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2
Background

The Global Nature of Greenhouse Warming

Greenhouse warming is global in at least two respects. First, greenhouse gases released anywhere in the world disperse rapidly in the global atmosphere. Neither the location of release nor the activity resulting in a release makes much difference. A molecule of CO2 from a cooking fire in Yellowstone or India is subject to the same laws of chemistry and physics in the atmosphere as a molecule from the exhaust pipe of a high-performance auto in Indiana or Europe. Second, the anticipated climatic effects include changes in the global circulation of air and water. Global average temperature is often used as an indicator of the various climatic effects. Climate change, however, has many facets: seasonal cycles and annual fluctuations of temperature and precipitation, wind speed and direction, and strength and direction of ocean currents. Although the results of climate change will differ from place to place, they derive from global processes.

Greenhouse Gas Emissions from Human Activities

Greenhouse warming is complicated in another, more fundamental way. The amounts released vary, of course, but virtually every form of human activity contributes some amount of greenhouse gas to the atmosphere or removes some from the atmosphere. Subsistence agriculture contributes its bit, as does modern industry and the consumption and use of modern goods and services. Growing trees remove CO2 from the atmosphere, but burning wood for heating and cooking releases CO2 into the atmosphere. Rice paddies and cattle contribute CH4. Industrial activities include releases of all the



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Page 5 2 Background The Global Nature of Greenhouse Warming Greenhouse warming is global in at least two respects. First, greenhouse gases released anywhere in the world disperse rapidly in the global atmosphere. Neither the location of release nor the activity resulting in a release makes much difference. A molecule of CO2 from a cooking fire in Yellowstone or India is subject to the same laws of chemistry and physics in the atmosphere as a molecule from the exhaust pipe of a high-performance auto in Indiana or Europe. Second, the anticipated climatic effects include changes in the global circulation of air and water. Global average temperature is often used as an indicator of the various climatic effects. Climate change, however, has many facets: seasonal cycles and annual fluctuations of temperature and precipitation, wind speed and direction, and strength and direction of ocean currents. Although the results of climate change will differ from place to place, they derive from global processes. Greenhouse Gas Emissions from Human Activities Greenhouse warming is complicated in another, more fundamental way. The amounts released vary, of course, but virtually every form of human activity contributes some amount of greenhouse gas to the atmosphere or removes some from the atmosphere. Subsistence agriculture contributes its bit, as does modern industry and the consumption and use of modern goods and services. Growing trees remove CO2 from the atmosphere, but burning wood for heating and cooking releases CO2 into the atmosphere. Rice paddies and cattle contribute CH4. Industrial activities include releases of all the

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Page 6 greenhouse gases to varying extents. In most societies the burning of fossil fuels for electricity and transportation is a major contributor. Since releases of greenhouse gases are connected to most economic activity, significant reductions in their emission may affect the economic competitiveness of individuals, firms, and nations. Avoiding additional greenhouse warming may be costly, it may create economic winners and losers, and it may alter trade balances. The Effects of World Population and Economic Growth The world's population today is 5.3 billion, and it is expected to continue to grow at about 1.7 percent per year at current rates of fertility. Figure 2.1 shows historical population growth and an estimate for 2000. This increasing population is one of the major factors affecting trends in greenhouse gas emissions. More people create greater demand for food, energy, clothing, and shelter. Producing such products emits greenhouse gases. Economic growth also produces more greenhouse gas emissions. If population grows with constant per capita income, more resources are used for food, clothing, and shelter. If per capita income grows in a constant population, the demand for goods also grows, particularly for health and education services, transportation, and housing. Most nations in the world have policies to reduce population growth rates, but all nations seek to achieve rapid growth in per capita income. The reduction of greenhouse gas emissions is well served by the first objective (reducing population growth) but, depending on the means used, can be in conflict with the second (growth in per capita income). The detailed links between population growth and greenhouse gas emissions are complex and not well understood. The developing countries that have reduced their population growth rates within the last 30 years did so only after rapidly increasing their standards of living. This often was accompanied by environmental degradation. Perhaps it will be possible to rapidly raise living standards without resulting in traditional patterns of pollution. Unfortunately, there are few examples to guide us. What is needed is a breakthrough in strategies for development, especially with respect to energy supply and demand. Developing countries experiencing rapid economic growth will need effective mitigation programs if they are to avoid substantial increases in their greenhouse gas emissions. Implementing new strategies will require funds that will probably be scarce if populations grow rapidly. Nevertheless, at any given per capita rate of greenhouse gas emissions, a smaller population means fewer emissions, as well as less stress on the environment in general.

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Page 7 image FIGURE 2.1 World population. SOURCE: C. McEvedy and R. Jones. 1978. Atlas of World Population History. Middlesex, United Kingdom: Penguin. Figure 6.2. Trends in Human Activities Affecting Greenhouse Gas Concentrations Table 2.1 presents emission estimates for five greenhouse gases (CO2, CH4, CFC-11, CFC-12, and N2O) that accounted for about 87 percent of the increase in the heat-trapping capacity of the atmosphere in the 1980s and about 92 percent of the increase over the previous 100 years. The table presents estimated 1985 emissions (in million tons per year) and converts non-CO2

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Page 8 TABLE 2.1 Estimated 1985 Global Greenhouse Gas Emissions from Human Activities   Greenhouse Gas CO2-equivalent   Emissions (Mt/yr) Emissions (Mt/yr) CO2 Emissions         Commercial energy 18,800 18,800 (57)   Tropical deforestation 2,600 2,600 (8)   Other 400 400 (1)   TOTAL 21,800 21,800 (66) CH4 Emissions         Fuel production 60 1,300 (4)   Enteric fermentation 70 1,500 (5)   Rice cultivation 110 2,300 (7)   Landfills 30 600 (2)   Tropical deforestation 20 400 (1)   Other 30 600 (2)   TOTAL 320 6,700 (20)b CFC-11 and CFC-12 Emissions         TOTAL 0.6 3,200 (10) N2O Emissions         Coal combustion 1 290 (>1)   Fertilizer use 1.5 440 (1)   Gain of cultivated land 0.4 120 (>1)   Tropical deforestation 0.5 150 (>1)   Fuel wood and industrial biomass 0.2 60 (>1)   Agricultural wastes 0.4 120 (>1)   TOTAL 4 1,180 (4)   TOTAL   32,880 (100) NOTE: Mt/yr = million (106) metric tons (t) per year. All entries are rounded because the exact values are controversial. aCO2-equivalent emissions are calculated from the Greenhouse Gas Emissions column by using the following multipliers: CO2 1 CH4 21 CFC-11 and -12 5,400 N2O 290 Numbers in parentheses are percentages of total. bTotal does not sum due to rounding errors. SOURCE: Adapted from U.S. Department of Energy. 1990. The Economics of Long-Term Global Climate Change: A Preliminary Assessment—Report of an Interagency Task Force. Springfield, Va.: National Technical Information Service.

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Page 9 TABLE 2.2 Carbon Dioxide Emission Estimates   1960 1970 1980 1988   Total Per Capita Total Per Capita Total Per Capita Total Per Capita East Germany 263.6 15.4 160.6 15.8 306.9 18.3 327.4 19.8 United States 2858.2 16.1 4273.5 20.9 4617.4 20.2 4804.1 19.4 Canada 193.2 10.6 333.3 15.4 424.6 17.6 437.8 16.9 Czechoslovakia 129.8 9.5 199.1 13.9 242.4 15.8 233.6 15.0 Australia 88.4 8.4 142.6 11.4 202.8 13.9 241.3 14.7 USSR 1452.4 6.6 2303.4 9.5 3283.5 12.5 3982.0 13.9 Poland 201.7 7.0 303.6 9.2 459.8 12.8 459.4 12.1 West Germany 544.9 9.9 736.6 12.1 762.7 12.5 669.9 11.0 United Kingdom 589.6 11.4 643.1 11.4 588.9 10.3 559.2 9.9 Romania 53.5 2.9 119.5 5.9 199.8 9.2 220.7 9.5 South Africa 98.6 5.5 149.6 6.6 213.4 7.7 284.2 8.4 Japan 234.3 2.6 742.1 7.3 934.6 8.1 989.3 8.1 Italy 110.4 2.2 286.0 5.5 372.5 6.6 359.7 6.2 France 274.3 5.9 426.1 8.4 484.4 9.2 320.1 5.9 Korea 49.1 0.4 52.1 1.5 125.8 3.3 204.6 4.8 Spain 12.8 1.5 110.7 3.3 198.7 5.5 187.7 4.8 Mexico 63.1 1.8 106.0 1.8 260.3 3.7 306.9 3.7 People's Republic of China 789.4 1.2 775.9 1.0 1490.1 1.5 2236.3 2.1 Brazil 46.9 0.7 86.5 0.7 176.7 1.5 202.4 1.5 India 121.7 0.4 195.4 0.4 350.2 0.4 600.6 0.7 NOTE: Emission estimates are rounded and expressed in million tons of CO2; per capita estimates are rounded and expressed in tons of CO2. All tons are metric. SOURCE: Adapted from Thomas A. Boden, Paul Kanciruk, and Michael P. Farrell. 1990. Trends '90: A Compendium of Data on Global Change. Oak Ridge, Tenn.: Oak Ridge National Laboratory. gases into CO2-equivalent emissions so that their respective contributions can be compared. These projections necessarily involve uncertainties. (Note that throughout this report tons (t) are metric; 1 Mt equals 1 million metric tons.) The United States is the world's largest contributor of greenhouse gas emissions. Table 2.2 shows total and per capita CO2 emissions (the dominant greenhouse gas emitted by human activity) for the United States and several other countries from 1960 to 1988, in order of their most recent per capita emissions. Two of the six countries with the largest total emissions are developing countries (People's Republic of China and India). Per capita

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Page 10 TABLE 2.3 Carbon Dioxide Emissions per Unit of Economic Activity (1988 to 1989)   Emissions (Mt CO2/yr) GNP (billions of $/yr) Emissions/GNP Ratio (Mt CO2/$1000 GNP) China 2236.3 372.3a 6.01b South Africa 284.2 79.0 3.60 Romania 220.7 79.8a 2.77b Poland 459.4 172.4a 2.66b India 600.6 237.9 2.52 East Germany 327.4 159.5a 2.05b Czechoslovakia 233.6 123.2a 1.90b Mexico 306.9 176.7 1.74 USSR 3982.0 2659.5a 1.50b South Korea 204.6 171.3 1.19 Canada 437.8 435.9 1.00 United States 4804.1 4880.1 0.98 Australia 241.3 246.0 0.98 United Kingdom 559.2 702.4 0.80 Brazil 202.4 323.6 0.63 West Germany 669.9 1201.8 0.56 Spain 187.7 340.3 0.55 Italy 359.7 828.9 0.43 Japan 989.3 2843.7 0.35 France 320.1 949.4 0.34 aEstimates of GNP for centrally planned economies are subject to large margins of error. These estimates are as much as 100 times larger than those from other sources that correct for availability of goods or use free-market exchange rates. bThe emissions/GNP is also likely to be underestimated for centrally planned economies. SOURCE: Table 2.2 above for CO2 emissions. For GNP, entries are from World Bank, 1990, World Development Report, 1990, World Bank, Washington, D.C., Table 3. For centrally planned economies other than China, estimates are from U.S. Central Intelligence Agency, World Factbook 1990. emissions in 1988 are lower than those in 1980 in several countries, including the United States, suggesting that some actions to reduce greenhouse warming are already being taken. It is also informative to compare emissions to economic activity. Table 2.3 shows CO2 emissions per unit of economic activity for recent emissions data. The table illustrates that some developing countries and centrally planned economies are large emitters of greenhouse gases per unit of

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Page 11 TABLE 2.4 Estimated Deforestation in the Tropics (thousand hectares)     Number of Countries Studied Total Land Area Forest Area 1980 Forest Area 1990 Annual Deforestation 1980–1990 Africa 15 609,500 289,700 241,500 4,800 Latin America 32 1,263,500 825,900 753,000 7,300 Asia 15 891,100 334,500 287,500 4,700   TOTAL 62 2,754,500 1,450,100 1,282,300 15,800 NOTE: Entries cover closed tropical forests. Closed forests have trees covering a high proportion of the ground and grass does not form a continuous layer on the forest floor. The numbers are indicative and should not be taken as regional averages. SOURCE: Committee on Forestry. 1990. Interim Report on Forest Resources Assessment 1990 Project, Tenth Session. Geneva, Switzerland: Food and Agriculture Organization of the United Nations. economic activity and that the United States is in the middle of the field. It also shows France with low emissions per unit of economic activity, probably because of its extensive reliance on nuclear power as a source of electricity. Table 2.4 shows recent estimates of deforestation in tropical forests for selected countries. About 80 percent of this wood is destroyed or used as fuel wood, and the remaining 20 percent is harvested for industrial or trade purposes. If the trees are burned, the CO2 they have stored is added to the air, and if they are replaced with plants that grow more slowly, less CO2 will be removed from the atmosphere.