less than “business as usual” (see Figure 3). In terms
of the Administration goal of reducing greenhouse gas intensity, the President’s
initiative is projected to reduce that intensity by 18% over the next 10 years; this
compares to a projected “business as usual” decline in intensity of 14% for the period
(see Figure 4).22 Even at this increased rate of intensity decline, the absolute amount
of emissions will continue to rise.
These projected emissions levels (and any implied reductions) are gross estimates
and do not take sinks into account. As previously noted, the baseline could be
revised, at least slightly. More importantly, such projections depend on
Figure 4: Greenhouse Gas Intensity: President’s
Initiative
Source: White House, Global Climate Change Policy Book, Feb. 14, 2002:
[http://www.epa.gov/globalwarming/publications/actions/us_position/bush_gccp_021402.pdf]
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 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.
22The 14% is about the same as for the 1990s decade (see Table 3 and accompanying text).

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Additional Variables Affecting Possible Reductions
If one is concerned about estimating possible reduction requirements in the
future, then two variables besides those affecting the projection of emissions
trendlines need to be considered. One is sequestration, which removes CO from the
2
atmosphere, thereby reducing gross emissions. The second is a series of proposed
trading mechanisms, which 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. Greenhouse
Gas Emissions, 1990 -1999
, 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 footnote23 that under the methodology agreed
23“Draft Decision on Implementation of the Kyoto Protocol on Climate Change,” adopted in
(continued...)

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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 mechanisms24 that can be
used to “supplement” domestic reductions; this offers the possibility that actual
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 Kyoto25; 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.26 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.27 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
23(...continued)
Bonn, Germany, July 23, 2001, footnote to Appendix Z.
24Kyoto Protocol, articles 4, 6, and 12; see also CRS Issue Brief IB97057, Global Climate
Change: Market-Based Strategies to Reduce Greenhouse Gases,
.
25Statement of Janet Yellen, Chair, President’s Council of Economic Advisors, House
Committee on Commerce, Subcommittee on Energy and Power, March 4, 1998.
26For 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.
27“Draft Decision on Implementation of the Kyoto Protocol on Climate Change,” adopted in
Bonn, Germany, July 23, 2001,

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trendline for aggregate greenhouse gas emissions is telling: for the United States, the
overall trend is inexorably 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 – reverse the upward trend in aggregate
greenhouse gas emissions by 2010.28
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 below 1990 – as the
Kyoto Protocol calls for – would require the continuing upward trend to turn down.
Even with the potential for emissions trading and sinks 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.
28The “advanced” scenario of the “New 5-Labs Study” projects the trend turning downward
after 2020.