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OCR for page 15
2
BACRGROIJND
GENESIS OF THE 8TlJDY
Global climate change emerged as a major issue in the United
States during the 1980s. As a result of national concern, Congress
adopted legislation in its 1989 Energy and Water Development
Appropriation Bill for studies to clarify and define the extent of
the problem and to recommend options for its management. The
legislation was based on the premise that emissions of greenhouse
gases (Gags) arising from energy production and use are significant
precursors of global climate change. Accordingly, in Public Law
100-371, Congress directed the secretary of energy to ask the
National Academy of Sciences and the National Academy of
Engineering to:
· assess the current state of research and development
(R&D) in the United States in alternative energy sources
"including, but not limited to, nuclear power, solar power,
renewable energy sources, improved methods of employing fossil
fuels, energy conservation, and energy efficiency";
~ suggest R&D strategies for stabs lizing the atmospheric
concentrations of GHGs that contribute to global climate change;
and
~ analyze what federal investments would encourage greater
private investment in alternative sources of energy.
This report presents the recommendations of the study
committee (Committee on Alternative Energy Research and Development
Strategies) appointed by the National Research Council in response
to the directive.
PROBLEM DESCRIPTION
A number of atmospheric gases absorb infrared radiation emitted
from the earth's surface and prevent its escape into space. This
trapping of infrared radiation is commonly referred to as the
greenhouse effect. The principal GHGs that are also constituents
of the atmosphere are carbon dioxide (CO ), water vapor (H2O), and
methane (CH43. Other important GHGs include ozone, nitrous oxide
(N2O), and the chlorofluorocarbons (CFCs); of these the CFCs have
no natural sources. Altogether, over 40 GHGs have been identified
so far, most of which are radiatively active. ,-3
GHGs must be present in the earth's atmosphere for the earth's
temperature to be suitable for life as we know it. However, human
15
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activities (primarily energy-related ones, as shown In Figure 2-
1) are increasing the atmospheric concentrations of many GHGs at
a rate that is faster than the rate of absorption by natural sinks.
The concern is that, if this rate of increase in the concentrations
of GHGs continues, climatic changes may arise that would have maj4Or
impacts on the natural environment and on human societies.
Scientific uncertainty exists, however, regarding the timing and
extent of potential glob,01,climate change from the accumulation of
GHGs in the atmosphere. ~
Principal GHGs associated with energy production and use
include CO2 emitted during the combustion of hydrocarbon fuels; CH4
emissions from coal mines and from the venting and leakage of
natural gas during drilling, production, and transmission; and
releases of CFCs from air conditioners, refrigeration equipment,
and the production of insulating materials. N2O emissions come
from the combustion of hydrocarbon fuels, including agricultural
biomass, and from the use of nitrogenous ferti liners.
The atmospheric concentration of CO2 is currently around 350
parts per million by volume (ppmv) , which is about 25 percent above
the preindustrial level of 280 ~ 10 ppm estimated for 1860
(Figure 2-2) and exceeds atmospheric concentrations that can be
inferred from geologic records.
On average, CO2 emissions from fossil fuel combustion have
increased by 4.3 percent per year since 1860 and are currently on
the order of 20 billion metric tons of CO2 or 5.5 billion metric
tons of carbon (OTC) per year out of a total of 6 to 8 GIC per year
from all man-made sources. The contribution to CO2 emissions of
hydrocarbons used for fuel depends on the carbon content of the
fuel per unit of combustion energy. Among the fossil fuels, per
quad (1035 Btu) of energy used, natural gas emits the least carbon
(14.5 million metric tons carbon, MTC); coal the most (25.1 MTC);
and petroleum an intermediate amount (20.3 MTC). Traditional
biomass fuels, such as crop residues and dung, release CO' to the
atmosphere in a balanced cycle of absorption and respirat' on. In
contrast, other biomass fuels such as firewood may provide either
a net annual source or sink for carbon, depending on whether the
underlying biomass stock is being depleted or increased,
respectively.
Although the concentrations by volume and the annual rate of
emissions of other GHGs such as CH4, the CFCs, and N2O are much less
than those of CO2, they cannot be ignored (Table 2-1~. Carbon
dioxide is nevertheless the single most signif icant anthropogenic
GHG from energy production and use (Figure 2-3), and its control
was the focus of this study.
16
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Energy tJse I
and Production
(57°/0)
CFCs
(1 7°'0)
\ I Other ~
_
Industrial
(3%)
l ~
Detorestation
(9°/0)
FIGURE 2-] Sources of GXGs. Energy production and use constitute
the largest human source of greenhouse gases, but
other activities are also significant.2
17
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350
330
310
.,'
~ _
~ - ,
290
270
FIGURE: 2 - 2
f
/
1740 1790 ~ 840
Year
Historical variation in
concentration. '2
18
/
,4
-
1890 1940 1990
atmospheric carbon dioxide
OCR for page 19
TABLE 2-1 Key Atmospheric Trace Gases Whose Concentrations Are
Increas ing,4
-
Concentrattona
~n 1985
Annual Rate of Increase
As of 1985
CO2 345 ppmv 1. 4 ppmv ~ 0 . 4% ~
CH4 1. 65 ppmv 18 . O ppbv (1.1%)
N2O 305 ppbv
CEC-11 220 pp~cv
CFC- 12 380 ppev
0.6 ppbv (0.296)
11.0 pptv (5. o%)b
1 9 . O pp tV ~ 5 . 0% ~ b
a Concentrations are global averages in 1985. Values shown for
the rate of increase are representative as of 1985.
b These chlorofluorocarbons will be phased out under the terms of
the Montreal Protocol that is now in force.
19
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1 880-1 980
1 980s
Other (8°~) .
LC'C 11 ~ -12 (8%)- ~
[
1 N2O (3°/O) ~
CH~(lS.Mo)
-
~ CO2 (66°~) 1
Her (13°/O)
. ~~
CFC-11 &-12 jet
1 N2O (6%)
CO2 (49%)
. 51 J
1 CH4(18%~
FIGURE 2-3 GIlGs responsible for increases in the greenhouse
effect worldwide .2
20
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Notwithstanding the uncertainties regarding climate change and
its consequences, the central task of this study was to determine
the priorities and federal strategies for energy R&D efforts and
the deployment of alternative energy technologies to significantly
reduce GHG emissions. The strategies are to include actions in both
the public and private sectors and consideration of how they might
mesh and complement one another.
THE GLOBAL CONTEXT
On the premise that increasing accumulation of GHGs increases
the probability that significant global waffling will occur, a major
goal would be to reduce atmospheric emissions of such gases,
especially CO2. Global fossil fuel energy resources are large and
include petroleum, coal, natural gas, tar sands, oil shale, and
deposits of bitumen.35 Approximately 80 percent of the world's coal
resources are in the United States, the U.S.S.R., and the People's
Republic of China, and coal is expected to be the dominant fuel
that will be used around the world over the next several decades.
Continued use of increasing amounts of fossil fuels, unconstrained
by considerations of the potential impacts of GHG emissions, could
lead to atmospheric accumulation of CO2 approaching concentrations
likely to initiate irreversible changes in the earth's climate.
Controls may therefore be required on the use of such fuels and
could be targeted to hold CO2 concentrations and the rate of
increase from exceeding some generally acceptable limits.
The U.S. Environmental Protection Agency's study, Policy
Options for Stabilizing Global Climate, 2 concluded that very large
reductions (on the order of 50 to 80 percent of current levels) in
worldwide CO2 emissions are required, starting now, to achieve
stabilization of atmospheric GHG concentrations at their current
levels. Despite considerable uncertainties in this estimate, it
raises at least two fundamental questions: (1) How much reduction
in the emissions of GHGs (from a specified baselines is achievable
with various energy production and end-use technologies? (2) What
would it take to implement those technologies (whether currently
available Or yet to be developed) and effectively replace their
less energy-inefficient or more polluting counterparts? As a first
step, this study addresses these questions for the electric power,
transportation, buildings, and industry sectors in the United
States.
Aside from the CFCs (phaseout of which is now governed by the
Montreal Protocol) , increases In worldwide emissions of CO2 and
other GHGs are expected to continue over the next century unless
strong public policies are adopted for their control . It is
further expected that the bulk of the emissions will result from
increasing exploitation of hydrocarbon fuels, primarily coal,
necessitated by energy demands from industrial iced countries such
as the United States and the U.S.S.R., from countries with
21
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expanding industrial development such as China and India, and from
growing populations. Concerted action by all countries is
essential if successful responses to regional and global
environmental problems such as acid rain and the greenhouse effect
are to be developed and implemented in a timely and effective
manner. What is still an open issue is how such action is to be
taken worldwide and what the roles and responsibilities of various
countries would be to assure its successful execution.
For developing countries, all of which will need more energy
to fuel their economic growth, even the prospect of restrictions
on the use of relatively cheap, easily accessible fossil fuels
raises questions of equity and fairness. Their vied is that the
bulk of the burden of reducing the use of fossil fuels ought to
rest on the industrialized countries, because annual consumption
of energy resources in those countries has thus far accounted for
about 80 percent of the worlds consumption and attendant emissions
of GHGs.
_ _ . . . . .
The United States is currently the primary contributor to the
greenhouse effect. According to a recent study, ]6 U. S. emissions
of CO have increased over the past 2 years, and the U.S. share of
global CO2 emissions in 1988 was estimated to be around one-
quarter. In this milieu there is growing opinion in the United
States that a number of innovative and cost-effective U.S. actions
are possible, which could significantly reduce GHG emissions from
the nation's current levels, establish a leadership position for
the United States with which to support other countries in similar
efforts, and create a setting in which actions needed world,7i'9de can
be planned and executed in a timely and concerted manner.
.
.
The committee appreciates the value in such a role being taken
by the United States even as it recognizes that unilateral action
taken solely bv one country will be much less ef festive than
,^ ,, _, ~
concerted actions. In the committee's view, developing a strategic
vision for the United States in terms of energy R&D and adoption
of alternative energy technologies that are low or even nonemitters
of GHGs is an important first step. The vision should then serve
and be used as a point of departure toward a broader program of
global cooperation and joint efforts for safeguarding the
environment. This study was approached with such a viewpoint and
expectation.
22
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NOTES AND REFERE ACES
1. See,
for example, A Primer on Greenhouse Gases: CO2, Report
No . TR040, DOE/NBB 0083, U. S . Department of Energy,
Of f ice of Energy Research, Of f ice of Basic Energy
Sciences, Carbon Dioxide Research Division, Washington,
D.C., March 1988.
2. U.S. Environmental Protection Auencv. Office of Policv.
Planning and Evaluation, Presentation to the Committee
on Alternative
_ , ~ ~
Energy Research and Development
strategies, National Research Council, Washington, D.C.,
June 12, 1989.
3. V. Ramanathan, R. J. Cicerone, H. B. Singh, and J. T. Kiehl,
''Trace Gas Trends and Their Potential Role in C1 imate
Change," Geophys. Res., 90: 5547-5566, 198S.
4. V. Ramanathan et al, "Climate and the Earth's Radiation
Buaget,'t Pnyslcs Today, p. 22, May 1989,
S. National Academy of Engineering, Energy: Production,
Consumption and Consequences, National Academy Press,
Washington, D.C., 1990.
6. National Academy of Engineering, Technology and the
Environment, National Academy Press. Washinaton, D.C.,
1989.
7. National Research
, ~ _, _ _ ~ _ _ , _ _ ,
Council. Global Chance and Our Common
Future, Forum Papers, National Academy Press, Washington,
D. C . 1989 .
8. Greenhouse Warming:
Abatement and
Adantation. Workshop
Proceedings, Resources tor One Future, Washington, D.C.,
June 14-15, 1988.
9. Energy Policies to Address Global Climate Change, Workshop
Proceedings (unpublished), University of California,
Davis, September 6-8, 1989.
10. Discussions regarding uncertainties are contained in a number
of published reports, including those cited above. For
a viewpoint that does not anticipate significant adverse
impacts of GHG emissions on climate, see Scientific
Perspectives on the Greenhouse Problem, George C.
Marshall Institute, Washington, D.C., 1989.
11. J.
F. Mitchell, "The Greenhouse Effect and Climate Change,"
Rev. Geophys. 27:115, February 1989.
23
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12. Data from 1958 to the present are from Keeling's observations
at Mauna Loa, Hawaii C. D. Keeling, D. J. Moss, and T.
P. Wholf, Measurements of Concentrations of Atmospheric
Carbon Dioxide at Mauna Loa Observatory Hawaii, 1958-
1986, Final Report for the Carbon Dioxide Information and
Analysis Center, Martin Marietta Energy Systems, Inc.,
Oak Ridge, Tenn. April 1987, and updated by National
Oceanic and Atmospheric Administration/Scripps
Institution of Oceanography, Boulder, Colo. May 1988~.
Data for the period 1740 to 1956 are taken from
measurements of air trapped in glacial ice sheets (A.
Neftel, E. Moor, H. Oeschger, and B. Stauffer, "Evidence
from Polar Ice Cores for the Increase in Atmospheric CO2
in Past Two Centuries", Nature, 315:45-47, 1985.
Stephen H. Schneider, "The Changing Climate," Sci. Am
September 1989.
Atmospheric Ozone 1985, World Meteorological Organization,
Geneva, 1985; see Chapter 3, pp. 56-116.
15. J. P. Riva, Jr., "Fossil Fuels" in Encyclopedia Britannica,
vol. 19, 588-612, 1987; "Oil Distribution and Production
Potential," Oil Gas J. 86~3~:58, 1988~; Domestic National
Gas Production, CRS Issue Brief, Congressional Research
Service, Library of Congress, Washington, D.C., May 2,
1989.
16. World Resources Institute study as referred to by M. Weisekopf
in "U.S. Contribution to Greenhouse Effect Rises," The
Washington Post, September 16, 1989.
17. Cool Energy: The Renewable Solution to Global Warming, Union
of Concerned Scientists, Cambridge, Mass., 1990.
18. "Global Change and Public Policy: A Special Issue," Earth
Ouest, 3~1), Spring 1989.
19. C. Schneider, "Preventing Climate Change," Issues Sci.` and
Tech., 5:~4), p. 55, Summer 1989.
24
Representative terms from entire chapter:
energy production
