Bartlett replies: Physicists acknowledge that population growth is a major cause of our energy problems. Why then do they offer all manner of diversionary suggestions but avoid addressing population growth limitation as a solution? Karo Michaelian suggests that “perhaps more important than population growth is individual energy consumption.” Reducing per capita annual consumption of energy is an important initial step. Reducing it in the US by 1% each year would be a real achievement. But US population growth is about 1.2% per year, so the achievement would not lower total consumption. Our national goal must be to reduce the total annual consumption of nonrenewable energy for many coming years. 1
Michaelian points out that annual per capita energy consumption in the US is 10 times that in developing nations. That fact emphasizes the importance of stopping US population growth, a course of action Michaelian seeks to avoid. How can we ask other countries to stop their population growth unless we are willing to set an example and stop our own?
It would be wrong to ask that “illiterate farmers in developing nations give up their natural desire for children.” In accord with Brian Tinsley’s call that “women receive education and job training so that they have an attractive alternative” to bearing children, I think we in the US should increase our support for domestic and foreign aid programs in education, economic opportunity, family planning, and maternal health, with the global goal that every child is a wanted child. That aid would cost much less than a war.
The population division of the United Nations, in a report released 24 February 2005, states that “by 2050 the world population is expected to reach 9.1 billion … and would still be adding 34 million persons annually.” So it is difficult to imagine that the solution suggested by Michaelian would be a happy one with the population growing for another 250 years to almost 9 billion people and with individuals in the developed world consuming energy at twice the rate of those in the developing world.
Social workers and politicians have mostly failed to address the population problem, so it follows that we scientists have the professional obligation to call attention to the fact that population growth is the most important problem humans face. By failing to do this, we are propagating a silent lie.
Michaelian observes that we are a long way from dissipating the energy that Earth receives from the Sun. That is probably less important than a comment I recently received from David Pimentel, a global agricultural scientist at Cornell University. Pimentel said that we humans currently appropriate for our own use about half of Earth’s net primary production of biomass.
Arthur Smith suggests that “the only way population will decrease sufficiently in coming decades is with a … dramatic increase in death rate.” There is evidence to the contrary. Fertility rates have dropped dramatically in many parts of the world, and much of Europe is at or near zero population growth.
Smith identifies the problems that must be addressed if nuclear power is to be expanded. In addition there is a political problem, if the citizens of all 50 states vote to prohibit the storage of nuclear waste in their respective states.
I agree with Smith that taxes on energy are needed to reduce consumption and to fund the needed large increases in research on renewable energy. A good first step would be to change the gasoline tax to a sales tax so that tax revenues would rise as gasoline prices rise.
