Debating the link between emissions and population

By Alex Ezeh, Alisha Graves, Wang Haibin, April 25, 2016

The United Nations projects that global population, about 7.4 billion today, will reach 11.2 billion in 2100 (with Africa accounting for the lion's share of growth). For anyone concerned about climate change, this is a sobering prospect. The world already struggles to limit carbon dioxide emissions, so what are the prospects for climate mitigation in a world with 50 percent more people? But proposals to slow population growth can encounter stiff resistance. The real problem, some argue, is that energy consumption will grow much faster than population as the world gets richer—and in any event, past initiatives to limit population growth have sometimes taken sinister forms. Below, experts from Nigeria, the United States, and China debate these questions: Are efforts to limit population growth a legitimate element of climate mitigation—and can they be pursued without exacting unacceptable ethical costs?

Round 1

Limiting carbon pollution—not carbon polluters

Is population an important variable in carbon emissions? Sure. But it's far from the only variable and by no means does it determine carbon emissions.

Take China, a country where growth trends for population and emissions have diverged widely in recent decades. China's population growth has slowed markedly since the early 1980s, when Beijing began enforcing a strict one-child policy. Average annual population growth was 1.25 percent between 1987 and 2000, but between 2000 and 2014 it was only 0.56 percent—half as high in the later period as in the earlier period. But carbon emissions tell a different story. Between 1987 and 2000, annual growth in carbon dioxide emissions was 4.75 percent. Between 2000 and 2014, the annual rate of growth increased to 12.7 percent—well over twice as high in the later period as in the earlier one.

This is all consistent with an equation known as the Kaya identity, which states that carbon dioxide emissions are the product of four factors. Human population is one of these factors. The other three are gross domestic product per capita; energy intensity (the amount of energy used per unit of gross domestic product); and carbon intensity (the amount of carbon dioxide produced per unit of energy used). The "other three" factors can ultimately be summarized in one number—emissions per capita—a number that can decline when people's behavior changes and nations achieve social progress. Social progress and economic growth can, as demonstrated by experiences in East Asia, Western Europe, and North America, reduce population growth rates. So the best way to limit carbon dioxide emissions is through altering behavior—not through limiting population.

Management and governance. Carbon dioxide emissions are a kind of pollution, but people nonetheless have a right to emit carbon dioxide as they go about their lives. Unfortunately, individual people have strong incentives to produce more carbon pollution than is in everyone's collective interest—that is, the "tragedy of the commons" comes into play. Lowering carbon dioxide emissions per capita, then, requires good management of people's emissions behavior, which in turn requires that low-carbon infrastructure and good carbon governance be established.

Low-carbon infrastructure includes, in addition to public transportation systems such as subways and high-speed railways, low-carbon energy generation systems such as wind and solar farms and electricity grids that link customers with low-carbon energy. In recent years, much of this has been established in Sichuan province, the area in southwestern China where I was born. For many centuries the farming families in Sichuan had burned biomass for cooking—but in the early 1990s, Sichuanese people began purchasing coal to burn in their stoves. Sichuan's coal, unfortunately, is generally of lower quality than the coal produced in most other Chinese provinces—its sulfur content is higher and its heating value is lower. In March 2014, however, drilling began at the giant Longwangmiao natural gas field in southern Sichuan. A pipeline soon began to transport gas from the field to nearby cities, towns, and villages. Natural gas is more expensive than coal or biomass, but farmers enthusiastically embraced natural gas for cooking because natural gas is cleaner and gas stoves make it very easy to adjust the flame—a very important issue in Sichuanese cuisine. The gas pipeline and other infrastructure elements have helped bring about an energy revolution for Sichuan's farming families—a revolution that, because natural gas entails much lower carbon dioxide emissions than coal, reduces emissions per capita.

But for climate mitigation, establishing good governance is as important as improving infrastructure. Low-carbon infrastructure is of little value if consumers are unable or unwilling to use it. Inconvenience and high costs can undercut the attractiveness of low-carbon infrastructure—if subways and high-speed railway systems are too expensive, for example, customers will shy away from them. Certain entities might even intentionally make it inconvenient to use low-carbon infrastructure. For example, the electricity grids in China are monopolized by two state-owned enterprises—the State Grid Corporation of China and the China Southern Power Grid Company. These companies prefer the stability of coal-fired electricity and other types of thermal electricity to intermittent energy sources such as wind. In China's currently sluggish economic environment, thermal electricity can meet nearly all electricity demand, and the grid companies are intentionally making it difficult to connect wind power to the grid. Under such circumstances it becomes very difficult, if not impossible, for customers to consume green electricity. So even if low-carbon infrastructure is perfect, utilization rates will be low if governance and management are poor.

Reducing emissions per capita depends among other things on supportive tax policy, pricing, and financing. For example, governments can "internalize" the otherwise externalized costs of high-carbon energy sources by levying carbon taxes on coal and oil. By implementing carbon taxes and providing subsidies for renewable energy, governments can support the development of low-carbon energy sources such as hydrogen-based power and wind and solar energy.

Getting educated. But is it possible to limit or reduce per capita emissions as societies get richer? Certainly, rich people are able to consume more of everything, including high-carbon energy. On the other hand, the recently concluded Paris climate agreement, in its requirement that developed countries provide developing countries with $100 billion a year for climate mitigation and adaptation, incorporates the idea that poor countries will be able to reduce their carbon emissions if they have more money on hand. But in today's China, a real threat exists that carbon dioxide emissions will increase because of poverty. China's economic growth is slowing. Many Chinese people are increasingly unable to pay extra for low-carbon energy and local governments are increasingly unable to subsidize such energy. Indeed, some government entities and poor consumers are returning to cheap, high-carbon energy sources such as coal. The weakening economy is harming air quality in China and also reducing ambitions for climate mitigation. The jury is still out on how economic fortunes will influence carbon emissions going forward.

Beyond building low-carbon infrastructure and establishing good governance, one more element is necessary for cutting carbon emissions—improving education, especially for girls. Good education allows people to understand the importance and urgency of reducing carbon emissions. In advanced societies with good education systems, consumption of high-carbon energy may eventually become taboo. Providing good education to girls in particular—again, as experiences in East Asia, Western Europe, and North America demonstrate—will allow women to pursue careers, delay childbearing, and give birth to fewer children. This process will naturally place limits on global human population and, albeit in an indirect way, help reduce carbon dioxide emissions.


Green sex for climate’s sake

There's no single solution for climate change, no magic bullet that can stabilize and eventually reduce the concentration of greenhouse gases in the atmosphere. But separating sex from childbearing represents an underappreciated opportunity to forestall climate disaster.

To be sure, addressing the climate challenge will require a wide range of approaches. Conservation policies must be implemented, and major investments are needed to develop and scale up renewable energy technologies. But another opportunity—often overlooked—is ensuring that every woman has both the information and the means to separate sex from childbearing. All over the world, whenever good family planning programs are put in place, couples choose to have fewer children. The family's health benefits, household resources per capita increase, and each couple's carbon footprint shrinks.

Perhaps the most important equation in the world is one made famous by John Holdren, currently a science and technology advisor to President Obama, and biologist Paul Ehrlich: I=PAT. "I" stands for impact on the environment, "P" for population, "A" for affluence, and "T" for technology. Technology can either ameliorate or intensify human beings' impact on the environment—but affluence and population have a straight multiplying effect. That is, affluence leads to increased consumption and pollution. Higher population means more carbon footprints on the biosphere. But there's a twist: Since per capita emissions in wealthy countries are much greater than in low-income countries, averting an unintended pregnancy in a high-emitting country will do more to help the climate than will averting a similar pregnancy in a low-emitting country.

Though many people acknowledge population's impact on the environment, few go on to mention that population growth is not a fait accompli. In industrialized countries, the average family in the middle of the 19th century had six or more children. Today, families in such countries produce on average about 2.4 children (near replacement level). More recently, in some developing countries, birth rates have fallen remarkably quickly, as in Iran, whose total fertility rate fell from more than five to less than three in just seven years. The fertility rate in Thailand, when voluntary family planning and safe abortion became widely available, fell from six children to 3.5 in 12 years—though it had taken the United States 58 years to make the same transition in the 19th century.

Coercive approaches to population, such as China's one-child policy and forced sterilization in India, should have no part in family planning. But when women are denied the information and means to separate sex from childbearing, pregnancy itself is coercive. So family planning services, from design to implementation, mustn't be about telling couples what to do; the point is giving couples what they want. The good news is that many family planning programs around the world do just that. In particular, they uphold a woman's right to determine how many children she has and when she has them.

For the climate, family planning's potential benefits are profound. A careful study of a voluntary family planning program in California demonstrates that family planning is the single most cost-effective way to abate carbon dioxide emissions. Spending $24 on wind energy averts 1 metric ton of carbon dioxide emissions. So does spending $51 on solar energy. But spending just $7 on family planning achieves the same result.

Lessons of the Sahel. Family planning as a means for mitigating climate change is a familiar enough idea, but family planning for adapting to climate change may sound far out. It is not. Because climate change negatively affects some staple crops, it worsens food insecurity in parts of the world. But according to a 2012 study that modeled climate change, food production, and population growth in Ethiopia, achieving low fertility by 2050 might fully make up for climate change's negative effects on Ethiopian agriculture. (A lower overall population means more calories are available per person.) Perhaps more tellingly, some rural women in Ethiopia say they are choosing smaller families to help them better deal with the negative effects of climate change. Women in Niger say that smaller families mean less competition for food during the lean season.

People concerned with humanity's fate in the face of climate change should pay sharp attention to the words and actions of these women. Niger and Ethiopia are countries of the Sahel, the semi-arid southern border of the Sahara desert. During the 1970s and 1980s, this region suffered massive drought and famine—making the Sahel among the first places on Earth to be ravaged by human-induced climate change. Today, unprecedented population growth and intensifying cycles of drought are undermining the region's food security and development. Yet for every woman in the region who currently uses contraception, three to four others want to space out or limit their childbearing but are not using contraception.

In the poorest countries, the net effect of slower population growth will likely be an increase in carbon emissions—economic conditions will improve and consumption will increase. And that's okay. Meeting women’s contraceptive needs in least-developed, highest-fertility nations is a precursor for development that could help lift nearly 1 billion people out of desperate poverty. On a global level, meanwhile, achieving the medium UN population projection for the end of the century—as opposed to the high projection—would keep more than 7 billion tons of carbon per year out of the atmosphere.

Where the link between population and environment is concerned, too many heads have been buried in the sand. Because of tragic, coercive population programs that have sometimes been enacted in the past, even people who appreciate population's impact on the environment can be afraid to attract criticism by expressing their views. National leaders need to escape this cloud of fear and clearly acknowledge that human beings have exceeded Earth’s carrying capacity. Influential people involved in development, natural resources, and of course climate must recognize that sustainable progress can't be achieved until population is stabilized. Equally important is ensuring international investment, on a level commensurate with the world’s need, in voluntary family planning and in quality education for adolescent girls.

In the wake of the Paris climate conference, many individuals may be wringing their hands—feeling powerless in the face of global climate change. But there is one highly important contribution to the climate that high-consuming couples can make: considering their carbon legacies when they plan their families.


Climate: Just one more reason for Africa to slow its population growth

There are those who perceive any effort to limit population growth as "population control." This is a term that chillingly evokes coercive state intervention to control individual reproductive behavior. Population control programs have rarely been implemented without exacting unacceptable ethical costs.

But there's a big difference between coercive state-led population control programs and efforts to slow rapid population growth. Population control programs target the actions of individuals. Efforts to slow the population growth rate, meanwhile, work within existing societal contexts and seek to produce voluntary change.

Population size and composition are among the key drivers of climate change. Whether there are 7 billion or 14 billion people on Earth matters on a fundamental level for the climate. But the relationship between population and planetary health is not straightforward. A child born in, say, North America will have a heavier carbon footprint than will her age-mate born in sub-Saharan Africa.

Regions with the heaviest carbon footprints are experiencing slower population growth than other regions. Many countries—including Japan and Russia, and most nations in Eastern Europe—are experiencing negative population growth. But this is not the case in sub-Saharan Africa. Between 1950 and 2000, the region’s population grew from fewer than 180 million to more than 642 million. Just since 2000, the region’s population has increased by half, to nearly 1 billion. By 2050, the population of sub-Saharan Africa is projected to more than double, to 2.1 billion—and 50 years after that, the region will be home to an estimated 4 billion people. Under that scenario, two out of every five human beings in 2100 will be sub-Saharan Africans.

Sub-Saharan Africa's carbon footprint is light. But the region's rapidly growing population has an environmental impact that is already very evident. Ecosystems such as tropical rain forests are degrading rapidly. Inefficient agricultural practices are creating undesirable land use changes. Biodiversity is diminishing. All these effects can be expected to intensify if Africa's population grows as projected.

African policy makers do care about the region’s rapid rate of population growth—but climate change is by no means the top reason why. In Africa, increased demand for basic services—without increased resources to pay for them—can stretch infrastructures beyond capacity. This makes each successive government in the region appear less effective than the regime that preceded it. Education is a good example of increasing demand for public services. UNESCO estimates that sub-Saharan Africa, to achieve universal primary and lower secondary school coverage by 2030, will require an additional 2.1 million primary school teachers and 2.5 million additional lower secondary school teachers. At the same time, demand for jobs, housing, and other necessities will also increase. Clearly, political leaders in sub-Saharan Africa face enormous challenges due to rapid population growth.

Political leaders are also concerned about population growth because they fear insecurity and instability. Extremists can find adherents more easily in a larger pool—especially in a large pool of young people whose poor education, poor employment prospects, and lack of options can leave them disenchanted.

Leaders also take an interest in population because of the potential for a so-called "demographic dividend"—that is, an improvement in a nation's economic prospects when its ratio of working-age to non–working age people increases.

So it’s no surprise that when African policy makers consider population growth, climate change is not central in their thinking. But what should be the key concern regarding the 4 billion Africans who might exist in 2100?

The issue isn't whether Africa, a continent of more than 3 billion hectares, has enough space for so many people. Even an Africa with 4 billion inhabitants would have far fewer people per unit of habitable land than India has today. Really, the key question is this: What type of people will these 4 billion Africans be? Will they be poor, sick, uneducated Africans trampling over each other to escape? Or will they be healthy, educated, productive Africans delighted to live on the continent of their birth and contributing to regional (and global) progress and development? Most of all, how can sub-Saharan Africa transform its demographic future into something manageable, development-oriented, and economically viable—while fully respecting individual reproductive choices?

African nations can change their demographic and development trajectories for the better if they vigorously pursue three key policy actions. The first is to provide universal access to family planning services, which have been shown to significantly reduce the number of children born even in poor, uneducated, and rural populations. An increase of just 15 percentage points in contraceptive prevalence is associated with a one-child reduction in the number of children born to the average woman. In sub-Saharan Africa, increasing contraceptive prevalence by 45 percentage points could reduce the total fertility rate from 4.7 to 1.7, which would bring the region’s population growth rate to below replacement levels.

The second key policy initiative involves efforts to delay marriage and childbearing. All else being equal, a population in which women begin having children at age 15 will have 25 percent more people after 60 years than a population in which women bear their first child at age 20. The longer a girl's marriage is delayed, the more opportunity she has for personal development—and the better it is for the entire country.

A third important step is to expand girls' access to education beyond the primary-school level. Women, if they receive additional education as girls, have fewer children; this has been demonstrated consistently. Improved education also provides women better opportunities for earning an income—precisely what developing countries need in order to achieve economic development. Implementing these three policy initiatives would lead to more sustainable, more durable, and (most importantly) quicker reductions in the population growth rate than any coercive government action would achieve.

The prospect of 4 billion Africans by 2100 can be cause for concern—or it could inspire commitments to invest in educational opportunities for girls, greater access to family planning, and delayed marriage. These steps would be transformative for the continent. They would generate development and promote economic growth in addition to reducing the demographic burden that contributes to climate change. But while African efforts to slow population growth will contribute to planetary health, one mustn't forget that the greatest culprits in the race to destroy the planet are the countries with the heaviest carbon footprints. Global initiatives and investment are required to support African countries as they work to achieve a demographic dividend—but these must be matched by appropriate, complementary efforts to mitigate the environmental damage wrought by countries expecting zero or even negative population growth.


Round 2

Better for climate: Good governance or green sex?

Population growth rate and population size—these are ideas that people sometimes confuse when they discuss population's role in climate change. The two are related, of course. But they differ significantly when it comes to policy options for mitigating population's effect on climate change.

Wang Haibin's first essay in this roundtable includes an example of such confusion. It's true, as Wang notes, that China's population growth rate—1.25 percent between 1987 and 2000—declined to 0.56 percent between 2000 and 2014. But Wang goes wrong when, while minimizing population's role in greenhouse gas emissions, he contrasts quickening growth in China's emissions to its slowing population growth. What he overlooks is that China's actual population—1.09 billion in 1987—increased to 1.27 billion in 2000 and to 1.37 billion in 2014. That's a very significant increase in population, even if the rate of population growth has been slower in recent years than in past ones. The truth is that increased population has had much to do with growth in China's carbon dioxide emissions.

To be sure, China's carbon footprint would be much heavier today if its population growth rate hadn't slowed since the 1980s. The Chinese Communist Party claims that the one-child policy averted 400 million birthsa number larger than the total population of any country in the world except India and China itself. The one-child policy cannot be condoned. But still one must acknowledge that it accomplished more for the global environment than any other state policy in the world.

The good news, though, is that population growth rates can be influenced by policies that—unlike the one-child policy—respect people's right to make individual reproductive choices. The same can't be said of a population's current size, which can only be drastically altered through unthinkable steps such as genocide and forced expulsion.

This brings me around to agreeing with Wang's Round One statement that "the best way to limit carbon dioxide emissions is through altering behavior—not through limiting population." I agree because limiting population, under any circumstances, is unethical and criminal. Limiting a population's growth rate, however, can be achieved by providing universal access to voluntary family planning services; encouraging females to marry later; and improving female education. These are effective policy tools that provide huge benefits for individuals, societies, and the environment. Indeed, where altering behavior for the climate's sake is concerned, the easiest approach of all is to help women avoid unplanned pregnancies.

Wang expresses enormous faith in the potential of good governance to address climate change—and in the capacity of individuals, once good governance has freed them from want, to act in ways that benefit the environment. But he overstates his point. He writes, for example, that "[w]here governance is poor, a larger population will likely entail more pollution" whereas, in well-governed societies, "greater population only increases the chances that humans will discover brilliant solutions to the challenges that face them." The problem with his reasoning is that richer countries pollute more than poorer countries, and larger populations (all else being equal) pollute more than smaller populations.

There's no denying that addressing climate change requires good governance of Earth's systems. Likewise, eradicating poverty depends in part on establishing good political governance. But addressing climate change while also ending poverty will be much, much easier if sex can be decoupled from childbearing everywhere in the world. Ending the tyranny of unplanned pregnancy is a key component in establishing the sort of green economy that can both lift people from poverty and help avert the worst consequences of climate change.

So our colleague Alisha Graves, who champions "green sex," has got the right idea. Go green!


Good governance is the climate key

Human beings must consume natural resources to survive. Therefore they produce carbon pollutants. The larger the human population, the greater the carbon emissions and the greater the consequences for the environment.

This is a fundamentally pessimistic outlook on the relationship between population and carbon emissions—and both my roundtable colleagues appear to be proponents of it.

A more optimistic alternative is the idea that human beings themselves, in the words of the late economist Julian Simon, are the "ultimate resource." Optimists would argue that although people consume natural resources and cause pollution, in the end they do more good through what they create than harm through what they consume. People will ultimately find ways to overcome pollution problems—and even turn pollutants into valuable resources.

These opposing viewpoints have one thing in common: Both are absolutist. Absolutist approaches to population generally entail problematic consequences.

In China, for example, political leaders over the past several decades implemented two sets of population policies that, though very different from one another, were both absolutist and problematic. Under Mao Zedong, the Chinese government took the position that a larger population would make the people mightier and the nation stronger. The government enacted policies that allowed and even encouraged more births. Then, in the late 1970s and early 1980s, the government changed its approach, deciding that a large population was a burden on the nation's economy and social structure. So Beijing initiated its coercive one-child policy—very controversial and broadly unpopular. In 2010 the government, finally recognizing that China's population was aging fast and its demographic dividend was fading, relaxed the one-child policy by allowing couples—if both individuals were only children—to have a second child. The policy has since been loosened further, and now there is essentially a two-child policy in China.

The truth is that population growth can be either an asset or a liability where mitigation of climate change is concerned. The real key in climate mitigation is whether societies exhibit good or bad governance.

Where governance is poor, a larger population will likely entail more pollution. Wherever it's a struggle simply to survive, people have no choice but to consume the natural resources within their reach, no matter how unsustainable and polluting their consumption may be. If coal, especially low-quality coal, is the cheapest energy resource, people will consume it. Moreover, people in poorly governed countries anticipate that future resources will be meager. They have no faith that society will provide for their care in old age. Concerned about this risk, they invest in their futures by producing many offspring when they are young. This leads to faster population growth.

Where good governance exists, societies are stable. Material necessities are abundant. To be sure, this leads to higher carbon dioxide emissions today. But it also gives people scope to solve problems and to make contributions to future well-being. Humans may not always be the "ultimate resource," as Simon would have it. But if human talent and knowledge are fully utilized, people can steadily expand the scope of usable resources, deepen resource utilization, and at the same time reduce pollution—including carbon pollution. In such societies, greater population only increases the chances that humans will discover brilliant solutions to the challenges that face them. Good governance frees people from worry and fear, giving them the time and resources to, for example, replace fossil fuels with low-carbon energy sources.

Since global warming is at least partially man-made, individuals must of course modify their behavior in certain ways. But ordinary people are not to blame for climate change. Bad governance is at fault. What needs to be contained is not population growth but rather bad governance.

So where my roundtable colleague Alisha Graves promotes "green sex" as a key element in climate mitigation, I would argue instead for green public administration, including good education and social welfare systems. Achieving green administration worldwide would do more for the climate than any approach to population ever could.


Family planning: The quick carbon payoff

In so many realms of national policy, the interests of the entire population must be balanced against the rights of individuals. And so it would seem to be with climate mitigation and family planning—how can nations reduce their carbon dioxide emissions if nothing prevents individuals from having as many babies as they want? But the truth lies deeper than that. Because so many individuals have more babies than they want, providing them the means to plan their families can help nations contain their total carbon emissions.

In Round One, Alex Ezeh wrote that "the greatest culprits in the race to destroy the planet are the countries with the heaviest carbon footprints." As an American, I admit that my country is guilty as charged. In 2011 (the most recent year for which World Bank figures are available), per capita carbon dioxide emissions in the United States were 17 metric tons. That is more than double the global per capita average. Meanwhile, about half of the pregnancies in the United States are unintended—and as of 2008, 60 percent of those pregnancies ended in birth. Under such circumstances, the United States should demonstrate much greater political commitment to family planning—and should make family planning an explicit element of national climate policy. By failing to promote family planning vigorously enough, the United States is both missing a large opportunity in climate mitigation and denying people the ability to make individual decisions about the size of their families.

Wang Haibin, meanwhile, focuses his climate mitigation ideas on "good carbon governance," writing that "the best way to limit carbon dioxide emissions is through altering [people's carbon-related] behavior—not through limiting population." It's thoroughly understandable that Wang might look suspiciously on pursuing climate mitigation through family planning. After all, China's one-child policy—in place for 35 years until it was replaced by a two-child policy late last year—was a coercive policy. It resulted in some tragic consequences for Chinese families, especially infanticide and forced sterilization, as well as national challenges in ensuring social services for the elderly.

But when Wang writes of "limiting population," he seems to imply that fertility cannot drop unless human rights are infringed upon. That is not the case, as demonstrated by examples from Thailand to Iran to Tunisia. Indeed, the entire paradigm of "limiting population"—which suggests outside control—ought to be replaced by a paradigm of freedom and personal choice (issues that Ezeh addressed eloquently in Round One). A woman who uses contraceptives doesn't merely limit her childbearing; she also exercises her individual right to determine the size of her family. When she does so, she realizes health benefits for herself and her children and eases pressure on the environment. It will be a great day when feminists, environmental advocates, and public health professionals can work together to seize the opportunity that universally available family planning represents.

Wang has written about the key role that governance plays in encouraging the use of clean energy. Where delivery of family planning services is concerned, good governance is nice—it makes things easier and cheaper—but it is not a necessary condition. To be sure, the countries with the highest fertility also tend to be among the least developed countries, the most corrupt, and the worst governed. But that is no excuse for delaying family planning until good governance emerges—to the contrary, appalling rates of maternal and infant mortality in the least developed countries demand that family planning be delivered now. Where good governance is lacking, a woman's ability to separate sex from childbirth can be a life-and-death issue. When public health programs provide women that ability, they not only empower women to exercise their right to determine the size of their families—they also make a meaningful contribution toward lowering emissions in the near future.

What do I mean by "the near future?" Well, if contraception prevents an unintended pregnancy today, the world will have one fewer carbon emitter in just 40 weeks' time—about the length of a full-term pregnancy.


Round 3

Cause here, effect there: The climate disconnect

If total human population increases by one person—or by 10 people—it makes no real difference to the climate. But if you multiply those numbers by 1 billion, the difference can be enormous. This observation may seem self-evident. But it's not so evident to my roundtable colleague Wang Haibin, whose emphasis on good governance as an answer to climate change wholly ignores population's influence on climate.

Earlier in Round Three, Wang wrote that "[I]t's a mistake to exaggerate population's role in carbon dioxide emissions" because "The core of global problems such as climate change is actual human behavior." It's hard to disagree with the second of those two statements. Human behavior is indeed the single most important force driving environmental change. Behavior in the bedroom drives population growth. Behavior at the dinner table changes agricultural systems, which can drive land use changes and biodiversity loss. Behavior in commuting to work can increase people's carbon footprints. It is "normal" human behaviors that contribute to the 36 gigatons of carbon dioxide emissions generated each year. Human behaviors at all levels—from the individual to the global—are damaging the natural systems on which life depends. And as people seek solutions to the environmental mess they have created and continue to create, no level of human behavior should be ignored.

I acknowledge it would be naïve to think that family planning services, if made universally available and accessible, would be the magic-bullet solution to the climate challenge. But it's equally naïve to suppose that population size and rate of population growth do not matter for carbon emissions. If human activity is driving changes to Earth's natural systems—and it is—one cannot argue that the size of human population, and the rate of population increase, do not matter. A small increase in population size means nothing. But an increase on the order of billions? That's something else entirely.

Universal access to voluntary family planning services is important because its immediate benefit is the prevention of unintended pregnancies—and 40 percent of the world's 213 million pregnancies each year are unintended.

This is not just a problem in the developing world; if anything, rates of unintended pregnancy are higher in more developed economies. But abortion is generally safe and legal in such countries, so unintended pregnancies don't necessarily result in unintended births (or loss of women's lives). This, unfortunately, is not the case in many developing countries in Africa, Asia, and Latin America and the Caribbean.

In Africa, as I argued in Round One, development priorities must include not just enhanced access to family planning services but also expanded educational opportunities for girls, and efforts to delay marriage and childbearing. These interventions can slow the continent's rate of population growth and can do much to address its environmental challenges: land use changes, loss of tropical rainforest, biodiversity loss, and desertification. If the continent's population doubles over the next 35 years, however, Africa will find it very difficult to address these challenges effectively.

There is commensurate work to be done in countries with much heavier carbon footprints. They must demonstrate that the "good governance" of which Wang is such a proponent can work for the benefit of the environment too. Decisions made at the individual, corporate, and even societal levels often fail to account for the environmental harm that present-day economic gains can cause. The lion’s share of damage to the environment burdens the poor, the developing world—and future generations. Where the causes and effects of climate change are concerned, there's a disconnect both in time and in space. This disconnect frustrates efforts to achieve global consensus on environmental stewardship.

But human beings have only one planet. Disagree as they might, they share a common destiny.


Population: Not the core emissions problem

I don't object to the "green sex" that my roundtable colleagues Alisha Graves and Alex Ezeh advocate—if "green sex" simply means that societies should help couples acquire the means and information necessary to prepare for, or avoid, childbearing. But I continue to believe that it's a mistake to exaggerate population's role in carbon dioxide emissions.

Indeed, population size is only loosely related to carbon dioxide emissions, and many forces exceed population in their importance to addressing climate change. After all, though "green sex" may slow population growth, it cannot guarantee that people's behavior outside the bedroom will be "green" at all. Green behavior, broadly defined, is the most critical factor in climate change mitigation and adaption.

Perhaps my point will become clearer if I compare carbon pollution with endemic disease—which, if regarded from a certain perspective, is itself a form of pollution. Both carbon pollution and endemic disease degrade humanity's environment. Both threaten health and life. But the threat of endemic disease doesn't necessarily increase as population grows. The proof of this is that human population today is at an all-time high—but because hygiene and medicine have advanced so much, terrible diseases such as smallpox and malaria have been eliminated or contained. Human beings, despite their record-high numbers, are today under far less threat from communicable disease than when, say, bubonic plague killed one-third of Europe's population.

Improvements in hygiene and medicine are both strongly related to good governance, whose importance I have already emphasized in this roundtable. Bad governance can allow endemic disease to rampage—and carbon pollution to grow unabated. It can cause far worse problems than "overpopulation" can. With good governance, meanwhile, society's burdens can be relieved despite temporary demographic burdens.

Admittedly, because the world isn't and won't become "flat," good governance is more difficult to achieve in some regions than in others. In some poor nations of Africa and West Asia, the prospect of good governance is dimmer than in, for example, the world's emerging economies. Carbon pollution isn't a severe problem in Africa and West Asia—but endemic disease, clean drinking water, and the depletion of arable land often are. For the people who live in such places, these forms of "pollution" are much more dangerous and deadly than carbon pollution is.

It's fine to put forth ideas, such as "green sex," that might help address carbon pollution. But I maintain that the solution to climate change will be found in the economic and social structures largely determined by governments—particularly great power governments. It's governments that can do the most to institute low-carbon energy systems such as nuclear energy. In 2014, nuclear energy accounted for only 4.4 percent of world primary energy consumption. If that percentage rose to, say, 40 percent—roughly, nuclear energy's share in France's primary energy consumption today—while low-carbon energy sources such as wind, solar, and hydroelectricity were also further developed, global carbon emissions could decrease even if population markedly increased.

Population, in and of itself, isn't the core of the carbon problem or any other problem on Earth. The core of global problems such as climate change is actual human behavior. And behavior outside the bedroom should be the main focus of climate mitigation efforts.


The real controversy about family planning and climate

No reasonable solution to climate change can be excluded from the world's arsenal of climate mitigation options. Family planning deserves a prominent place in that arsenal because of population's profound implications for future global emissions. Because population will be a much bigger factor in emissions in the century's second half than in its first, decision makers may be inclined to push family planning down the list of climate priorities. But population growth must slow in the current decade if desirable population changes are to occur later on. That is the nature of demographic momentum.

Too often, family planning is treated as taboo in policy debates. It simply slides off the policy table. This isn't because population's importance to carbon emissions is poorly understood. Far from it—the Intergovernmental Panel on Climate Change, the world’s foremost authority on climate change, has identified reproductive health services, including modern family planning, as an opportunity "to reduce emissions of warming [climate-altering pollutants] and at the same time improve health." But many climate discussions, even when otherwise excellent, simply overlook family planning. A new World Bank report on climate change and poverty, for example, mentions population growth more than 10 times, either as a contributor to climate change or as an impediment to climate adaptation in poor countries. But the report's authors, in 70 pages of proposed solutions, make no mention of contraception. As I wrote earlier in this roundtable, people who appreciate population's impact on the environment can be afraid of the criticism they'll attract if they openly advocate family planning. But the real controversy is that voluntary family planning is systematically excluded from recommendations about how to achieve climate mitigation and adaptation, despite the evidence that it plays such an important role.

Revolutionary shift. My roundtable colleague Wang Haibin wrote in Round Two that people in poorly governed countries "invest in their futures by producing many offspring when they are young." I am always skeptical about such claims—they are grounded in economists' over-reliance on the rationality of human behavior. Sex is not usually a rational act. It is an animal instinct inherited from our ape ancestors.

For heterosexual couples, a large family is the default outcome of normal sexual activity. Most people can avoid this outcome only by taking consistent preventive measures over the course of decades. Even so, contraceptives sometimes fail, so women need access to safe abortion services or else they will risk their lives trying to end an unintended pregnancy. The idea that children represent rational decisions is, to adapt language used by my colleagues Martha Campbell and Malcolm Potts, a mirage—you only see it if you think that the world is full of people who, like yourself, can make easy, actionable decisions about whether and when to have children.

Another key factor in the climate equation—consumption—may be as irrational as sex is. From an early age, people in wealthy societies are confronted with marketing that aims to manipulate their behavior. This engenders very powerful desires to consume more than necessary. For the environment, the effects are disastrous. And with most nations on Earth now on a path toward development, how long will the carbon footprints of developing countries remain lighter than those of developed countries?

One of the most effective responses to climate change may also be the most difficult: reining in excessive consumption. What's needed is a revolutionary, planet-saving shift in economics—one that might begin with defining success in terms other than material wealth. If the global economic paradigm does not respect the limits that the biosphere imposes, it is time to change the economic paradigm.

Earth is just a tiny island adrift in infinite space. We must acknowledge that reality for the sake of our children.


Topics: Climate Change


Share: [addthis tool="addthis_inline_share_toolbox_w1sw"]


Receive Email