ONE: Paradigms, Environmentalism, and Demography

The chapter points out that the current paradigm of environmentalists ignores the negative impact that human population size has on the biosphere. To counter this lack of concern with population size and growth, the chapter uses graphs to show that the ecological footprint of the global human population has appreciably expanded since the 1960s; that the numerical increase of the global population remains substantial even though the rate of population growth and the total fertility rate have fallen; and that large numbers of human beings are projected to be added each decade to the global population until at least the year 2050.

In one noteworthy respect, scholarship is comparable to a chain—just as a chain cannot be stronger than its weakest link, a scholarly project cannot be better than its lowest-quality component. Accordingly, whether scholarship utilizes numeric data or relies on non-numeric information, its output will suffer if any part of the scholarship is problematic. With this in mind, I turn to a key component of scholarship, viz., paradigms.

1.1 Paradigms in scholarship

Paradigms play an important role in scholarship because they involve the assumptions that direct scholars to the phenomena that should be studied and tell scholars how to study the phenomena.1 A paradigm that is defective can, therefore, hold back scholarship and the advance of knowledge.2 Although a discipline that uses a faulty paradigm may still add to the store of knowledge,3 it would make greater contributions, and/or would make the contributions sooner, if its paradigm was not defective. A faulty paradigm is, then, manifestly undesirable. Of course, scholars in every discipline want to avoid a faulty paradigm, because their output must eventually be useful, and when disciplines differ in the utility of their scholarship, they will differ in financial support and prestige. The marketplace of ideas, in brief, gives scholars a strong incentive to be on guard against flaws in their paradigms. Nonetheless, recognizing and removing established paradigm flaws is not easy and does not occur quickly.4

In law, scholarship employs several paradigms and appears to be adding more,5 probably because law draws on many non-law disciplines.6 Naturally, not all non-law disciplines beneficial to law are static; at least some of them are in flux. As a result, paradigm evolution occurs, and indeed is required, in law and its areas of specialization. Such evolution is particularly needed in environmental-law scholarship, because the paradigm of environmental law at the present time ignores a key cause of the damage that has been and is being done to the biosphere. However, in ignoring a principal source of damage to the biosphere, environmental law is not alone. The paradigm in the field of ‘sustainability science,’ for example, is neglecting this cause, too, and hence is proving unable to solve problems that are relevant to it.7 Consequently, environmental law as well as sustainability science—disciplines that are obvious allies8—need to amend or replace their current paradigms. Unless and until they do so, their ability to alleviate, let alone eliminate, pertinent problem-causing agents will be severely limited.

1.2 The paradigm in environmentalism

In the present book, I hope to persuade scholars who use the now-popular paradigms of environmentalism to alter those paradigms. Specifically, I point to the numerical size and growth of the human population, a phenomenon that is left out of the current focus of environmental law and other environmentally concerned disciplines.9 This omission is as regrettable as it is important:10 The numerical growth of the human population has been central to the onset, and will be key to the intensity, of the Anthropocene. As a result, human-population growth, by reducing ‘[b]iodiversity and nature’s regulating contributions to people,’11 is putting the future of Homo sapiens in danger.12 Scholars in environmental disciplines may believe that the biosphere of the planet has been hurt by economic growth rather than by population growth, but the degradation of the biosphere is not solely due to economic growth. Despite disagreement over the relative importance of each factor, both of them harm the biosphere, and population growth cannot be simply brushed aside.13 Unfortunately, however, population growth and ways to halt it are off-limits as a topic for consideration today.14

In confronting the phenomenon of human-population growth, we should, however, be mindful of a key point: Population growth occurs in social setting, not in a social void. I thus tie population growth to human society and to a critical property of every human society, viz., the existence and operation of a society as a system. Otherwise said, human fertility, mortality, and migration—the demographic processes that determine population size—are products of human societies and, hence, of systems. Law and government policy, too, arise and operate within societal systems. In short, environmentalism must incorporate population growth and the social-system context of population growth into its thinking, and until it does, environmentally oriented scholarship and the solutions it proposes to biospheric problems will suffer.

I note that, while some human societies in the past may have experienced large, rapid declines in the number of people in their populations because population size had gone beyond what was supportable by the biosphere, the evidence advanced for this possibility has been questioned.15 Nonetheless, population overshoot and collapse cannot be summarily dismissed in light of a recent study that modeled such an event in Europe during the fourteenth century A.D.16 Moreover, population overshoot and collapse is a distinct possibility today.17 The prudent course of action for Homo sapiens, therefore, is to avoid having a population that is too large. Failure to prevent overpopulation, and reduce excessive human numbers, may have severe consequences—consequences that may develop suddenly and, at least in the short run, be irreversible. In other words, signals backed by credible evidence ought not to be ignored when they flash orange or red and tell us that the number of human beings on Earth is approaching, and may have already exceeded, the population size that can be adequately and permanently supported.

Let us look briefly at such a signal. According to the estimates in Figure 1.1,18 amounts and types of resource consumption and disposal across the countries of the world have, since the 1970s, demanded more than one Earth to supply the human population with enough ‘biologically productive land and water … to produce all the resources it consumes and to absorb the waste it generates, using prevailing technology and resource management practices.’19 Figure 1.1 shows, too, that this human-created pressure on the biosphere has been undergoing a secular increase over time and that the increase has been substantial. Notably, for almost the entire period since 2010, roughly 1.7 Earths were necessary to take care of the human population. In short, far too much is being asked of the planet by its human population.

A bar chart plots years versus number of earths needed by global human population.
Figure 1.1:

Pressure of Homo sapiens on the biosphere: world, 1961–2018

Source: Data from Global Footprint Network; graph by author (see note 19 in this chapter).

Unfortunately, scientists have not definitively identified the precise threshold at which the numerical size of the human population passes the threshold that triggers severe reactions in the biosphere.20 Furthermore, this threshold may not be constant over time, and it may be reduced by human activities that degrade the biosphere. The ‘ecological footprint’21 of Homo sapiens graphed in Figure 1.1 should be of deep concern, therefore, because it indicates that the population of human beings presently on the planet has exceeded, and is increasingly exceeding, what the biosphere can supply given prevailing levels and patterns of resource consumption and disposal. Notably, other evidence also leads to this conclusion.22 In effect, Homo sapiens has been a borrower from a biospheric bank, and it may be a reckless borrower because it may lack the wherewithal to cover the loans that it has taken out.

Remarkably, humans appear to have just minimal awareness of the damage that the numerical size of their population is inflicting on the biosphere. Of course, from one perspective, the lack of widespread and intense interest in overpopulation should not be surprising. Hominids have been on Earth for millions of years,23 and modern Homo sapiens has been around for millennia—by one estimate, for around 141,000 years.24 Overpopulation as a global problem is thus an exceedingly recent development, and given social inertia, human societies do not yet recognize the role of population size in generating significant societal concerns even though these concerns cover a wide range, for example, crime and inter-group conflict, epidemics of high-fatality disease, elevated levels of migration, and long-lasting food insecurity.25 A corollary of the societal incognizance of the demographic cause of these concerns is, unsurprisingly, that individual societal members who are personally worried about the environment are not necessarily worried about population growth. Certainly, the two attitudes are not strongly related among residents of the United States,26 this despite the disproportionately large and long-standing ecological impact of Americans.27 In the Anthropocene, however, the two attitudes ought to be tightly linked.

1.3 Lessons in human demography

The pressure that Homo sapiens places on the biosphere at a given point in time is a function of two factors—(1) the total number of people and (2) how much the average individual person consumes and, as a corollary of consumption, how much waste the average person generates. Arithmetically, the aggregate amount of human pressure on the biosphere is the product of (1) multiplied by (2). Nonetheless, present-day environmentally concerned scholars concentrate generally on just (2) and, unlike a half-century ago, ignore (1).28 Among environmental-law scholars, the neglect of population size and growth may be partly due to the youth of environmental law as a specialty.29 In any environmentally oriented discipline, however, the neglect of the population factor is curious, and there are at least three reasons why. The first is that many of the problems that Homo sapiens confronts at the present time, and appears likely to continue confronting for decades to come, are exacerbated if not created by the numerical size and/or growth of the human population.30 The second reason is that environmentally concerned scholars are presumed to be cognizant of, and to pay attention to, all types of agents that pose a threat to the biosphere. Indeed, these scholars have been drawn to, if not accepted, the concept of the Anthropocene, and although the Anthropocene has not yet been formally recognized as a geological epoch,31 it is, by definition, a period in which human beings are a major, if not the principal, source of global change in the biosphere.32 The demographic dimensions of Homo sapiens, in short, are obviously relevant in the Anthropocene, and the lack of concern in the paradigm of environmentalism with the number of humans on the planet is puzzling.

The absence of human-population size and growth from the paradigm of environmentalism is odd for a third reason as well. Since this reason is more complicated than the first two, it requires a lengthier discussion. Globally, the numerical size of the population of Homo sapiens is steadily increasing even though the rate of population growth and rates of age-specific fertility have come down. The numerical expansion of the human population each year, moreover, is considerable. However, because environmentalists have failed to engage with demography, they have not grasped the difference between the course of change in numerical additions to the human population, on the one hand, and the course of change in the rate of human-population growth and in age-specific fertility rates, on the other. The absence of an understanding of the difference, in turn, appears to have led environmentalists to discount the numerical size and growth of the human population as an agent in environmental degradation. As a result, underscoring the difference—a task that I undertake next—may help to promote an appreciation of the importance of the number of human beings to the biosphere.

1.3.1 Numerical growth and rate of growth of the human population

All else being equal, the pressure on the biosphere that is created by human beings mounts as the numerical size of the population of Homo sapiens becomes larger, and even if the pressure per person declines, increments in population size can offset the per capita decline. Critically, while growth in the number of people occupying planet Earth occurred slowly for a long time, it has been large in absolute amount for decades.33 Figure 1.2, which is derived from data published by the United Nations Population Division, includes two gauges of yearly change in the global human population since the mid-twentieth century.34 One gauge is the number of people added to the human population of the planet from the middle of one year to the middle of the following year. These numbers, in millions, are represented by the vertical bars in the inner region of Figure 1.2; the numeric values for the bars are shown on the left vertical axis. The second gauge is the rate at which the population of Homo sapiens increased annually, that is, the percent changes in population size from the middle of one year to the middle of the next. The rates are represented by the solid line in the inner region of the figure; the numeric values for the line are shown on the right vertical axis.

A line and bar chart plots percent increase from prior year and numerical increase in millions from prior year.
Figure 1.2:

Yearly numerical and rate of growth of the human population of the world since the mid-twentieth century

Source: Data from United Nations; calculations and graph by author (see note 34 in this chapter).

Figure 1.2 tells us that the world has had a gain of no less than 79,000,000 people each year since 2000; in the latest year, which covers mid-2019 to mid-2020, the gain exceeded 81,000,000 people. Figure 1.2 also reveals that numerical growth can be substantial even though the growth rate is falling. Indeed, during a period in the early twenty-first century, numerical growth increased while the growth rate decreased. The reason for this divergence is mathematical—the size of the base to which the yearly growth rate applied was becoming larger, and the enlargement of the base more than made up for the reduction in the growth rate.35

1.3.2 Numerical growth of the human population and the total fertility rate

Figure 1.3, like Figure 1.2, includes the number of people added annually to the population of the world, but Figure 1.3 substitutes the total fertility rate (TFR) for the rate at which the number of people grew. In Figure 1.3, the hollow circles connected by the solid line in the inner region represent the TFR, and the right vertical axis displays the numeric values of the TFR. Figure 1.3 uses data published by the United Nations Population Division.36

Perhaps surprisingly, the TFR, despite being a popular demographic measure of childbearing, is often misunderstood. In particular, the TFR is frequently thought to be completed family size for a given year, that is, the number of children born to the average woman who exited her childbearing period in that year. The latter number (completed family size), however, is supplied by the Cumulative Birth Rate, not by the TFR.37 The TFR is the number of live births that the average female in a cohort of females that enters its childbearing period in a particular calendar year will have over the course of the childbearing period of the cohort, but the calculated number of births (that is, the TFR) comes with qualifications — the average female is assumed to survive to the end of the childbearing period of her cohort, and as she moves through the childbearing period, she is assumed to experience at each age the fertility rate that prevailed during the calendar year in which her cohort began its childbearing period. The fertility rate at each age is known as an ‘age-specific fertility rate,’ and since the childbearing period of a woman is generally assumed by demographers to start at age 15 and last through age 49,38 the TFR is based on—or, more exactly, is the sum of—35 age-specific fertility rates. The TFR is thus a projection of ‘the mean number of children who would be born to a woman during her lifetime, if she were to spend her childbearing years conforming to the age-specific fertility rates that have been measured in a given year’39 and lives until her 50th birthday, the age when and after which the incidence of childbearing is presumed to be zero. As the TFR considers the age-specific fertility rates in a particular year to remain constant over time, the TFR is a measure not of actual fertility but, rather, of the fertility that would occur under an unchanging set of age-specific fertility rates, viz., the rates that obtained in the year for which the TFR is calculated. Of course, age-specific fertility rates vary from one year to another, and hence the TFR will differ between years.

An understanding of what the TFR measures (and does not measure) may be facilitated by an illustration of how the TFR is calculated. To show the calculation procedure, I use data for the world as a whole during the time interval 2010–2015. The first column of the three columns in Table 1.1 lists five-year age ranges (rather than single years of age) in which females are assumed to be capable of bearing children. For each of the five-year age ranges, the second column presents estimates, published by the United Nations Population Division, of the mean fertility rate in the world as a whole.40 The third column, which is based on the second column, reports the aggregate fertility rates within each age range. Because every age range in the example includes five years (seen in column 1), the rates in the second column were multiplied by five to obtain the rates in the third column. The third column thus supplies global age-specific fertility rates in 2010–2015 for all females in the five-year age ranges of the childbearing period, that is, shows the number of births per 1,000 childbearing-capable females during 2010–2015. As the third column reveals, the TFR, expressed as the projected mean number of lifetime live births to females whose fifteenth birthday occurred during 2010–2015, was 2,517 live births per 1,000 women, or 2.517 live births per woman.

Table 1.1:

Total fertility rate (illustrative calculation)

Age range Number of births

per 1,000 females (mean of age range)
Number of births per 1,000 females

(all ages in age range)













Σ = 503.4







Σ = 2517.04

The preceding discussion may help the reader to interpret the TFR and Figure 1.3. The TFR is shown in Figure 1.3 for the midpoints of successive five-year intervals, with the first TFR being at the midpoint of 1950–1955, the second TFR being at the midpoint of 1955–1960, and the last TFR being at the midpoint of 2015–2020. As the figure reveals, the TFR of the world population is much lower today than it was in the middle of the twentieth century: In the early 1950s, live births per woman were projected to be roughly five, but just seven decades later, a woman was projected to produce only half this number of children. Nonetheless, the long-term downward trend in the TFR from the midpoint of the last century to the present time has not prevented yearly growth of the world population from being large and becoming larger.41 For example, during the 1950s, world population grew by less than 54,000,000 people annually; from 2005 onward, growth has exceeded 80,000,000 people annually.

A line and bar chart plots total fertility rate versus years and numerical increase in millions from prior year versus years.
Figure 1.3:

Yearly numerical growth and total fertility rates of the human population of the world since the mid-twentieth century

Source: Data from United Nations; calculations and graph by author (see notes 34 and 36 in this chapter).

To understand the substantial growth of the global population, a further aspect of the TFR must be kept in mind: A particular numeric value of the TFR does not by itself reveal whether a population is at, above, or below ‘replacement-level fertility,’ that is, the mean number of live births per woman that eventually produces a stable population size.42 The exact mean number of live births per woman at which a population will stop growing can differ across populations and across time, that is, can differ between two or more populations at a single point in time and can also differ within a single population between two or more points in time. Such differences are possible because whether a population replaces itself does not depend solely on childbearing. Population replacement in a society depends, too, on (1) rates of mortality among females before the age at which childbearing is presumed to end and (2) the ratio at birth of the number of males to the number of females, that is, the sex ratio.43 A mean of two live births per woman is replacement-level fertility when, and only when, (1) females do not die before the aging process takes them out of the demography-defined childbearing period and (2) equal numbers of females and males are born.44 Of course, neither of the foregoing happens in reality: Not all females survive until the end of the childbearing period, and males outnumber females at birth.45 A demographic estimate of the replacement-level fertility rate for a population at a particular point in time, therefore, must employ age-specific fertility rates, female mortality rates, and the sex ratio at birth in the population at that time.46 If the foregoing factors remain constant over an extended period, a population in which the TFR is equal to the replacement-level fertility rate will become numerically stable.47

Essentially, then, the replacement-level fertility rate, like the TFR, is an assumption-grounded prediction, and since demographic change usually occurs slowly in the human species, a human population will normally not become numerically flat in a short span of time. The human population of the world, in other words, will probably not reach a numerical plateau in the immediate future. The continuation of human-population growth may be surprising given the increase that has been occurring in the share of the world population that has a TFR no higher than its replacement-level fertility rate.48 Such surprise, however, comes from an optimism that, regrettably, appears to be unwarranted.

1.3.3 Future numerical growth of the human population

As we have seen, the number of human beings who live on planet Earth has not stopped its upward climb, and the magnitude of the climb has been substantial. Figure 1.4 shows that additions to human-population size are likely to be large over the next several decades, too. Figure 1.4 is based on data from the United Nations Population Division and portrays world population growth over each ten-year interval from 2020 to 2050—intervals that are not far in the future and hence are reasonably predictable. The figure was developed using the estimate of world population size in 2020 and projections of future growth in the size of the population to the year 2050.49 From the projections, I calculated the average yearly numerical increase in population that was forecast for the decade of 2020 to 2030, for the decade of 2030 to 2040, and for the decade of 2040 to 2050. The calculations for each decade employed three projections (or ‘variants’) of world population growth, viz., low, medium, and high.50 Figure 1.4 graphs the results of the calculations. The bars in the inner region of the figure, together with the left vertical axis, show the mean number of people predicted to be added annually to the population of the world during the decade that precedes the year designated on the horizontal axis.

A bar chart plots mean annual in millions last ten years versus years.
Figure 1.4:

Projected average yearly numerical increase of the human population: world, 2020 to 2030, 2030 to 2040, 2040 to 2050

Source: Data from United Nations; calculations and graph by author (see note 49 in this chapter).

As Figure 1.4 makes plain, the forecasted yearly additions to the global population in coming decades are sizeable: Even though the magnitude of the additions will decrease, the human population will grow significantly. For example, during the last decade covered by the figure (that is, 2040 to 2050), the average yearly addition is predicted to be around 40,000,000 under the low-growth scenario, nearly 54,000,000 under the medium-growth scenario, and over 68,000,000 under the high-growth scenario.

The projections in Figure 1.4 involve large numbers of people, but might the projections be too high? The future is always subject to uncertainties, of course, and one that is pertinent here results from the ongoing COVID-19 pandemic.51 The projected increases that are graphed in Figure 1.4 are derived from mid-year population sizes, and the last estimated (that is, as opposed to projected) mid-year population was for 2020,52 shortly after the inception of the pandemic. Importantly, the vast majority of confirmed deaths attributed to COVID-19 happened subsequent to July 1, 202053 and thus might significantly reduce population growth in years after 2020. However, the increase in mortality due to the pandemic may be followed by a post-pandemic rise in fertility: The pandemic and its appreciable impact on human mortality54 constitute a major, though presumably short-term, disruption of social life, and such a disruption may lead to an increase in childbearing.55 An appreciably larger volume of disruption-caused childbearing can, in turn, have an impact on population size if this delayed childbearing more than makes up for the births that would have happened earlier, that is, is responsible for a final number of births per woman that exceeds the number that would have occurred in the absence of the pandemic.

1.4 A concluding comment

As Chapter Two elaborates, numerical additions to the population of Homo sapiens harm both the biosphere and human societies. The harms will not be prevented by an ostrich-like response to the situation, however, because even with innovations in technology and changes in consumption styles that reduce the biospheric effect of the average individual, humankind in the aggregate is outstripping the ability of the biosphere to provide for its needs. ‘[T]he overall condition of the global environment has continued to deteriorate’ over the last two decades, the United Nations Environment Programme observed in 2019, and projected decreases in demand ‘for key environmental resources … will be inadequate to reduce the pressure on already-stressed environmental systems.’56 The extent to which demands have been placed on the environment is indicated by the emergence of efforts to mine minerals on objects in space (for example, asteroids),57 but even mining in space appears unlikely to forestall problems other than shortages of (some) mineral resources. Based on available evidence, the problems are becoming more probable and their potential severity is increasing. They may, moreover, have no easy solutions. As a result, the problems may force human societies to decide between courses of action that differ only in the type and/or harshness of their negative repercussions. The human species, in short, is going beyond simple risk-taking; it is gambling and does not understand that gamblers must ‘decide upon three things at the start: the rules of the game, the stake, and the quitting time.’58 Homo sapiens is not in control of either the first or the second of these requisites, and seems unmindful of the third.

  • View in gallery
    Figure 1.1:

    Pressure of Homo sapiens on the biosphere: world, 1961–2018

  • View in gallery
    Figure 1.2:

    Yearly numerical and rate of growth of the human population of the world since the mid-twentieth century

  • View in gallery
    Figure 1.3:

    Yearly numerical growth and total fertility rates of the human population of the world since the mid-twentieth century

  • View in gallery
    Figure 1.4:

    Projected average yearly numerical increase of the human population: world, 2020 to 2030, 2030 to 2040, 2040 to 2050

Content Metrics

May 2022 onwards Past Year Past 30 Days
Abstract Views 5 5 0
Full Text Views 19 19 8
PDF Downloads 22 22 11