How Do Environmental Historians Think About Population in the Anthropocene?

The Anthropocene, in this chapter at least, refers to the period since the middle of the twentieth century, one of unusual turbulence in Earth history and the history of the global environment. In 1950, about 2.5 billion humans walked the Earth. By 2025, some 8.3 billion did. Human numbers grew at their fastest rate between 1963 and 1968, topping 2 percent annually. Many scientists and scholars concluded that the growth surge in human numbers accounted for global environmental turbulence. 

Environmental historians, by and large, have seen matters differently. An academic tribe that came into existence only in the 1970s, and therefore children of the Anthropocene, environmental historians have attached comparatively little significance to population growth as a driving force of environmental change. That holds true for their work on any time period, including the Anthropocene. In this chapter, I will support that claim by reference to Anglophone big-picture environmental history and will speculate about the reasons environmental historians prefer to rely on other explanations for environmental changes. I will end by summarizing my own thoughts on the significance of population for environmental history. 

The earliest overview of global environmental history was the only one to award population a central role. Clive Ponting, a Foreign Office mandarin and popular historian writing in the late 1980s, gave population explanatory weight when considering medieval woodland clearances in Europe and nearly the whole range of environmental changes since 1800. As he reached the end of his book, in a passage surveying the entirety of human history, he seemed even more impressed by the significance of population growth: “Overwhelmingly the most important departure from basic ecological constraints has been the increase in human numbers beyond the level that could be supported by natural ecosystems” (Ponting 1991, 120–21, 240–66, 393–95, quotation 393). 

Professional historians in his wake were less impressed by what Ponting (1991) called “the weight of numbers.” J. Donald Hughes, a historian of the ancient Mediterranean, attributes environmental change to population growth when discussing the ancient Maya, medieval Europe, Polynesian expansion, and the “contemporary” (he wrote in the late 1990s) world. Nowhere did Hughes give it the significance that Ponting did (Hughes 2001, 42–48, 85–87, 115–18, 210–22). Joachim Radkau, also writing in the late 1990s, mentioned population in passing several times, but never emphasized it in accounting for environmental change (Radkau 2002). Felipe Fernández-Armesto published a much longer global environmental history in the same year as Hughes, but said much less about population in it. He mentions it only rarely in passing, never giving it causal importance. When he comes up to the present, he finds anxiety about population growth unwarranted, noting that it has slowed considerably since its peak (Fernández- Armesto 2001, 175, 216, 458–59). 

It took nearly two decades before another flurry of global environmental histories appeared. Daniel Headrick, primarily a historian of technology, touched on population sparingly in his global environmental history. He considered it important in driving the spatial expansion of Neolithic farming and as a result (not a cause) of twentieth-century irrigation agriculture. Headrick’s passages on population focus on epidemics and population decline as often as on population growth (Headrick 2020, 93–94, 307–11). Peter Frankopan, a Byzantinist turned world historian, discussed population in his global environmental history survey only as a subject of anxiety among late twentieth-century observers, notably Paul Ehrlich (Frankopan 2023, 582–86). Frank Uekötter, whose prior work focused on Germany and the United States, published a sprawling global environmental history that mentions population only in the same way as Frankopan, pointing out how “delicate” discussions of population growth were (Uekötter 2023, 502). Sunil Amrith, a specialist on the modern Indian Ocean world, whose global environmental history was published almost the same moment as Frankopan’s and Uekötter’s, did a little more with population. He provides figures at various points, details the post-1945 surge in global population, and notes at several points the importance of quests for food and expansions of agriculture in disrupting environments (Amrith 2024, 248–49, 295, 335).

Interestingly, the most recent general overview of world environmental history breaks with the trend of the past twenty-five years and ascribes much greater importance to population growth. In 2025, one of the pioneers of US environmental history, Donald Worster, turned his hand to global-scale environmental history. For decades, in his classic works on the Dust Bowl and irrigation in the US West, Worster emphasized what he called the “culture of capitalism” as the key variable behind environmental change. But in his first genuinely global work, one that spans millennia, he finds that ordinary animal ambitions, quests for food and sex, are at the root of all history, including that of environmental change. Population growth plays a much larger role in his narrative than in any of the global overviews since Ponting’s (Worster 2025). 

All these works present visions of global environmental history extending back at least to the dawn of agriculture, with the exception of Amrith’s, which modestly surveys only a millennium. John Richards also wrote a global environmental history, albeit of a mere three centuries (1500 to 1800). He touched on the history of population growth in specific regional contexts, such as Japan, China, Britain, and Mexico. Like many others, he saw it as significant in driving the spatial expansion of agriculture at times, but no more than that (Richards 2003, 112–15, 162–63, 205–06, 372–74). A few geographers, most notably Ian Simmons, also wrote global environmental histories. Simmons wrote much more about population, of human and other species in his efforts to present explanations for environmental change (Simmons 1989, 2008).

China, until recently the most populous country in the world, is a plausible place to look for environmental history that comes to grips with questions of population size and growth. Chinese population data are fairly good, and official censuses date back to the Han Dynasty. The Chinese intellectual tradition has included a component of population anxiety, although not (so far as I know) with respect to environmental concerns, since at least the late eighteenth century. In the 1790s, both Hong Liangji (1746–1809), a member of the literati class, and even the Qianlong Emperor himself expressed concerns that the population was growing so fast that hunger might result. General studies of Chinese environmental history (in English) include those by Robert Marks (2012), which begins with the first human occupation of the land; Mark Elvin (2004), which explores primarily the centuries between 1000 and 1800; Stevan Harrell (2023), which covers the post-1949 era in detail; and Judith Shapiro (2001), on the Mao years (1949–1976). Both Marks and Harrell attribute major significance and devote considerable attention to population growth and size. They consider it in connection with agricultural expansion and urbanization, among other ways. Elvin does not dwell on population, nor does Shapiro. Both prefer to see the efforts of the state as the crucial variable shaping environmental history in China. Worster (2025), however, who in his global overview pays great attention to China, is much more ready to attribute a leading role to population growth in Chinese environmental history. 

India, now the most populous country in the world, lacks good historical data on population size and growth before the 1860s. That might help to account for the lack of interest shown by those environmental historians who have attempted broad syntheses of the subcontinent’s experience. The density of pedestrians on New Delhi’s streets helped to inspire Paul and Anne Ehrlich’s (1968) influential screed against population growth, but working, living in, and writing about India had no such effect on environmental historians. The pioneering synthesis, Gadgil and Guha (1992), attributes no importance to population and mentions it only in passing. Trautmann (2015), whose work is mainly on ancient India, for which population data are negligible, says next to nothing about population. The same is true of Fisher (2018), even though his book includes the last two centuries, for which reasonably reliable data are available. Habib (2010) gives population data and estimates some attention without saying whether or not population mattered for the environment, although perhaps we can assume he thought it did, because he treats it head-on. Population does not figure among Chakrabarti’s Critical Themes in Environmental History of India (2020), which takes up pollution, forests, wildlife, and policies related thereto. 

While indeed environmental historians are unlikely to say much about or attribute much importance to population size or growth, that contrasts sharply with environmental writing more generally. Since the 1940s, jeremiads concerning the parlous effects of population growth on the environment, globally, regionally, and, more rarely, locally, have come thick and fast. Why might environmental historians, on the strength of this sample, dissent?

One plausible explanation is that a large proportion of environmental history focuses on eras in which population growth was not conspicuous or indeed was negligible. Population concerns often did not turn up in the documents on which historians typically rely. This would be true of just about everywhere prior to 1800. States responsible for creating and archiving documents were more often concerned that they had too few taxpayers and conscripts, rather than too many mouths to feed.

Moreover, a significant proportion of environmental history treats times and places that are without reliable population data, as noted above with respect to India, making it hard to argue for the significance or insignificance of population matters with respect to the environment or indeed to anything else. This data deficiency is strong for precolonial Africa and Southeast Asia, where documentation on everything is scant and archaeology is thin. But the deficiency is pretty strong for many parts of the world before 1800, least so probably Europe and China. In many cases, archaeology alone, lately buttressed by paleogenetics, provides population estimates—but saddled with vast error terms.

In addition, the interests of many environmental historians steer them in directions other than population. Roughly one-third of environmental history treats the history of ideas about humans and nature, and those ideas, prior to the late 1940s, almost never included considerations of population growth or size. Thus, colleagues have carefully parsed the output of George Perkins Marsh or John Muir and found little to nothing about population. Of the ten figures profiled in Ramachandra Guha’s (2025) study of Indian environmental thought, only Radhakamal Mukerjee (Bengali sociologist, 1889–1968) and K. M. Munshi (Gujarati politician and novelist, 1887–1971) seem to have regarded India’s population size or growth rate worthy of consideration. 

Another sizeable chunk of environmental his-tory work concerns policy, law, regulation, and attempted administration of the relationships between humans and nature. This subset, then, is about efforts to remedy perceived problems. It mainly concerns the last sixty years and those societies that have most eagerly embraced environmental regulation. In these last six decades, those societies, primarily in Europe, North America, and Japan, have been among those with the slower-growing populations, and so those debating policy, laws, and regulations have rarely foregrounded population as opposed to industrial pollution, environmental health, or conservation. Perhaps because regulating population growth or size appeared both difficult and controversial, the politicians, bureaucrats, think tankers, and so forth, whose pronouncements provide the source material for this sort of environmental history, set it aside, whatever their beliefs on the matter may have been. And so this variety of environmental history has also found little to say on the subject.

However, that still leaves a substantial portion of environmental history that tries to explain environmental changes themselves and focuses on themes such as forests, soils, land use, pollution, fisheries, wildlife abundance, climate, and so forth. Authors laboring in these vineyards are more likely to take up population than those focused on ideas or policy, but still far from sure to do so. In some cases, that is likely so for the reasons noted above, the lack of data or of concern about population in the times and places under study. It may also be the case that authors simply don’t consider population growth or size significant and feel no compulsion to say anything about things they judge unimportant. But one cannot dismiss the possibility that scholars fear the response of readers should they attribute environmental significance to population growth or size, because that invites the neo-Malthusian label and sometimes intimations of dark motives. Few environmental historians wish to be painted as unsympathetic to the fast-growing populations of the world, who are, for the most part, poor and exploited.

Questions of the environmental consequences of population growth or decline are not the only ones one can ask. Environmental historians have given little—too little—attention to the consequences and causes of large flows of migration. The environmental impacts of a Salvadoran family in El Salvador are quite different from their impacts if they leave home for the suburbs of Washington, DC, as several thousand have done. Something similar may be said of Filipino migrants to California, Northern Europeans who migrated to Southern Brazil, or Russians who moved to the Russian Far East. Conversely, environmental changes may spur migrations (Armiero and Tucker 2017). 

The influence of environments on population history has garnered no more attention in environmental history than the influence of population on environments. Practitioners of environmental history, by and large, are sensitive to the charge of environmental determinism. Most of us, however, probably accept that deserts (without massive irrigation) are likely to have supported only low population densities and that well-watered, fertile lands supported higher densities. In this general sense, we are almost all comfortable with the banal reality that environments have influenced population size. 

Beyond that, environmental historians on the whole are content with the observation that changing environments often changed population trajectories at local and regional scales. Climate change and the retreat of polar ice sheets at the end of the Pleistocene opened far more of the Earth to human habitation and invited population growth. The several early transitions to farming all accelerated population growth while hampering human health. Soil salinization in ancient Mesopotamia (ca. 1900 BCE) checked growth and perhaps instigated decline. The adoption of specific crops such as rice (with high per-hectare yields and high labor requirements) changed both landscapes and, indirectly, population size. The spread of malaria to various lowlands constrained population growth, and the eventual control or elimination of malaria in modern times unleashed it. Improved sanitation after 1870 or so provoked hitherto unachieved population growth and size in cities, enabling the rapid urbanization of our species. The chemicals and novel crop variants of the Green Revolution increased global agricultural output by about one-third (since 1960), without which the global population could not have attained 8.3 billion. By and large, beyond the banal, it is with respect to agriculture and disease environments that practitioners of environmental history seem likeliest to suggest that environments have affected population.

For my own part—and here at last I feel on firmer ground—I think my own view of the significance of population in environmental history evolved early in my career and then more or less froze. When I first came to environmental concerns in the 1980s, I assumed that population growth was a cardinal variable, important almost always and everywhere. I was loosely familiar, like billions of others, with the anxieties surrounding population growth. My initial foray into environmental history (McNeill 1992) concerned mountain villages around the Mediterranean; that research underscored this belief, but with the proviso that I came to consider population decline as well as growth as sources of environmental destabilization. That resulted from visiting scores of communities on sloping terrain where rural exodus had left insufficient labor power to maintain terraced hillsides and, in some cases, delicate irrigation networks, such as the Alpujarra of southeastern Spain. Terraces and irrigation channels fell to ruin, and soils washed down to the plains or out to sea. 

Preparing to write Something New Under the Sun (McNeill 2000), which took me out of the unrepresentative environments of the upland Mediterranean, fundamentally changed my mind. After a few years of thinking about other places around the world, where rural exodus and terraced agriculture were either absent or insignificant, I ended up with a different view, one that I still hold without much modification (McNeill 2006; McNeill and Engelke 2016; McNeill 2026). 

In the first place, it now seems to me, there is little utility in trying to evaluate the significance of population for the environment holistically, either historically or in the present moment, because while population size and growth rate may be (in fortunate cases) accurately measured, “environment” is a concept that enfolds many different things, from coral reef health to stratospheric ozone concentrations. To get anywhere, it is necessary to unpack the term and concept “environment” into manageable and measurable, or at least estimatable, parts, and to consider the specifics of various settings. As historians go, I am partial to generalization and synthesis, but in this case find it unhelpful. 

Just how population growth or decline affects environments depends on many things, including preexisting population densities, the resilience of ecosystems, the technologies in play, and which parts of “the environment” are under consideration. The drastic depletion of several species of whales since 1900 has next to nothing to do with population size or growth rate (indeed, the most enthusiastic whaling nations during the period of sharpest decline, from 1946 to 1985—Norway, Iceland, Japan, and the USSR—have been among those with the most stable populations). The quantities of nuclear waste in the world have little to do with population size or growth. The same is true for the robustness of the stratospheric ozone layer. In these latter two cases, new(ish) technologies and their uptake by governments and companies are far more important than population. However, most deforestation in world history, at least until the 1960s, has been driven by population growth and the impulse to clear more land in order to grow more food crops. 

The circumstances under which population growth is most environmentally consequential are probably those of novel settlement, when people first arrived somewhere. That is because population growth starts from zero. A good example is New Zealand, where humans first landed about 1250 CE and disrupted what had long been an isolated sanctuary for Cretaceous period lifeforms. The Maori population appears to have grown quickly over two or three centuries, during which it depleted the easily hunted and collected food supply and drove some species, most famously the moa, to extinction. The initial settlement of the Americas, at least 15,000 years ago, also seems to have led to mass extinctions. In both cases, the technologies involved—fire, spears, clubs—did not greatly amplify a single human’s impact, at least not by modern standards. Thus, in New Zealand and the Americas, the difference between the tiny initial population and that achieved several centuries later proved powerful. So did prey species’ inexperience with the risks posed by teams of intelligent, weapon-wielding, human hunters. 

The circumstances under which population growth is least disruptive probably occur wherever intensive labor is required to counter some prior human environmental impact. For example, in hilly landscapes, when people first start to farm, they often trigger rapid soil erosion, as in the case of the Machakos Hills in Eastern Kenya. After some generations, however, population growth can, and in the Kenyan case did, yield enough labor power to build and maintain terraces, checking soil erosion. In these settings, as in the Spanish Alpujarra in the late twentieth century, it is population decline, rather than growth, that is most disruptive. Maintaining the terraces of the Andes, Java, or Southern China without dense populations and abundant labor would be close to impossible. The same is true of intensely irrigated landscapes that require regular maintenance. In short, places that feature what scholars sometimes call “landesque capital” are subject to dramatic environmental change—and from the human point of view, degradation—when labor runs short. 

Examples extend beyond mountain terraces and irrigated lands. Everywhere that painstaking labor had created landscape equilibria (among soils, waters, and biota), population decline proved destabilizing. Returning to East Africa: by the late nineteenth century, people had learned how to contain the domain of the tsetse fly, and thereby trypanosomiasis, by judicious bush burning, which restricted tsetse habitat. However, a catastrophic rinderpest epidemic swept across East Africa in the 1890s, killing upward of 90 percent of cattle and bringing famine to pastoral populations. With fewer people (the Maasai lost as much as two-thirds of their numbers to starvation), the practice of regular bush burning collapsed, woodlands encroached on grasslands, tsetse habitat expanded, and trypanosomiasis flared up into both epizootics and epidemics lasting into the 1930s. Such examples, which could be multiplied indefinitely, show that no simple formula (e.g., more people, more environmental change) can fit every situation. 

With respect to the twentieth century, I claimed that taking all aspects of the environment together, by far the most important variable in generating the tumultuous environmental epoch now often called the Anthropocene was the energy system, which was and is 75 to 85 percent based on fossil fuels. This was a judgment, not a calculation. I still think it is correct and that population growth and size are of lesser importance—but far from trivial for some varieties of environmental change. For instance, the proportion of land occupied by dwellings and roads is probably powerfully affected by population levels. Until the late nineteenth century, so were the quantities of water pollution derived from human wastes. (Now, sanitation technology matters more.) For carbon dioxide loading of the atmosphere, the chief driving force behind the dominant environmental concern of the twenty-first century, I estimated (McNeill 2000, 272–73) that population growth accounted for about one-fifth of the additional CO2 (1890 to 1990), and again for the years 1900 to 2025 (McNeill 2026, 270). Others, working only with data from the late twentieth century—when the rate of population growth peaked—calculated a proportion of around one-third. I still think much the same way about the twentieth and twenty-first centuries: energy systems have been the primary source of turbulence, more so than population growth, ideologies, geopolitical rivalries, or anything else, although all those things (and more) have mattered. 

The emphasis I placed on the fossil-fuel-based energy systems contrasts with what I judge the majority view among environmental historians, a view that puts capitalism at the center of explanations for modern—which can mean post-1450 or post-1800 in this context—environmental turbulence. I dissented in 2000 and still do, on the grounds that what I chose to call “the growth fetish” of modern societies was characteristic, if not quite universal, regardless of the prevailing system of political economy or ideology. It derived more from geopolitical rivalry than from anything else. Seow’s (2021) study of a giant coal mine in Manchuria, which at various times was run by Chinese nationalists, Japanese imperialists, Soviet communists, and Chinese communists, is an elegant inquiry into the matter. He finds that everyone ran the mine roughly the same way, exploiting workers and damaging the surrounding environment in their common quest for more coal. 

In Anthropocene conditions, where population densities are already high (by historical standards), it could be that the impact of further population growth would be different from that in the past: the addition of another 2 billion might trigger some nonlinear response in the Earth system that adding the previous 2 billion did not. Dire predictions were once commonplace, but thus far have not come to pass. If they do come to pass, we should know soon. That is because, if the demographers’ crystal ball is in good repair, global population growth will likely cease by 2070 or so. 

At that point, scenarios of environmental instability associated with population decline will be more likely than any linked to population growth. Those scenarios are likely to play out locally in the form of resurgent vegetation and wildlife, accelerated destruction of landesque capital, and other local trends, rather than posing hazards on grander scales, that is, for the governing biogeochemical cycles of the Earth or for climate.