Full text of "1982 Exxon Primer On CO2 Greenhouse Effect"

ESEARCH AND ENGINEERING COMPANY P.0 BOX 101. FLORHAM PARK, NEW JERSEY 07 9 32 M. B. GLASER Cable: ENGREXXON, N.Y. Manager Environmental Affairs Programs November 12, 1982 CO t "Greenhouse" Effect 82EAP 266 TO: See Distribution List Attached Attached for your information and guidance is briefing material on the CO 2 "Greenhouse" Effect which is receiving increased attention in both the scientific and popular press as an emerging environmental issue. A brief summary is provided along with a more detailed technical review prepared by CPPD. The material has been given wide circulation to Exxon management and is intended to familiarize Exxon personnel with the subject. It may be used as a basis for discussing the issue with outsiders as may be appropriate. However, it should be restricted -to -Exxon personnel and not distributed externally. MBG : rva Very truly yours , M. B. GLASER I f Attachments H. N. WEINBERG NOV 1 5 1982 i \ Distribution List R. W. Cohen M. J. Connor, Jr. E. E. David, Jr. C. M. Eidt, Jr. W. R. Epperly R. L. Hirsch T. G. Kaufmann D. G. Levine G. H. Long J. R. Riley H. R. Savage A. Schriesheim J. F. Taylor D. T. Wade H. N. Weinberg CC> "GREENHOUSE EFFECT" 2 SUMMARY Atmospheric monitoring programs show the level of carbon dioxide in the atmosphere has increased about 8t over the last twenty-five years and now stands at about 3^0 ppm. This observed increase is believed to be the con- tinuation of a trend which began in the middle of the last century with the start of the Industrial Revolution. Fossil fuel combustion and the clearing of virgin forests (deforestation) are believed to be the primary anthropogenic contributors although the relative contribution of each is uncertain. The carbon dioxide content of the atmosphere is of concern since it can affect global climate. Carbon dioxide and other trace gases_ contained in the atmosphere such as water vapor, ozone, methane, carbon monoxide, oxides ^ of nitrogen, etc. absorb part of the infrared rays reradiated by the earth. This increase in absorbed energy warms the atmosphere inducing warming at the earth's surface. This phenomenon is referred to as the "greenhouse effect". Predictions of the climatological impact of a carbon dioxide induced ."greenhouse effect" draw upon various mathematical models to gauge the tem- perature increase. The scientific community generally discusses the impact in terms of doubling of the current carbon dioxide content in order to get beyond the noise level of the data. We estimate doubling could occur around the year 2090 based upon fossil fuel requirements projected in Exxon's long range energy outlook. The question of which predictions and which models best simulate a carbon dioxide induced climate change is still being debated by the scientific community. Our best estimate is that doubling of the current concentration could increase average global temperature by about 1.3° to 3.1 C. The increase would not be uniform over the earth's surfacg with the polar caps likely to see temperature increases on the order of 10°C and the equator little, if any, increase. Considerable uncertainty also surrounds the possible impact on society of such a warming trend, should it occur. At the low end of the predicted temperature range there could be some impact on agricultural growth and rainfall patterns which could be beneficial in some regions and detrimental in others. At the high end, some scientists suggest there could be considerable adverse impact including the flooding of some coastal land masses as a result of a rise in sea level due to melting of the An tare tig ice sheet. Such an effect would not take place until centuries after a 3°C global average temperature increase actually occurred. There is currently no unambiguous scientific evidence that the earth is warming. If the earth is on a warming trend, we're not likely to detect it before 1995 — This is about the earliest projection of when the temperature EC-1 1-5/A3 - 2 - might rise the 0.5 needed to get beyond the range of normal temperature fluctuations. On the other hand, if climate modeling uncertainties have exaggerated the temperature rise, it is possible that. a carbon dioxide induced "greenhouse effect" may not be detected until 2020 at" the earliest. The "greenhouse effect" is not likely to cause substantial climatic changes until the average global temperature rises at least 1°c above todays levels. This could occur in the second to third quarter of the next century. However, there is concern among some scientific groups that once the effects are measurable, they might not be reversible and little could be done to correct the situation in the short term. Therefore, a number of environmental groups are calling for action now to prevent an undesirable future situation from developing. Mitigation of the "greenhouse effect" would require major reductions in fossil fuel combustion. Shifting between fossil fuels is .not a feasible alternative because of limited long-term supply availability for certain fuels although* oil does produce about 185 less carbon dioxide per Btu of heat released than coal, and gas about 325 less than oil. The energy outlook suggests synthetic fuels will have a negligible impact at least through the mid 21st century contributing less than 105 of the total carbon dioxide released from fossil fuel combustion by the year 2050. This low level includes the expected contribution from carbonate decomposition which occurs during shale oil recovery and assumes essentially no efficiency improvements in synthetic fuels processes above those currently achievable. Overall, the current outlook suggests potentially serious climate problems are not likely to occur until the late 21st century or perhaps beyond at projected energy demand rates. This should provide time to resolve uncertain- ties regarding the overall carbon cycle and the contribution of fossil fuel combustion as well as the role of the oceans as a reservoir for both heat and carbon dioxide. It should also allow time to better define the effect of carbon dioxide and other infrared absorbing gases on surface climate. Making significant changes in energy consumption patterns now to deal with this potential problem amid all the scientific uncertainties would be premature in view of the severe impact such moves could have on the world's economies and societies. EC-1 1-5/A4 PROPRIETARY INFORMATION FOR AUTHORIZED COMPANY USE ONLY 4 C0 2 GREENHOUSE EFFECT A TECHNICAL REVIEW PREPARED BY THE COORDINATION AND PLANNING DIVISION EXXON RESEARCH AND ENGINEERING COMPANY APRIL 1, 1982 1 * C0 2 GREENHOUSE EFFECT A TECHNICAL REVIEW TABLE OF CONTENTS PAGE NO. Background 2 Sources and Disposition of Atmospheric Carbon Dioxide - The Carbon Cycle. 2 Description of Potential Impact on Weather, Climate, and Land Availability 6 Major Research Programs Underway 15 Future Energy Scenarios and Their Potential Impact on Atmospheric Carbon Dioxide 17 Forecast Based on Fossil Fuel Projected in Exxon Long Range Energy Outlook 19 Detection of a C0 2 Induced Greenhouse Effect 26 Bibliography 30 EC-1 1-5/A5 - 2 - C0 2 GREENHOUSE EFFECT Background The buildup of C0 ? in the atmosphere has been monitored continuously at the National Oceanic and Atmospheric Administration's (NOAA) Observatory at Mauna Loa, Hawaii, and periodically in other places since 1957. In addition to observing a trend between 1957-1979 that showed atmospheric CC> 2 increasing from 315 to 337 ppm. Keeling and others also observed a seasonal variability ranging from 6 to 10 ppm between a low at the end of the summer growing season (due to photosynthesis) and a high at the end of winter (due to fossil fuel burning for heat, and biomass decay). There is little doubt that these obser- vations indicate a growth of atmospheric C0 2 (see Figure 1). It is also believed that the growth of atmospheric C0 2 has been occurring since the . * middle of the past century, i.e., coincident with the start of the Industrial Revolution. There is, however, great uncertainty as to whether the atmos- pheric CO concentration prior to the Industrial Revolution (ca., 1850) was 290-300 ppm which one would arrive at by assuming atmospheric C0 2 growth is due to fossil fuel burning and cement manufacturing, or 260-270 ppm based on carbon isotope measurements in tree rings. The information on C0 2 concentra- tion prior to 1850 is important because it would help establish the validity of climatic predictions with respect to the inception of a C0 2 induced "greenhouse effect". The "greenhouse effect" refers to the absorbtion by C0 2 and other trace gases contained in the atmosphere (such as water vapor, ozone, carbon monoxide, oxides of nitrogen, freons, and methane) of part of the infrared radiation which is reradiated by the earth. An increase in absorbed energy via this route would warm the earth's surface causing changes in climate affecting • atmospheric and ocean temperatures, rainfall patterns, soil moisture, and over centuries potentially melting the polar ice caps. Sources and Disposition of Atmospheric Carbon Dioxide - The Carbon Cycle The relative contributions of biomass oxidation (mainly due to deforestation) and fossil fuel combustion to the observed atmospheric C0 2 increase are not known. There are fairly good indications that the annual growth of atmospheric CO is on the order of 2.5 to 3.0 Gt/a* of carbon and the net quantity of carbon absorbed by the ocean is similarly 2.5 to 3 Gt/a. Thus, these two sinks (atmosphere and ocean) can account for the total fossil carbon burned (including 0.3 GtC/a** from cement manufacturing) which is on the order of 5-6 Gt/a and does not allow much room for a net contribution of biomass : Q • Gt/a = gigatons per annum = 10 metric tons per year. ** GtC/a = gigatons carbon per annum = 10 y metric tons of carbon per year. EC-1 1-5/A6 MAUNA LOA. HAWAII BASELINE STATION Figure X Modern record of atmospheric CO, concentrations. Mean monthly concentration measurements at Mauna Loa, Hawaii. Annual changes in parentheses arc based on incomplete records; the solid dots are interpolated values (source; - 4 - carbon. Yet, highly respected scientists such as Wood well, Bolin and others have postulated a net biomass contribution to atmospheric CO* that ranges from 1 to perhaps 8 Gt/a of carbon. During 1980, a number of different groups produced new estimates of the contribution of organic- terrestial fluxes to atmospheric C0 2 . A consensus has not been reached, but estimates of the net annual terrestial biosphere emissions to the atmosphere now range between a 4 GtC/a source and a 2 GtC/a sink. Figure 2 summarizes the fluxes and reservoirs for the carbon cycle. It should be noted that the net biosphere contribution was assumed to be 0-2 GtC/a. The rate of forest clearing has been estimated at 0.5J to 1.5J per year of the existing area. Forests occupy about 50 x 10°kni out of about 150 x 10 & km 2 of continental land, and store about 650 Gt of carbon. One can easily see that if 0.5% of the world’s forests are cleared per year, this could contribute about 3.0 Gt/a of carbon to the atmosphere. Even if reforestation were contributing significantly to balancing the CO from deforestation, the total carbon stored in new trees tends to be only a small fraction of the net carbon emitted. It should be noted, however, that the rate of forest clearing and reforestation are not known accurately at this time. If deforestation is indeed contributing to atmospheric CO*, then another sink for carbon must be found, and the impact of fossil fuel must be considered in the context of such a sink. The magnitude of the carbon fluxes shown in Figure 2 between. the atmosphere and the terrestial biosphere, and the atmosphere and the oceans are not precisely known. The flow of carbon between these reservoir pairs is generally assumed to have been in equilibrium prior to the Industrial Revolution. However, the errors in the estimated magnitude of these major fluxes are probably larger than the magnitude of the estimated man-made carbon fluxes, i.e., fossil fuels and deforestation. The man-made fluxes are assumed to be the only ones that have disturbed the equilibrium that is believed to have existed before the Industrial Revolution, and they can be estimated independently of the major fluxes. The man-made carbon fluxes are balanced in Figure 2 between the known growth rate of atmospheric carbon and the oceans. The carbon flux to the atmosphere is 6Gt/a from fossil fuels and cement manufacturing (cement manu- facturing contributes about 4% of non-biosphere anthropogenic carbon) and 2Gt/a from deforestation, while 4Gt/a return to the ocean, resulting in a 50t carbon retention rate in the atmosphere. One cannot rule out, in view of the inherent uncertainty of the major fluxes, that the biosphere may be a net sink and the oceans may absorb much less of the man-made C0 2 . Projections of scientists active in the area indicate that the contribution of deforestation, which may have been substantial in the past, will diminish in comparison to the expected rate of fossil fuel combustion in the future. A few years ago a number of scientists hypothesized that a doubling of the amount of carbon dioxide in the atmosphere could occur as early as 2035. This hypothesis is generally not acceptable anymore because of the global curtail- ment of fossil fuel usage. Calculations recently completed at Exxon Research EC-1 1-5/A7 I FIGURE 2 Exchangeable Carbon Reservoirs and Fluxes Atmosphere Fossil Fuels Terrestrial Oceans and Shale Biosphere Surface Intermediate, Deep Ocean and Sediments I ( ) = Size of Carbon Reservoirs In Billions of Molrlc Tons of Carbon Fluxes (arrows) = Exchange of Carbon Between Reservoirs In Billions of Metric Tons of Carbon per Year . - 6 - and Engineering Company using the energy projections from the • Corporate Planning Department’s 21st Century Study*, indicate that a doubling of the 1979 atmospheric C0_ concentration could occur at about 2090. If synthetic fuels are not developed and fossil fuel needs are met..by new gas and petroleum discoveries, then the atmospheric CO^ doubling time would be- delayed by about 5 years to the late 2090's. Figure 3 summarizes the projected growth of atmospheric C0 ? concentration based on the Exxon 21st Century Study-High Growth scenario. Is well as an estimate of the average global temperaiture increase which might then occur above the current temperature. It is now clear that the doubling time will occur much later in the future than pre- viously postulated because of the decreasing rate of fossil fuel usage due to lower demand. Description of Potential Impact on Weather, Climate, and Land Availability The most widely accepted calculations carried on thus far on the potential impact on climate of doubling the carbon dioxide content of the atmosphere use general circulation models (GCM) . These models indicate that an increase in global average temperature of 3° + 1.5°C is most likely. Such changes - in temperature are expected to occur with uneven geographic distribution with greater warming occurring at the higher latitudes, i.e., the polar regions. This is due to increased absorption of solar radiation energy on the darker polar surfaces that would become exposed when ice and snow cover melt due to increasing temperature (see Figure 4). There have been other calculations using radiative convective models and energy balance models which project average temperature increases on the order of 0.75 C for a doubling of C0_. These calculations are compared in Figure 5. Figure 6 summarizes possible temperature increases due to various changes in atmospheric C0 2 concentration. If the atmospheric CO- content had been 295 ppm prior to the Industrial Revolution, and an average global temperature increase above climate noise is detectable at the present time, this would add credibility to the general -circulation models. However, if the C0 2 concentration and been 265 ppm grior to the Industrial Revolution, then detecting a temperature effect of 0.£ C now would imply that the temperature for a doubling of C0 2 would be 1.9 C & The projected temperatures for both alternatives fall witnin the 3 + 1.5 C range. Temperature projections for alternate scenarios will be discussed later. Climate modeling was studied by a committee of the National Research Council, chaired by Jules G. Charney of MIT, and the conclusions are summarized in * The n 21st Century Study" referred to here and in other places in this report has been superseded by a new energy study called the "2030 Study" . The new study projects energy demands that are lower than the earlier figures, but not sufficiently different to change any of the conclusions of this report. EC-1 1-5/A8 -7- Figure .3 GROWTH OF ATMOSPHERIC CO2 AND AVERAGE GLOBAL TEMPERATURE INCREASE AS A FUNCTION OF TIME AVERAGE TEMPERATURE INCREASE,' Altitude l Figure 4 Basis : Temperature Change (°C) Due to Doubling CO? Concentrations Computed by the U.S. National Oceanic and Atmospheric Administration using their general circulation model. \ 2 x C0 2 — Standard I Oo Decrease In Temperature Figure 5 Change in surface air temperature (°K) c 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 • r~ i 1 I l ~T~ 1 1 Radiative . “““ • • •• • • • •# • • 0 i 1 •• 1 • 1 convective • # models 0 Energy • 0 0 balance • models _ — — • • • # • GCMs The change in globally averaged surface air temperature resulting from a doubling of atmospheric CO, as given by a variety of radiative-convective, energy balance, and global circulation (GCM) models. (From W. L. Gales, Oregon Stale University Technical Report no. 4.) - 10 - Figure 6 Estimates of the Change in Global Average Surface Temperature Due to Various Changes Tn CO2 Concentration. Shading Shows Present Range of Natural Fluctuations. r Figure 7 Example o( a scenario ol possible soil moisture patterns on a warmer Earth. It Is based on paleodimalk reconstructions ol the Altllhermal Period (4S00 to MOO years ago), comparisons o( recent warm and cold years In the Northern Hemisphere, and a climate model experiment. (For a discussion ol these sources ol Information see Appendix C.) Where two or more ol these sources agree on the direction ol the change we have Indicated the area ol agreement with a dashed line and a label. \ 11 their report titled, "Carbon Dioxide and Climate: A Scientific Assessment." This National Research Council study concluded that there are major uncertain- ties in these models in terms of the timing for a doubling of C0 2 and the resulting temperature increase. These uncertainties ..center around the thermal capacity of the oceans. The oceans have been assumed to consist of a rela- tively thin, well mixed surface layer averaging about 70 meters in depth in . most of the general circulation models, and the transfer of heat into the deep ocean is essentially infinitely slow. The Charney panel felt, however, that the amount of heat carried by the deep ocean has been under estimated and the oceans will slow the' temperature increase due to doubling of atmospheric C0_. The Charney group estimated that the delay in heating resulting from the effect of the oceans could delay the expected temperature increase due to a doubling of CO by a few decades. Accordingly, the time when the tempera- ture increases discussed above are reached must be assumed to have occurred at an instantaneous equilibrium. Along with a temperature increase, other climatological changes are expected to occur including an uneven global distribution of increased rainfall and * increased evaporation. These disturbances in the existing global water dis- tribution balance would have dramatic impact on soil moisture, and in turn, on agriculture i Recently, Manabe et al . , using GCM's calculated that the zonal mean value of soil moisture in summer declines significantly in two separate zones of middle and high latitudes in response to an increase in the CO- concentration of air. This C0 2 induced summer dryness results not only from the earlier ending of the snowmelt season, but also from the earlier occurrence of the spring to summer reduction in rainfall rate. The former effect is particularly important in high latitudes, whereas the latter effect becomes important in middle latitudes. Other statistically significant changes include large increases in both soil moisture and runoff rates at high latitudes during most of the annual cycle with the exception of the summer season. The penetration of moisture rich, warm air into high latitudes is responsible for these increases. The state-of-the-art in climate modeling allows only gross global zoning while some of the expected results from temperature increases of the magnitude indicated are quite dramatic. For example, areas that were deserts 4,000 to 8,000 years ago in the Altithermal period (when the global average temperature was some 2°C higher than present), may in due time return to deserts. Conversely, some areas which are deserts now were formerly agricultural regions. It is postulated that part of the Sahara Desert in Africa was quite wet 2,000 to 8,000 years ago. The American Midwest, on the other hand, was much drier, and it is projected that the Midwest would again become drier should there be a temperature increase of the magnitude postulated for a doubling of atmospheric C0 2 (see Figure 7). In addition to the effects of climate on global agriculture, there are some potentially catastrophic events that must be considered. For example, if the Antarctic ice sheet which is anchored on land should melt, then this EC-11-5/A9 - 13 - could cause a rise in sea level' on the order of 5 meters. Such a rise would cause flooding on much of the U.S. East Coast, including the State of Florida and Washington, D.C. The melting rate of polar ice is being studied by a number of glacialogists. Estimates for the melting of the West Anarctica ice sheet range from hundreds of years to a thousand years. EtKns and Epstein observed a 45 mm raise in mean sea level. They account for the rise by assuming that the top 70 m of the oceans has warmed by 0.3°C from 1890 to 1940 (as has the atmosphere) causing a 24 mm rise in sea level due to thermal expansion. They attribute the rest of the sea level rise to melting of polar ice. However, melting 51 Tt (10 * metric tonnes) of ice would reduce ocean temperature by 0.2 C, and explain why the global mean surface temperature has not increased as predicted by C0 2 greenhouse theories. In an American Association for the Advancement of Science (AAAS) and Department of Energy (DOE) sponsored workshop on the environmental and societal conse- quences of a possible CC> 2 induced climate change, other factors such as the environmental effects of C0_ concentration on weeds and pests were considered. The general consensus was that these unmanaged species would tend to thrive with increasing average global temperature. The managed biosphere, such as agriculture, would also tend to benefit from atmospheric CO growth. This is a consequence of CO benefiting agriculture, provided the other key nutrients, phosphorous and nitrogen, are present in the right proportions. Agricultural water needs can be met by new irrigation techniques that require less water. In addition, with higher C0_ and higher temperature conditions, the amount of water needed by agricultural plants may be reduced. It is expected that bioscience contributions could point the way for dealing with climatological disruptions of the magnitude indicated above. As a result of the workshop, research in 11 areas was recommended: C 0 ? fertilizat i°n could have broad beneficial effects on agricul- ture. These effects need to be studied in detail and for a variety — of plant, soil and climatic conditions. 2. There is a need for a fuller understanding of the dynamics of cur- rents and water masses in the Arctic Ocean. 3. It is necessary to determine whether there was deglaciation of the West Antarctic ice sheet about 120,000 years ago and whether this caused a rise in global sea levels at that time. If this occurred, then the information could serve as an analog of future deglaciation. 4. It is necessary to develop and use scenarios which integrate (a) information about population, resources, energy consumption and fuel mixes; (b) buildup of atmospheric CO*; (c) response of the climate system; (d) effects on various biological systems, especially agri- cultural, economic and social consequences, international and interregional conflicts; and (e) possible feedback among these forces. EC-1 1-5/A10 14 - 5. CO induced warming is predicted to be much greater at the polar regions. There could also be positive feedback mechanisms as de- posits of peat, containing large reservoirs of organic carbon, are exposed to oxidation. Similarly, thawing might also release large quantities of carbon currently sequestered as methane hydrates. Quantitative estimates of these possible effects are needed. 6. Although all biological systems are likely to be affected, the most severe economic effects could be on agriculture. There is a need to examine methods for alleviating environmental stress on renewable resource production — food, fiber, animal, agriculture, tree crops, etc. 7. Information exists on the relationship of cultivated and non- cultivated biomes to climatic fluctuations. Similarly, there is considerable information on the response of various nations and economic sectors to climatic variations over the past few hundred years. This information, which is currently scattered and not uniformly presented or calibrated, is thus of limited usefulness. 8. Studies of climate effects are recommended for the semi-arid tropics because of the relatively large populations in these countries and because of special sensitivity to climate. 9. There are situations (soil erosion, salinization, or the collapse of irrigation systems) which are recommended for study as indicators of how societies respond, and how they might learn to cope and adapt more effectively to a shift in global climate. 10. Research is recommended on the flow of information on risk percep- tion and decision making to and from both laymen and experts, the physiological aspects of understanding and perception, and the factors that influence decision making. IT. There is a need to be sure that "lifetime" exposure to elevated C0^ poses no risks to the health of humans or animals. Health effects^ associated with changes in the climate sensitive parameters, or stress associated with climate related famine or migration could be significant, and deserve study. In terms of the societal and institutional responses to an increase in C0-, the AAAS-DOE workshop participants felt that society can adapt to the increase in CO- and that this problem is not as significant to mankind as a nuclear holocaust or world famine. Finally, in an analysis of the issues associated with economic and geopolitical consequences, it was felt that society can adapt to a CO increase within economic constraints that will be existing at the time. Some adaptive measures that were tested would not consume more than a few percent of the gross national product estimated in the middle of the next century. EC-1 1-5/A1 1 - 15 - Major Research Programs Underway The Department of Energy (DOE) which is acting as a focal point for the U.S. government in this area is planning to issue two reports to the scientific community and to policy makers. The first one, summarizing- five years of study is due in 1984, and the second one in 1989. The current plan is to invest approximately 10 years of research and assessment prior to recommending policy decisions in this area which impact greatly on the energy needs and scenarios for the U.S. and the world.” The strategic elements of the United States national total CO^ program are summarized in Figure 8. Much of the government sponsored effort to date has focused on delineating the research needed to enhance our understanding of the potential problems. Accordingly, a number of workshops and symposia were held to this end. The consensus of the key research needs is summarized in Figure^ 8 under the heading "Research Program Results." To date, most of the research effort has been concentrated on the first two research categories. It should be noted, however, that this research started in 1979 and there are few results to report. The most ambitious project being conducted at this time is called "Transient Tracer in the Ocean (TTO) ." This research, jointly funded by the DOE and the National Science Foundation (NSF) , is a 4M$ project to investigate ocean mixing processes in order to enhance the understanding of how surface water C0„ is mixed into the deep ocean... Tracers normally found in the ocean, such as ' X, 3 H, 3 He, ”Kr and iV Ar, are monitored in the North Atlantic Ocean from oceanographic vessels. In addition to the mixing of surface waters into the bottom layers, carbon can be added to deep waters by the oxidation of organic matter and the dissolution of calcium carbonate. In order to separate these three processes and deter- mine their relative significance, precise total carbon dioxide, alkalinity, and calcium concentration data are needed to construct and test mathematical models. Preliminary analysis of the limited data indicates that (1) lateral processes dominate the distribution of calcium and inorganic carbon in the deep oceans away from the polar regions, (2) the amount of calcium carbonate dissociated in the deep oceans is only a fraction of the previously estimated value, and (3) the excess CO. may have penetrated farther into the deep oceans than the currently available models predict. Ultimately, CO. in the air should find its way into the deep ocean sedi- ments. As currently understood, the deeper sediments have thus far been little affected by the fossil fuel era because of the slow mixing of the ocean. A group of scientists examined the contention that some shallow water sediments could now be dissolving and thus providing a sink for atmospheric CO , and concluded that the extent of dissolution is not great enough to ha£e a large effect on the global carbon cycle. It would be helpful if reliable estimates of the CO^ concentration in the air could be obtained for the years prior to 1957. when the modern measurements EC-1 1-5/A12 A NATIONAL PROGRAM ON CARBON DIOXIDE ENVIRONMENT AND SOCIETY - 17 - began. Old Smithsonian Astrophysical Observatory plates of the solar spectrum taken in the early twentieth century might provide such an opportunity if they could be properly interpreted. A method for reducing the data has been developed and estimates of the CO concentration should be available next year. As mentioned previously, determination of the CO- concentrations prior to the Industrial Revolution would help ascertain tne validity of climate models, and thus the likely temperature due to a doubling of atmospheric CO^. Groups in Europe have used Antarctic and Greenland ice cores to independently estimate the C0_ concentrations in the more distant past. While it is difficult to measure the CO- content of the dated ice cores, the results suggest that the atmospheric C0_ concentration during the height of the last ice age (about 18,000 years ago: may have been about half its present value. This is consistent with recently published speculations derived from examina- . tion of the composition of ocean sediment cores. There are currently approximately AO carbon cycle and climate research pro- jects in about 25 different institutions. Many of these projects are either supported jointly by the DOE and other agencies or exclusively by other agencies. The 1982 Federal budget request for CO- research was 23.9M$. The DOE, as the lead agency, would be allocated 1A.0M$, NSF 6.AM$, NOAA 2.5M$, and the Department of Agriculture 1.0M$. Future Energy Scenarios and Their Potential Impact on Atmospheric Carbon Dioxide A number of future energy scenarios have been studied in relation to the C0 2 problem. These include such unlikely scenarios as stopping all fossil fuel combustion at the 1980 rate, looking at the delay in doubling time, and maintaining the pre-1973 fuel growth rate. Other studies have investigated the market penetration of non-fossil fuel technologies, such as nuclear, and its impact on C0-. It should be noted, however, that fuel technology would need about 50 years to penetrate and achieve roughly half of the total market. Thus, even if solar or nuclear technologies were to be considered viable alternatives, they would not really displace fossil fuel energy for the next A0 to 50 years, and CO- growth would have to be estimated based on realistic market displacement 01 the fossil fuel technologies. A draft report from Massachusetts Institute of Technology (MIT) and Oak Ridge (ORNL) authored by D. Rose and others considered the societal and techno- logical inertia vis a vis decision making on the C0 2 issue. The C0 2 problem was considered as the major potential constraint on^fossil fuel use: It was estimated in the study that the CO- problem may curtail fossil fuel use before physical depletion occurs. ^Considerable effort was devoted in the study to "option space," i.e., what are the potential energy alternatives, how long would it take to introduce them, and what type of material resources would be needed for effective market penetration. On reviewing the report we addressed only the technical questions relating to C0 2 , and did not evaluate the plausibility of the scenarios relating to energy use in the future. EC-11-5/A13 - 18 - The study considered the implications of limiting atmospheric CO 2 at two different levels: 1 . Rate of C0 2 addition to the atmosphere be limited to 450-500 ppm in 50 years. 2. The concentration ceiling for atmospheric C0 2 be in the range of 500-1000 ppm. The rationale for choosing these limits is economic. If the rate of C0 2 increase is too rapid, then society may not be able to economically adapt to the resulting climate change. The second limit is based on a level where the harm due to C0_ would greatly exceed the societal benefits that produced the CO . The second limit can be illustrated as an assumed threshold for inducing great irreversible harm to our planet, such as causing a large ocean level rise due to melting polar ice. In addition to improving the use of energy sources as a means of gaining time to understand the problem, it was concluded that vigorous development of non-fossil energy sources be initiated as soon' as possible. The study appears to be based on reasonable assumptions but has an inherent bias towards the accelerated development of non-fossil energy sources which, based on the present state-of-the-art, implies nuclear energy. In his analysis. Rose introduced the concept of AIT (action initiation time), defined as the time when policies to modify or restrain fossil fuel use actually start to be effective. Based on this concept. Rose projects non- fossil growth rates of 6 to 9S/a over 40 to 50 years in order to limit atmo- spheric CO- to 500 to 700 ppm. These rates can be put in perspective by noting that such growth rates were achieved for natural gas introduction. However, nuclear or solar sources would have severe restrictions because such technologies are not as economically and politically attractive, techno- logically straightforward, and are encountering social and environmental opposition. In addition. Rose points out that the rate of growth of manufac- turing facilities required to achieve a 6-9%/a growth rate in non-fossil fuel power generation is so large that it would be equivalent to increasing each year the U.S. power equipment manufacturing capability by an amount equivalent to the current capacity. The study also indicated that other energy-use-related greenhouse gases (viz. carbon monoxide, methane, and oxides of nitrogen) may significantly contribute to a global warming. We believe the contribution of these gases to a global warming is highly speculative. Furthermore, N 2 0, the only oxide of nitrogen that could contribute to a global warming is produced primarily by the micro- bial oxidation of ammonia from fertilizer use, and to a lesser extent from the combustion of fossil fuels. Additionally, N 2 0 is more reactive than C0 2 and is expected to have a relatively shorter atmospheric residence time. In EC-1 1-5/A14 - 19 - a similar vein, methane is primarily emitted to the atmosphere via the anaerobic fermentation of organic material. The contribution of anthropogenic activities (mining, industrial processes, and combustion) are 15 to 105 of the total atmospheric methane sources. The atmospheric destruction of methane is more rapid than that of CO , and tends to yield CO, water vapor and formalde- hyde. Also, methane is believed to contribute to tropospheric ozone formation by oxidizing to CO,. The CO in the atmosphere can be traced to anthopogenic sources (50 to 6017 and to the atmospheric oxidation of methane (305). The major CO sink is oxidation (70 to 905) to CO,. One can therefore consider CO and methane as precursors to CO,. Accordingly, CO and methane ultimately contribute to climatological effects as part of atmospheric C0 2 . The ^0, on the other hand, may not be directly related to fossil fuel combustion. One should question whether the other "greenhouse" gases should be considered part of the CO problem in view of the uncertainties regarding their connection to energy 2 use. It is not clear, at this time, whether their effect would be additive to CO^. i Forecast Based on Fossil Fuel Projected in Exxon 1 s Long Range Energy Outlook As part of the Exxon 21st Century Study, the rate of fossil fuel CO, emis- sions was estimated in late 1981. Specifically, the "High Case" volumetric data provided by the Corporate Planning Department was used to estimate the potential growth of atmospheric CO,. The volumetric data was converted to an energy basis (Quads/a = 10 5 BtO/year) using 5.55 MBtu/B for U.S., 5.64 MBtu/B for Canada and 5.85 MBtu/B for all other countries. In addition, a shale processing loss was added using a constant rate of 27*55 of the primary energy consumption from shale. This was based on the assumption that above ground retorting of relatively high quality oil shale 030 gallons/ton) would be recovered with a thermal efficiency of 805, and in-situ recovery of rela- tively poor oil shale 015 gallons/ton) would be accomplished with a thermal efficiency of 655. These efficiencies were averaged over the U.S. resource base to arrive at 72.55. Table 1 summarizes the primary energy consumption of fossil fuels. - The total carbon dioxide that can be emitted from primary fossil fuels was estimated using the following factors i Oil = 170 lb C0 2 /MBtu = 21.0 MtCVQuad. Gas = 115 lb COg/MBtu = 14.2 MtC/Quad. Coal = 207 lb COg/MBtu =25.6 MtC/Quad. In addition, the quantity of carbon dioxide that could be emitted from the decomposition of carbonate minerals in processing U.S. oil shale was estimated by averaging this potentially large CO, source over the Green River forma- tion resource base. It should be notea that poorer shale resources tend to » MtC = million metric tons of carbon. EC-1 1-5/A15 PRIMARY ENERGY CONSUMPTION OF FOSSIL FUELS l 21st i CENTURY STUDY- -HIGH CASE Quads/a Year 1979 1990 2000 2015 2030 2050 Oil • U.S. 37.09 33.32 32.01 35.35 • 36.35 36.80 Canada 4.06 4.30 4.71 5.62 6.09 5.97 Others 96.62 111.93 128.16 139.63 148.57 132.75 Total 137.77 149.55 164.88 180.60 191.01 • 175.52 Gas U.S. 20.95 17.83 17.24 • 15.98 16.87 17.42 Canada 1.83 2.51 2.88 3.48 4.38 4.73 Others 30.88 55.54 74.95; 86.24 99.65 108.68 Total 53.66 75.88 95.07 105.70 120.90 130.83 Coal U.S. 14.69 20.14 28.66 37.19 43.17 55.10 Canada 0.80 1.37 1.98 2.72 3.62 5.35 Others 60.17 81.44 103.90 125.55 175.55 261.14 Total 75.66 102.95 134.54 " 165.41 ’ 222.54 321.59 Fossil Fuels World Total 267.09 328.38 394.49 451.71 534 .45 i 627.94 Kate %/a 1.90 1.85 0.91 1.13' 0.81 - 21 - emit much more CO- from carbonate minerals than the more desirable high quality resources for the same quantity of shale oil produced. It was further assumed that 65} of the carbonate minerals decompose during processing. This very conservative assumption is based on the average of 100} decomposition that may occur in "hot spots" during in-situ recovery and 3£} decomposition that is generally observed in above ground retorting. Table 2 summarizes the total C0 ? produced in GtC/a. Please note that C0 2 emissions resulting from CO mixed with natural gas in producing wells can be substantial, but due to the unavailability of quantitative data this factor was assumed to contribute about 5} additional CO- currently rising to 15} in the year 2050. This trend of C0 2 contamination or natural gas is consistent with recent Exxon experience. The contributions of shale oil to primary fossil fuel energy and primary fossil fuel carbon are summarized in’ Table 3. This table shows that the fraction of shale oil CO- emissions to total C0 2 is greater' than the corresponding contribution of shale oil energy to total energy. Table 3 also indicates the breakdown between CO- generated in producing and consuming shale oil, and that due to carbonate mineral decomposition. Table 4 presents the estimated total quantities of C0 2 emitted to the environment as GtC, the growth of C0 2 in the atmosphere in ppm (v) , and average global temperature increase in °C over 1979 as the base year. In order to estimate the buildup of atmospheric C0-, it was assumed that the average atmospheric C0_ concentration was 337 ppm in 1979. The fraction of CO- accumulated in the atmosphere was assumed to be 0.535 of the total fossil fuel CO . This number is derived from the observed historic ratio of total atmospheric CO- to total fossil fuel C0 2 . Inherent in this number is the assumption that biomass and cement production did not contribute to atmospheric CO . It should be noted, however, that this method of calculation would tend to predict total anthropogenic C0 2 as long as the ratio of biomass and cement manufacture to fossil fuel consumption remains constant. The average temperature increase since 1979 was estimated, assuming that a doubling of CO- would cause an average global temperature increase of 3.0° + 1.5 C. It was also assumed that fossil fuel carbon would grow at a rate of 0.8}/a between 2050 and 2080, which is a reasonable decrease from the 0.97}/a rate projected between 2030 and 2050. The following section analyzes the implications of the temperature rise due to C0 2 doubling with respect to initial detection of a greenhouse effect. One variation of the High Case scenario was considered. It was assumed that adequate quantities of oil and gas would be discovered to exactly match those estimated to be produced from synthetic fuels in the High Case scenario, and thus balance the primary energy needs of the 21st Century Study. The net quantity of carbon that would be saved is summarized in Table 5. The implica- tions of the synfuel losses are compared with the High Case in Figure 3. Ihe overall impact is relatively minor. EC-11-5/A16 I , TABLE 2 PRIMARY CARBON DIOXIDE' (AS CARBON) ,21st CENTURY STUDY GtC/a Year 1979 1990 2000 Oil 2.90 3.15 3.47 Inorganic Carbon - 0.01 0.05 Total Oil 2.90 3.16 “ 3.52 Gas 0.76 1.08 1.35 CO 2 in Gas 0.04 0.11 0.15 Total Gas 0.80 1.19 1.50 Total Coal 1.93 2.64 3.45 World Total 5.63 7.00 8.47 Rate %/a 2.00 • 1.92 2015 2030 2050 3.79 4.01 ' 3.69 0.19 0.27 0.40 3.98 4.28 4.09 1.50 1.72 1.86 0.18 0.22 0.28 1.68 1.94 2.14 4.24 5.70 8.24 9.90 11.92 14.47 05 1.25 0.97 0.80 TABLE 3 OIL SHALE LIQUID FUELS PRIMARY ENERGY CONSUMPTION AND CARBON DIOXIDE (AS CARBON) PRODUCTION 21st CENTURY STUDY — HIGH CASE Year 1979 1990 2000 2015 2030 2050 U.S. Shale, Quads/a — 1.01 3.65 14.38 . 20.66 30.79 Other Shale — 0.21 1.49 2.56 5.55 11.10 Total 1.21 5.14 16.94 26.21 41.89 % Primary Shale Energy/Primary Fossil Fuels Energy — 0.35 1.30 3.75 4.90 6.67 1 K5 Shale Carbon, GtC/A — 0.03 0.11 0.36 0.55 0.88 IjO 1 Carbonate Carbon — 0.01 0.05 0.19 0.27 0.40 Total — 0.04 0.16 0.55 0.82 1.28 % Primary Shale Carbon/Primary Fossil Fuel Carbon — 0.55 1.89 - 5.55 6.87 ! 8.85 \ TADLE 4 ESTIMATED ATMOSPHERIC CO 2 CONCENTRATION AND AVERAGE TEMPERATURE INCREASE 21st CENTURY STUDY — HIGH CASE Emitted, GtC Stored in Atmosphere, GtC Atmospheric Concentration, ppm Average Tempera ture Year Incremental Cummulative Incremental Cummulative Incremental Cummulative Increase, °C 1979 — — T- 715 — / 337 0 1990 69.3 69.3 37.1 752 17.5 355 0.22 2000 77.2 146.5 ” 4 1 . 3 793 19.5 374 0.'5 2015 137.5 284.0 73.6 867 34.7 409 0.8V | 2030 163.3 447.3 87.4 954 41.2 450 N> 1.25 * 2050 263.5 710.8 141.0 1095 66.5 516 1.84 2080 490.6 1201.4 262.5 1358 123.7 640 2.78 2090 191.3 1392.7 102.3 1160 48.2 688 3.09 TABLE 5 1 ESTIMATED INCREMENTAL CO 2 CONTRIBUTION FROM SYNTHETIC FUELS TO ATMOSPHERIC CO 2 CONCENTRATION AND AVERAGE GLOBAL TEMPERATURE INCREASE t GtC/ a ' 0 Year 1990 2000 2015 2030 2050 2080 Shale Loss Carbonate Decomposition Total Shale 0.004 0.013 0.017 0.025 0.047 0.072 0.069 0.186 0.255 0.114 0.267 0.381 0.181 0.398 0.579 Coal Loss 0.018 0.067 0.136 0.276 0.535 Total Synfuels Loss 0.035 0.139 0.391 0.657 1.114 • Rate %/a » 14.8 7.1 3.5 2.7 2.0 Incremental COj# GtC - 0.80 3.73 7.73 . 17.38 45.79 Cummulative CC^, GtC - 0.80 4.53 12.26 29.64 . 75.43 Incremental Atmospheric COj# ppm - 0.2 0.9 1.9 4.4 11.5 Cummulative Atmospheric COj* PP 01 - 0.2 1.1 • 3.1 7.5 19 Net Atmospheric CO ^ PP m 355 374 407 446 506 1 616 Average Temperature Increase, °C 0.22 0.45 0.82 1.21 1.76 2.61 \ - 26 - Detection of a C0 2 Greenhouse Effect It is anticipated by most, scientists that a general consensus regarding the likelihood and implications of a CO induced greenhouse effect will not be reached until such time as a significant temperature increase can be detected above the natural random temperature fluctuations in average global climate. These fluctuations are assumed to be +0.5 C. The earliest that such dis- creet signals will be able to be measured is one of the major uncertainties of the C0 2 issue. A number of climatologists claim that they are currently measuring a tempera- ture signal (above climate noise) due to a C0 2 induced greenhouse effect, while the majority do not expect such a signal to be detectable before the year 2000. In order to quantify the implications of detecting a greenhouse effect now, as opposed to the year 2000, estimates were made on temperature _ projections as a function of the C0 2 concentration .that existed prior to the Industrial Revolution. Available data on CO concentration prior to the Industrial Revolution tend to fall into two groups: 260 to 270 ppm or 290 to 300 ppm. In Table 6, possible temperature increases were estimated as a function of initial CO concentrations of 265 and 295 ppm. Temperatures were projected for three cases, viz., (1) a temperature increase of 3 C occurs if current CO concentration doubles, (2) the greenhouse effect is detectable now (19797, and (3) the greenhouse affect is detected in the year 2000. One can see in Table 6 that if a doubling of atmospheric C0 2 will cause a 3°C rise in temperature, then we should have seen a temperature increase above climate noise if initial CO- concentration was 265 ppm, or be on the threshold of detecting such an effect now, if the initial concentration was 295 ppm. If we assume that we are on the threshold of detecting a greenhouse effect, then the average temperature due to a doubling of C0 2 will be 1.9 C for an initial CO concentration of 265, or 3.1°C for an initial concentration of 295 ppm. Finally, if the greenhouse effect is detected in the year 2000, then the doubling temperature for initial C0 2 concentrations of 265 and 295 ppm will be 1.3° and 1.7°C, respectively. Based on these estimates, one concludes that a doubling of current concentrations of CO will probably not cause an average global temperature rise much in excess of 3 C, or the effect should be detectable at the present time. Alternatively, if the greenhouse effect is not detected until 2000, then the temperature due to a C0 2 doubling will probably be under 2°C. Using the Exxon 21st Century Study as a basis for fossil fuel growth patterns, the average global temperature increases due to CO would range between 0.8 and 1.6 C by 2030. A doubling of atmospheric CO* woflld be extropolated from the fossil fuel consumption rates of the 21st Century Study to occur at about the year 2090 with the temperature increase ranging between 1.3° and 3-1°C. The projected range presented above is considerably lower than. the generally accepted range of 1.5 to 4.5 C. Figure 9 illustrates EC-1 1-5/A17 TABLE o 4 EFFECT OF PRE- INDUSTRIAL ATMOSPHERIC CO 2 CONCENTRATION ON GLOBAL AVERAGE TEMPERATURE INCREASE > Temperature, °C ■ — :ir — r r — 7T~ Atmospheric C02 Concentration, ppm Time Doubl ing ~2'090 Detected 1979 Detected 265 2000 295 (Instantaneous Equilibrium) 265 295 265 295 1,000 ~2140 4.3 4.4 2.8 4.6 1.9 2.5 800 st/2110 3.6 3.6 2.3 3.7 1.4 2.1 674 (Doubling) ~ 2090 3.0 3.0 1.9 3.1 1.3 1.7 451 2030 1.7 1.5 1.1 1.6 0.6 0.9 375 2000 1.1 0.9 0.7 0.9 . 0.5 0.5 337 (Current) 1979 0.8 0.5 0.5 0.5 0.3 0.3 295 ~1850 0.3 0 0.2 0 0.2 0 265 —1850 0 - 0 - 0 - 1 Change of global mean temperature -28- Figure 9 Range of Global Mean Temperature From 1850 to the Present with the Projected Instantaneous Climatic Response to - - • - - Increasing CO 2 Concentrations. - 29 - the behavior of the mean global temperature from 1850 to the present, contained within an envelop scaled to include the random temperature fluctuations, and projected into the future to include the 1.3° to 3.1°C range of uncertainty noted above for the C0 2 effect. Depending on the actual global energy demand and supply, it is possible that . some of the concerns about C0 2 growth due to fossil fuel combustion may be reduced if fossil fuel use is^decreased due to high price, scarcity, and unavailability. The above discussion assumes that an instantaneous climatic response results from an increase in atmospheric C0_ concentration. In actuality, the temperature effect would likely lag the C0 2 change by about 20 years because the oceans would tend to damp out temperature changes. Given the long term nature of the potential problem and the uncertainties involved, it would appear that there is time for further study and monitoring before specific actions need be taken. At the present time, that action would likely be curtailment of fossil fuel consumption which would undoubtedly seriously impact the world's economies and societies. Key points needing -better definition include the impact of fossil fuel combusion and the role of the oceans in the carbon cycle and the interactive effect of carbon dioxide and other trace atmospheric gases on climate. EC-1 1-5/A18 - 30 - BIBLIOGRAPHY Ad Hoc Study Group on Carbon Dioxide and Climate. 1979. Carbon Dioxide and Climate; A Scientific Assessment . Wash. DC; Nat. Acad. Sci. 25 pp. Adams, J. A. S. , Mantovani, M. S. M. , Lundell, L. L. 1977. Wood versus fossil fuel as a source of excess. carbon dioxide in the atmosphere; A preliminary report. Science 196:54-56. American Friends Service Committee (AFSC) 1972. The Agnes Piaster and the Federal Response . Philadelphia, Pa.: AFSC. Andrews, J. T. , Mears, A., Miller, G. H. , Pheasant, D. R. 1972. Holocene late glacial maximum and marine transgression in the Eastern Canadian Arctic. Nature Phys. Sci . 239:147-49. % Arrhenius, S. 1896. On the fluence of carbonic acid in the air upon the temperature of the ground. Philos. Mag . 41:237-76. 4 Augustsson, T. , Ramanathan, V. 1977. A radiative-convective model study of the CO^ climate problem. J. Atmos. Sci . 34:448-51. Bacastow, R. 1979. Dip in the atmospheric CO- level during the mid 1960s. J. Geophys. Res . 84:3108-14. Bacastow, R. 1976. Modulation of atmospheric carbon dioxide by the Southern Oscillation. Nature 261:116-18. Bacastow, R. B. , Keeling, C. D. 1973. Atmospheric carbon dioxide and radio carbon in the natural carbon cycle: Changes from A.D. 1700 to 2070 as deduced from a geochemical model. In Carbon and the Biosphere . C0NF 720510, ed. G. M. Woodwell, E. V. Pecan, pp. 86-135. Springfield, Va.: NTIS. Bach, W. 1976. Global Air Pollution and Climate Change. Rev. Geophys. Space Phys . 14:429-74. Bach, W. , Pankrath, J., Williams, J. 1980. Interactions of Energy and Climate . D. Reidel, Dordrecht, Holland. Baes, C. F. Jr., Goeller, H. E. , Olsen, J. S. , Rotty, R. M. 1977. Carbon Dioxide and Climate: The Uncontrolled Experiment. Am. Sci . 65:310-20. Baker, E. J., McPhee, J. G. 1975. Land Use Management and Regulation in Hazardous Areas: A Research Assessment , Boulder, Co: Inst. Behav. Sci . 124 pp. EC-11-5/A19 - 31 - Barney, G. 0. 1980. The global 2000 report to the President. A report prepared by the Council on Environmental Quality and the Department of State. NTIS. Berger, R. , and Libby, W. F. I960. Equilibration of Atmospheric Carbon Dioxide with Sea Water: Possible Enzymatic Control of the Rate. Science. 1395-6. Boisvert, R. N. 1975. Impact of Floods and Flood Management Policy on Area Economic Development and Recovery . Dept. Agric. Econ., Cornell Univ., Ithaca, NY. 71 pp. Bolin, B., Degeus, E. T. , Kempe, S. , Ketner, P., eds. 1979. The Global Carbon Cycle , SCOPE 13. New York: Wiley. 491 pp. Bolin, B. 1977. Changes of land biota and their importance for the carbon - cycle. Science. 196:613-15. “““““ % Bolin, B. , Bischof, W. 1970. Variations of the carbon dioxide content of the atmosphere in the northern hemisphere. Tellus 29:171-80. Broeker, W. S. 1975. Climatic Change: Are We on the Brink of a Pronounced Global Warming? Science . 189:460-3. Broecker, W. S., Takahashi, T. , Simpson, H. J., Peng, T. -H. 1979. Fate of fossil fuel carbon dioxide and the global carbon budget.' Science . 206:409-18. Broecker, W. S. , Thurber, D. L. , Goodard, J., Ku, T. -L., Matthews, R. K. t Mesolella, K. J. 1968. Milankovitch hypothesis supported by precise dating of coral reefs and deep-sea sediments. Science . 159:298-300. Bryan, K., Komro, F. G., Manabe, S. , Spelman, M. J. 1982. Transient climate response to increasing atmospheric carbon dioxide. Science . 215:56-8. Bryson, R. A., Wendland, W. M., Ives, J. E. , Andrews, J. T. 1969. Radiocarbon isochrones on the disintegration of the Laurentide ice sheet. Arctic Alpine Res . 1:1-14. Budd, W. , Mclnnes, B. 1978. Modeling surging glaciers and periodic surging of the Antarctic ice sheet. In Climatic Change and Variability: A Southern Perspective , ed. A. B. Pittock, L. A. Frakes, D. Jenssen, J. A. Peterson, J. W. Zillman, pp. 228-34. New York: Cambridge Univ. Press. 455 pp. Budd, W. F., Jenssen, D., Radok, U. 1971. Derived Physical Characteristics of the Antarctic Ice Sheet, Mark 1 . Univ. Melbourne Meteor. Dept. Publ. No. 18, Melbourne, Australia. 178 pp. EC-1 1-5/A20 - 32 - Callendar, G. S. 1938. The artificial production of carbon dioxide and its influence on temperature. Q. J. Roy. Meteor. Soc . 64:223-27. Carbon Dioxide and Climate Research Program. 1979. . Summary of the Carbon Dioxide Effects Research and Assessment Program . U. S, Dept. of Energy. Wash. D.C. 37 PP* Cess, R. D., Hameed, S. , Hogan, J. S. 1980. Response of the global climate to changes in atmospheric chemical composition due to fossil fuel burning. ASHE Paper 80-WA/HT-3. Chen, K., Winter, R. C., Bergman, J. K. 1980. Carbon Dioxide from Fossil Fuels-Adapting to Uncertainty. Energy Policy , 8:318-330. Choudhury, B. , Kukla, G. 1979. Impact of C0 2 on cooling of snow and water surfaces. Nature . 280:668-71. Clark, J. A., Lingle, C. S. 1977. Future sea-level changes due to West Antarctic ice sheet fluctuations. Nature . 269:206-9. Climate Research Board. 1979. Toward a U.S. Climate Program Plan . Wash. D.C.: Nat. Acad. Sci. 91 PP. Cochrane, H. C. , Haas, J. E. , Bowden, M. J., Kates, R. W. 1974. Social Science Perspectives on the Coming San Francisco Earthquake: Economic Impact, Prediction and Reconstruction . Natural Hazard Res. Working Pap. No. 25, Inst. Behav. Sci., Univ. Colo., Boulder, Co. 82 pp. Colvill, A. J. 1977. Movement of Antarctic ice fronts measured from satel- lite imagery. Polar Record . 18:390-94. Committee on Climate and Weather Fluctuations and Agricultural Production. 1979. Climate and Food . Wash. D.C. : Nat. Acad. Sci. 212 pp. Council on Environmental Quality. 1981. Global energy futures and the carbon dioxide problem. Dacy, D. D. , Kunreuther, H. 1969. The Economics of Natural Disasters . New York: The Free Press. Delmas, R. J., Ascencio, J. M., Legrand, M. 1980. Polar ice evidence that atmospheric CO,, 20,000 yr BP was 505 of present. Nature . 284:155-7. Denton, G. H. , Armstrong, R. L. , Stuiver, M. 1971. The late Cenozoic glacial history of Antarctica. In The Late Cenozoic Glacial Ages , ed. K. Turekian, pp. 267-306. New Haven: Yale Univ. Press. Economic Development Council of Northeastern Pennsylvania. 1972. Economic Impact of Tropical Storm Agnes on Luzerne County . Flood Recovery Task Force, Inc. Philadelphia, Pa. EC-1 1-5/A21 - 33 - Enrlich, P. R. , Ehrlich, A. H. , Holdren, J. P. 1977. Ecoscience . San Francisco: Freeman. 1051 pp. Etkins, R. , Epstein, E. S. 1982. The rise of global' mean sea level as an indication of climate change. Science . 215:287-9. Elliott, W. P., Machta, L. , eds. 1979. Workshop on the Global Effects of Carbon Dioxide from Fossil Fuels . C0NF-770385, Springfield, Va: NTIS. 122 pp. Flohn, H. 1974. Background of a geophysical model of the initiation of the next glaciation. Quat. Res . 4:385-404. Flohn, H. 1978. Abrupt events in climatic history. Climatic change and variability: A southern perspective , Ed. A. B. Pittock, et al.. New York: Cambridge Univ. Press, pp 124-34. Flohri, H. 1980. Possible climatic consequences of a man-made global warming. IIASA Report RR-80-30. 92 pp. Garvey, E. A., Prahl, R. , measurement system. Nazimek, K., Shaw, H. IEEE Trans, on Instr. 1982. Exxon global C0_ and Heasur. IM-3 1 : 32-35 . Geophysics Study Committee. 1977. Climate, Climatic Change and Water Supply . Wash. D. C. Nat. Acad. Sci.- 132 pp. Gilmour, A. E. 1979. Ross ice shelf sea temperature. Science . 203:438-39. Ginsburg, N. 1972. The lure of tidewater: The problem of the interface between land and sea. In Pacem in Maribus , ed. E. M. Borgese, pp. 32-41. New York: Dodd Mead. 382 pp. Giovinetto, M. B. 1970. The Antarctic ice sheet and its bimodel response to climate. In Int. Symp. Antarctic Glaciol. Explor . Int. Assoc. Sci. Hydrology (IASH) Commission on Snow and Ice. Publ. No. 86, pp. 347-58. Wash. D.C.: IASH (c/o Am. Geophys. Union). Glantz, M. 1979. A political view of CO^. Nature . 280:189-90. Gornitz, V., Lebedeff, S., and Hansen, J. 1982. Global sea level trend in the past century. Science . 215:1611-4. Hameed, S., Cess, R. D. 1980. Impact of a global warming on biospheric sources of methane and its climatic consequences. ASME Paper 80-WA/HT-2. Hameed, S. ,.Cess, R. D., Hogan, J. S. 1980. Response of the global climate to changes in atmospheric chemical composition due to fossil fuel burning. J. Geophys. Res . 85:7537-45. Hansen, J., et. al., 1981. Climate impact of increasing atmospheric carbon dioxide. Science. 213:957-66. EC-1 1-5/A22 - 34 - Hirschler, M. M. 1981. Man's emission of carbon dioxide into the atmosphere. Atmos. Environ . 15:719-27. Hoffert, M. I. 1974. Global distributions of atmospheric carbon dioxide in the fossil-fuel era: A projection. Atmos. Envir . 8:1225-49. Hollin, J. T. 1965. Wilson's theory of ice ages. Nature . 208:12-16. Hollin, J. T. 1969. .Ice sheet surges and the geological record. Can. J . Earth Sci . 6:903-10. Hollin, J. T. 1972. Interglacial climates and Antarctic ice surges. Quat. Res. 2:401-8. Hoyt, D. V. 1979. An emperical determination of the heating of the earth by ’the carbon dioxide greenhouse effect. Nature . 282:388-90. Hughes, T. 1973. Is the West Antarctic ice sheet disintegrating? J. Geophys . Res . 78:7844-7910. Hughes, T. 1977. West Antarctic ice streams. Rev. Geophys. Space Phys . 15:1-46. Hughes, T. 1975. The West Antarctic ice sheet: Instability, disintegration and initiation of ice ages. Rev. Geophys. Space Phys . 13:502-26. Hughes, T. 1980. Climatic warming and collapse of the West Antarctic Ice Sheet. In Workshop on Environmental and Societal Consequences of a Potential CCL Induced Climate Wanning . Wash. D.C. : USD0E. In press. Idso, S. B. 1980. The climatological significance of a doubling of earth's ’atmospheric carbon dioxide concentration. Science 207:1462-3. Ives, J. D., Andrews, J. T. , Barry, R. G. 1975. Growth and decay of the Laurentide ice sheet and comparisons with Fenno-Scandinavia. Naturwissenschaften 62:118-25. Jacobs, S. S., Gordon, A. L. , Ardai, J. L. Jr., 1979. Circulation and melting beneath the Ross ice shelf. Science 203: 439-43. Jason. 1979. The Long Term Impact of Atmospheric Carbon Dioxide on Climate . Tech. Rep. JSR-78-07. SRI Int., Arlington, Va. 184 pp. Jason. 1980. The Carbon Dioxide Problem: DOE Program and General Assess- ment . Tech. Rep. JSR-80-06. SRI Int., Arlington, VA. 37 PP- Kahn, H. , Brown, W. , Martel, L. 1976. The Next 200 Years: A Scenario for America and the World. New York: Morrow. 241 pp. EC-1 1-5/A23 - 35 - Keeling, C. D. , Bacastow, R. B. 1977. Impact of industrial gases on climate. In Energy and Climate , ed. Geophys. Res. Board, pp 72-95. Wash. D.C.: Nat. Acad. Sci. 158 pp. Keeling, C. D. , Bacastow, R. B., Bainbridge, A. E. , Ekdahl,-G. A., Jr., Guenther, P. R. , Waterman, L. S., Chin, J. F. S. 1976. Atmospheric carbon dioxide variations at Mauna Loa Observatory, Hawaii. Tellus 28:538-51. Keeling, C. D. , Adams, J. A. Jr., Ekdahl, Jr., C. A., Guenther, P. R. 1976. Atmospheric carbon dioxide variations at the South Pole. Tellus . 28:552-64. Kellogg, W. W. , Schneider, S. H. 1978. Global air pollution and climate change. IEEE Trans. Geosci. Electron . GEl6:44-50. Kellogg, W. W. , 1977. Effects of human activities on global climate. WMO ■ Tech . Note No. 156. WMO No. 486, World Meteor. Org., Geneva Switz. 47* pp. Kellogg, W. W. , Mead, M., eds. 1977. The atmospheric resources: Will mankind behave rationally? In The Atmosphere: Endangered and Endanger- ing . Fogarty Inti. Cent. Proc. No. 39, Publ. No. NIH 77-1065. Wash. D.C. : Nat. Inst. Health, pp. 75-92. Kellogg, W. S. , Schwave, R. 1981. Climate Change and Society . Westview Press, Colorado. Kneese, A. V. 1977. Economics and the Environment . New York: Penguin. Kopec, R. J. 1971. Global climate change and the impact of a maximum sea level on coastal development. J. Geog . 70:541-50. Kukla, G., and Gavin, J. 1981. Recent Changes in The Snow and Ice Marginal Belt. Science . 214:497-503. Laurmann, J. A. 1979. Market penetration characteristics for energy pro- duction and atmospheric carbon dioxide growth. Science 205:896-98. Lave, L. B. , Seskin, E. P. 1977. Air Pollution and Human Health . Baltimore: John Hopkins Univ. 368 pp. MacDonald, G. J. F. 1978. An overview of the impact of carbon dioxide on climate. Mitre Corporation Report M78-79. Machta, L., Telegades, K. 1974. In Weather and Climate Modification , ed. W. N. Hess, pp. 697-725. New York: Wiley. Machta, L. 1972. Mauna Loa and global trends in air quality. Bull. Am . Meteor, Soc. 53-402:20. EC-1 1-5/A24 - 36 - Madden, R. A., Ramanathan, V. 1980. Detecting climate change due to increas- ing carbon dioxide. Science . 209:763-8. Manabe, S., Wetherald, R. T. 1975. The effects of doubling the CO concen- tration on the climate of a general circulation model. ~‘J. Atmos. Sci. 32:3-15. Manabe, S. , Wetherald, R. T. 1980. On the distribution of climate change resulting from an increase in CO ' content of the atmosphere. J. Atmos. Sci. 37:99-118. d Manabe, S., Wetherald, R. T. , Stouffer, R. T. 1981. Summer Dryness Due to an Increase of Atmospheric CO^ Concentration. Climate Change . 3:347-86. Marchetti, C. 1975. Chem. Econ. Eng . Rev. 7:9-15. Marchetti, C. 1977. On geoengineering and the CO- problem. Climatic Change . 1:59-68. Marland, G. , Rotty, R. M. 1 979 - Carbon dioxide and climate. Rev. Geophys.- Space Phys . 17:1813-24. McRae, J. E. , Graedel, T. E. 1979. Carbon dioxide in the urban atmosphere: Dependencies and trends. J. Geophys. Res . 84:5011-17. Meadows, D. H. , Meadows, D. L. , Randers, J., Behrens, W. W. III. 1972. The Limits to Growth . New York: Universe Books, 241 pp. Mercer, J. H. 1978. West Antarctic ice sheet and C0_ greenhouse effect: A threat of disaster. Nature 277:321-25. Mercer, J. 1968. Antarctic ice and Sangamon sea level. In Int. Assoc. Sci . Hydrol . Commission of Snow and Ice, General Assembly of Bern, Publ. No, 79, PP- 217-25. Meyer-Abich, K. 1980. Socioeconomic impacts of climate changes and the comparative changes of alternative political responses — prevention, compensation and adaptation. Climatic Change 3 (No. 3) In Press. Michel, R. L., Linick, R. W. , Williams, P. M. 1979. Tritium and Carbon-14 distributions in seawater from under the Ross ice shelf project ice hole. Science 203:445-46. Mileti, D. S. 1975. Natural Hazard Warning Systems in the United States: A Research Assessment . Inst. Behav. Sci., Univ. Colo., Boulder, Colo. 97 PP. National Climate Program Office. 1979. National Climate Program Preliminary 5-year Plan . N0AA. Wash. D.C. 150 pp. EC-1 1-5/A25 - 37 - National Defense University. 1978. Climate Change to the Year 2000 . Wash. D.C.: Nat. Defense Univ. 109 pp. Neumann, A. D. , Moore, W. S. 1975. Sea level events-and Pleistocene coral ages in the northern Bahamas. Quat. Res . 5:215-24. Newell, R. E. , Dopplick, T. G. 1979. Questions concerning the possible influence of anthropogenic CO on atmospheric temperature. J. Appl . Meteor . 18:822-5. Niethaus, F. 1976. A non-linear eight level tandem model to calculate the future C0 ^ and C-14 burden to the atmosphere . IIASA Rep. RM-76-35, Int. Inst 7 Appl. Syst. Anal., Laxenburg, Austria. Nordhaus, W. D. 1977. Economic growth and climate: The carbon dioxide problem. AM. Econ . Rev. 67 : 3^* 1—46 . Panel on the Public Policy Implications of Earthquake Prediction. 1975. Earthquake Prediction and Public Policy . Wash. D.C. : Nat. Acad. Sci. 142 PP. Pearman, G. I. 1977. Further studies of the comparability of baseline atmos- pheric carbon dioxide measurements. Tellus 29: 171-80. Pearson, C. , Pryor, A. 1977. Environment: North and South An Economic Interpretation . New York: Wiley 355 pp. Perry, A. M. Fulkerson, W. 1982. Energy supply and demand implications of CO^. Presented at the AAAS Meeting, Washington D.C. Ramanathan, V., Lian, M. S. , Cess, R. D. 1979. Increased atmospheric C0_: Zonal and seasonal estimates of the effect on the radiation energy balance and surface temperature. J. Geophys. Res . 84:4949-58. Rasmussen, R. A., Khalil, M. A. K. 1981. Increase in the concentration of atmospheric methane. Atmos. Environ . 15:883-6. sRisk/Impact Panel. 1980. Report of the Risk/Impact Panel of the U.S. NRC Comm, on Nuclear and Alternative Energy Systems. Risks and Impacts of Alternative Energy Systems . Wash. D.C.: Nat. Acad. Sci. In Press. Robin, G. de Q. 1975. Ice shelves and ice flow. Nature 253:168-72. Rust, B. W. , Rotty, R. M. , Marland, G. 1979. Inferences drawn from atmos- pheric C0^ data. J. Geophys. Res . 84:3115-22. Schneider, S. H. 1975. On the carbon dioxide-climate confusion. J. Atmos. Sci . 32-2060-66. Schneider, S. H. , Temkin, R. L. 1977. In Climatic Change , ed. J. Gribbin, pp. 228-46. Oxford: Cambridge Univ. Press. EC-1 1-5/A26 - 38 - » Schneider, S. H. , Washington, W. M., Chervin, R. M. 1978. Cloudiness as a climatic feedback mechanism: Effects on cloud amounts of prescribed global and regional surface temperature changes in the NCAR GCM. J. Atmos Sci . 35:2207-21. Schneider, S. H., Thompson, S. L. 1979. Carbon dioxide and climate change;. Importance of the transient response. J. Geophys. Res . Submitted for publication. Schneider, S. H. , with L. E. Mesirow, 1976. The Genesis Strategy: Climate and Global Survival . New York: Plenum. 419 PP* Schneider, S. H. 1979. Comparative Risk Assessment of Energy Systems. Energy — the International Journal 4:91 9-3 1 • Schneider, S. H. Chen, R. S. 1980. Carbon dioxide warming and coastline flooding: Physical factors and climate impact. Ann. Rev. Energy . •5:107-40. Schneider, S. H. , Morton, L. 1981. The Primordial Bond: Exploring Connec- , tions Between Man and Nature Through the Humanities and the Sciences . New York: Lleunum. In Press. Seiler, W. , Crutzen, P. J. 1980. Estimates of gross and net fluxes of carbon between the biosphere and the atmosphere from biomass burning. Climatic Change . 2:207-47. Siegenthaler , U., Oeschger, H. 1978. Predicting future atmospheric carbon dioxide levels. Science . 199:388-95. Smil, V., Miltin, D. 1974. Carbon dioxide — alternative futures. Atmos . Envir . 8:1213-23. Stuiver, M. 1978. Atmospheric carbon dioxide and carbon reservoir changes. Science 199:253-58. Study of Man’s Impact on Climate (SMIC). 1971. Inadvertent Climate Modifica- tion: Report of the Study of Man's Impact on Climate . Cambridge, Mass.: MIT Press 308 pp. Sugden, D. E. , Clapperton, C. M. 1980. West Antarctic ice sheet fluctuations in the Antarctic peninsula area. Nature . 286-378-81. Sunquist, E. T. , Miller, G. A. 1980. Oil shales and carbon dioxide. Science. 208:740-1. Suomi, V. E., Chairman Climate Research Board, NRC. 1980. A strategy for the National Climate Program. National Academy of Sciences. Takahashi, I., Yoshino, M. M. 1978. Climate Change and Food Production . Tokyo: Univ. Tokyo Press. 433 PP* EC-1 1-5/A27 • X I - 39 - Thomas, R. H. , Sanderson, T. J. 0., Rose, R. E. 1979. Effect of climatic warming on the West Antarctic ice sheet. Nature 277:355-58. Thomas, R. 1979. Ice sheets and ice shelves. Rev. Geophys. Space Phys. 17:1257-58, 1273-76. Thomas, R. H. 1979. West Antarctic ice sheet: Present day thinning and holocene retreat of the margins. Science . 205:1257-58. * Thomas R. H. 1976. thickening of the Ross Ice Shelf and equilibrium state of the West Antarctic ice sheet. Nature 259-180-83. Thompson, S. L. , Schneider, S. H. 1979. A seasonal zonal energy balance climate model with an interactive lower layer. J. Geophys. Res. 84:24-01-14. U. S. Comm, for Global Atmos. Res. Program. 1975. ' Understanding Climatic Change: A Program for Action . Wash. D.C.: Nat. Acad. Sci. 239 pp. Weertman, J. 1976. Glaciology's grand unsolved problem. Nature 260:284-86.- Weertman, J. 1974. Stability of the junction of an ice sheet and an ice shelf. J. Glaciol 13:3-11. Williams, J. ed. 1978. Carbon Dioxide, Climate and Society . New York: Pergamon. 332 pp. Wilson, A. T. 1969. The climatic effects of large-scale surges of ice sheets. Can J. Earth Sci . 6:911-18. Wang, W. C., Yung, Y. L. , Lacis, A. A., Mo, T. , Hansen, J. E. 1976. Green- house effects due to man-made perturbations of trace gases. Science. 194:685-90. Wittwer; S. H. 1980. Carbon dioxide and climate change: an agricultural perspective. J. Soil and Water Conserv . 35:116-120. Wong, C. S. 1978. Carbon dioxide — A global environmental problem in the future. Marine Pollution Bulletin . 9:257-64. - Wood we 11, G. M. , Whittaker, R. H. , Reiners, W. A., Likens, G. E. , Delwiche, C. C. , Botkin, D. B. 1978. The biota and the world carbon budget. Science 199:141-46. Wood well, G. M. 1978. The carbon dioxide question. Scientific American. 238:34-43. ‘ EC-1 1-5/A28