There is a more compelling reason than climate change for reining in the consumption of fossil fuels and fostering the development of renewable and nuclear energy sources. This reason complements and perhaps even supersedes arguments based on energy independence and national security: There is a strong likelihood that the Earth's endowment of economically exploitable fossil fuels will near exhaustion within 70 years. This is based on data compiled by the U.S. Energy Information Administration and the mathematics of the doubling time for growth.
Our energy problems must be viewed in the context of the global economy, the growth of which is linked directly to growth in energy consumption. Over the past several decades, global energy consumption has grown by about 2 percent a year and is thus doubling every 35 years. At present, fossil fuels generate 85 percent of the energy driving the world economy, with roughly equal contributions from coal, oil and natural gas.
If the Asian economies continue to boom, the rate of global energy consumption will have to accelerate. In addition, the peoples of the developing world understandably would like to raise their standard of living to that enjoyed in the developed world. This will require a roughly five-fold increase in the global per capita consumption of energy. Given that the world population is likely to grow by about 50 percent by the end of this century, there will need to be roughly an eight-fold increase in the global use of energy to reach equality in the world standard of living. Thus the question is whether fossil fuels can meet the ever-increasing demand for energy.
Let us first consider oil. The rate of global oil consumption is about 30 billion barrels per year. If it continues to increase by 2 percent per year, it will reach 60 billion barrels per year in 35 years and 120 billion barrels in 70 years. Thus by the time children born today retire, the human race will have burned roughly 4.8 trillion barrels of oil. This is at least three times greater than the "easy" oil still left in the Earth's crust. Even if we generously estimate the oil in shale at 2 trillion barrels, the oil age is likely to end before today's children retire. Unless, of course, the global economy slows to a crawl, we shift to smaller cars and scooters and the rate of population growth comes to an abrupt halt.
Total consumption of natural gas over the next 70 years will amount to 15,000 trillion cubic feet, which is more than double the estimated world reserves of 6,400 trillion cubic feet. Coal consumption over the next 70 years will amount to 1.2 trillion tons, which is 20 percent more than the estimated recoverable reserves of 1 trillion tons. Thus today's kids might witness the end of the fossil fuel era, and the exhaustion of the Earth's endowment of fossil fuels will leave humanity less than half way to its goal of a developed world standard of living for everyone.
All this makes it imperative that steps be taken to conserve fossil fuels and use them more efficiently. It is also imperative that renewable sources of solar energy be exploited to the maximum extent possible and that the use of nuclear energy be expanded as rapidly as safety concerns permit.
Expanding nuclear power to a level where it could replace fossil fuels will require a huge investment of energy. Today 435 nuclear power plants supply about 6 percent of the world's energy, with fossil fuels supplying about 85 percent. To replace fossil fuels with nuclear power and allow for an eight fold increase in total consumption over the next 70 years, mankind will have to construct about 50,000 new nuclear plants, or nearly two new plants per day.
If we delay such expansion, there may come a point where the remaining fossil fuels will be insufficient to meet the required expansion. If this were to happen, human energy consumption then would be forever limited to that provided by solar, geothermal and tidal sources.
Finally we need to explore whether a vibrant economy can be developed that does not depend on the growth of population and energy use, an economy devoted primarily to maintenance rather than growth, because even a nuclear-based solution is a temporary one. Indefinite doubling of the use of non-renewable energy, including nuclear, will eventually (in just 10 doublings) produce so much waste heat that Earth's temperature will have to increase by tens of degrees centigrade in order to radiate it into outer space.