Global energy use has risen nearly 70 percent since 1971 and is poised to continue its steady increase over the next several decades, fueled by economic expansion and development  . Energy demand has risen at just over 2 percent per year for the past 25 years and will continue to climb at about this same rate over the next 15 years if current energy use patterns persist, according to the International Energy Agency (IEA). Along with rising energy use comes a concomitant increase in greenhouse gas emissions from fossil fuels and an anticipated increase in global warming. Fossil fuels supply roughly 90 percent of the world’s commercial energy; energy-related emissions account for more than 80 percent of the carbon dioxide (CO2) released into the atmosphere each year . By 2010, IEA projects that global energy consumption – and annual CO2 emissions – will have risen by almost 50 percent from 1993 levels  . (See Global Energy Use Is Projected to Rise.)
|Global Energy Use is Projected to Rise|
|Past and Projected Trends in Energy Demand, 1970-2010
|Source: International Energy Agency, World Energy Outlook 1996, (OECD, Paris, 1996), pp. 237-285; International Energy Agency, Energy Statistics and Balances, on diskette (OECD, Paris, 1997).
Note: a. Assumes current energy use patterns dominate future consumption.
Policies to promote greater energy efficiency – in generation, transmission, and at the point of final use in factories, appliances, or carsâ€”could curb this rate of growth significantly. IEA projections that incorporate such policies show just a 34-percent rise in energy use from 1993 to 2010, with emissions increasing 36 percent. (See Saving Energy Cuts CO2 Emissions.) More aggressive policies might be able to cut the growth rate still more. But even with substantial efforts to use energy more efficiently, future economic development will still entail a significant rise in energy use, at least in the developing world   .
In the developed world, energy use per capita is already extremely high and continues to increase slowly. By contrast, the most rapid growth is now occurring in developing countries, where energy use is still low compared with that in more affluent nations. Developing nations account for more than 80 percentof world population, but consume only about one third of the world’s energy.
That will likely change quickly. The developing nations’ share of commercial energy consumption is expected to grow to nearly 40 percent by 2010  . CO2 emissions would rise even faster to about 45 percent of global emissions . The factors driving this increased energy demand in the developing world include rapid industrial expansion and infrastructure improvement; high population growth and urbanization; and rising incomes that enable families to purchase energy-consuming appliances and cars they could not afford before. Even so, in 30 years, per capita energy consumption in the developing world is still likely to be only one fifth of what it is in the industrialized world today .
Increased use of fossil fuels and consequent growth in CO2 emissions will be particularly intense in China and south Asia, where dependence on coal, which produces the highest CO2 emissions of any fossil fuel, is high. Coal generates more than 70 percent of the electricity in China and more than 60 percent in south Asia; electricity demand is rising at 6 to 7 percent per year in these regions, which may result in a doubling of CO2 emissions in these nations between 1990 and 2010 .
The implications of these emission trends for the global climate are sobering. CO2 levels in the atmosphere are already rising at an annual rate of about 1.5 parts per million (ppm) from human activities . Even keeping CO2 emissions roughly at today’s levels – hardly a simple taskâ€”would result in a doubling of the CO2 concentration in the atmosphere from its preindustrial level by the end of the 21st Century, with the CO2 concentration continuing to rise for another century after that before stabilizing . With the higher CO2 emissions projected for the decades ahead, atmospheric CO2 concentrations are likely to double much sooner and keep rising to much higher levels before stabilizing.
Just how this will affect the global climate is uncertain, but the Intergovernmental Panel on Climate Change (IPCC), which represents the consensus of the international scientific community, estimates that current emission patterns are likely to increase Earth’s average temperature 1o C to 3.5oC by 2100, and raise sea levels 15 to 95 centimeters . (See Changing Environments, Changing Health.)
IPCC calculations clearly show that the Earth is already committed to some global warming, based on past and current emissions, but it is possible to stabilize atmospheric CO2 concentrations in the future to try to minimize warming in the centuries ahead. Doing so will require reductions in CO2 emissions to levels far below today’s emissions  . Taking action will not be easy, because current market conditions favor continued reliance on cheap and abundant fossil fuels. But unless actions are taken now to increase energy efficiency, substitute cleaner fuels such as natural gas for coal, and hasten the development and adoption of renewable energy technologies, the accumulated burden of CO2 will continue to grow.
References and notes
1. International Energy Agency, Energy Statistics and Balances, on diskette (Organisation for Economic Co-Operation and Development, Paris, 1997).
2. International Energy Agency, World Energy Outlook 1996 (Organisation for Economic Co-Operation and Development, Paris, 1996), pp. 18-19; p. 237, Table A-5.
3. World Resources Institute in collaboration with the United Nations Environment Programme, the United Nations Development Programme, and the World Bank, World Resources 1996-97 (Oxford University Press, New York, 1996), pp. 328-330, Tables 14.2 and 14.4. For more on commercial energy production, see Data Table 15.3, Energy Production and Consumption, 1985-95.
4. Op. cit. 2.
5. International Energy Agency tracks world energy trends and uses this information, along with predictions of economic and population growth and the rate of new technology development, to model future energy use and carbon dioxide emissions.
6. Energy Sector Management Assistance Programme, Annual Report 1995 (The World Bank, Washington, D.C., 1996), p. 1.
7. Jose Goldemberg, “Energy Needs in Developing Countries and Sustainability,” Science, Vol. 269 (1995), pp. 1058-59.
8. Op. cit. 2, pp. 18-19, 58.
9. Op. cit. 2, p. 2.
10. In addition to their consumption of commercial energy, developing nations also use considerable quantities of traditional biomass fuels such as wood, crop residues, and dung. Roughly 85 percent of all biomass fuels are consumed in the developing world.
11. Op. cit. 2, p. 59, Table 2.2.
12. Op. cit. 6.
13. Op. cit. 2, p. 59, Table 2.2; p. 60.
14. J.T. Houghton et al., eds., Climate Change 1995: The Science of Climate Change, published for Intergovernmental Panel on Climate Change, in collaboration with the World Meteorological Organization and the United Nations Environment Programme (Cambridge University Press, Cambridge, U.K., 1996), p. 15, Table 1.
15. Ibid, p. 25.
16. Op. cit. 14, p. 6.
17. Op. cit. 14, pp. 3, 25.
18. T. Wigley, R. Richels, and J. Edmonds, “Economic and Environmental Choices in the Stabilization of Atmospheric CO2 Concentrations,” Nature