A larger global population means a larger demand for everything--most urgently, energy. And although Earth's resources have apparently stretched further than Paul Ehrlich infamously predicted four decades ago in his book The Population Bomb, the mounting climate problem suggests that the consequences of overconsumption (namely of coal and other fossil fuels that produce heat-trapping greenhouse gases) may still be inevitable. Below, our five discussants explore how population growth relates to the world's spiraling energy needs and whether addressing it can help provide a solution to the climate problem.
It's true that in places where birthrates remain high, e.g. sub-Saharan Africa, per-capita emissions are quite low. Joseph Chamie and Betsy Hartmann see this as reason not to pursue a population policy to reduce emissions. We argue that full access to contraception in such regions can help with emissions reduction because per capita emissions must rise in order for people to be lifted out of poverty. The environmental impact of development can be reduced if there are fewer poor people needing to make the transition.
Relentless population growth means eventually reaching a limit of environmental collapse where the supply of crucial, irreplaceable resources (e.g., water and land) is grossly exceeded. If one doesn't have the purchasing power to acquire such resources from others, the only options are to migrate as environmental refugees; accept international handouts forever; or die by starvation, disease, or slaughter. This is demographic entrapment. It's a highly inconvenient truth. Thus, we use the terminology but reject unambiguously the dreadful baggage (e.g. "lifeboat ethics") added by Maurice King, Garrett Hardin, or anyone else.
John Guillebaud was brought up in Rwanda, preferring Kinyarwanda to English until age six. He has visited the Genocide Museum in Kigali and wept for his boyhood friend, Husi Kajuga, and his family, who lie there in a mass grave. There were fewer than 2 million Rwandans when John played with Husi during the 1940s, but 8 million by the 1994 genocide. Resource-poor Rwanda had grown no larger in that time. James Gasana, Rwanda's minister of agriculture and environment from 1990-1992, asserts unequivocally the relevance of population growth to the genocide, though Betsy should note we accept in addition the major roles of inequity and longstanding ethnic divisions fomented by outsiders--the United Nations also shares some culpability. (See Linda Melvern's "Conspiracy to Murder: The Rwandan Genocide.")
For the whole planet to avoid the fate of Rwanda, we say "Malthusian thinking" needs rehabilitation. Since Malthus first highlighted population in 1798, humans have multiplied sevenfold. Economists thought we'd disproved Malthus with Norman Borlaug's green revolution, which ushered in a spectacular increase in food production. Yet that improved technology is wholly dependent upon fossil fuels for fertilizers, tractors, and transport. When our fossil fuels are gone, there will be a vast surplus population whose energy needs Earth will no longer be able to supply, and it will be too late for family planning. But if properly resourced now, family planning can still help by minimizing the number of new arrivals who will produce additional greenhouse gases as they rise from poverty.
Contraception is a remarkable invention, uniquely available to our species. A common myth is that large families among poor couples are a calculated choice, based on high child mortality and the social security factor. These factors have some relevance, but our experience is that large families happen chiefly because couples aren't empowered to prevent them. Frequent sex is human nature, which makes avoiding conception difficult--for everyone. The difficulty increases in the many settings where women's rights are abused, where contraceptives are in short supply, where the extent and range of barriers to their use aren't well understood, and where misinformation stifles demand.
We agree that we must also pursue everything in Betsy's penultimate paragraph. What would it mean to us as individuals to sufficiently reduce per-capita emissions in the high-consuming countries (mainly North American and Europe)? To reach the maximum sustainable global biocapacity--given our current population--of 1.83 global hectares (gha) per person, we would need to reduce our mean footprint from 6.4 gha to 3.7 gha per person, or further if the small ecological footprints of low-consuming countries increase. But we won't achieve that 42-percent reduction through minor gestures such as unplugging electronics and recycling. We need to fly half as much; shift massively from cars to bicycles and public transportation; eat half as much meat; buy half the amount of goods; tolerate less air conditioning in hot weather and less heating in cold weather; and if all that doesn't work, institute rationing, as in time of war--all of which entails reducing consumer appetites and fully implementing a "reduce, reuse, and recycle" culture.
The current unrest in Haiti and elsewhere over food prices underlines the real conflict between growing population pressure and the limited biocapacity of a warming planet. We urgently need to balance the equation by reducing population, but not by population control--Betsy's word, never ours. Rather, we should wisely and compassionately demonstrate the necessity through education, through the media, by example, and above all, by meeting women's needs and everyone's right to have fewer children by choice, not chance.
We all agree that climate change is a serious threat to environmental and human health. Precisely because of its seriousness, we don't have time to bark up the proverbial wrong tree. Population control isn't the solution to global warming. In much of the world, birthrates are coming down toward replacement level. In places where they remain relatively high, e.g. sub-Saharan Africa, per-capita emissions are quite low.
Focusing on population growth not only diverts us from the real problems and solutions at hand, but it could undermine the achievements made at the 1994 U.N. International Conference on Population and Development in Cairo. The Cairo conference criticized top-down population control programs that violate human rights and argued that women's empowerment and the provision of safe, voluntary birth control and reproductive health services were a much better approach to the population problem. It condemned coercion and criticized the use of incentives and disincentives in family planning programs.
Therefore, I'm troubled to read Joseph Chamie's concluding remarks that suggest it may be necessary to override individual rights through government-mandated legislation, programs, and incentives to achieve population stabilization. (Fred Meyerson also suggests the use of tax and other economic incentives to this end.) Readers of this discussion might do well to familiarize themselves with the dark history of population control programs that gave family planning a bad name by sacrificing women's health and basic human rights. (In particular, see Fatal Misconceptions: The Struggle to Control World Population by Columbia University historian Matthew Connelly.)
I'm similarly distressed by Joe's advocacy of the views of Kingsley Davis and Garrett Hardin regarding the need for coercive programs when voluntary programs fall short of their intended goals. Hardin, author of the 1968 Science article "Tragedy of the Commons," was a known eugenicist and advocate of lifeboat ethics--throw the poor overboard so the rich can live. As late as 1993, he accepted funding from the Pioneer Fund, the major supporter of eugenics research in the United States, which he stated in the introduction to his book, Living Within Limits . (For more on Hardin's connection to eugenics, see The Legacy of Malthus: The Social Costs of the New Scientific Racism by Allan Chase.) Moreover, his notion of the tragedy of the commons was ahistorical and analytically flawed, ignoring how communities over the centuries have regulated access to common resources.
I cannot state too strongly that we don't want to dredge up these outmoded (and in my mind, immoral) ideas as part of some hypothetical solution to overpopulation and climate change. Instead, we need to expand women's rights and human rights and support the Cairo reforms, which are under attack from fundamentalists and anti-abortion forces, not undermine them. We also need to support immigrant rights. Recent scaremongering press reports and studies about human tides of climate refugees swarming the European Union and the United States aren't based on solid empirical evidence and play into the hands of nativist forces.
I've already written about what I see as the real solutions to the climate crisis. These include demilitarization; technology transfer and the greening of industrialization in countries such as India and China; investment in alternative energy development and mass transport; challenging the overconsumption logic of global capitalism; and ensuring that corporate energy giants do not gain windfall profits from carbon taxes and trading schemes and that poor people don't bear the burden of the energy transition. Indeed, responding to climate change presents an opportunity to redirect our development path toward social and environmental justice. Rather than doomsday thinking, we need to support scientists, engineers, architects, artists, builders, politicians, and community organizers to get on with the concrete business of reducing emissions and developing alternative technologies.
One final thought: Several here have suggested it's somehow easier to reduce population growth than emissions and that people are necessarily averse to changing their lifestyles and consumption habits. In contrast, I believe there's great scope for a cultural transition toward sustainability in the developed world. Overconsumption hardly buys happiness. If measured by the amount of antidepressants consumed daily, the United States is perhaps the most unhappy place on Earth. A saner lifestyle of less consumption but more security--e.g. universal access to health care, something many Europeans enjoy--is a trade-off many in the United States might willingly accept. We shouldn't underestimate the capacity for people to change and work together for the common good.
The increase in world population and greenhouse gas emissions is widely acknowledged to have serious implications for human well-being and all other life on Earth. But what can be done about it?
Any attempt to address this question must take two political realities into account: (1) The international community has adopted a "rights-based" approach to population and development issues; and (2) nations are sovereign to formulate and implement their own domestic policies, actions, and laws to address population, development, and greenhouse gas emissions.
The fundamental reproductive right is enshrined as Principle 8 in the Cairo Consensus: "All couples and individuals have the basic right to decide freely and responsibly the number and spacing of their children." Population policies that limit or curtail this principle, such as China's one-child policy, are widely condemned for violating fundamental human rights.
The adoption of the Universal Declaration of Human Rights recognized the right to migrate more than 50 years ago. Article 13 states, "Everyone has the right to leave any country, including his own, and to return to his country." But while everyone has the right to leave their country, they don't have the right to enter another country. As a consequence, the supply of potential migrants greatly exceeds demand for them, with the result being tens of millions of illegal migrants moving to more developed and industrialized regions. A recent European Union study predicts an influx of "environmental" immigrants will sweep Europe following land loss, failing harvests, and environmental conflicts in the world's poorest countries, leading to social unrest on the continent.
With respect to development, the international community similarly adopted the Declaration on the Right to Development. "The right to development is an inalienable human right by virtue of which every human person and all peoples are entitled to participate in, contribute to, and enjoy economic, social, cultural, and political development,” its first article states. Not surprisingly, countries interpret this inalienable right differently. On the one hand, less developed nations assert their sovereign right to development, emphasizing that their citizens shouldn't be unfairly disadvantaged by restrictions that didn't exist when the industrialized nations developed. Conversely, many developed nations have stressed that the right to development isn't absolute and should be linked to environmental concerns, in particular global warming."
Balancing fundamental human rights with global societal concerns, such as climate change, raises many challenges. While many may believe that the rights of the individual reign supreme, there are limits when greater societal well-being is under threat. In the coming years, we'll need policies and programs to ensure that individual behavior is compatible with sustainable living standards for the broader world community.
As I said earlier in this roundtable, crying wolf about the population bomb and making dire forecasts of imminent global famine too frequently undermines the credibility of legitimate concerns that governments and scientists have about the consequences of rapid population growth. Misidentifying the major factors of climate change and environmental degradation is also likely to retard progress in finding sustainable, long-term solutions, as Betsy Hartmann has emphasized in this discussion.
Certainly national population policies--particularly those relating to fertility and international migration--play an important mitigating role by decreasing aggregate economic demand for energy and resources, especially in more developed countries. But reducing national population growth rates involves more than simply reducing unintended fertility. In many less developed countries, especially in Africa and South and West Asia, policies and programs need to address family size preferences that are well above replacement-level fertility. In more developed countries, particularly the United States, immigration must slow in order to achieve population stabilization.
International organizations and nongovernmental organizations can help foster global cooperation among nations to reach agreed upon commitments. But the responsibility to deal with these critical issues remains largely with individual countries. For some nations, voluntary behavioral changes may be sufficient to alter demographic trends and unsustainable, environmentally damaging practices. However, as Kingsley Davis and then Garrett Hardin forcefully argued in Science in 1967 and 1968, respectively, voluntary programs to modify individual behavior tend to fall short of intended goals. In such cases, legislation, programs, and incentives that encourage responsible parenting and sustainable resource use must be mandated in order to achieve population stabilization and reduce greenhouse gas emissions.
Because this is the last round of our discussion, I'd like to make specific policy recommendations that address the related challenges of population growth and greenhouse gas emissions.
First, in a world where climate change will have significant adverse effects on resources and human welfare, we should do everything possible to quickly slow the current annual growth rate of more than 75 million people and stabilize global population.
To achieve this, the United States should increase its assistance for population programs by $1 billion annually and reestablish global leadership in this area. If other donor countries also increase their support for population programs, it should be possible to achieve universal access to family planning and to satisfy global unmet need within five years. As a result, the population growth rate could be reduced by about 30 percent.
Supplying contraceptives and reproductive health services isn't sufficient to reach population stabilization, particularly where fertility rates and preferences remain high. It will also be necessary to increase the demand for family planning services and to communicate the benefits of smaller families. Television and radio programs, including serial dramas, have often proven effective in reaching underserved populations and increasing awareness of contraception--and the desire to use it. In many cases, these programs have also lowered average family size preference. (See the Population Media Center for more.)
One hundred million dollars per year in additional funding could be sufficient to ensure that these "demand-side" programs reach the widest possible audience in the developing world, and in the developed world where needed. Some of this money should be spent on further research as to which media approaches are most effective, assessments of the immediate and long-term results of past and current programs, and developing new communication methodologies in a rapidly changing media environment. There's no bright line between "supply" and "demand" family planning efforts. If media programs are successful, they increase the demand for services.
It's important to remember that in a world of 6.7 billion people, every year, 50 million or so teenagers enter their reproductive years, and we will always need new approaches to communicate with them. A recent Centers for Disease Control and Prevention report that found 25 percent of U.S. teenage girls have at least one sexually transmitted disease and the country's continued high teenage pregnancy rates are strong indications that this challenge never ends--even in developed countries.
While $1.1 billion is a lot of money, it amounts to less than what the United States currently spends on the Iraq War every three days. It's a human welfare investment that can improve our image globally and help us avoid the perils to our species posed by a rising population and an unstable or diminishing resource base as the climate changes more rapidly.
Suppose the combination of supply- and demand-side programs isn't sufficient to stabilize population globally? First, I would recommend increasing funding for the development of new forms of contraception, which has decreased in recent years because of political and social pressure. As long as contraception in the United States has an average annual failure rate of nearly 10 percent, there's obviously work to be done. Second, we should reexamine the web of incentives and disincentives for having children, both in the United States and internationally. Tax and other economic incentives should be continuously reconsidered to make population stabilization more likely.
Stabilizing world population this century, even at 8.5 billion or 9 billion people (the most optimistic realistic scenario) won't avoid serious climate change, but it's a relatively easy first step. It will make both mitigation and adaptation much less difficult than a world of 10 billion or more people, where we're now headed under current population policy.
Reducing per-capita emissions is the second critical (and much more difficult) task. As I documented earlier in this discussion, average global per-capita emissions haven't changed in nearly 40 years. The only viable way to lower them is to make the price of emitting greenhouse gases so high that it's in everyone's best interest to reduce consumption and turn to other technologies for producing energy, goods, and services. This will involve significant economic and social change and disruption, but then so did the industrial and fossil-fuel revolutions of the past 200 years that fostered the population growth that brought us to this demographic and climate crisis.
I agree with Joe Chamie's assessment that even if we could dramatically reduce unintended pregnancies, it wouldn't have much impact on curbing global greenhouse gas emissions. In any case, there's no magic bullet for reducing unintended pregnancies. Access to safe contraception and abortion is vitally important, but unintended pregnancies aren't merely the result of lack of family planning services. There are entrenched, gendered power dynamics at work within households, communities, and nations worldwide. For example, a woman might be pressured by her husband, in-laws, or her religious or ethnic community to have a child she herself doesn't want. Or more commonly, a woman who becomes pregnant when contraception fails might decide that even though the timing's not perfect, she will have the child anyway. In other cases, family planning services may exist, but be of such poor quality that a woman decides not to use them even if she wants to space her children.
We also need to look critically at the notions of carrying capacity and demographic entrapment that John Guillebaud and Martin Desvaux emphasize. Carrying capacity evolved as an analytical tool in the fields of ecology and conservation biology to estimate the maximum number of animals of a particular species that a habitat can support indefinitely. However, applied to people and their environments, it's woefully inadequate, as many scholars have noted. (See How Many People Can the Earth Support? and the American Association for the Advancement of Science's "Atlas of Population and Development.") The concept of carrying capacity assumes that population growth damages the environment, and in the context of human society, inadequately considers the role of technological change. It also overlooks the importance of trade between different regions and ignores structural economic, political, and social inequalities that shape patterns of resource use.
The notion of demographic entrapment--that starvation and slaughter will result from humans grossly overshooting carrying capacity in regions like sub-Saharan Africa--is highly problematic, both scientifically and ethically. Missing from this simple Malthusian narrative are the role of governments in fomenting ethnic violence (i.e., Rwanda), consideration for inequitable patterns of land ownership and terms of trade, and attention to the disproportionate contributions of different perpetrators to environmental degradation--i.e., peasants versus commercial agriculture and corporate resource extraction.
In a highly controversial (and, I would argue, morally reprehensible) September 1990 Lancet article, Maurice King, the main advocate of demographic entrapment theory, argued that public health programs in severely overpopulated areas shouldn't orally rehydrate babies suffering from dysentery. In other words, they should be left to die. Surely, we don't want to go down that road, either in this debate or in discussions of health and population policies in general.
Let's further examine the assumption that population growth is de facto bad for the environment. While population growth may decrease the size of landholdings, it can also expand the family labor supply, encouraging more labor-intensive cultivation and conservation techniques. Declining landholdings in Rwanda, for instance, have been associated with more investments in soil conservation and better managed tree densities per unit of land. (See "Effects of Demographic and Related Microeconomic Change on Land Quality in Hills and Mountains of Developing Countries" and The Lie of the Land: Challenging Received Wisdom on the African Environment, which disputes the overdramatization of environmental degradation in African countries.)
It's also important to remember that violent conflict in sub-Saharan Africa is more often linked to resource abundance (diamonds in Sierra Leone, minerals in the Congo) than to resource scarcity. (See Greed and Grievance: Economic Agendas in Civil Wars.)
A more constructive road to follow--and one that we've neglected so far--is exploring the role of militarism in climate change. The U.S. military is a major consumer of fossil fuels, in peace and wartime. The Iraq War is costing us billions of dollars that could be better spent on developing sustainable technologies and energy supplies. Not to mention, a militarized society is a less democratic society that will impede our ability to develop broad popular consensus to effectively address global warming.
I'm more optimistic than Fred Meyerson and John and Martin. I see great potential in the intersection of peace, social justice, and environmental movements to push for an equitable and sustainable energy transition. There is no magic blueprint for how to do that, and the challenge will be to get a diverse group of actors to the table so that it's not just corporate business as usual. Networks like the Durban Group for Climate Justice point the way toward more ecologically sound and socially just approaches to addressing global warming. Malthusian doomsday thinking will get us nowhere.
Joe Chamie calls targeting unintended fertility a "delay tactic" that hinders the immediate pursuit of reducing resource consumption. Again, we want to reiterate that we don't view this as an either-or proposition. Instead, to avoid catastrophic climate change, we believe that the international community should pursue the methods that Fred Meyerson describes below to reverse population growth and ways in which to reduce resource consumption.
The time we have available to achieve both of these goals is key. As stated previously, the United Nations currently projects [PDF] that world population will reach about 9 billion by 2050. Meanwhile, David Rutledge at the California Institute of Technology recently looked at projections for the depletion of conventional oil, gas, and coal reserves based on the application of M. King Hubbert's technique for determining peak oil and estimated that, by 2076, 90 percent of these reserves will be gone.
This is a much shorter timescale than previously believed--especially for coal, where mainstream predictions had indicated up to a 250-year supply. Rutledge's projections for coal production take into account new assessments of the recoverability of coal reserves, which may not be as accessible as once thought, and it's possible that earlier coal forecasts were based on current usage rates and didn't factor in acceleration from population growth and increased affluence. Several countries have already severely downgraded their reserves: In 2004, Germany, the largest coal producer in the European Union, reduced its estimated black coal reserves by 99 percent and its brown coal reserves by 80 percent.
Aside from the devastating climate effects of burning all our fossil fuel, if demographers and Rutledge are correct, in less than 70 years, humankind will number 9 billion and energy will be scarce and expensive. Assuming that current growth in renewables and nuclear energy could provide 60 percent of the current world energy needs by 2075, Rutledge lays out the stark challenge facing humankind: Cut energy demand to 40 percent less than it is today and reduce global population to around 5 billion. We think this population target is still too high, given that Routledge doesn't take into account attrition in agriculture and land availability by that time.
Because nearly one-half of the world's population is under the age of 25, placing them in the midst or still ahead of their childbearing years, reversing population growth cannot be achieved before 2050. Only a catastrophic die-off could make it happen sooner. The alternative is Fred's top-tier prioritization of voluntary family planning, plus education and media outreach now. Further delay means that we must contend with nearly a billion extra humans to feed and clothe every decade.
It's all very well and good to say, as Joe does, that in Africa, "per-capita emissions are already so low that lower birthrates would not make a noticeable dent in total global emissions." But this implies tolerating an appalling status quo: Who among us doesn't passionately want to see the poorest people of the world escape their unacceptable poverty? It's not difficult to understand that one less person born into poverty is one less person who needs to be helped out of poverty--a development process that cannot occur without increased energy consumption and (in the medium term) more carbon-dioxide emissions per person.
The data we gave in our first post showed that in 2003, Africa had a per-capita ecological footprint of 1.1 global hectares (gha) against an available biocapacity of 1.3 gha per person. In other words, more than a 17.6-percent increase in Africa's population will make it impossible for even underdeveloped states to sustain their current populations due to space, energy, and (especially) water constraints. As Africa doesn't have the same buffer of wealth as the developed countries possessed when they crossed the line of unsustainability, that process will have a much harsher impact on Africans. One of us (John Guillebaud) was born and brought up in Burundi and Rwanda, and from recent visits, he knows firsthand how many sub-Saharan African countries are already on the verge of demographic entrapment. Once the environmental carrying capacity is grossly exceeded, the only likely outcomes are starvation, disease, interethnic violence and genocide, migration (and to where?), and/or dependence on aid from the international community.
Few would disagree that helping women and men who want to avoid or delay pregnancy is a laudable goal that contributes to the well-being of individuals, families, communities, and nations. The international community acknowledged this as a fundamental principle of population policy in the Report of the International Conference on Population and Development (PDF) (also known as "The Cairo Consensus") which states, "All couples and individuals have the basic right to decide freely and responsibly the number and spacing of their children, and to have the information, education, and means to do so." However, fulfilling this ideal is unlikely to significantly impact overall greenhouse gas emissions.
Fred Meyerson uses the cautious term "unintended fertility" to reference the unintended half of all U.S. pregnancies and the 200 million women in developing countries who would like to avoid or delay pregnancy. But he erroneously conflates the idea of contraception, which is largely a matter of timing, with the issue of greenhouse gas emissions, which is a function of absolute human numbers-- and the distribution of those numbers among more- and less-developed nations.
Fertility surveys have found that most couples worldwide want at least two children. In many less-developed countries in Africa, Asia, and South America, people tend to want at least three children (often with a preference for sons). This is to say that even with family planning resources in place, reducing "unintended fertility"--i.e. unplanned pregnancies--will not necessarily lead to replacement level fertility in less-developed regions, nor reduce average family size in more developed regions.
The average global birthrate is 2.6 children per woman, equaling approximately 136 million births per year. Minus annual deaths, that's a net growth of about 78 million people per year. If all nations instantly reached replacement-level fertility, thereby eventually stabilizing the population as Fred and others advocate, the total global number of births would fall to about 120 million annually, about a 12-percent reduction.
But the Devil is in the details: The net reduction in births matters less than the distribution of regional demographic shifts. Nearly all of the more-developed nations have below replacement fertility levels. Many of these countries, such as Germany, Italy, Japan, and Russia, are actively seeking to raise fertility levels for reasons of economics and social welfare. In fact, if all more-developed, industrialized countries reach replacement-level fertility, their total number of annual births would increase by 30 percent, or about 4 million births.
Other dynamics are at work, as well. In the United States, where fertility is already at the replacement level, and in Europe, where fertility is well below replacement, immigration is the primary driving force behind most of the projected population growth. While immigration does not contribute to an increase in the absolute number of humans on Earth, it does shift people into relatively higher consumption brackets. In the unlikely event that immigration were to cease, U.S. population by mid-century would be 80 percent smaller than projected, a much greater demographic impact than reducing unintended fertility.
The vast majority of the 200 million women Fred cites are in Africa and Asia. The greatest demand for reducing unintended fertility is in Africa, where per-capita emissions are already so low that lower birth rates would not make a noticeable dent in total global emissions. This tactic could work better in China and India. China, the largest country in the world, is expected to soon overtake the United States as the world's biggest source of greenhouse gasses--if it hasn't already. If current trends continue, some experts believe that China's greenhouse gas emissions will likely exceed that of all industrialized countries combined during the next 25 years. This is due to both increasing local consumption and massive exports of commodities like steel and concrete.
But again, the fertility level in China is already 1.7. Reducing unintended fertility in China would have little effect on the country's production of greenhouse gasses. Moreover, if China were to relax its one-child policy and fertility increased to replacement level, the country's annual number of births would increase by nearly 30 percent, or approximately 5 million additional births.
To be fair, annual births in India would drop by about 4 million if it were to reach replacement-level fertility, and the birth rates in the populous nations of Brazil and Indonesia would also drop by 5 and 2 percent, respectively, as their fertility levels are already near replacement level. But as is widely acknowledged, these and the other less-developed countries are only responsible for one-fifth of the global carbon dioxide buildup that has accumulated in the atmosphere during the last century.
Given these circumstances, focusing on reducing unintended fertility to address climate change--in particular to decrease global greenhouse gas emissions-- strikes me as a delay tactic. Instead, the focus should be on significantly and immediately reducing damaging patterns of production and consumption. That's where we can make the real difference.
There is agreement in our discussion about the need to provide family planning, reproductive health services, and related education to everyone on the planet in a noncoercive way. There's also general agreement that doing so would reduce unintended births, slow population growth, and reduce greenhouse gas emissions, thereby helping with climate change mitigation and adaptation. One difference is that several of us, myself included, feel that stopping emissions growth and climate change will be unattainable without universal, effective family planning programs and population stabilization.
The international community should restore the goal of universal access to family planning as a top-tier priority, to protect both the climate and human wellbeing. How can we satisfy current unmet need for contraception and reproductive health services? It is a matter of both political will and money.
About 200 million women in developing countries would like to prevent or delay pregnancy but can't because they lack access to effective contraception. Reaching and helping these women and their partners is critical for climate and human development policy. A consensus of population and health care scientists and organizations estimates that developed nations would need to donate $5 billion per year (almost ten times the current levels) to reach these women with family planning services. (See " Family Planning and Reproductive Health: The Link to Environmental Preservation" [PDF] for more). While this is a significant amount, it's small in comparison to other expenditures. For instance, the United States spends more than $5 billion on the Iraq war every two weeks, and the same amount on Medicare programs every few days.
The United States should take the lead. The largest and most effective international family planning program in history was pioneered by the United States Agency for International Development (USAID) in the 1960s. The United States continues to be the largest donor globally to international family planning efforts. However, since the 1980's, decay in funding levels, quality of programs, and political support--along with inflation--has caused the U.S. international family planning programs to fall behind in constant dollar terms and in relation to the needs of a global population growing by more than 75 million people per year.
If the United States were to increase its assistance for population programs by $1 billion annually, and other donor countries contributed their share, it should be possible to satisfy the global unmet need for family planning within five years. As a result, the population growth rate could be reduced by about 30 percent, with a similar decrease in the growth of greenhouse gas emissions.
Much of the technical knowledge about family planning resides in U.S. institutions (nongovernmental organizations, foundations, and universities), and U.S. political and technical leaders could quickly revitalize this field. The United States could work closely with the U.N. Population Fund; the World Bank; European organizations, and other donor countries; as well as NGOs such as the International Planned Parenthood Federation, the Planned Parenthood Federation of America, Pathfinder, and the Population Council to quickly and strongly push forward on international family planning. Past efforts have shown how effective noncoercive programs can be, even in extremely poor countries such as Bangladesh and Kenya; and these programs have many other social and developmental benefits.
Developed countries, beginning with the United States, also need to improve their reproductive health services and education. For instance, the United States should be able to lower its unintended pregnancy rate from nearly 50 percent to around 20 percent, the current rate in several European countries, as discussed in my earlier comments. If the Netherlands can do it, the United States can, too. Decreasing unintended pregnancy rates in America would slow population growth and greenhouse gas emissions.
Universal access to family planning is no panacea, nor is it sufficient on its own to achieve population stabilization. We should discuss population education and media programs that affect the demand for services and their effectiveness in subsequent rounds of this debate. But lowering unintended fertility is the necessary first step toward population stability--and the climate mitigation and adaptation benefits that come with it.
With due respect to Betsy Hartmann, we will not "break loose from the population debate." The data demonstrate clearly that removing the many barriers to family planning worldwide--including simply making contraceptives realistically accessible and providing correct birth-control information within female education--is among what Betsy terms "the real tasks at hand." Although it's not the only remedy needed to blunt climate change, it's an utterly crucial and tragically underfunded one.
As numerous surveys and 80 million unwanted conceptions annually demonstrate, the good news is that this is an unmet need, and meeting it worldwide is possible with relatively little extra funding--a few billion dollars as opposed to the trillions of dollars needed to combat climate change. Can anyone show us consumer survey data of a deep unmet need perceived among people to reduce their consumption?
It's not helpful to polarize the debate between those for whom the roots of poverty and environmental degradation are, to quote Betsy, "located in structural economic, political, and social (including gender) inequalities" and those who "see [the roots] in overpopulation." The two viewpoints are complementary. Having fewer people on the planet doesn't produce or reinforce those inequalities. In fact, we would argue the opposite: Consumers generate growth and profits; therefore, economic growth strategy involves encouraging more consumers, which produces more waste and emissions. Costs must be kept down to stimulate sales growth, so manufacturing goes to poorer countries where unemployed people will work for low wages. That's why we still effectively have widespread slave labor 200 years after it was abolished! Of course, these inequalities are wrong.
History shows that while world population increased from 2.5 billion people to 6 billion people in the second half of the twentieth century, it is likely that those in a constant state of hunger more than doubled from 500 million to 1.2 billion during the same period. (See "The Fatal Inheritance," p. 77 for more.) Trying to eliminate these inequalities without addressing further population growth (properly resourced, and, as Betsy would rightly emphasize, in a gender-empowering and totally non-coercive way) is simply pouring gasoline on the flames of poverty.
Betsy, can you not see that climate change--just one example of humanity's environmental impact-- is caused in large measure by the sheer number of climate changERS contributing (i.e. us humans)? We've been able to multiply sevenfold in the last 200 years only because of the transient availability of fossil fuels, which are non-renewable, and humankind has appropriated in the process major portions of all the planet's resources for our selfish use. We lost sight of the fact that Earth has limits. When species multiply beyond the capacity of their environment, nature provides no alternative to a die off. Unprecedented global disasters loom and all of us are the problem: The rich, because of how they wastefully over consume (that must change), and the poor, because of their reasonable aspirations to leave poverty, which means increased consumption and hence inevitably more greenhouse gas production per person. And the number of persons in both subsets of the population is steadily increasing.
Unremitting population growth can only end in tears. As we argued in our previous post, we need an urgent plan to curb overpopulation. We challenge readers to refute the global ecological footprint data that show how Earth cannot feasibly accommodate, at least without a continuation of unacceptable poverty, the 9 billion humans that current demographic momentum (PDF) makes certain.
Even now, there are too many people for the average resources per capita that we're consuming. Footprint analysis clearly demonstrates this. We need a paradigm shift in political and cultural thinking to accept the need for population reduction, in almost every country, down to environmentally sustainable levels.
I'm glad we agree that universal access to noncoercive family planning and reproductive health services should be an important goal of international development policy. However, this doesn't necessarily mean we've reached a consensus. I'd like to clarify several points of difference.
First, although the distinction may seem subtle, there's a big difference between family planning services designed primarily to reduce birthrates and those premised on the belief that quality reproductive health care is a fundamental right, regardless of its impact on population growth. At the clinical level, services crafted mainly to reduce birthrates--even if they're not directly coercive--often treat women more as targets than as clients. Namely, they neglect medical screening and follow-up and promote riskier contraceptives such as Depo Provera and Norplant because they're ostensibly more effective in reducing birthrates. In the drive for demographic results, quality of care and freedom of choice end up taking a backseat. Two recent books, Population Politics and Development and Reproducing Inequities, do an excellent job of exploring this dynamic in Tanzania and Haiti respectively.
A second point is that there is a profound difference in the worldviews of those who see the roots of poverty and environmental degradation in overpopulation, and those who locate them in structural economic, political, and social (including gender) inequalities. In Bangladesh, where I lived in the 1970s, villagers were poor not because they had too many children, but because centuries of colonial rule and corrupt governance concentrated land, resources, and power in the hands of a few. Meanwhile, high rates of infant and child mortality meant that parents had to have many children in order to ensure that a few would survive to take care of them in old age.
After witnessing such inequalities, I could never again accept the simplistic--and often elitist--assumptions of Malthusian thought. In addition to scapegoating the poor, Malthusianism, trapped as it is in a rigid man-versus-nature dichotomy, tells us little about the complex causes of environmental degradation from a social or natural science perspective. (Today birthrates have declined in Bangladesh because of improvements in child health care and social and economic changes that encourage smaller families.)
I've spent much of my career trying to understand why Malthusianism is such a persistent and popular belief system, especially in the United States. Ironically, one of the current reasons is the strength of the anti-abortion movement and its success in reducing U.S. international family planning assistance. In order to mobilize support and appeal to conservatives in Congress, some population/family planning agencies strategically resort to fear-based appeals (e.g. overpopulation as a threat to national security) even if they don't actually believe their own rhetoric. And so women's rights activists often find themselves caught between a virulent anti-abortion movement on the one hand and advocates of population control on the other. (There's a parallel here with the rhetoric about how climate change will cause wars and mass migration, as some environmental lobbyists in Washington deploy these alarmist arguments in order to get conservatives to support legislation on reducing carbon emissions.)
We must start thinking outside the box--and off the grid--in terms of solutions to the climate crisis. I disagree with Fred Meyerson that population growth is easier to manage than per-capita emissions and also with John Guillebaud and Martin Desvaux's pessimism about renewables. (I also don't see how we could possibly get to a population of 2.8 billion any time soon without coercion and/or mass death--not a prospect I would look forward to.)
If possible, I'd like to see this debate take a different turn: Let's seriously consider how we might fundamentally transform our capitalist, consumerist culture to live in more socially and environmentally sustainable ways. In the United States, we've lived for so long now under the depressing shadow of a right-wing militarist and anti-environmental regime that we're losing our capacity for creative political imagination. We need to revive that capacity--now.
A recent New York Times piece, "Rethinking the Meat Guzzler," examined the health, environmental, and climate consequences of industrial meat production and provided the basic message that we could have a big impact on the environment simply by changing the way we eat. Meanwhile, in Germany and Scandinavia, homebuilding is being revolutionized and energy efficiency is being fine-tuned to an unprecedented degree. So let's break loose from the population debate and get on with the real tasks at hand.
This debate is taking an unfortunate turn. In my view, it's not a matter of prioritizing a number of different issues; it's pursuing all of those issues at once.
In a few years, the world's population will grow to 7 billion people. Around 2025, population will likely reach 8 billion people. Nearly all of this growth will take place in developing regions, particularly sub-Saharan Africa and South Asia. What happens after 2025 depends a great deal on what happens to fertility levels. If current fertility levels remain constant, world population will reach nearly 12 billion people by 2050 and more than 40 billion people by the end of the twenty-first century. Even if all countries instantly reached and remained at a replacement fertility level of two children per woman, world population would continue to grow to more than 8 billion people by 2050.
Similarly, emissions rates seem certain to continue growing--with the potential to accelerate, as developing countries industrialize their economies. Understandably, the populations of these countries want to raise their living standards. And current trends unmistakably detail how even small living-standard improvements in developing countries will increase global greenhouse gas emissions.
The impending challenges of population growth and climate change are well known to policy makers, development experts, and concerned citizens. Moreover, the solutions to these mounting challenges aren't a secret. The international community has already identified and adopted scores of recommendations at the numerous U.N. conferences and summits held on the topic during the past two decades. For example, the following recommendation comes from the 1994 International Conference on Population and Development in Cairo:
"Recognizing that the ultimate goal is the improvement of the quality of life of present and future generations, the objective is to facilitate the demographic transition as soon as possible in countries where there is an imbalance between demographic rates and social, economic, and environmental goals, while fully respecting human rights. This process will contribute to the stabilization of the world population, and, together with changes in unsustainable patterns of production and consumption, to sustainable development and economic growth."
Unfortunately, governments in both developed and developing regions lack the political will to implement agreed upon recommendations and commitments. For instance, preventing unwanted pregnancies is neither difficult nor costly. Achieving this goal would benefit individual families, society as a whole, and development efforts. Likewise, we can reduce carbon emissions by improving the efficiency of motor vehicles and expanding mass transit. Stagnation on these steps is due to cultural resistance as well as the absence of strong and enlightened political leadership to counter powerful social and economic interests.
The steps needed to address the consequences of rapid population growth and increasing carbon emissions will differ among regions because of varying demographic, economic, and social conditions. Namely, most industrialized countries will need to do more with respect to carbon emissions, while most developing countries will need to do more with respect to fertility rates.
In brief, let's stop debating either-or scenarios: Either we focus our efforts on population growth or greenhouse gas emissions. The same holds true when deciding how to address the other vital issues facing humanity--poverty, education, housing, aging, health, food, water. The right approach is focusing on all of the above.
Betsy Hartmann believes that we are not "on the brink of demographic disaster." I disagree. We're already in the middle of a demographic disaster at the global scale in environmental terms. I concur with John Guillebaud and Martin Desvaux that the world's population is living beyond its collective environmental means. Because of the long lag times associated with human demographic change, we need to act immediately to change that course.
Global per-capita carbon emissions from fossil fuel have remained nearly constant for almost 40 years (currently about 1.2 metric tons [mt] of carbon per person). Therefore, as global population increases in 2008 by a projected 77 million people, we’ll see an increase of about 92 million mt of emissions. In effect, in terms of emissions, we're adding the equivalent of another Brazil or Australia to the planet every year.
Just stabilizing total emissions at current levels, while keeping pace with population growth, would require reducing global per-capita emissions by 1.2 percent each year. We haven’t managed to decrease per-capita emissions by 1 percent in the last 38 years combined. The Intergovernmental Panel on Climate Change, former Vice President Al Gore, and many well-intentioned scientific, media, and activist campaigns haven’t changed that fact. And because of the rapid economic growth and increased coal use in China and elsewhere, we may now be headed for higher per-capita emissions.
We've had much more success with managing population. The global population growth rate has decreased from 2.1 percent in 1970 to 1.2 percent today, as a result of family planning programs and improved education. If we could reduce global unintended pregnancy rates to the lower levels that already exist in many European countries, population growth would slow further. As I wrote in my December 3 opening statement, for both environmental and social reasons, we should act quickly to address the fact that almost 50 percent of U.S. pregnancies are unintended, through improved education and services.
However, there are large constituencies in favor of high birthrates and continuous population growth, including religious and business groups. In a front-page story last month, USA Today reported that the fertility rates in the United Stated rose above 2.1 children per woman for the first time since 1971, partly as a result of unintended pregnancies in all age groups. The article also states that a high fertility rate is important to industrialized nations for social and economic reasons such as social security and job replacement. "Be fruitful and multiply" also plays well in churches and corporate boardrooms.
In addition, many human rights groups, women's organizations, and individuals agree with Betsy's position that any discussion of population policy in numerical terms necessarily leads to coercion and racism. This creates an unintentional de facto alliance between those groups and some of the aforementioned business and religious organizations: They all want to suppress dialogue and policies that relate specifically to reducing population growth.
Meanwhile, there's insufficient evidence that population is likely to stabilize with current policies and funding. Betsy states, "The United Nations projects that world population will eventually stabilize, falling to 8.3 billion in 2175." She therefore feels that we don't need to worry about population growth. This is an unwise assumption. Long-term population projections (some only decades into the future) have been notoriously inaccurate. A projection 170 years into the future is little more than a mathematical exercise, often involving simple assumptions that key variables such as fertility and mortality rates will converge and remain constant. Constancy is a state that is rarely, if ever, found in nature.
Joseph Chamie headed the U.N. Population Division for many years. I hope he will discuss the assumptions behind the U.N. projections in his next posting, and whether or not it is wise to rely on those projections to make climate policy decisions.
If human history or nature is any guide, I believe there's a very low probability that fertility rates will stabilize at the replacement level. It's more likely that some regions will continue to experience high fertility and growth. Therefore, if we want to stabilize population globally, geographical areas with below replacement fertility will also need to exist.
I think it will be easier to reduce unintended pregnancies and births, which we know how to do successfully through improved reproductive health services and education, than to reduce per-capita emissions, where our track record is poor. We can achieve this without coercion and also protect humankind and the planet from the interrelated challenges of population growth and climate change.
There's clear evidence that even now, the world's population is living beyond its collective means. The World Wildlife Fund's "Living Planet Report 2006," which publishes biocapacity (i.e., the potential productivity of cropland, forests, fisheries, and fresh water) and per-capita ecological footprint data generated by the Global Footprinting Network provides the most comprehensive existing data.
By their estimate, our total consumption of 13.685 billion global hectares (gha) represents a 22-percent overshoot of Earth's total biocapacity, which is estimated as 11.22 billion gha. This overshoot is possible only because we can (temporarily) substitute or supplement our biological resources by exploiting our finite supply of fossil fuels.
Fossil fuels (coal, oil, and natural gas) provide concentrated energy derived from the sun over millions of years. Renewable energy is essentially harvested in real time--directly through photovoltaic technology or indirectly via wind and wave action. Because renewables are intrinsically far less energy dense than fossil fuels, they cannot replace even the current world power requirement, let alone the requirement that will result from a more overpopulated planet. Furthermore, the more promising sources of renewable energy (wind and solar) can only be harnessed intermittently. It'll be impossible for renewables to satisfy the energy needs of high- or even medium-income countries after fossil fuel and uranium resources have been depleted. Even if self-sustaining nuclear power becomes viable, a world without artificial fertilizers, air transport, and other essential petroleum products will be incapable of sustaining even today's population. It follows that a sustainable future is only possible through a combination of reducing consumer numbers and per-capita consumption. Indeed, the situation is now so serious that it makes little sense to talk about slowing population growth unless in the context of taking the first step toward reversing it.
As global population increases, the maximum sustainable (by which we mean indefinitely supportable) ecological footprint each person can have is proportionally reduced. For a sustainable footprint of 6.4 gha per person, which is the mean ecological footprint for residents of high-income countries, maximum world population is 1.8 billion. (To put that figure in context, U.S. citizens consume 9.6 gha each on average; Europeans consume 4.8 gha.) Around 6 billion people (90 percent of today's population) could be supported at 1.9 gha per person, the mean ecological footprint for middle-income countries, and around 14 billion people could scrape by at a marginal existence of 0.8 gha per person, which is the average biocapacity consumed by inhabitants of low-income countries. The latter implies utterly unacceptable poverty and is less than each African consumed in 2003 (1.1 gha per person).
These figures signify maximum values; any drop in biocapacity through climate change (such as desertification or flooding) will reduce them.
The proportionality [PDF] of these numbers demands that higher footprint lifestyles at one end of the spectrum force lower footprint lifestyles at the other. If we want everyone on Earth to live at the moderate mean consumption level represented by a footprint of 4 gha per person (comparable to Portugal, South Korea, and Kazakhstan), then we must plan--through applying our contraceptive technology wisely, democratically, and compassionately--for a maximum world population of 2.8 billion. If we fail, then we must prepare for nature to do it through viruses, violence, starvation, and climate-change-intensified disasters such as hurricanes, droughts, and rising sea levels. It's sobering to think that it would take more than five planets to support everyone on Earth at the average footprint level of U.S. residents. If we're ever to achieve worldwide equity, we must look at reducing not only consumption, but also population, which is often a taboo subject. The years ahead will reveal just how intelligent we are as a species.
In her comments here, Betsy Hartmann perpetuates some infamous myths about people who have a quantitative concern about human population. The first is that such concern diverts attention from the need that she rightly highlights, to take action on climate justice and related humanitarian issues. But why the dichotomy? Can't we be concerned about human needs as well as human numbers?
The second myth is that being concerned about population leads intrinsically to coercion. Why so? At the Optimum Population Trust, despite our well-justified anxiety about human numbers on a finite planet, we reject coercion--for many good reasons that can be found in our paper, "Youthquake" [PDF]. Countries as varied as Thailand, Tunisia, and Iran have cut their average family size in half simply by removing a range of barriers to meeting women's family planning needs--and they did so as quickly as China, where coercion played a role.
As Fred Meyerson rightly says, one-third of global pregnancies are unintended. Or as we put it, "Too many accidents are caused by humans, and too many humans are caused by accidents." These accidents are avoidable through making the choice of voluntary family planning available and accessible to women in every bedroom in every society, so that every child might be a wanted child.
First, I want to make clear that I strongly support women's right to safe, voluntary, and accessible birth-control services--as an end in itself, not as a means to drive down population growth rates. When population control is the objective, the quality of family planning services suffers and coercive methods often override freedom of choice.
Secondly, I don't think we're on the brink of demographic disaster. Yes, world population is still growing and expected to reach 9 billion by 2050. However, demographers agree that the era of rapid growth has concluded. Population growth rates peaked in the 1960s due to dramatic reductions in death rates and increased life expectancy. Since then, with increasing education, urbanization, and women’s work outside the home, birthrates have fallen in almost every part of the world and will likely continue to do so, particularly as urbanization accelerates. The figure given by the Population Reference Bureau in 2005 for the global average number of births per woman was 2.7, and it may be lower now: It's widely accepted that there is a demographic convergence toward smaller families across the globe. The United Nations projects that world population will eventually stabilize, falling to 8.3 billion in 2175.
In terms of global warming, I agree with Joseph Chamie that the main task is to reverse damaging patterns of production and consumption and developing new technologies. I believe we should focus our efforts on the following:
Reducing carbon emissions. We need massive investments in the development of alternative (non-nuclear) energy sources and new, greener technologies. (I am against further nuclear power development because of its cost, dangerous waste, safety risks, and the links with atomic weapon production and proliferation.) Given the industrialized nations' historical contribution to greenhouse gas emissions, they have a responsibility to help countries such as India and China leapfrog the heavy use of fossil fuels in the industrialization process. In the United States, we need to drastically reduce our carbon footprint. One important first step would be investing in energy efficient public transportation, which reduces dependence on the private automobile. (I've often wondered why so many U.S. environmentalists are keener on a one-child policy than a one-car policy, as if it is somehow easier and more ethically acceptable to force down birth rates than to address overconsumption.)
Climate justice. Climate change adaptation and mitigation measures could provide an opportunity to more equitably distribute resources and power. In industrialized countries, rather than allowing the benefits of carbon tax, cap-and-trade, and sequestering schemes to flow to the energy giants and other corporate interests, policies could instead be designed to help poor and middle-class people offset higher energy costs and to support public investment in health, education, and environmental improvements. In developing countries, attention should focus on reducing poor people's vulnerability to environmental changes related to global warming, such as sea-level rise in Bangladesh or increased rainfall variation in Africa.
A focus on population diverts us from the need to take action on these critical concerns. Moreover, intentionally or not, images of overpopulation tend to reinforce racist stereotypes of the world's poorest people, demonizing those who are the least responsible for global warming. Recent rhetoric about the risk of "climate refugees" swarming toward Western borders similarly reinforces rising anti-immigrant sentiment (see my November 2007 article, "War Talk and Climate Change" for more.) Environmentalists need to steer clear of these stereotypes if they want to build democratic alliances across borders to seriously address the urgent problem of climate change.
Clearly, population growth is an important aspect of environmental stress, as every man, woman, and child requires food, water, clothing, shelter, and energy. However, it isn't necessarily the root cause of climate change.
In many places, population is growing slowly (much of Europe, for instance) and the population of some countries is actually declining (Japan and Russia come to mind); yet those populations continue to negatively impact Earth's climate. Industrialized countries are responsible for approximately four-fifths of the world's carbon dioxide buildup despite representing less than one-fifth of its population. On a per capita basis, the disparity is even more striking: For example, the average American contributes roughly five times the amount of carbon dioxide to the atmosphere as the average Mexican citizen, and nearly twenty times as much as the average Indian citizen. Raising the living standards of populations in developing countries--certainly a desirable goal--is also likely to worsen climate change.
Furthermore, halting population growth would help, but not resolve the climate problem alone. Even if all countries instantly reached and remained at replacement fertility levels of two children per woman, world population would continue to grow to more than 8 billion by 2050. Avoiding unwanted pregnancies is laudable and would improve the lives of many couples and families, but its impact on future population growth is small. Crying wolf about the population bomb too often retards progress in finding sustainable climate solutions.
Yes, it's important to reduce population growth, but safeguarding Earth's atmosphere requires much more. New technologies need to be developed--along with pursuing significant reductions and reversals in damaging patterns of production and consumption. Both will no doubt prove costly and difficult. But the alternative is a disastrous tragedy for the world's population.
Human population continues to grow by more than 75 million people annually. Since the first Earth Day in 1970, global population and annual carbon dioxide emissions have both increased by about 70 percent. As a result, per capita emission rates remain steady at about 1.2 metric tons (mt) of carbon per person per year.
Unfortunately, the 1997 Kyoto Protocol has had little measurable effect on per capita emissions, even in the countries that have agreed to national targets. Emissions in Western Europe reached 2 mt per person back in 1970 and have fluctuated just above that level ever since. The same plateau phenomenon, which appears to be related to stages in development, happened in the early 1970s in "centrally planned Europe," which includes Russia and the former Soviet republics.
Per capita carbon emissions in the United States also leveled off around 1970 at a much higher rate--above 5.5 mt per person--and have barely budged since, through recessions, economic booms, and swings in energy markets. From 1970 to 2004, U.S. population and emissions both rose by 43 percent.
More than any another factor, population growth drives rising carbon emissions, and the U.S. Census Bureau and United Nations both project that global population, currently 6.6 billion, will surpass 9 billion before 2050.
It is, of course, possible that per capita emissions could decrease in the future, but a number of factors make this difficult. First, emission patterns are "sticky" due to slow turnover in our energy-intensive infrastructure, including power plants, housing, and vehicle fleets. Established consumption behavior is hard to change, by either individuals or nations.
Second, while global per capita emissions have been relatively flat for decades, there is now more risk that they will rise, not fall, in the near future. Coal (which releases the most carbon per unit of energy when burned) is more abundant and less constrained than petroleum and gas. As oil becomes scarce and expensive, and population growth and development drive up energy demand, coal use has grown dramatically in recent years, particularly in China, but also in the United States and India.
Finally, many developing countries that are experiencing explosive economic growth have not yet reached per capita emissions plateaus and also have rapidly rising populations. All these factors more than wipe out the minor savings associated with my family (and others) switching to compact fluorescent bulbs and efficient front-loading washers.
The implication is that one of the best strategies for reducing future greenhouse gas emissions is population stabilization, as quickly as can be achieved by non-coercive means.
But is stabilization likely or possible? The United Nations projects that global population will eventually peak well above 9 billion, based on the assumption that fertility rates in every country on the planet will converge at 1.85 children per woman (below the 2.1 replacement fertility level), and that most countries will achieve this target, or close to it, by 2050. This critical assumption, adopted relatively recently by demographers, is based only on a mathematical formula, and perhaps some wishful thinking. It is quite possible that global population could surge well beyond even current projections.
Unfortunately, given our current trajectory, the disruptions, hardship, and conflict caused by climate change and variability may well increase death rates (and decrease life expectancy) before declining fertility stabilizes population.
So, I believe the best course of action for both human well-being and climate policy is to quickly devote as many resources as possible to reducing unwanted pregnancy, so that we reach stabilization. Almost half of all pregnancies in the United States, and one-third globally, are unintended. We can do better than that, and several countries already have.
This will require rehabilitation of the population policy and family planning fields, which have been attacked, shunned, and splintered in recent decades. Conservatives are often against sex education, contraception, and abortion, and they like growth--both in population and the economy. Liberals usually support individual human rights above all else and fear the "coercion" label, and therefore avoid discussion of population policy and stabilization. The combination is a tragic stalemate that leads to more population growth. We need to get over it.
And certainly population policy should be front and center at the U.N. Framework Convention on Climate Change meeting, which begins today in Bali.