Energy according to "The State of the Planet"

What will life be like on planet Earth fifty years from now? How many people will there be? How will we be fed? What sources will meet our energy needs? And what will happen to global climate? These questions, and more, have recently been addressed by an eight-part series spanning four issues of Science magazine called “The State of the Planet.” As H. Jesse Smith states in the introduction to this series, “The Shape We're In” (Science, 203, 1171 (14 Nov 2003)), “As global population increases, and the demands we make on our natural resources grow even faster, it becomes even more clear that the well-being we seek is imperiled by what we do.” The eight issues addressed in the series are human population, diversity, soils and food, fisheries, water, energy, air, and climate.

In examining “Energy Resources and Global Development” (Science, 302, 1528-1531 (28 Nov 2003), Jeffrey Chow, Raymond Kopp, and Paul Portney of Resources for the Future begin by listing the “proved, economically recoverable fossil fuel reserves”: almost a trillion metric tons of coal, 0.5% of which was burned in 2000; more than a trillion barrels of oil, 3% of which was burned in 2000, more than 150 trillion cubic meters of natural gas, 1.6% of which was burned in 2000; to this they added more than three million metric tons of uranium, 2% of which was used in 2000. Of the 370 Exajoules of energy used by the world in 2000, 44% came from petroleum, 26% from natural gas, 25% from coal, 2.5% from hydroelectricity, 2.4% from nuclear fission, and 0.2% from other renewable sources (not including unmarketed biomass in the developing world).

“Although fossil fuel reserves are in no danger of diminishing in the foreseeable future,” they write, “should the world continue to consume all or even a large fraction of these resources through normal combustion processes, the release of additional greenhouse gases into the atmosphere would likely have substantial consequences for the global climate.” “Besides greenhouse gas emissions,” they add, “fossil fuel production and use come with other environmental costs.” They go on the observe that “. . . the traditional alternatives to fossil energy -- hydroelectricity and nuclear power -- have environmental and social costs that limit their viability as long-term fuel substitutes. In addition to the drawback of being near saturation, hydroelectric power infrastructure causes dramatic alterations in riparian ecosystems and often the inundation of human settlements and terrestrial habitat. Fissile power, too, is unlikely to expand because of objections to waste disposal and concerns over weapons proliferation.”

Although “. . . no primary energy source and its associated technology are completely free of environmental and other drawbacks,” these authors go on to point out that “the environmental costs of fossil, hydroelectric, and nuclear energy consumption could drive the world toward alternative sources before scarcity becomes a significant issue.” “Renewable energy sources will become prevalent only if they can be more competitive than fossil fuels in terms of relative prices.” And just as cellular phones are ushering developing countries into modern communication without centralized wire networks, new methods of generating electricity in developing countries will employ small plants near their point of use rather than large central generating plants. Although the world will eventually shift to renewable energy “because, in time, supplies of fossil fuels will become too costly,” these authors state that “for the next 25 to 50 years, however, this seems not to be a likely prospect. With energy choices driven by relative prices, fossil fuels will dominate energy use for many years to come. These fuels remain relatively inexpensive, and they are supported by a very broad and long-lived infrastructure. . . . Very powerful constituencies exist worldwide to ensure that investments in this infrastructure are protected.”