In response to the question, “Can family planning save us from global warming catastrophe?” Nancy Birdsall (1994) seems to argue “No, family planning can not save us from global warming catastrophe, but it can help alleviate the problem.” In an article titled “Another Look At Population and Global Warming,” Birdsall asserts that a decline in population growth can not be “key” to reducing, or even levelling-off, greenhouse gas emissions because, first of all, reductions in population growth take a long time to accumulate, and second, reductions in population growth can only indirectly affect global warming through reductions of fossil fuel emissions and reductions in deforestation.[1]Contrary to how this statement may make it may seem, Birdsall is not entirely pessimistic about the effects of population growth decline on greenhouse gas emissions. She makes the additional case that efforts to reduce population growth in developing countries, countries where the threats of population growth are most severe, may be more cost-effective than other efforts or programs to reduce greenhouse gas emissions and combat global warming. Birdsall, bases this assertion upon the notion that the environmental advantages of population growth reduction would be greater if efforts to reduce population growth were concentrated on developing countries versus developed countries because developing countries are those on the verge of experiencing rapid increases in greenhouse gas emissions as they become more populated, more industrialized and more wealthy. According to Birdsall, the costs of educating men and women in developing countries about family planning and fertility are minimal compared to the benefits this effort may have upon local greenhouse gas emissions and, subsequently, the global environment.
Birdsall’s primary objective in her essay is to establish the fact that population growth reduction is neither a powerful nor reliable tool for combating global warming. She accomplishes this task by, first, discussing the minimal effects of slower population growth on short-run and long-run population sizes in the developing world. Birdsall points to the World Bank’s 1991 population and fertility projections to make this case. These projections reveal that even a “rapid” reduction in the average population growth rate of all developing countries (including China and excluding Eastern Europe and the former USSR) would result in a substantial increase in the population size of this group of countries over the next 150 years.[2] For example, a reduction in the average population growth rate from 1.86 in 1985-2000 to 0.64 in 2025-2050 to 0.13 in 2075-2100 to, finally, 0.04 in 2125-2150 would supposedly cause the population size of the developing world to increase from about 3.7 billion in 1985 to about 8.4 billion by 2100 and about 8.7 billion by 2150.[3] The reasons for this substantial increase in population size despite the “rapid” reduction in the population growth rate are that current total fertility rates in developing countries are, on average, very high (well above the replacement ratio of 2.1), and it often takes a few generations for a population to significantly adjust its reproductive patterns. According to Birdsall, the World Bank predicts that the developing world will not complete its transition to replacement-level fertility until about the year 2050. This means that fertility rates in the developing world will remain high even as mortality rates among this group of countries decline due to improved economic and social conditions. Thus, the demographic momentum of the developing world will cause the population sizes of developing countries to increase substantially despite any “standard” or “rapid” reductions in population growth.[4]
Birdsall further doubts the notion that slower population growth can significantly reduce greenhouse gas emissions based upon evidence that reductions in population growth have a minimal impact upon fossil fuel emission levels and deforestation rates in the developing world. According to Birdsall, the two principal mechanisms through which population growth can contribute to the potential for global warming are increased fossil fuel emission levels and increased deforestation.[5] She reasons that, at a given level of per capita income, a larger population is likely to produce higher levels of fossil fuel emissions because this population has a greater demand for energy for power, industry, and transport. She reasons further that a larger population also has a greater demand for housing developments, woodfuel, and infrastructure which likely leads to an increase in the rate of deforestation and a subsequent accumulation of carbon dioxide in the atmosphere. According to Birdsall’s findings, however, these mechanisms are not significantly operant in the developing world.
In terms of the relationship between population growth and fossil fuel emission levels, specifically, Birdsall reports that the potential for affecting future population size is greatest in those developing countries where per capita emissions are currently the lowest.[6] For example, Africa is expected to have the greatest decline in population size by the year 2150 if population growth rates throughout the entire developing world fall at a uniform “rapid” pace, but Africa currently produces the least amount of fossil fuel emissions. China, on the other hand, is expected to have the smallest decline in population size by the year 2150, and it, due to its heavy use of coal, currently produces the greatest amount of fossil fuel emissions among developing countries. Thus, a “rapid” reduction of the developing world’s population growth rate would not significantly affect those countries that need to be most affected in order for fossil fuel emission levels to substantially decline. Birdsall contributes more to this notion that slower population growth is not a significant factor in the decline of fossil fuel emission levels by suggesting that a smaller population may even produce higher per capita emissions if per capita income levels are fixed and manufacturers are required to substitute energy for labor in production.[7] If this situation occurs, then fertility decline could actually increase fossil fuel emission levels in some developing countries.
With regard to deforestation, Birdsall reports that some decline in deforestation will occur as a result of slower population growth in the developing world; however, this decline is insignificant when compared to the amount of carbon that will be released into the atmosphere even under the best population reduction scenarios. The demographic momentum of the developing world makes it so that any “feasible” reduction in the population growth rate of the developing world would have very little impact upon the future population size of this group of countries.[8] As previously stated, a “rapid” decline in the population growth rate from 1.86 in 1985-2000 to 0.13 in 2075-2100 is expected to allow the population size of the developing world to more than double - grow from about 3.7 billion in 1985 to 8.4 billion by 2100.[9] This means that the level of greenhouse gas emissions produced by the developing world’s population in the year 2100 is expected to be very high as well. Birdsall predicts that if, by the year 2100, the developing world has per capita emissions similar to the current world average of 1.2 metric tons, then the total annual global emissions of greenhouse gases under the “rapid” population growth decline scenario will be about 12.0 billion tons.[10] This figure is twice as large as the 1988 global emission level of 5.9 billion tons. Birdsall argues that, with such high levels of greenhouse gas emissions, no realistic reduction in deforestation could have a significant effect. Birdsall’s econometric analyses roughly predict that a one percent decline in the rate of population growth would reduce annual rates of deforestation in all developing countries by between 0.3 and 0.5 percent.[11] Therefore, under a “rapid” fertility decline scenario, the rates of deforestation in Africa would fall from roughly 2 percent to about 1.4 percent during the next 25-35 years. Over this same period, the rate of deforestation in Brazil would fall from about 2.3 percent to 2.2 percent, and the rate of deforestation in Indonesia would fall from roughly 1.4 percent to over 1.3 percent.[12] These minor reductions in deforestation over the next 25-35 years would only reduce forest loss by about 9,000 square kilometers per year and total carbon emissions by about 1.6 percent.[13] According to Birdsall, these reductions are “small.”[14]
The only real optimism in Birdsall’s argument about the effects of slower population growth on greenhouse gas emissions is regarding the cost-effectiveness of slower population growth compared to other methods of combating global warming. Although Birdsall strongly maintains, throughout her essay, that the role slower population growth can play in reducing greenhouse gas emissions is small, she does not say that this role is pointless, negative, or a step in the wrong direction. In fact, Birdsall compares the slower population growth method of combating global warming to the “carbon tax” method and finds that the slower population growth method may be equally, if not more, cost-effective.[15] The carbon tax method is based upon a series of studies conducted by William Nordhaus (1991, Environmental Protection Agency) about the elasticity of energy supply and interfuel substitutions. He uses the results of his studies to develop a “cost-reduction schedule” of the marginal cost of reducing greenhouse gas emissions. This schedule allows him to predict the level of taxation necessary to reduce emissions at each margin. Nordhaus estimates that a 10 percent reduction in global carbon emissions would require a tax of about $20 per ton.[16] He also estimates that a 20 percent reduction in global carbon emissions would require a tax of over $50 per ton and a 50 percent reduction would require a tax of about $130 per ton.[17] These estimates indicate that the costs of further reductions in greenhouse gas emissions rise rapidly under the carbon tax method.
Comparatively, the costs per ton of a 10 percent, 20 percent, and 50 percent reduction in greenhouse gas emissions are expected to be low under the slower population growth method. irdsall estimates the costs of averted births (which translates as slower population growth) and subsequent reductions in greenhouse gas emissions by looking at the potential costs of contraceptive services and family planning programs in the developing world. Susan Cochrane and Fredrick Sai of the World Bank Health and Nutrition Division (1991) report that the costs of contraception in developing countries range from about $3 for sterilization in Indonesia to about $25 for pill use in Honduras and Morocco.[18] This extensive range of contraception costs means that the costs per birth averted in the developing world can fall within a wide range as well. Birdsall uses the mean figure of $220 per birth averted for the purposes of her essay and argument. This figure is in between the estimated cost per birth averted in high-mortality countries where about 20 percent of women report wanting no more children and the estimated cost per birth averted in high-mortality countries where about 30 percent of women report wanting no more children. At $220 per birth averted and an average of about 20-60 tons of carbon emissions produced by one person during his or her lifetime, the cost of reducing greenhouse gas emissions in the developing world through contraception and family planning programs is between $4 and $11 per ton ($220/60 and $220/20).[19] These costs are significantly less that the costs of reducing greenhouse gas emissions through the carbon tax method.
Birdsall recognizes that her estimate of $220 per birth averted may be incorrect; however, she argues that $220 is more likely an over-estimation of the cost per birth averted rather than an under-estimation. She bases her assumption upon the notion that most of the more populated developing countries (countries in Africa and the Middle East) currently have limited family planning services and high total fertility rates. According to Birdsall, as more women in these countries decide that they want fewer children as a result of increased family planning programs, then the costs per birth averted will decline.[20] Additionally, Birdsall speculates that improvements in contraceptive technology will drive down the costs of averting births as well.
In a second analysis of the cost-effectiveness of reducing greenhouse gas emissions through slower population growth, Birdsall looks at the costs of averting births in the developing world by educating women and girls. Based upon the econometric studies of Lawrence Summers (1992) and 1985 World Bank fertility projections, Birdsall “conservatively” predicts that, in developing countries, each additional year of a girl’s schooling results in a reduction of fertility by 3 percent.[21] Summers reports that the annual cost of raising female enrollment in developing countries to the level of enrollment in developed countries would be about $ 6 billion. At this price, annual births in the developing world would fall by about 34 million (based upon Birdsall’s estimation of 3 percent fewer births per year of additional education) and the annual reduction in carbon emissions would range from about 640 million tons to 1.9 billions tons (depending upon how much carbon one individual is expected to produce during his or her lifetime). Thus, the average cost of reducing greenhouse gas emissions through education of women and girls would be between $3 and $9 per ton ($6 billion/1.9 billion and $6 billion/640 million).[22] These costs are even below those predicted for the slower population growth method of averting births through increased contraception and family planning programs.
Although Birdsall is not convinced that slower population growth is a powerful and entirely effective tool for combating global warming, she does believe that it may be more cost-effective than other methods of reducing greenhouse gas emissions in the developing world. According to Birdsall, slower population growth would have a limited impact upon fossil fuel emission levels and rates of deforestation. Yet, she also seems to admit that it may be more important to recognize that slower population growth would have some impact. Birdsall’s analyses reveal that slower rates of population growth lead to slightly lower levels of fossil fuel emissions and slightly lower rates of deforestation in the very long-run. The fact, however, that the cost of reducing the population growth rate is less than the cost of combating global warming through other, more conventional, methods (a carbon tax) encourages Birdsall to support the slower population growth method to some degree. In this respect, she is neither entirely disapproving or approving of the notion that slower population growth can “save us from global warming.”
Source:
Birdsall, Nancy. “Another Look At Population and Global Warming.” In United Nations, Population, Environment, and Development: Report of an Expert Group Meeting on Population, Environment, and Development, 20-24 Jan 1992. United Nations, NY. 1994, pgs. 39-54.
[2] Ibid., 44.
[3] Ibid., 43-44.
[4] Ibid.
[5] Ibid., 40.
[6] Ibid., 46.
[7] Ibid., 47.
[8] Ibid.
[9] Ibid., 43-44.
[10] Ibid., 45.
[11] Ibid., 47.
[12] Ibid.
[13] Ibid.
[14] Ibid., 39.
[15] Ibid., 48.
[16] Ibid., 49.
[17] Ibid.
[18] Ibid.
[19] Ibid.
[20] Ibid.
[21] Ibid., 50.
[22] Ibid.