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Philip Cafaro, associate professor of philosophy at Colorado State University, is author of Thoreau’s Living Ethics (University of Georgia Press, 2004). He is currently completing a book on the ethics of immigration, with the working title Bleeding Hearts and Empty Promises: A Liberal Rethinks Immigration. A former ranger with the U.S. National Park Service, he has had two children and one vasectomy. Winthrop Staples III, a wildlife biologist, has conducted research on the North American lynx and the Amur leopard. He also worked to recover the American chestnut tree and as a bear technician in Denali National Park. His master’s thesis in environmental philosophy is titled “For a Species Moral Right to Exist: The Imperative of an Adequate Environmental Ethics” (Colorado State University, 2009). This Backgrounder is adapted from a forthcoming article in Environmental Ethics.

This Backgrounder argues that a serious commitment to environmentalism entails ending America’s population growth by implementing a more restrictive immigration policy. The need to limit immigration necessar­ily follows when we combine a clear statement of our main environmental goals — living sustainably and sharing the landscape generously with other species — with uncontro­versial accounts of our current demographic trajectory and of the negative environmental effects of U.S. population growth, nationally and globally.

At the current level of 1.5 million immigrants per year, America’s population of 306 million is set to increase to over 700 million people by 2100. Recent “reform” proposals would actually increase immigration to over two million annually, which has the potential to nearly triple our population to over 850 million by the end of the century. Conversely, scaling back immigration to 200,000 per year would greatly reduce America’s population growth, according to studies by the U.S. Census Bureau.

Given the many issues that environmentalists must deal with and the contentious nature of immigration debates, it is understandable that many of us would prefer to avoid them. But the reality is that across the country, environmentalists are losing the battle to create a sustainable society and protect wild nature. Sprawl development destroys 2.2 million acres of wild lands and agricultural lands each year; over 1300 plant and animal species remain on the endangered species list, with more added each year; water shortages in the west and southeast are being used to justify new river-killing dams and reservoirs; and U.S. carbon emissions continue to rise. Obviously, we haven’t figured out how to create a sustainable society with 300 million inhabitants. It’s not plausible to think we will be able to do so with two or three times as many people.

Still, there are arguments against reducing U.S. immigration that deserve consideration. In what follows, we analyze the main moral, environmental, and economic arguments for the mass immigration status quo, or for even more expansive immigration policies. In the end, we find them unconvincing. We conclude that Americans must choose between allowing continued high levels of immigration and creating a sustainable society.

Introduction

The environmental argument for reducing immigration to the United States is relatively straightforward and is based on the following five premises:

Immigration levels are at a historic high and immigration is now the main driver of U.S. population growth. Population growth contributes significantly to a host of environmental problems within our borders. A growing population increases America’s large environmental footprint beyond our borders and our disproportionate role in stressing global environmental systems. In order to seriously address environmental problems at home and become good global environmental citizens, we must stop U.S. population growth. We are morally obligated to address our environmental problems and become good global environmental citizens.

Therefore, we should limit immigration to the United States to the extent needed to stop U.S. population growth.

This conclusion rests on a straightforward commitment to mainstream environmentalism, easily confirmed empirical premises, and logic. Despite this, it is not the consensus position among American environmentalists.

Some environmentalists support continued high levels of immigration, while most are uncomfortable with the topic and avoid discussing it. So strong is this aversion that groups such as the Sierra Club, which during the 1970s prominently featured strong commitments to U.S. population stabilization, have dropped domestic population growth as an issue.1 Several years ago, the group Zero Population Growth went so far as to change its name to Population Connection (“PC” for short).

In 2006, the United States passed the 300 million mark in population — that’s 95 million more people than were here for the first Earth Day in 1970 — with little comment from environmentalists. In 2007, as Congress debated the first major overhaul of immigration policy in nearly 20 years, leaders from the principal environmental organizations remained silent about proposals that could have added hundreds of millions more Americans during the 21st century.

Like immigration policy for the past 50 years, immigration policy for the next 50 looks likely to be set with no regard for its environmental consequences. We believe this is a bad thing. As committed environmentalists, we would like to see our government set immigration policy (and all government policy) within the context of a commitment to sustainability. We don’t believe that the goals we share with our fellow environmentalists and with a large majority of our fellow citizens — clean air and clean water; livable, uncrowded cities; sharing the land with the full complement of its native flora and fauna — are compatible with continued population growth. It is time to rein in this growth — or forthrightly renounce the hope of living sustainably here in the United States.

Defending the Argument

Our claim, then, is that “the environmental argument” is sound and that America should scale back immigration. Some readers will disagree. So let’s look at the argument in more detail.

Immigration levels are at a historic high and immigration is now the main driver of U.S. population growth. Consider some demographic history. Between 1900 and 2000, the U.S. population almost quadrupled, from 76 million to 281 million people. The largest decadal population increase was also the most recent: a 32.7 million increase between 1990 and 2000.2 This population growth resulted from a mixture of natural increase and immigration, which, as Figure 1 shows, has varied widely over the past century.

From 1880 to the mid-1920s, America experienced an immigration boom, “the Great Wave,” during which immigration averaged 600,000 annually. U.S. population numbers grew rapidly in these years, due to a combination of high birth rates and high levels of immigration. For the next 40 years, from 1925 to 1965, the United States had a relatively restrictive immigration policy, which allowed 200,000 people into the country annually, on average. The U.S. population grew substantially during this time, too, from 115 million to 194 million, primarily due to high rates of natural increase. During the 1950s, for example, American women had an average of 3.5 children each, far above the 2.1 total fertility rate (TFR) necessary to maintain the population of a nation with modern health care and sanitation.

By the 1970s, American women were averaging fewer babies — in 1975 the TFR stood at a lowest-ever 1.7 — and the United States was well-positioned to transition from a growing to a stable population. One study found that without post-1970 immigration, the U.S. population would have leveled off below 250 million in the first few decades of this century.3 It didn’t happen, however, because in 1965 and several times thereafter, Congress greatly increased immigration levels. Between 1965 and 1990, immigration averaged one million people annually — five times the average in the previous four decades. Since 1990, immigration has increased even more, to approximately 1.5 million annually (one million legal and half a million illegal) — the highest rate in history.

For these reasons, the United States population has continued to grow, resulting in a missed opportunity to get one key aspect of sustainability — human numbers — under control. Currently our population stands at over 306 million people, and it continues to grow rapidly.

Such is our demographic past; what of our demographic future? The Grand Council of the Iroquois famously looked “seven generations” out concerning the impacts of their decisions. Looking four generations into the future, in 2000 the U.S. Census Bureau released the population projections in Table 1.

Each of the three projections or “series” holds fertility rates steady, while varying immigration levels, so annual immigration rates make the main difference between them. Under the zero immigration projection, the U.S. population continues to grow throughout the 21st century, adding over 100 million people by 2100. Under the middle projection, with immigration a little less than one million annually, we instead add nearly 300 million people and almost double our population by 2100. And under the highest scenario, with over two million immigrants annually, our population nearly triples by 2100, adding almost 600 million more people by the end of the century. Obviously, according to the Census Bureau, immigration makes a huge difference to future U.S. population numbers.4 So our first premise is true.

Population growth contributes significantly to a host of environmental problems within our borders. For example in the past two decades sprawl, defined as new development on the fringes of existing urban and suburban areas, has come to be recognized as an important environmental problem in the United States. Between 1982 and 2001, the United States converted 34 million acres of forest, cropland, and pasture to developed uses, an area the size of Illinois. The average annual rate of land conversion increased from 1.4 million acres to 2.2 million acres over this time, and continues on an upward trend.5 Sprawl is an environmental problem for lots of reasons, including increased energy consumption, water consumption, air pollution, and habitat loss for wildlife. Habitat loss is by far the number one cause of species endangerment in the United States;6 unsurprisingly, some of the worst sprawl centers (such as southern Florida and the Los Angeles basin) also contain large numbers of endangered species.

What causes sprawl? Transportation policies that favor building roads over mass transit appear to be important sprawl generators. So are zoning laws that encourage “leapfrog” developments far out into the country, and tax policies that allow builders to pass many of the costs of new development on to current taxpayers rather than new home buyers. Between 1970 and 1990, these and other factors caused Americans’ per capita land use in the hundred largest metropolitan areas to increase 22.6 percent. In these same areas during this same period, however, the amount of developed land increased 51.5 percent.7

What accounts for this discrepancy? The number one cause of sprawl, by far: population growth. New houses, new shopping centers, and new roads are being built for new residents. As Figure 2 illustrates, in recent decades, cities and states with the highest population growth rates have also shown the most sprawl.

The most comprehensive study to date on the causes of sprawl in the United States analyzed several dozen possible factors. Grouping together all those factors that can increase per capita land use and comparing these with the single factor of more “capitas,” it found that in America between 1982 and 1997, 52 percent of sprawl was attributable to population increase, while 48 percent was attributable to misguided policies that increased land use per person.8

Some “smart growth” advocates resist the conclusion that population growth is an important sprawl factor, partly because they don’t want to obscure the need for good planning and land use policies. They point out that several metropolitan areas that lost population in recent decades exhibited significant sprawl, including St. Louis, Detroit, and Pittsburgh. Of America’s 100 largest metropolitan areas, 11 lost population between 1970 and 1990, yet they sprawled an average of 26 percent (see figure 2a). This shows that poor land use planning and bad transportation, zoning, and tax policies are indeed important in generating sprawl.

On the other hand, cities with growing populations sprawled even more. Several states that managed to decrease their per capita land use during this period also sprawled, due to high rates of population growth. From 1982 to 1995, Nevada decreased its per capita land use 26 percent while sprawling 37 percent, due to a whopping 90 percent population increase. Arizona decreased per capita land use 13 percent while its population increased 58 percent, generating 40 percent sprawl.9 This shows that population growth also causes sprawl.

The bottom line is that if we want to stop sprawl we must change the transportation, tax, zoning, and population policies that encourage it. We will not stop sprawl if we simply accept as inevitable that factor — population increase — which the best research shows accounts for over half of the problem. Nor will we solve our other major domestic environmental problems. That is because our second premise also is true.

A growing population increases America’s large environmental footprint beyond our borders and our disproportionate role in stressing global environmental systems. Consider global warming. Nothing mortifies American environmentalists more than our country’s failure to show leadership in dealing with this, the most important environmental challenge facing the world in the 21st century. As the world’s largest economy and historically largest greenhouse gas emitter, the United States has a moral obligation to lead the world in meeting this challenge. A good start would be striving to stabilize greenhouse gas emissions at 1990 levels (the Kyoto protocol, rejected by the United States, calls for an initial reduction of 5 percent below 1990 levels). Meeting even this modest objective will prove difficult, however, if our population continues to grow.

Look at the numbers. The United States’ CO2 emissions increased 20.4 percent between 1990 and 2005, from 4,991 to 6,009 million metric tons.10 That means we would have to decrease our emissions by 20.4 percent per person to get back to 1990 levels, at our current population. But if we double our population, as we are on track to do in six or seven decades, we will have to decrease per capita emissions 58.5 percent in order to reduce CO2 emissions to 1990 levels — almost three times as great a per capita reduction. Such reductions will be much more expensive and demand greater sacrifice from Americans. They are thus less likely to happen.

“Hold on a minute,” critics may respond. “We can and should cut our carbon emissions 60 percent or even more. The technologies exist and America is wealthy enough to meet our moral obligation to address global warming. The problem, above all, is Americans’ hoggish overconsumption.”

We agree.11 Limiting consumption must play an important role in addressing global warming. American environmentalists should work to enact policies that reduce our fossil fuel consumption as much as possible. Such policies should include increased taxes on fossil fuels, redirecting transportation funding from highway construction to mass transit, heavy subsidies for wind and solar power, large increases in auto fuel standards, improved building codes that reduce the energy needed for heating and cooling, and more.

However, re-engineering the world’s largest economy and changing the consumption patterns of hundreds of millions of people are immense undertakings that will be difficult, expensive and (we may assume) only partly successful. Al Gore has stated that global warming is “the moral challenge of our time;” many of us agree with him. But if Americans are serious about doing our part to limit global warming, the “multiplier effect” of population growth is too important to ignore.

Again, look at the numbers. Between 1990 and 2003, U.S. per capita CO2 emissions increased 3.2 percent, while total U.S. CO2 emissions increased 20.2 percent.12 Why the discrepancy? During that same period, America’s population increased 16.1 percent.13 More people drove more cars, built more houses, etc. Population growth greatly increased total emissions, and it is total emissions, not per capita emissions, that quantify our full contribution to global warming.

Before we go on, please note: we do not claim that by itself, halting U.S. population growth will solve sprawl, or meet our global warming responsibilities. On the contrary, Americans must reduce our per capita consumption of land and energy in order to meet these challenges. On the other hand, the evidence clearly shows that recent population growth has increased Americans’ total land and energy consumption and made these problems even worse. Americans must address both overconsumption and overpopulation if we hope to create a sustainable society and contribute to a sustainable world.14

Clearly premises two and three are true: U.S. population growth contributes seriously to both domestic and global environmental problems. Can we go further, and state that reining in population growth is essential to environmental success? Yes, we can.

In order to seriously address environmental problems at home and become good global environmental citizens, we must stop U.S. population growth. It is of course possible to spin out scenarios in which America’s population doubles, triples, or quadruples, and yet we still manage, through miracles of technological creativity or ethical self-sacrifice, to become ecologically sustainable. Perhaps, as techie magazines like Discover and Wired periodically suggest, we may begin building farms in high rises and let the rest of the landscape return to nature. Perhaps Americans will start taking seriously Jesus’ sayings about the unimportance of wealth and material possessions, and focus instead on what is really important in life (“for where your treasure is, there will your heart be also.”)

Meanwhile, back in the real world, such scenarios are implausible. They are therefore morally suspect as a basis for action (or inaction). Given the difficulties of getting 300 million Americans to curb their consumption, there is no reason to think we will be able to achieve sustainability with two or three times as many Americans. (Indeed, there are good reasons to think that 300 million Americans is already much too high. For example, scientists David and Marcia Pimentel suggest a U.S. population of 40 to 100 million might be truly sustainable, given the right environmental policies and consumption levels.15)

Environmentalists sometimes assume an infinite elasticity in our ability to reduce environmentally harmful consumption. This might have made sense 30 years ago, when our paradigm for such consumption was burning leaded gasoline or spraying deodorants that contained ozone-depleting CFCs. We could spend some money, remove lead or CFCs from those particular products, and continue happily consuming, minus the negative environmental effects.

Today, as human beings cook the earth and cause the sixth great extinction episode in our planet’s history, we measure environmentally harmful consumption in terms of our carbon footprints and the hectares of land necessary to sustain our consumption choices (land which is then not available as habitat for other species). Such personal impacts can and should be reduced. But because carbon emissions and basic resource use are implicated in almost all our consumption acts, they cannot be reduced to zero. As the cost of greener substitutes increases, the general public and then environmentalists themselves refuse to pay them. As we move beyond changing consumption patterns in ways that perhaps more efficiently provide the benefits people want, and instead ask them to reduce consumption of goods and services that they desire or enjoy, sustainability becomes a much harder sell.

American environmentalists need to remember that future consumption levels will be set both by government policies and by many billions of individual consumption decisions. These policies and decisions will be made not just by environmentalists, but also by people who are relatively unmoved by environmental considerations. Any reasonable scenario for creating a sustainable society must take this into account. Furthermore, even environmentalists tend to fade to a lighter shade of green when consuming less would seriously harm what we consider our quality of life.

Take us, for example. Your authors are serious environmentalists. One of us bicycles to work every day and recently spent tens of thousands of dollars to retrofit his house with a state-of-the-art heating system. The other lives in a small apartment with few extraneous possessions and has spent much of the last few decades working to protect endangered wildlife. Still, we drive our cars, when that is necessary or convenient. We eat fairly conventional diets. We occasionally fly on airplanes to visit relatives or attend scholarly conferences. We might be willing to do without some of these amenities, in order to help create a sustainable society. Still, there are limits . . . and we suspect that long before we reach ours, our fellow citizens will have reached theirs.

In other words, we can imagine Americans living and consuming at the levels of western European or Japanese citizens. We see this as a goal worth striving for politically. We cannot imagine Americans (or western Europeans or Japanese, for that matter) voluntarily living and consuming at the levels of the average Mexican citizen, much less the level of the average citizen of Nigeria or Bangladesh. Barring universal enlightenment or dire catastrophe, these aren’t live political options (regardless of whether a few thousand or even a few million hard-core environmentalists succeed in creating ultra-low consumption lifestyles in the midst of our high consumption culture). Nevertheless, it is urgent that the United States move toward creating a sustainable society.

Such considerations suggest that while we cannot prove that our fourth premise is true, it is highly probable: We must stop U.S. population growth in order to meet our environmental responsibilities. Of course, population stabilization would not guarantee sustainability, but it would make it possible. In philosophical terms, stabilizing our population is a necessary but not a sufficient condition for creating a sustainable society. If we are good environmentalists, that should be good enough. That we are good environmentalists can be stated as follows.

We are morally obligated to address our environmental problems and become good global environmental citizens. We will not argue for this premise here, or provide a detailed statement of what it amounts to in practice. Environmentalism means many things to many people. Still, there are two general goals to which most environmentalists subscribe: (1) creating societies that leave sufficient natural resources for future human generations to live good lives; and (2) sharing the landscape generously with nonhuman beings. Let’s call this “generous sustainability,” to differentiate it from more selfish, economically-defined conceptions of sustainability.16

We believe a moral commitment to “generous sustainability” captures the core of environmentalism. Numerous surveys in recent decades have shown that a large majority of Americans, from across the political spectrum, support these environmental goals. A commitment to generous sustainability is also explicitly endorsed by almost all philosophers writing about environmental ethics today. However, trying to convince skeptics of the truth of our fifth premise would require an article in itself (or perhaps a whole book!).17 Here, then, we take this moral commitment as a given, for the purpose of our argument.

To sum up, we claim that premises 1 through 5 of “the environmental argument for reducing immigration” are true — or at least that any serious environmentalist needs to treat them as true. But our conclusion necessarily follows from them. Therefore, our conclusion is also true: we should limit immigration into the United States to the extent needed to stop U.S. population growth.

Our Proposal — and the Alternatives

We propose, then, that the United States reduce immigration by taking the following measures:

Cut legal immigration from one million to 200,000 per year (the level allowed during the middle of the last century).

Reduce illegal immigration by strictly enforcing sanctions against employers who hire illegal workers (it is fruitless to try to lower legal immigration levels while ignoring or condoning illegal immigration).

Rework trade agreements, and increase and better target development aid, to help people live better lives in their own countries.

Such a policy would allow some of the benefits of immigration to continue (providing asylum for political refugees, allowing small influxes of workers with special skills, etc.) while helping the United States move toward population stabilization. Because our current TFR of 2.05 is right around “replacement rate” (2.1) and because reducing immigration would likely help drive our TFR even lower, such stabilization is no wild eco-fantasy. The United States is nearly there, if we are willing to limit immigration (this also holds true for other developed nations, whose TFRs tend to be even lower than the United States’).

This proposal is solidly within the mainstream of the best thinking on sustainability. As the President’s Council on Sustainable Development put it in 1996: “Managing population growth, resources, and wastes is essential to ensuring that the total impact of these factors is within the bounds of sustainability. Stabilizing the population without changing consumption and waste production patterns would not be enough, but it would make an immensely challenging task more manageable. In the United States, each is necessary; neither alone is sufficient.” One of the Council’s 10 major suggestions for creating a sustainable society was: “Move toward stabilization of U.S. population.”18

Many readers will instinctively recoil from our proposal. But we contend that paeans to sustainability, or talk of nonhuman beings having an intrinsic value that we need to respect, or reminders that God calls us to be good stewards of His creation, or earnest expressions of our strong environmental feelings, are all mere cant, when coupled with a blithe acceptance of the doubling or tripling of America’s human population. In the second half of this paper, we address some of the main objections that might be raised against our proposal. But at a minimum, we insist that readers unwilling to reduce immigration into the United States own the demographic and environmental implications of their positions.

If you support the immigration status quo of 1.5 million immigrants annually, then you also support increasing America’s population to over 700 million people by 2100.

If you support an immigration policy along the lines of the Bush/Kennedy/McCain bill of 2007, which might have increased immigration to 2 and ¼ million people annually, then you also support nearly tripling America’s population to over 850 million people by 2100.

If you support these scenarios or anything like them, then you don’t just support drastically increasing America’s human population. You also support more cars, more houses, more malls, more power lines, more concrete and asphalt. You support less habitat and resources for wildlife; fewer forests, prairies and wetlands; fewer wild fewer birds and wild mammals (except perhaps for house sparrows, rats and a few other human commensals). You support replacing these other species with human beings and our economic support systems.

In other words: if you support these scenarios or anything like them, then you reject generous sustainability. Given the grave dangers flagged in the I.P.C.C. climate change reports and the 2005 Millennium Ecosystem Assessment, if you support anything like these scenarios, you cannot even plausibly claim to support a narrow, anthropocentric sustainability. We turn now to the question of whether despite this conflict with sustainability, justice demands a permissive immigration policy.

Objections

Moral Arguments: Rights. Perhaps the most important objections raised against restrictive immigration policies are that they are unjust, because they are unfair to potential immigrants. One concise way of stating this is to say that would-be immigrants have a right to live and work in the United States. While some immigrants’ rights proponents argue for abolishing national borders altogether, most assert a general human right to freely move and settle without regard to national borders, subject to reasonable state restrictions to keep out criminals and prevent gross harms to receiving societies.

Clearly this right does not exist in American law. The Constitution names no right to immigrate, and the Supreme Court has consistently upheld the federal government’s right to regulate immigration into the country. Neither does such a right exist in international law. The U.N. Universal Declaration of Human Rights does not assert a general human right to immigrate into the country of one’s choice, nor do other major framework international rights treaties.19 Proponents, then, claim first the existence of a moral right to immigrate freely across borders, and second that national laws should be amended accordingly. What arguments do they provide for creating this new and important legal right?

Political theorist Chandran Kukathas gives the following “liberal egalitarian” argument for open borders. From a proper universalistic moral point of view, he maintains, citizens of rich countries have no special claims to the resources and opportunities into which they have been born. “Egalitarianism demands that the Earth’s resources be distributed as equally as possible,” he writes, “and one particularly effective mechanism for facilitating this is freedom of movement.” Egalitarians want to equalize not just resources, but opportunities. Allowing people to migrate from poor, overcrowded countries with high unemployment and little chance for economic advancement to wealthier, less crowded countries equalizes opportunities. “Our starting point,” Kukathas suggests, “should be a recognition of our common humanity and the idea that both the resources of the Earth and the cooperation of our fellows are things to which no one has any privileged entitlement.” For these reasons, “the movement of peoples should be free.”20

This is a powerful argument, since it rests on egalitarian values that many people share. It also relies on the common thought: “what right do I have to ‘shut the door’ on people who are just as good as I am and who, through no fault of their own, have been born into less happy circumstances?” Kukathas’ argument may speak particularly strongly to people who feel some sympathy with egalitarianism, but not enough to do anything about it personally. For it says to wealthy Americans: “You don’t have to give up anything yourself to help poor people overseas live better lives. You can fulfill any moral obligations you may have toward them by allowing them to come here and cut your grass, cook your food, and diaper your children.”

Nevertheless, despite these strengths, there are good reasons to reject the liberal egalitarian argument for open borders. Any rights claim must be tested against its effects on all interested parties — not just the parties pressing the claim. Even widely accepted, fundamental human rights must be balanced against other rights and other important interests.

As we have seen, current high levels of immigration into the United States are leading to a larger population, which makes it much harder to share the landscape generously with nonhuman beings. Allowing a general right to immigrate into the United States would greatly accelerate this process. With “open borders,” the interests of nonhuman nature would be sacrificed completely to the interests of people. The economic interests of would-be immigrants would trump the very existence of many nonhuman organisms, endangered species, and wild places in the United States.

Kukathas (and most immigrants’ rights advocates) can accept this trade-off. As the previous quotes illustrate, Kukathas sees nature essentially as “the Earth’s resources;” the only question to ask about them is how people may divide them up fairly and efficiently. In seeking to make sense of Australian environmentalists’ arguments for limiting immigration, he reduces these to worries that “parks and sewerage services” will be “degraded” — a revealingly soulless way of speaking.21

But those of us who reject this anthropocentric perspective must consider the interests of the nonhuman beings that would be displaced by an ever-increasing human presence. We ourselves believe that the human appropriation of natural landscapes has progressed so far in America that any further appropriation is unjust. Some readers might not be willing to go that far (although if that is the case, we wonder what you are waiting for). But it is important to realize that accepting a general right to immigrate leaves no room to take nature’s interests seriously, in the United States or elsewhere, since it undermines any possibility of limiting the human appropriation of nature. For this reason alone, it must be rejected by anyone committed to generous sustainability.

A general right to immigrate also would conflict with American citizens’ right to self-government. Immigration can change the character of a society, for better or worse; large-scale immigration can change a society quickly, radically, and irrevocably (just ask the Tibetans). Since self-government is a fundamental and well-established human right, the citizens of particular nations arguably should retain, through their elected officials, significant control over immigration policies. As Michael Walzer puts it, in an influential discussion of immigration:

“Admission and exclusion are at the core of communal independence. They suggest the deepest meaning of self-determination. Without them, there could not be communities of [a specific] character, historically stable, ongoing associations of men and women with some special commitment to one another and some special sense of their common life.”22

The citizens of a nation may work hard to create particular kinds of societies: societies that are sustainable, for example, or that limit inequalities of wealth, or that treat women and men as equals. They typically develop feelings of affiliation and social commitments that have great value in themselves and that enable communal projects that create further value. It seems wrong to suggest that these achievements, which may provide meaning, secure justice, and contribute substantially to people’s quality of life, must be compromised because people in other countries are having too many children, or have failed to create decent societies themselves. Such a situation does not call for the creation of a new right that undermines the self-government of others. Instead it suggests that would-be immigrants need to take up responsibilities for self-government that they and their leaders have neglected in their own countries.23

Environmentalists also worry that increasing human numbers will rob future generations of their right to enjoy a healthy environment with its full complement of native species. As your authors watch increasing numbers of people displace wildlife along Colorado’s Front Range, we recall a rueful passage from Henry Thoreau’s journal, as he reflected on his own Concord landscape:

When I consider that the nobler animals have been exterminated here, I cannot but feel as if I lived in a tamed, and, as it were, emasculated country . . . I take infinite pains to know the phenomena of the spring, thinking that I have here the entire poem, and then, to my chagrin, I hear that it is but an imperfect copy that I possess and have read, that my ancestors have torn out many of the first leaves and grandest passages, and mutilated it in many places.24

We believe that like Thoreau, our descendants will “wish to know an entire heaven and an entire Earth.” Since a growing population undermines the right of future Americans to enjoy a safe, clean environment and to know and explore wild nature, we must reject a general right to freely immigrate into the United States.

For American environmentalists, the interests of nonhuman nature, the right and responsibility of self-government, and our concern for future generations, all come together in our efforts to create a sustainable society. Because we take this responsibility seriously and because it cannot be achieved without stopping America’s population growth, we must reject a general right to immigrate into the United States.

Please note: this discussion does not deny the importance of human rights. It presupposes them. Rights allow us to protect important human interests and create egalitarian societies that maximize opportunities for people to flourish. We believe rights are justified ultimately because they contribute to such human flourishing. But when rights are pressed so far as to undermine human or nonhuman flourishing, they should be rejected.25

Moral Arguments: Welfare. Even if no general right to immigrate exists, however, there might still be good moral reasons for upholding the permissive immigration status quo. Consider the following welfare-based

argument.

Approximately one and a half million people immigrate into the United States each year, and clearly the majority believe they will improve their own or their families’ welfare by doing so. Otherwise they wouldn’t come. Immigrants may find educational, vocational, or other personal opportunities in the United States that they would otherwise be denied. Immigrants coming from some countries may significantly improve their own or their families’ health and longevity. All else being equal, the potential improvements in would-be immigrants’ welfare seem to make a powerful argument for continuing to allow mass immigration.

Of course, all else is not equal, as we have already shown. Whatever may once have been the case, today continued mass immigration into the United States threatens the very existence of many nonhuman beings and species. It compromises future generations’ right to a decent environment, both here and abroad. It makes it easier for common citizens and wealthy elites in other countries to ignore the conditions that are driving so many people to emigrate in the first place. In addition, economists have shown that mass immigration drives down the wages of working-class Americans and increases economic inequality in the United States.26 For all these reasons, the “welfare” argument does not make a convincing case for continuing high levels of immigration. Indeed, we believe current high immigration levels are so harmful to the welfare of nonhuman beings and poor Americans, that our immigration policy is unjust toward those two groups.27

Still, immigration’s benefits to new immigrants remain substantial, and welfare arguments of the sort just canvassed cannot be ignored. They point to a responsibility, not to immigrants per se, but to people around the globe who live in poverty, insecurity, and injustice. Even the most generous immigration policies will not help most of them, since only a small percentage can conceivably emigrate from their home countries, and the worst off rarely have the resources to do so. The wealthy people of the world — including not just citizens of “the West,” but hundreds of millions of people in the developing world — owe the world’s poor people something. Not the lucky few millions who manage to immigrate to the West, but the billions who will have to sink or swim where they are. Just what do we owe them?

We’re not sure. In One World: the Ethics of Globalization, Peter Singer argues that wealthy individuals and nations can and should increase and better target charity and foreign aid, to improve conditions for poor people overseas.28 We find Singer’s arguments convincing, although his account mostly ignores the responsibilities third-world elites have to create economically just societies and poor third-world citizens have to fight for them. Views about the scope of our “global” obligations and the best ways to fulfill them are likely to vary widely. However, we hope most of you will agree that wealthy people — West and East — have a prima facie duty to share some of our wealth and help the world’s poor people live better lives. Rather than try to justify this duty, we’ll finish with three brief comments on its proper scope and pursuit.

First, mass immigration is neither a sufficient nor an efficient means of meeting it. Inviting the world’s poor to America to become our servants is a poor substitute for helping them create safe, just, flourishing societies where they live. Even taking the most positive view possible of its effects on immigrants, mass immigration does nothing for the vast majority of the world’s poor.29

Second, serious environmentalists will not allow efforts to help poor people, run roughshod over their environmental commitments. Serious and immediate human needs may sometimes overrule our prima facie duties to protect wild nature and preserve a healthy environment. But committed environmentalists cannot interpret our social duties in ways that make our environmental duties impossible to fulfill.

Third, fortunately, our prima facie duty to help the world’s poor may be pursued in ways that do not undermine efforts to meet our prima facie environmental duties. The United States government should be much more generous and intelligent with development aid to poor countries (America ranks near the bottom among western democracies in per capita foreign aid, and much of this comes as military aid that actually harms poor people). It should fully fund international family planning efforts, which help both nature and the poor. It should set trade policies to benefit poor workers and protect nature, rather than to maximize trade. The United States should pressure foreign governments to respect their citizens’ rights, as mandated by international law. Individual Americans should support charities with effective international aid programs, such as Oxfam and the United Nations Children’s Fund. We should cultivate personal and professional friendships across borders, in an effort to understand and appreciate our fellow human beings.

All these efforts, and more, may be taken up, without embracing mass immigration. Mass immigration is no substitute for such efforts. Most important, endless population growth is incompatible with creating just, sustainable, flourishing societies here in the United States and abroad. Far from undermining our policy proposal to reduce immigration into the United States, considerations of justice in fact support that proposal.

It is an interesting question that should take precedence when justice and sustainability conflict. Here we need not hazard an answer to this question, since both justice and sustainability point us toward a more restrictive U.S. immigration policy.

Environmental Arguments. Environmentalists sometimes give specifically environmental reasons for supporting — or at least tolerating — high levels of immigration. One common argument says that we should focus on consumption, not population as the root cause of our environmental problems. “Don’t buy big suburban houses; don’t buy gas guzzlers; don’t put air conditioners in those houses and cars. Americans’ high level of consumption is the problem — not our population.”

This argument is appealing because it seems to put the responsibility for change where it belongs: not on poor immigrants but on average Americans, who do consume too much and who could consume less without harming their quality of life. But as we have seen, it is Americans’ overall consumption that determines our environment impact. Overall consumption equals per capita consumption multiplied by population. So if high consumption is a problem, population growth must be, too.

In a variation on this theme, immigrant advocates sometimes assert that immigrants (or perhaps “recent immigrants,” or “most recent immigrants”) consume less than the average American. One problem with this argument is that there are apparently no good figures comparing immigrants’ and native-born Americans’ consumption patterns. But the main problem is that it focuses on a moment in time, rather than thinking through the long-term effects of population growth.

Immigrants’ lower consumption levels, if they exist, are presumably a function of their relative poverty. However immigrants are not coming to America to live in poverty, but to achieve “the American dream” and pass greater opportunities on to their children and grandchildren. Two million more immigrants this year may mean 10 million more Americans 100 years from now — and if history is any guide, those 10 million Americans will live pretty much like other Americans. The descendants of last century’s Jewish and Italian immigrants do not seem to consume less than the average American today; there is no reason to think that the descendants of today’s Mexican and Chinese immigrants will consume less than the average American 100 years from now. Bottom line: If American consumption levels are too high, the problem is only made worse by population growth.

Another argument made by many American environmentalists is that overpopulation is important, but that it is a global, not national issue that can only be solved through international action. The world’s population increased by 76 million people in 2006 and 95 percent of that increase occurred in the developing world. Rather than cutting immigration to keep our own population from growing, they argue, we should fund family planning overseas. We should provide more foreign aid, and redirect trade and other government policies to help the poor, so fewer of them will feel compelled to leave their countries in order to live decent lives. If we do these things, we will act humanely and help both poor people and the environment.

Before analyzing this argument, we should pause for a moment to appreciate its oddity. No one argues: “Deforestation is a global problem, therefore we shouldn’t worry about deforestation in our own country, or on the local landscape.” Or: “Species loss is a global problem, therefore we should fund species protection efforts elsewhere, to the exclusion of efforts where we live.” Those who care about deforestation or species extinction often work especially hard to prevent them in the places they know best, and are applauded for doing so. Besides, “global” efforts to halt deforestation and species loss are largely a summing up of local and national efforts focused on particular forests and species. This is how environmentalism works, when it works. Advocates for an exclusively global approach to overpopulation owe us explanations for why this one issue should play out differently and how it could play out differently, while still leading to environmentally acceptable results. But no such arguments are forthcoming, and none seem remotely plausible.

Comforting as it is, the “globalist” argument fails, partly because it mischaracterizes overpopulation, which in fact can occur at various scales. It makes sense to say: “The world is overpopulated; we do not know whether essential global ecosystem services can be sustained at these numbers over the long haul.” But it also makes sense to say: “Tokyo is overpopulated; its sidewalks, streets and trains are so crowded that there is no room to move.” Or: “Nigeria is overpopulated; its population is so large and is growing so fast that it has trouble providing jobs for its young adults, or building sufficient water and sewer facilities for its cities.” And just as Tokyo’s citizens may try to alleviate local air pollution and Nigeria’s citizens may try to protect their remnant forests, so they may try to address local or national overpopulation. After all, they will have to live directly with their failure to do so and they cannot wait for the world to solve all its problems before they act to solve their own.

Returning to the United States, a strong case can be made that we are overpopulated right now. Signs of stressed ecosystems and lost biodiversity abound. Certainly we have not yet found a way to bring air and water pollution within limits acceptable to human health, nor have we stemmed the loss of productive farmlands and wildlife habitat, nor have we recovered more than a handful of the hundreds of species we have endangered. And as we have seen when considering global warming, a large and growing population also makes it much harder for Americans to live up to our environmental responsibilities as global citizens.

Let us be clear: Advocates for international action are correct that wealthy countries should help poor countries stabilize their populations. However, “think globally, don’t act locally” is terrible advice. It is possible and necessary to work on multiple levels at once. We can make more generous contributions to the United Nations Population Fund and cut back on national immigration levels and limit local building permits. Efforts at one level and in one place can only strengthen efforts at other levels and in other places. Meanwhile, population growth is a problem in America right now. If you live in the United States, the chances are good that your community is threatened by environmentally damaging development that is being caused (or justified, in the planning stages) by population growth.

But why should this matter? For finally, some environmentalists argue that immigration just moves people around, so it is (or may be) environmentally neutral, or even benign. As one reader of an earlier version of this paper commented: “Efforts to reduce overpopulation in New York or the United States do not help alleviate overpopulation worldwide, because people who aren’t let in have to go someplace else.” Added another reader: “Ecological damage may be worse if people remain in their home countries rather than immigrating to the United States. Immigration restrictions seem to privilege the U.S.’s wild places over other, perhaps more biodiverse, places around the world.”

Although one of us has spent time overseas working to protect endangered species, we plead guilty to a special concern for America’s wildlife and wild lands. But we don’t apologize for it. Environmentalism necessarily involves love, connection, and efforts to protect particular places. Environmentalists should think long and hard before advocating anything that weakens this “local focus,” because a passionate connection to places that are “near and dear” to us is how environmentalism works, in Boston or Beijing. This doesn’t involve believing American (or Chinese) landscapes are more valuable than others. It involves acting as if they are the most important landscapes in the world and using our most accessible political levers to protect them. Although questions about the justice of moral particularism are vexed, we believe that a large degree of “environmental particularism” is justified, on both ethical and pragmatic grounds.30 At a time when Americans move on average once every six years, arguing that we should further downplay our ties to particular places and communities is a bad idea. That some environmentalists would even consider it shows how attempts to avoid population issues tend to warp our judgment.

However, cosmopolitan ethical universalists who reject our parochial concern for protecting America’s native species and unique landscapes, should still support our proposal to reduce immigration into the United States, since doing so would also benefit the rest of the world. This is because moving people to America, far from being environmentally benign or neutral, increases overall global resource consumption and pollution. This in turn threatens to weaken the already-stressed global ecosystem services that we all depend upon — with the world’s poorest people facing the greatest danger from possible ecological failures.

Consider Table 2, which compares the average Americans’ “ecological footprint” with averages from our 10 largest immigration “source” countries. On average, immigrating from nine of these 10 countries greatly increases an individual’s ecological footprint — and the ecological footprints of his or her descendants — by 100 percent to 1,000 percent or more. In the case of Mexico, which accounts for nearly a third of all immigration to America, immigration increases individuals’ consumption and pollution approximately 350 percent.31 There probably are cases where immigrants consume more but do less ecological damage than they would have had they remained in their countries of origin (slash-and-burn agriculturalists inhabiting biologically-rich forests?), but clearly these are the exceptions. More Americans is bad news for America’s native flora and fauna. But given global warming, it is also bad news for poor people living in the Sahel or in the Bhramaputra Delta.

Now, if emigration helped America’s source countries get their own demographic houses in order, or opened up an ecological space that they used to create more sustainable or just societies, a case might be made for continuing to allow mass immigration into the United States. Instead, America’s permissive immigration policies appear to enable demographic and ecological irresponsibility and continuing social injustice. As an example, consider Guatemala, where currently about 10 percent of the adult population lives and works in the United States. and a recent poll showed that most young Guatemalans hope to do so in the future. Guatemalan women’s TFR averaged 4.6 children in 2005, for an annual growth rate of 2.4 percent per year.32 The Guatemalan government outlaws abortion (except when a mother’s life is at risk) and does little to encourage contraception. Guatemala has high deforestation rates and an unjust, highly inequitable distribution of wealth. But there is little effort to change any of this, perhaps because the negative effects of local overpopulation are lessened through immigration and counterbalanced, for many individuals, by the positive incentives of having more remittances from family members in the United States.

Americans should do what we can to help other countries move toward sustainability, whether that means increasing funds for green development projects, or shutting off the “safety valve” that allows political elites to postpone necessary reforms. But we believe that our primary responsibility is to create a sustainable society in the United States. Not just because our local environmental duties are important. Not just because this is the main way we may further our responsibilities as global citizens. Perhaps most significant would be the powerful example of the world’s wealthiest nation — the land of “The Apprentice” and “Who Wants to Be a Millionaire?” — rejecting the path of endless growth and embracing sustainability. Limiting immigration into the United States and stabilizing our population would send a powerful message around the world that the time to create just, sustainable societies is now.

Economic Arguments. This brings us to a final class of objections to our proposal: economic objections. Many pro-business proponents praise mass immigration above all for increasing economic growth. Immigration brings in poor unskilled workers willing to work physically demanding jobs for less money than native-born Americans, and highly trained professionals with the specialized skills needed by high-tech companies. It thus helps businesses meet their needs and grow. Immigration creates more domestic consumers; as Tamar Jacoby puts it: “Foreign workers emerging at the end of the day from the meatpacking plant or the carpet factory buy groceries and shoes for their children; on Saturday, they buy washing machines and then hire plumbers to install them.” Immigration also reduces the cost of many goods and services, and this too increases overall consumption. In all these ways, immigration results in “a bigger, more productive economy.”33 That is why the Wall Street Journal, the U.S. Chamber of Commerce, and other important business organs strongly support mass immigration (and in the case of the Journal, “open borders”).

On the other hand, focusing on whether mass immigration is “good for the economy” ignores the fact that any immigration policy creates economic winners and losers. According to Harvard economist George Borjas, “immigration induces a substantial redistribution of wealth, away from workers who compete with immigrants and toward employers and other users of immigrant services.”34 This is because, compared to other industrialized nations, the United States imports a much higher percentage of less-educated, lower-skilled workers. Borjas notes that “between 1980 and 1995, immigration increased the number of high school dropouts by 21 percent and the number of high school graduates by only 4 percent.” During this same period, the wage disparity between these two groups increased 11 percent, with perhaps half of that disparity a result of mass immigration.35 Borjas calculates that between 1980 and 2000, immigration reduced the average annual earnings of high school dropouts by 7.4 percent, or $1,800 on an average salary of $25,000.36 For these workers, who could least afford it, real wages actually declined during this period.

While the economic effects of immigration are complex and the details are open to debate, it appears that over the past few decades high immigration levels have contributed to increased economic growth, lower wages for the poorest Americans, and an increase in economic inequality in the United States. Continued high levels of immigration will likely further these trends. Far from strengthening the case for continued mass immigration, these effects provide three additional reasons to oppose it.

First, an immigration policy that benefits rich citizens (who hire immigrants) at the expense of poor citizens (who compete with them) seems prima facie unjust.37 If Americans want to help poor foreigners, we should not do so on the backs of our own poor citizens. (Liberal proponents of mass immigration are as loath to accept its effects on workers’ wages as they are to accept its demographic and environmental effects. But this is willed ignorance. After all, trade groups representing landscapers and restaurant owners lobby for increased immigration precisely because it allows their members to hire workers for less money.)

Second, accepting greater economic inequality in exchange for greater overall wealth seems a foolish trade-off for Americans today. We are already wealthy enough to provide for our real needs and reasonable desires. Further wealth when combined with greater inequality is a recipe for frustration, envy, and social

tension.

Third, mass immigration’s contribution to economic growth, far from being a net good, gives environmentalists their most important reason to oppose it. Human economic activity is the primary driver of ecological degradation. Future generations are going to have to reject the paradigm of an ever-growing economy and instead develop a sustainable economy that respects ecological limits.38 The sooner we get cracking on this, the better. Here in the United States, economic and demographic “growthism” are intimately intertwined — yet another reason why American environmentalists cannot ignore domestic population issues.

We contend, then, that economic considerations also support our immigration policy proposal — on a proper understanding of “economy.” Eighty-five years ago, in a talk to the Albuquerque Chamber of Commerce (which he once headed), Aldo Leopold asked: “What, concretely, is our ambition as a city? ‘100,000 by 1930’ — we have blazoned it forth like an army with banners…. Can anyone deny that the vast fund of time, brains, and money now devoted to making our city big would actually make it better if diverted to betterment instead of bigness?” Civic-mindedness may be a force for good, Leopold added, but went on to ask his “boosters,” somewhat plaintively: “Is it too much to hope that this force, harnessed to a finer ideal, may some day accomplish good as well as big things? That our future standard of civic values may even exclude quantity, obtained at the expense of quality, as not worth while?”39

No, this is not too much to hope. Without such a society-wide “revaluation of economic values,” environmentalism will not succeed. We must redefine “the good life” in less materialistic terms and create economies designed to sustain a finite number of such good lives — not to grow indefinitely. These are daunting tasks, but they are not optional for serious environmentalists. In America, where we habitually mistake bigness for goodness and quantity for quality, these tasks are even more urgent. And as Leopold understood, population growth is an important part of the overall picture.

Conclusion

We have presented our reasons for limiting immigration into the United States and responded to the most common and consequential objections to our proposal. In the end, we return to our primary argument. Immigration is now the main driver of American population growth. Continued American population growth is incompatible with sustainability, nationally or globally. Therefore environmentalists committed to sustainability should support reducing current high levels of U.S. immigration. Not just on pain of contradiction, but on pain of failure.

Americans must choose between sustainability and continued population growth. We cannot have both.

End Notes

1 Roy Beck and Leon Kolankiewicz, “The Environmental Movement’s Retreat from Advocating U.S. Population Stabilization (1970-1998): A First Draft of History,” Journal of Policy History 12 (2000): 123-156.

2 U.S. Census Bureau, Decennial Censuses of Population, 1900 to 2000.

3 Leon Bouvier, “The Impact of Immigration on United States’ Population Size: 1950-2050” (Washington, DC: Negative Population Growth, 1998).

4 In fact, immigrants tend to have more children than native-born citizens, thus raising America’s overall TFR. Since these projections hold TFR steady under all three scenarios, they almost certainly understate immigration’s contribution to population growth. We think they also obscure the ability of the United States to transition to a stable population, if we are willing to drastically reduce immigration.

5 “National Resources Inventory 2001, Urbanization and Development of Rural Land.” Natural Resources Conservation Service, U.S. Department of Agriculture (www.nrcs.usda.gov/technical/land/nri01/nri01dev.html).

6 D.S. Wilcove, D. Rothstein, J. Dubow, A. Phillips, and E. Losos, ‘‘Quantifying Threats to Imperiled Species in the United States: Assessing the Relative Importance of Habitat Destruction, Alien Species, Pollution, Overexploitation, and Disease,’’ BioScience 48 (1998): 607–615.

7 Roy Beck, Leon Kolankiewicz and Steven Camarota, Outsmarting Smart Growth: Population Growth, Immigration, and the Problem of Sprawl (Washington, DC: Center for Immigration Studies, 2003), p.5.

8 Ibid.

9 Ibid., pp.68-69.

10 Energy Information Administration, U.S. Department of Energy, “Emissions of Greenhouse Gases in the United States 2005,” November 2006 (ftp://ftp.eia.doe.gov/pub/oiaf/1605/cdrom/pdf/ggrpt/057305.pdf).

11 See for example Philip Cafaro, “Less is More: Economic Consumption and the Good Life,” Philosophy Today (1998) 42: 26-39; and Philip Cafaro, “Economic Consumption, Pleasure and the Good Life,” Journal of Social Philosophy (2001) 32: 471-486.

12 Carbon Dioxide Information Analysis Center, U.S. Department of Energy, “National Fossil Fuel CO2 Emissions — All Countries” (http://cdiac.ornl.gov/trends/emis/tre_coun.htm).

13 U.S. Census Bureau, International Data Base, “Country Summaries.” All census bureau 14 Simple logic suggests that endless human population growth is incompatible with (in chronological order) generous sustainability, anthropocentric sustainability, basic human happiness, and the laws of physics. Sooner or later, human beings will have to face population issues squarely. Better sooner!

15 David and Marcia Pimentel, “Land, Energy and Water: The Constraints Governing Ideal U.S. Population Size” (Washington, DC: Negative Population Growth, 1990).

16 Even those holding narrower anthropocentric conceptions of sustainability should arguably advocate reducing U.S. immigration, for the good of future generations in the United States and abroad. Even if all you care about is people, you might think there can be too many of us.

17 Actually the book has been written. See Holmes Rolston, III, Environmental Ethics (Philadelphia: Temple University Press, 1988).

18 President’s Council on Sustainable Development, Sustainable America: A New Consensus for Prosperity, Opportunity, and a Healthy Environment for the Future (Washington, DC: 1996).

19 See for example the European Convention for the Protection of Human Rights and Fundamental Freedoms (1950) or the International Covenant on Civil and Political Rights (1966). Article 13 of the U.N. Declaration asserts: “Everyone has the right to freedom of movement and residence within the borders of each state” (emphasis added). Here the right of movement and residence is clearly limited to a citizen’s home country. Article 14 asserts: “Everyone has the right to seek and to enjoy in other countries asylum from persecution.” But this is a right to temporary refuge, not permanent settlement or full citizenship. Most immigrants to the United States are not fleeing persecution but trying to better their lives; hence the right of asylum does not come close to justifying their right to immigrate into the United States. And since our immigration proposal accommodates legitimate asylum claims, it does not run afoul of article 14.

20 Chandran Kukathas, “Immigration,” in Hugh LaFollette (ed.), The Oxford Handbook of Practical Ethics (Oxford: Oxford University Press, 2003), pp.571-2, 586.

21 Ibid., p.574.

22 Michael Walzer, Spheres of Justice: A Defense of Pluralism and Equality (New York: Basic Books, 1983), p. 62. Current attempts to increase immigration into the United Stats run afoul of the right to self-government more directly. Polls consistently show Americans want less immigration, not more. Surely in a democracy, their desires should be taken into account.

23 In researching a book on the ethics of immigration, the lead author has asked numerous immigrants from Mexico and Central America why they came to the United States. Invariably, they spoke of “corruption” and the fact that a poor man or woman cannot make a good life in their countries. What is the proper response to this? Surely not: “Well then, let Mexico go to the dogs! Come to America, and bring all your relatives!” Better: “Mexico needs to reform itself. You need to get to work; what can Americans do to help?” Respondents usually just sighed at the suggestion that their countries might be reformed — but we think their fatalism is part of the problem.

24 Henry Thoreau, Journal, volume VIII (New York: Dover Press: 1962), pp.220-221 (March 23, 1856).

25 As philosopher Holmes Rolston puts it: “human rights are welcome where they are nonrival with the health of the [ecological] system. But human rights that claim to trump the system are doubtful rights.” Conserving Natural Value (New York: Columbia University Press, 1994), p.233.

26 George Borjas, Heaven’s Door: Immigration Policy and the American Economy (Princeton: Princeton University Press, 1999).

27 Ryan Pevnick, Philip Cafaro and Mathias Risse, “An Exchange: The Morality of Immigration,” Ethics & International Affairs 22 (2008): 241-259.

28 Peter Singer, One World: The Ethics of Globalization (New Haven: Yale University Press, 2002).

29 One caveat is that particularly for some Latin American countries, remittances from workers in the United States are an important source of income for immigrants’ families. But these economic benefits must be weighed against the dispersal and break up of families, an important social cost. They must be weighed against the cost of enabling these countries’ continued failure to create just and sustainable societies.

30 Moral particularism is the position that we are justified in valuing those with whom we have family, neighborhood, or citizenship ties more highly than people in general. It can be contrasted with ethical universalism or cosmopolitanism: the position that a true morality values all people equally. While commonsense morality exhibits a high degree of moral particularism, moral philosophers tend to be moral universalists (although there are numerous exceptions).

31 Recent evidence also suggests that immigration leads to increased family size: 3.5 children for recent Mexican immigrants in the United States, compared to 2.4 children for women remaining in Mexico. Steven Camarota, “Birth Rates Among Immigrants in America: Comparing Fertility in the U.S. and Home Countries” (Washington, DC: Center for Immigration Studies, 2005).

32 United Nations Population Division, U.N. Department of Economic and Social Affairs, “National Trends in Population, Resources, Environment and Development 2005, ” www.un.org/esa/population/publications/countryprofile/index.htm.

33 Tamar Jacoby, “Immigration Nation,” Foreign Affairs (November/December 2006): 55.

34 George Borjas, Heaven’s Door, p.13.

35 Ibid., p.11.

36 George Borjas, “Increasing the Supply of Labor Through Immigration: Measuring the Impact on Native-Born Workers” (Washington, DC: Center for Immigration Studies, 2004), p. 6.

37 Stephen Macedo, “The moral dilemma of U.S. immigration policy: open borders vs. social justice?” in Carol Swain (ed.), Debating Immigration (Cambridge: Cambridge University Press, 2007).

38 Herman Daly, Beyond Growth: The Economics of Sustainable Development (Boston: Beacon Press, 1996); Brian Czech, “Economic growth as a limiting factor for wildlife conservation,” Wildlife Society Bulletin 28 (2000):4-15.

39 Aldo Leopold, “A Criticism of the Booster Spirit,” in Leopold, The River of the Mother of God and Other Essays (Madison: University of Wisconsin Press, 1991). Leopold also addresses population issues in his lecture “Ecology and Politics” in the same volume (pp. 281-286).