19.0 Introduction

In John Steinbeck’s famous book The Grapes of Wrath, the main character, Tom Joad, returns to the family farm in Oklahoma during the dust bowl of the early 1930s to find his family evicted by the local land company and their house abandoned. He asks his now-crazy neighbor, Muley, “What’s the idear of kickin’ folks off?” Muley replies:

You know what kinda years we been havin’. Dust coming up and spoilin’ ever’thing so a man didn’t get enough crop to plug up an ant’s ass…. An’ the folks that owns the lan’ says, “We can’t afford to keep no tenants.” An’ they says, “The share a tenant gets is just the margin a profit we can’t afford to lose.” An’ they says, “If we put all our land in one piece we can jus’ hardly make her pay.” So they tractored all the tenants off the lan’.¹

Joad’s family hits the road for California, the promised land, only to arrive midwinter with thousands of others, finding “no kinda work for three months,” misery, and starvation. In the final scene of the book, one of the women, whose baby has just been born dead from malnourishment, breast feeds a starving 50-year-old man.

Joad’s story illustrates the process of economic development in a nutshell. The United States in the 1930s, 1940s, and 1950s saw a transition from small-scale, labor-intensive farming to highly mechanized, chemical-intensive, large-scale agriculture. In the process, with particular force during the great depression and dust-bowl times, tens of thousands of farmers were pushed off the land through evictions, as large landowners consolidated small plots of land into larger, technically more efficient units. From 1950 to 1990, the number of farm residents in the United States dropped from 23 million to 4.5 million. Many of these farmers were African Americans from the South, who subsequently migrated to industrial cities in the North and Midwest.

This agrarian transition away from an economy based on traditional small farming to one based on large-scale, market-oriented agriculture has to date been a universal feature of market-driven economic development. The traditional economic development challenge is to productively absorb the millions of workers—holding now-useless farming skills, often illiterate or semiliterate—who are “freed up” from agriculture. In the traditional model, increases in agricultural productivity keep food prices low, benefiting urban consumers. At the same time, surplus labor from the agricultural sector fuels growth in other areas, leading to a rise in general living standards and “successful development.”

The worldwide depression of the 1930s, the backdrop for The Grapes of Wrath, made this a difficult task. In the United States, we were rather fortunate. For a period of about 30 years after the Depression ended, much of the displaced, unskilled agricultural labor was absorbed by the booming manufacturing economy of the 1950s and 1960s. But, the tragic experience of Joad’s family is unfortunately a common one in many developing countries. On the one hand, traditional agriculture has become less and less viable, in part because of government policies such as subsidized credit favoring large-scale agriculture. On the other hand, many (but not all) poor countries have been stuck in a virtual depression for the last three decades. Large-scale, capital-intensive agriculture has displaced tens of millions of Third-World farmers. These workers then migrated to less suitable, ecologically sensitive land, became landless agricultural laborers (often able to find “no kinda work” for many months), or else moved to urban shantytowns in search of jobs in the stagnant industrial or state sectors.

The central point of this chapter is that “solving” the economic development problem—providing productive work and income for displaced farmers and their children—is part and parcel of addressing local and global environmental concerns. Sustainability, defined in Chapter 8 as preventing the deterioration of average living standards for future generations, cannot be achieved unless poverty is directly addressed, because poverty and environmental degradation go hand in hand. Yet, the environmental consequences of economic growth can no longer be ignored; overall living standards do not rise automatically with economic growth as conventionally defined.

The specter of rapid population growth hanging over this entire picture is intimately connected with desperately high rates of poverty. As we discuss later, poor people have rational economic reasons for preferring large families. A basic lesson is thus that providing cheap birth control—throwing condoms at the problem—is only one part of a successful strategy for reducing birth rates in developing countries. Providing health, education, and employment opportunities for the poor majority, especially for young women, and then coupling this with comprehensive family planning services must be part of an effective package for reducing population growth rates.

Beyond poverty and population, the environmental damage people cause depends not only on our absolute numbers but also on the natural capital depleted and waste products generated by each person. The average person born in the United States, Europe, or Japan has a dramatically larger impact on the global environment than does a child from a poor country. Yesterday—spent driving my daughter to school, writing this book at my computer (with occasional trips to the refrigerator), taking the family out for a burger at dinnertime, and watching TV in my nice warm house—I arguably contributed more to global warming, ozone depletion, and tropical deforestation than a typical Brazilian would in a month or two. As an upper middle class American, I consume more than 100 times the resources used by the average individual from a poor country.

This, of course, is just another way of restating the IPAT equation from Chapter 9. Total environmental damage can be decomposed into three parts: the number of people, consumption per capita, and the damage caused by each unit of consumption. The “population” problem is indeed concentrated in poor countries; 90 percent of world population growth in the next century will occur in the developing world. However, through legal and illegal immigration, poor-country population pressure spills over into affluent countries. For example, largely as a result of legal immigration, the U.S. population is expected to increase by 33 percent (to 403 million) by 2050.²

By contrast, the “consumption” problem is currently centered in the rich countries. This too has begun to change as a growing number of poor-country residents aspire to the consumption levels found in rich countries. The point here is not to make us feel guilty about our affluent lifestyle. Rather, we need to recognize that to address global environmental challenges, one needs to focus as much attention on reducing the environmental impact of high consumption in rich countries as reducing population growth in poor countries.

This chapter provides an overview of these complex and interrelated topics: poverty, rapid population growth in the South, overconsumption in the North, environmental degradation, and sustainable economic development.

19.1 Poverty and the Environment

In rich countries, it is commonly assumed that environmental quality can be improved only by sacrificing material consumption. Indeed, this is the whole premise behind benefit–cost analysis laid out in the first part of the book. In poor countries, by contrast, a broad-based growth in income will, in many respects, tend to improve the quality of the environment. This section discusses four of the close connections between poverty and the environment.

1. For poor people, many environmental problems are problems of poverty. The biggest environmental health threat facing most people in poor countries is unsafe drinking water, compounded by inadequate sewage facilities. About 1 billion people are without access to improved water, and more than 2.6 billion are without adequate sanitation. Billions of illnesses and millions of deaths each year are attributed to water pollution.³

   In developing countries, exposure to indoor air pollution (smoke) from cooking and heating sources in fact outweighs urban air pollution as a cause of premature death. Some half a billion people are exposed to unsafe levels of indoor smoke, and 1.6 million die each year from exposure. Another 800,000 die in developing countries from exposure to urban air pollution.⁴

2. Poor people cannot afford to conserve resources. Out of economic necessity, poor people often put an unsustainable burden on the natural capital in their immediate environment. Urban residents scour the immediate countryside for fuel—firewood or animal dung—and this leads to deforestation or the elimination of fertilizer sources. Landless farmers are pushed into overfarming small plots, farming on steep mountain slopes that soon wash out, or farming in clear-cut rain forests incapable of sustaining agriculture.

   While poor people in search of subsistence often stress their immediate environment beyond easy repair, the much higher consumption levels of rich-country residents have a substantially larger global impact. For example, commercial ranching for beef exports to European markets has had a bigger impact on Brazilian deforestation than small farmers have. We address the impact of rich-country consumption on environmental degradation later. But, subsistence also needs to play an important role.

3. Richer people “demand” more pollution control. As per-capita income rises in a country, people begin to express a more effective demand for pollution control. Figure 19.1 illustrates cross-country data for two pollutants—ambient concentrations of particulate matter $\left(\text{PM}-10\right)$ and per-capita production of carbon dioxide. The former, a regulated air pollutant, first rises as per-capita income grows, and then it begins to fall. Table 19.1 illustrates the same general relationship observed for $\text{PM}-10$ with city-specific data for sulfur dioxide from a selection of cities. ${\text{SO}}_2$ concentrations—reflective of unregulated heavy industry, coal combustion, and auto traffic—are low in the urban areas of low-income countries, tend to rise in fast-growing low- and middle-income cities, and then fall again in urban areas in wealthy countries. By contrast, the unregulated or lightly regulated pollutant, carbon dioxide, grows with per-capita income.

   The inverted U-shape displayed by the particulate and ${\text{SO}}_2$ pollution can sometimes be seen in other urban air pollutants and reflects what has been called the Environmental Kuznets Curve (EKC) hypothesis. This hypothesis states that as economic growth proceeds, certain types of pollution problems first get worse and then get better. (The original Kuznets curve hypothesized a similar relationship between the inequality of income and wealth and economic growth.) What might explain an environmental Kuznets curve? Partly education. As income rises, so do levels of awareness regarding environmental threats. Partly, it could be explained by expanding democracy. As income rises, political participation tends to increase. As a result, people are provided the opportunity to express a political demand for pollution control. Partly, it has to do with a shift in industrial composition—wealthier countries rely more on services and other relatively “clean” industries, while less-developed countries have more basic manufacturing and mining. (Indeed, some of the improvement in air quality in developed countries may simply reflect a leakage of dirty manufacturing industries to poor countries.) Finally, the relationship can be explained by relative risk considerations: when life spans are short due to inadequate nutrition or access to basic health care, the concerns about respiratory, neurological, and reproductive diseases, or cancer from pollution, are dampened.

   As this discussion indicates, per-capita income as shown in Figure 19.1 and Table 19.1 is in fact “standing in” for a variety of political and economic social changes that accompany economic development. For this reason, the simplistic Environmental Kuznets Curve hypothesis—that growth alone leads to pollution reductions—has not held up to scrutiny, but it has sparked much further research.⁵ In addition, Figure 19.1 clearly reveals that lightly regulated or unregulated pollutants such as solid waste and carbon dioxide increase in tandem with income and production levels. Hazardous waste production is also probably highly correlated with per-capita income. As regulations on these pollutants become more stringent, will their per capita generation also begin to decline in wealthier countries? The graphs in Figure 19.1 cannot predict this.

   

   City	(Per-Capita GDP) $2008	Ambient SO2, 2001 (µg/m3)
   High Income, Low Pollution
   Los Angeles	46,700	9
   Tokyo	34,900	19
   Prague	24,000	14
   Low to Middle Income, High Pollution
   Mexico City	14,900	74
   Rio de Janeiro	10,300	129
   Cairo	5,000	69
   Beijing	4,900	90
   Low Income, Low Pollution
   Quito	8,000	22
   Manila	3,500	33
   Delhi	2,900	24

4. Population growth slows with increased income. The final link between poverty and the environment lies in income growth as a means of population control. As we will see in the next section, as societies grow wealthier, families almost universally have fewer children.

To summarize, there are four key and related connections driving improvements in environmental quality along with economic development: access to clean water and decent indoor air quality, less pressure on local subsistence resources, the “EKC effect,” and a transition to smaller families. The point here is that in poor countries, one need not “trade off” rising material living standards for improved environmental quality. In fact, the only effective way to improve environmental conditions is to alleviate the tremendous poverty faced by many of the people in these nations.

19.2 The Population Picture in Perspective

When my (Eban’s) grandparents were born at the turn of the twentieth century, there were about 1.6 billion people alive on the planet. When my parents were born, around 1930, that number had risen to 2 billion. On my own birthday in 1960, I joined some 3 billion inhabitants. When my first daughter turned two in 1990, global population had climbed to 5.3 billion. If she has a child, her daughter or son will be born in a world with about 8 billion other people. And if my grandchild lives to be 80, he or she will likely die, at the end of the twenty-first century, on a planet supporting somewhere between 9 and 13 billion people.

Figure 19.2 provides a graphical representation of world population growth spanning these five generations, 200 years. Under the UN’s “medium” scenario, effective population control is achieved over the next few decades. This means that the global average number of children per woman falls from the current value of 2.5 to 2.25 by 2045 and then to replacement level—2.0—by 2090. Given these assumptions, population should hit about 9.8 billion in 2050 and then stabilize at around 11 billion at the end of the century. That would be roughly a third more people than are alive today.⁶

Note that medium doesn’t mean that this prediction will come true without serious changes—in particular, it requires rapid, widespread adoption of birth control measures beyond the current level. By contrast, a world in which fertility rates don’t fall at all leads to a 2100 population headed to 16 billion people, the pessimistic line on the chart. On the other hand, should we experience more rapid declines in fertility, the global population could actually begin to decrease in the second half of the twentieth century. To illustrate how sensitive these predictions are, Figure 19.1 differs substantially from the same figure in the last edition of this book. At the time, the UN was predicting the most likely outcome in 2100 to be 10 billion people—1 billion less than that currently predicted!

How high could the number realistically go? The number is uncertain. At some point, growth would be forcibly checked by large-scale famine, disease, war, or ecological disaster. In an interesting book called How Many People Can the Earth Support? the author culled results from some 60 studies (dating back to 1679!) and found answers that tended to range from 4 to 16 billion.⁷

Given the magnitude of the environmental problems we face today, it is challenging to imagine the impact that 10 billion of us will have on the planetary ecosystem, let alone 16 billion. Population pressure must clearly be counted as a major global environmental threat in the medium and long term. At the more local level, population growth is increasingly overwhelming the ability of poor-country governments to provide educational, health, and sanitary services. As poverty deepens in these countries, environmental stresses multiply for the reasons discussed in the previous section.

In Chapter 9, we discussed the Malthusian perspective on population growth— named after the famous 18th-century economist Thomas Malthus. Reviewing briefly, Malthus predicted that a population growing at a geometric rate would soon outstrip the (slower) growth of food supply, leading to a catastrophic “natural check” on population—war, famine, or disease. But Malthus’s gloomy prediction has yet to come true on a global scale; as we saw earlier, population growth continues even in the face of substantial poverty worldwide. To date, we have avoided a Malthusian fate because of impressive technological developments in the field of agriculture—the so-called Green Revolution also discussed in Chapter 9.

Moreover, Malthus’s basic assumption, that population growth grows geometrically, does not always hold. Not including immigration, wealthy countries have very low population growth rates, often below zero. The availability of effective birth control, not foreseen by Malthus, has meant that families are able to control their “natural” reproductive tendencies if they so desire. In general, the motivation to control family size appears to be greater for wealthier families.

The complex link between rising incomes and lower population growth is discussed later. But its presence has led some observers to argue that poor countries are merely passing through a high-population growth phase. This phase resulted from a decline in death rates, due in turn to the introduction of modern medicine in the 1940s and 1950s. As average incomes rise in these countries, it is argued, birth rates will fall and a “natural” demographic transition to low population growth will occur.

Indeed, population growth rates worldwide were low, less than 1 percent from 1900 to 1950. As modern health-care practices spread in the 1950s, however, growth rates in the developing world exploded to well over 2 percent. After cresting in the late 1960s, population growth rates have fallen in many places including China and India, the middle-income countries, and the developed countries: globally, the rate of population growth fell to 1.3 percent from 1995 to 2000. The population problem has “taken care of itself” to a remarkable extent in countries such as South Korea, which experienced rapid and widely shared economic growth. Population growth rates in that country fell from 2.4 percent in 1960 to 0.2 percent in 2011.

The 1990s saw generally good news on the population front. During the 2-year period from 1994 to 1996 alone, the United Nations lowered its global estimate of the number of children per woman from 3.10 to 2.96. Again, these small changes add up to a big drop in projected numbers over a half century. Nafis Sadik, director of the United Nations Population Fund, credited the fertility decline to the fact that many countries began lifting family planning restrictions in the early 1980s.⁸

At the same time, tragically, population growth in Africa and Southeast Asia slowed due to the devastating impact of the AIDS virus. In Southern Africa, several countries have seen life expectancy reduced to more than half, and population growth rates dropped from highs of 2 to 3 percent in the late 1980s. Economic decline in Eastern Europe also reduced life expectancy in that region. However, in recent years and in most countries, people are living longer lives. And while fertility declines have continued throughout the developing world, still, the downward trend has slowed a bit this decade, leading the UN to up their latest estimate of global population likely by the end of this century.

As a group, the least developed countries still have high fertility and population growth rates. In these nations, rapid population growth continues to pose an ecological and economic development problem. The United Nations predicts that by 2050, some 67 developing countries will have twice their current population. Some have argued that, in these regions, a vicious cycle is developing: poverty generating high rates of population growth that generate more poverty, which leads to higher levels of population growth, and so on. For such countries, economic growth alone may not break this cycle; without aggressive measures to control population growth, the demographic transition to low population growth rates experienced by other countries may be delayed for some time.⁹

19.3 An Economic Approach to Family Size

At several points in this chapter, we have asserted that higher incomes tend to be associated with lower population growth rates. As a general rule, this is true, both across countries and within countries. In Colombia, Malaysia, and Brazil, for example, the poorest 20 percent of households support, on average, 30 percent of the nation’s children. By contrast, the wealthiest 20 percent of households have only 9 percent of the children.¹⁰ Yet, the relationship is not a hard-and-fast one. For example, the high-income oil-exporting countries tend to have high fertility rates, while low- and medium-income countries such as Sri Lanka and China have reduced their population growth rates to low levels. In the United States, poor families (including families on welfare) are not larger than the average.

Many factors determine family size—religious and cultural norms obviously play a prominent role. Yet, the strength of the poverty–fertility relationship suggests that economic factors are quite important as well. Evidently, people choose to vary their family size depending on their income level. So, this suggests the following:

Let us look a little more closely at the issue of desired family size. The fact that children provide economic insurance and an income supplement does not necessarily mean that a big family is advantageous. Given limited resources, a family could potentially obtain comparable economic benefits following one of two approaches: a high-investment strategy with one or two children or a low-investment strategy with many children.

The high-investment strategy would involve focusing all available resources on one or two children—ensuring that they survived infancy, were provided with a healthy diet, and went on to attend school. Such a child might well land a good job and substantially increase the family income. In contrast, the low-investment strategy would be to have many children, recognizing that one or more would likely die young but that the remainder would survive to contribute a small amount to the family income and insurance network. In short, the low-investment strategy is to substitute quantity for quality.¹¹

While, in principle, both strategies are open to all, for our farm laborer family with their limited resources and restricted access to public services, the high-investment strategy is very difficult to pursue. Moreover, it is tremendously risky; suppose that after 5 years of intensive investment, a single child dies. Thus, they generally prefer five children to two. Yet, as income rises, the high-investment strategy begins to be more attractive. Resources for the long-term (15- to 18-year) investment are more readily available, and access to better health care means that the chances of premature death decline.

The analysis of the poverty–fertility link in this section suggests an effective route to population control: changing parents’ economic family plan from a low- to high-investment strategy that focuses on the “quality” rather than the “quantity” of children.

19.4 Controlling Population Growth

The benefit–cost model of family size is a crude one, omitting as it does the important issues of culture, kinship, religion, love, and affection. Yet, it does a good job of explaining the strong relationship between poverty and fertility observed in many places around the world. In particular, because there are good economic reasons for poor people to have large families, simple provision of low-cost birth control is unlikely to solve the population problem (though it would certainly help). Can we use this benefit–cost model to suggest other effective policies for controlling population growth?

19.5 Consumption and the Global Environment

Population-control advocates (like us) are sometimes accused by people in poor countries of racism or even genocide. Why, they ask, do you recommend aggressive, if noncoercive, steps to limit the numbers of (mostly) black or brown people in poor countries, when, in fact, the vast majority of global ecological damage can be traced directly or indirectly to the affluent lifestyles of the (mostly) white people in rich countries?

There are two elements to the consumption–pollution link. The first is straightforward. Because inhabitants of rich countries are responsible for over two-thirds of global economic activity, at least two-thirds of global pollution can be laid at our doorstep. The richest 20 percent of the world’s population—including the developed countries—consume 76 percent of the world’s output.²¹ As a result, rich-country consumption has to date been responsible for most of the global atmospheric pollution—global warming, ozone depletion, acid rain, and radioactive contamination. Rich countries have had by far the biggest impact on polluting and overfishing the oceans. And rich-country inhabitants have generated mountains of toxic wastes that are now, on occasion, finding their way to poor countries for disposal.

In addition to generating global pollution problems, there is a second element to the consumption–pollution link. High levels of consumption demand in rich countries have been responsible for an unsustainable drawdown in environmental quality and the stock of natural capital in many poor countries. One prominent example is the so-called hamburger connection to rainforest depletion. The expansion of beef ranching for export in Latin America has led to a destruction of the region’s rainforest resource without sufficient compensating investment in created capital.

Many poor countries rely on the export of primary resources or agricultural commodities to earn money for imported fuel, food, consumer goods, and weapons. In principle, this trade is environmentally sustainable. However, sustainability requires that any drawdown in the stock of natural capital—whether oil or mineral reserves, rainforest resources, topsoil, or air and water quality—be compensated for by investment in created capital. As we discussed in Chapters 8 and 9, if a nation’s natural capital is depleted faster than new capital is created, then unsustainable development occurs.

The overwhelming demand for resources in rich countries—ranging from gasoline to steel to bananas to beef—has in many cases depleted the natural capital stock in poor countries, without commensurate investment in created capital. Why has this occurred? Historically, colonial governments tended to drain resource-generated wealth from their colonies, investing little in human capital or infrastructure. In the postcolonial period, falling relative prices for primary resources, low taxes on politically powerful resource-based industries, and high levels of spending on military and imported consumption goods by ruling elites have constrained investment in created capital. Finally, the burden of debt repayment has led to a flow of created wealth from poor to rich countries over the last few decades.

During the 1970s, First-World banks loaned tremendous sums of money to government agencies and private companies in poor countries around the world. Latin America’s external debt, for example, rose from $7.2 billion in 1960 to $315.3 billion in 1982. It is not fully clear what motivated this irresponsible lending binge; however, little of the money was productively invested. Much of it financed imports of consumer goods from First-World countries or else disappeared into private bank accounts. Since the 1980s, a series of rescheduling and compromises have been worked out. Most recently, debts are in the process of being canceled for some of the poorest, highly indebted countries in the world, a move resulting in part from public pressure such as U2 singer Bono’s high-profile antipoverty campaign. But, most developing countries remain deeply in debt, and over the last three decades, tens of billions of dollars of capital have continued to flow from the poor to the rich. Under these circumstances, some developing countries have been liquidating natural resources to pay off debts and have been unable to reinvest the resource rents productively.²²

The point here is not to assign blame to rich countries or ruling elites for the poverty in the former colonies. Rather, the point is simply to recognize that high levels of rich-country demand can have as much to do with environmental damage in poor countries as do high population growth rates. Thus, growing, transporting, and cooking a year’s worth of today’s breakfast—a banana (Ecuador), a cup of coffee (Guatemala), and a chocolate donut (cocoa, Ghana; sugar, Honduras) uses up about $400 of market resources. This process contributes much more to environmental degradation in those countries—pesticide contamination of water, loss of topsoil, deforestation, and global warming—than does providing breakfast for a person whose entire yearly income is $400 or less.

This is also not to say that trade in agricultural commodities or any other goods is, on balance, bad for the environment. We take up the issue of trade policy in the next chapter. Rather, to ensure sustainability, the gains from trade must be invested in created capital sufficient to offset the drawdown in natural capital. If they are not, then rich-country consumption leads to unsustainable development in poor countries as surely as does rapid population growth.

This section has discussed the two ways in which high levels of consumption in rich countries and environmental problems, both global and those in poor countries, are linked. At the global level, an obvious and direct correspondence exists between consumption of resources such as fish, timber, and oil and global pollution issues such as climate change. But, in addition, high levels of demand in rich countries have indirectly promoted a drawdown of the stock of natural capital and environmental quality in poor countries. If natural capital depleted through resource or pollution-intensive exports is not being replaced by investment in created capital, high consumption levels in rich countries can fuel unsustainable resource depletion in poor countries. Many argue that this kind of unsustainable development has in fact been occurring. Given these links, are the critics of population control right? Are neo-Malthusians, perhaps motivated by unconscious racism, focusing on the wrong problem?

We argue instead that both overpopulation and overconsumption pose serious threats to the global environment and sustainable development in poor countries. There is mounting evidence that rapid population growth dramatically compounds the problem of economic development, thereby putting tremendous pressure on local environments. Moreover, as the poor both grow in number and aspire to living standards found in the developed world, their impact on global environmental problems becomes more and more significant. In 2010, for example, China surpassed the United States as the main contributor to global warming.

Yet, we are indeed being shortsighted, at best, if we insist solely on blaming the reproductive behavior of poor people in poor countries both for their own environmental problems and for the global ones to which they contribute. High levels of consumption in affluent countries are primarily responsible for the global environmental crisis, including global warming, and have indirectly promoted an unsustainable drawdown of natural capital in many poor countries.

Earlier in the book (Chapter 11), we discussed a variety of tools for addressing the overconsumption problem in wealthier countries. So far in this chapter, we have examined theoretical links between poverty, population growth, and consumption in the North. Is there a path to sustainable development?

19.6 Envisioning a Sustainable Future

When one surveys the often overwhelming and interrelated problems of environmental degradation, poverty, population growth, overconsumption, and political powerlessness in poor countries, hopes for a future brighter than the present can seem dim. Yet, what promise does exist comes from an increasing ecological recognition that the earth is genuinely a single spaceship. In the last several decades, citizens in rich countries have started to become aware that the life-support systems of our own affluent lifestyles, and those of our children, are critically affected by the economic security of poor children in São Paolo, Brazil, in the Ghanaian countryside, and indeed throughout the world. Global environmental threats such as global warming, ozone depletion, and biodiversity loss due to deforestation, as well as increasing legal and illegal immigration by the poor, remind us that we ignore our less fortunate sisters and brothers at our own peril.

This recognition is indeed recent. The term sustainable development itself gained widespread currency only in 1987 with the publication of a book by the United Nations called, suitably, Our Common Future. Also known as the Brundtland Commission Report, after the commission’s chair Gro Brundtland, the report sought to serve a warning—a brighter future can be imagined, but it will not come without hard and conscious work on our part.

The report called for urgent national and international action to support sustainable development. Although written more than 25 years ago, the key challenges laid out by the Brundtland Commission remain the same today. Underlying all the discussion is one common thread: together, developing and developed countries must undertake real investments to achieve a sustainable future.

Since the Brundtland report was issued, the UN has provided a forum for continuous focus on poverty reduction and sustainable development. In 2000, the organization established eight Millennium Development Goals (MDGs), including the eradication of extreme poverty and hunger, providing universal primary education, and fostering gender equity. Goal 7 was to “Ensure Environmental Sustainability,” with specific calls to halt the loss of biodiversity and to cut in half the population lacking access to safe drinking water and sanitation. The UN had no authority to enforce these goals: instead, they were adopted as guidelines for action by government, business, and civil society.

Thanks in large measure to poverty reduction in China, the goal of cutting extreme poverty in half was in fact achieved by 2010. Environmental goals were met in some countries, but not generally. In 2015, the MDGs were replaced with a new set of UN aspirations, the Sustainable Development Goals (SDGs). There are 17 SDGs ranging across the intertwined issues in this chapter, including poverty reduction, climate change, women’s empowerment, biodiversity loss, hunger and food security, protection of the oceans, inequality, livable cities—and one area on which we will focus in the next chapter: peace, justice, and strong institutions.²³

As with the MDGs, the UN has only moral authority and its convening power to support progress on the SDGs. Similarly to the Brundtland report, the goals provide guidance and inspiration for communities, governments, and private sector actors who are seeking a way through toward a sustainable future. At the end of the day, policies to achieve the SDGs must come from the bottom up—including from cities, national governments, and corporations.

Note that there is one issue highlighted in our discussion that is missing from the list of goals: population. This reflects the general UN consensus that rapid population growth is a symptom, not a cause, of poverty and unsustainable development. Given gender equity, education, food security, and economic development under the UN view, population pressures will take care of themselves.

The basic message of the SDGs again is that on a global level, environmental concerns cannot be separated from broader questions of sustainable development. The only route to achieve protection of forests and biodiversity, reduction in greenhouse gas emissions, sustainable management of the oceans—and population control—is to also help ensure a prosperous future for the people who depend on these resources.

In summary, the UN’s leadership on sustainable development has yielded two lessons. First, through the vision it provides of a sustainable planetary future, it suggests a framework for analyzing national and international environmental policy. In the following chapters, we will look at a variety of tools available for coping with the worldwide environmental crisis. We now have a number of questions to ask about such policies: What are the impacts on women’s empowerment? On improving food security? On promoting the development and diffusion of clean technology? On resource conservation? The answers, of course, will be complex and often contradictory, but these sustainability steps are the fronts on which simultaneous progress must be made.

The second lesson is that it truly is our common future. Whether the planet will ultimately accommodate 10 billion people in a sustainable fashion, or 13 billion in a downward spiral of environmental degradation, conflict, and impoverishment, is a decision entirely in our hands. And by our hands, we mean the people who are reading this book. We are the beneficiaries of 400 years of “dirty” development; we are also the richest people ever to walk the face of the earth. As such, we are the ones with the ability to design policies to channel global resources into resolving these problems, and we are the ones who will determine whether our favored historical position is ultimately sustainable or not.

Where do the resources come from? Successful developing countries are the ones who channel resource rents and gains from trade into their own economies. Globally, a major potential source of capital is military spending. The world spends well over a trillion dollars a year on arms, and in many cases, the poor countries are buying from the rich ones. For just a few weeks of global military expenditure, substantial progress could be made in addressing the problems of population growth and resource conservation.

The political challenge involved in diverting resources from military to social and environmental spending is formidable. Equally challenging are policies such as debt relief to invest in sustainable development in poor countries. And yet, we are personally more optimistic that the challenge can be met today than we were 35 years ago, when as students we first confronted the relentless mathematics of population growth and its intimate relationship with the desperate poverty found worldwide.

In the 1970s and 1980s, a belief sometimes prevailed that the rich could grow richer while the poor grew poorer, that we in the wealthy countries could in some sense wall off the poverty and population problems of the developing world.²⁴ Today, worldwide environmental threats—global warming, ozone depletion, and loss of biological diversity—have made this position less and less tenable. For the first time in history, rich countries now have a direct and increasingly important economic stake in helping poor countries to achieve sustainable development. Because this can be done most effectively by improving the lives of the poorest on the planet, achieving a sustainable future is a real possibility.

19.7 Summary

This chapter has outlined the fundamental connections between poverty, population growth, overconsumption, and sustainable development. The first step was to characterize the general challenge of economic development as productively absorbing labor freed up in the agrarian transition from small-scale, labor-intensive farming to large-scale, capital-intensive agriculture. It is important to note that, while the agrarian transition has to date been a universal feature of development, the speed at which it occurs is greatly affected by government policies, such as subsidized credit for large farmers, or subsidies that depress food prices and thus discourage food production by small farmers.

Due to an increasing awareness of the importance of natural capital as an input into economic growth as well as of negative environmental externalities as an outcome of economic growth, interest has shifted away from traditional development models to those focusing on sustainable development. Because sustainability is defined in terms of the welfare of the average individual over time, and the average individual in less-developed countries is quite poor, sustainable development must concentrate attention on the status of the poor.

Sustainable development will tend to increase environmental quality for four reasons. First, exposure to two of the most pressing environmental problems in poor countries—polluted water and indoor air pollution (smoke)—is a direct result of poverty. Second, poor people cannot afford to conserve resources, and so they often put unsustainable pressure on their local environment. Third, as incomes rise, for a variety of reasons, certain regulated pollutant concentrations decline. Finally, income growth is one of the most effective population-control measures available.

There is a debate on the extent of the population problem. On one side are those who foresee a “natural” demographic transition to a stable global population as economic progress proceeds in poor countries. By contrast, neo-Malthusians have argued that a vicious cycle is developing, in which poverty leads to high population growth rates that engender more poverty. Such a cycle, they argue, has already begun to overwhelm the beneficial effects of economic growth in many places. As a result, they are worried that the demographic transition is stalling out and that global population will rise far above the 10 billion figure before being checked by physical or social limits.

The debate between neo-Malthusians and proponents of a natural demographic transition is about whether the global population will rise in the next 100 years to 9 to 10 billion, or 13 to 15 billion. From a policy point of view, however, there is little disagreement. Both sides agree that effective, noncoercive population-control methods can speed up the demographic transition and should be implemented.

Controlling population growth is not as simple as dispensing low-cost birth control devices, though this certainly helps. Poor people often have good economic reasons for having large families. Parents around the world depend on children for economic insurance and income supplements. Because of limited opportunities, and risk, poor families tend to pursue a low-investment, “quantity” strategy when choosing family size. Encouraging families to adopt a high-investment, “quality” strategy is the crux of an effective population-control program.

Balanced economic growth and general economic redistribution are the most effective ways to alleviate poverty and thus make a high-investment strategy feasible for many families. However, such outcomes, desirable for many reasons, have often been difficult to achieve. Yet, even poor countries have had success in achieving lower birth rates by pursuing a mixture of three policies: (1) reducing infant and childhood mortality; (2) improving access to education, especially for women; and (3) providing comprehensive family planning services. (Of course, these policies are also a form of redistribution of income and can help promote balanced growth.) Finally, coercive measures, both economic and physical, have been employed by China to control population growth. Aside from important moral issues, outside of China, such programs are likely to be counterproductive.

The pressure that people place on their environment depends not only on absolute numbers but also on the number of goods they consume and the damage that each good causes. While in some poor countries, overpopulation is the primary threat to both local and global environmental quality, in rich countries, consumption behavior is the problem. The consumption–pollution link arises from both the disproportionate share of global consumption engaged in by rich countries and the potential for an unsustainable drawdown of natural capital and environmental resources fueled by rich-country consumption. High levels of debt are among the factors that have made it difficult for poor countries to productively reinvest the resource rents that are generated from trading away their natural capital.

Is a sustainable future possible? The Sustainable Development Goals provide a framework for evaluating progress along a series of intertwined social and environmental steps. All these options require investment and ultimately must be funded to some degree by rich countries. The increasing recognition that rich-country welfare depends on sustainable progress in poor countries makes this program at least potentially feasible from a political perspective. One possible pool of resources to finance the sustainable development program can be found in the current world expenditures on military hardware and personnel.

1. 19.0 In large measure, successful traditional economic development means productively absorbing the labor freed up in the agrarian transition. Because poverty and environmental degradation go hand in hand, economic development is required for sustainability; however, sustainable development must also recognize the environmental costs of economic growth.
2. 19.1 There are four connections between poverty and environmental quality. (1) Poor people suffer from unsafe drinking water, inadequate sewage, and indoor air pollution. (2) Poor people degrade local resources because they cannot afford not to. (3) Some regulated pollutants display an inverted U-shape as a function of income. This relationship has generated the Environmental Kuznets Curve hypothesis and, may be due to education–relative risk considerations, political demand for pollution control, and a shift in industrial composition. (4) Wealthier people tend to have lower rates of population growth.
3. 19.2 Median and “highly pessimistic” population growth scenarios are laid out in this section. Under the former, world population will stabilize at 11 billion people; under the latter, it will increase dramatically over the next century to 16 billion. Growth predictions change rapidly with small changes in fertility rates. To date, the Malthusian population trap, resulting from an arithmetic growth in food supply and a geometric growth in population, has been avoided. This is due in part to the Green Revolution and in part to the demographic transition to low birth rates in rich countries. However, a vicious cycle, in which population growth leads to poverty that sustains high population growth, remains a concern in some developing countries.
4. 19.3 The poverty–fertility relationship is explained by an economic model in which all parents seek economic insurance and an income supplement from children. Due to lack of resources and risk, poor parents choose a low-investment (quantity) strategy, rather than a high-investment (quality) strategy.
5. 19.4 Based on the model, population growth can be controlled in the following ways: (1) balanced economic growth and/or redistribution of income (perhaps via land reform), (2) reduced infant and childhood mortality, (3) access to education (educated parents have a higher opportunity cost of time, education can also enhance women’s status and decision-making ability in a patriarchal culture), and (4) comprehensive family planning. These measures, designed to change parental behavior by increasing opportunity, have proven successful. In addition to such measures, China has employed more coercive forms of population control in its One-Child Policy.
6. 19.5 There are two elements to the consumption–pollution link. (1) Because rich countries consume most of the world’s resources, we are responsible for most of the world’s global pollution problems. (2) Rich-country demand can lead to an unsustainable drawdown in natural capital in poor countries.
7. 19.6 The UN has provided leadership in establishing guideposts for sustainable development beginning with the Brundtland Report, then the Millennium Development Goals (MDGs), and then in 2015, the Sustainable Development Goals (SDGs). These systems provide concrete, nonbinding metrics for a series of interlocking social and environmental goals, to assess progress toward sustainability. Each of these steps will cost money, some of which will have to come from high-income countries. One source of funding would be to divert funds from global military spending.

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