The Specter of Population Growth: Global Environmental Deterioration and the Ironies of History

As an archaeologist, anthropologist, and environmental scientist I am interested in the strategies people develop, individually and in groups, to interact with their social, political, and ecological milieu. The impact of population growth and density is a major consideration in such work, at least if one considers the genealogy of literature on this subject. Population growth causes people to adapt to their environment in particular ways, to expand their patterns of exploitation and to intensify them. Neo-evolutionary models of historical change also suggest that this relation between population size, density, and strategy fosters particular societal-wide responses, particularly increased complexity. A common narrative can be seen in the work of Julian Steward (1949), just to name one. Population growth eventually reaches a particular environmental threshold and carrying capacity. People then intensify how they adapt to produce more food. Often, especially in arid regions, this causes highly integrated adaptive strategies, like complex irrigation systems. Managers evolve to administer the new infrastructure and, over time, these managers become leaders and, if we follow Wittfogel (1957), kings and eventually despots.

However, population growth has taken on a new identity in current academic and popular debates on environmental change and global degradation. We are told that population growth, when unrestrained, has its limits. Once these limits are achieved, degradation ensues. This is a huge, common-sense notion. It pervades the writings of engaged journalists, such as the important work of Elizabeth Kolbert (2006), whose articles in the New Yorker have brought needed attention to global climate change. Other popular writers, like Jared Diamond (2005), also pull on the specter of population growth as a major variable in global deterioration. Garret Hardin’s (1968) now famous essay Tragedy of the Commons likewise suggests that population growth inevitably causes mismanagement, leading to tragedy for all.

This is, as many know, a basic proposition of Neo-Malthusian approaches on demographic change. Thomas Malthus argued that populations will grow geometrically (meaning exponentially), as a natural phenomenon, until they can no longer be supported. If you don’t know what exponential growth is, check out the applet on this website. The fundamental “check” on population growth is the finite productive potential of land and resources: “For Malthus, land...was an ultimate and inelastic constraint...a relatively inflexible environmental ceiling on population” (Netting 1993:276, 279). Malthus argued that the constant growth of population leads to increased work for fewer returns, misery, and eventually population decline or even collapse. Consequently, population growth is a threat not only to the survival of humanity but also to its moral fabric: “the superior power of population cannot be checked, without producing misery or vice, the ample portion of these too bitter ingredients in the cup of human life...bear too convincing a testimony (Malthus 1798:11).

Sounds pretty grim, eh? As an anthropologist, I study the flexible strategies people develop, and people tend to be pretty good at managing the sizes of their families and their environmental strategies. I recall Ester Boserups’ (1965) famous book where she flipped Malthus on his head: Population growth was the cause not the consequence of people’s adaptive strategies. This might not sound like a big contradiction but it is. Malthus thought that every technological shift would create more hungry people, causing more shifts. Boserup, instead, argued little about food and more about labor. People get less out of their work the more people they have working, so they intensify. The significance of Boserup is that people are not automatons but they adapt and innovate. 

That said, we are still left with the potentially parasitic notion of population.

A basic question then is the following: does increased population growth cause people to over-exploit and degrade their environment? This is an important historical question. It is caught up into debates in developmental policy since WWII. It is caught up in debates regarding the apparent “irrationality” of the economic behavior and family sizes of people living in peripheral nations, what used to be called the Third World. These people have too many children, thereby keeping them poor, we are told. Or they engage in irrational behavior. In terms of the latter, I am reminded of Marvin Harris’ (1966) famous article on the Hindu practice of ahimsa and not slaughtering cows in India. Sadly, the valid criticism of his hyper-deterministic perspective that relegated religion to an epiphenomenon obscures what his central message was: Stop calling these people irrational!

Unfortunately, demographic models of change are too ahistorical. They ignore how poverty is produced as a relation of inequality—increasingly global stratification—not population growth. It is a story we see in popular media and is one reinforced by socially sloppy scientists. It simplifies understanding and, in so doing, creates an inaccurate portrayal of historical reality. It blames. But it blames people long the victims of global power dynamics. This is as common in commentary about global development as it is in statements on domestic policy. The end result is a story that reinforces power differentials and blames the global poor for their poverty. I am constantly reminded of Amartya Sen's (1981) famous book on food, famines, and political economic entitlements (and by entitlements he doesn't mean social welfare programs but, rather, the institutionalized structures that support the interests of the wealthy). During the great Bangladesh famine in the 1940s, the military was mobilized. But they were not mobilized to distribute food but, rather, to protect the stocks of food sitting in stores owned by wealthy merchants.

I think there are some relatively easy ways to illustrate that degradation, waste, etc. are not positively correlated with population increase. One could, for example, consider U.S. agricultural subsidies. For example, between 1995 and 2010, the US government spent 77 billion dollars for corn production alone. Is this done because we have a lot more hungry corn eaters in the US? Of course not. The incredible corn surplus we use is connected to multiple international processes, particularly markets. One could say, well, this allows for the increased production of ethanol that, when added to gasoline, helps reduce our dependence on foreign oil. Perhaps. Another aspect of corn subsidy and surplus is the ability to flood other markets. NAFTA, for instance, greatly reduced the tariffs of US exports to Mexico (by about 1/3^rd, I think). This, of course, has several consequences. It reduces the market value of corn produced in Mexico. It makes farming less economically viable in Mexico. With 1992 changes to the Mexican constitution, indigenously controlled lands (ejidos) can now more easily be sold. Farmers slowly abandon farming. A huge irony I always note is that when you eat a tortilla in Mexico—the place where corn was born and where corn is a huge symbol of national identity (so much so that people will take to the streets shouting “Sin Maíz No Hay País”)—there is a good chance it was made with corn grown in the United States. What do unemployed farmers and their kids do? Well, some become immigrants to the United States. Others get involved in the drug trade. Another huge irony: two of the most common issues everyday Americans hear about Mexico on the news are directly the product of US foreign policy. Paul Robbins sums this process up in his introductory text on political ecology: "All of these spheres of activity are further arranged along linked axes of money, influence, and control. They are part of systems of power and influence that, unlike the imagined steady march of the population 'explosion,' are tractable to challenge and reform" (Robbins 2004:13).

I think there are other easy ways to illustrate the problems with blaming population increase so easily and ahistorically. Consider CO2 emissions. Within the past 50 years, CO2 emissions globally have increased dramatically. Check out the Keeling Curve below that demonstrates the increasing CO2 concentrations. Good evidence demonstrates a correlation between CO2 levels and global temperature. Check out the two diagrams from the Vostok ice core. You see clearly that CO2 and temperature are closely correlated for the past 400,000 years. One could say, well, it shows cycling and maybe we are just on an up-cycle. Perhaps, but consider this. If you compare the Vostok data with the Keeling curve, at no point in the past 400,000 years has CO2 concentrations been as high as they are now. Pretty scary.

Ok. Let’s go back to population increase. Let’s assume that CO2 levels are a product of wasteful, deleterious consumption strategies. I do not doubt that population growth plays a role here. But if population growth is the culprit of such waste, surely the countries experiencing more population growth are to blame, right? Check out the figure I made using UN population data. World populations are increasing dramatically. However, the “most developed” nations are not contributing to this process but “developing nations” are. In fact, the US is in negative population growth.

So, based upon the seemingly common sense view of population, shouldn’t global ecological deterioration be the fault of “developing nations”? Well, let’s consider CO2 levels as a proxy. Here is a map made (not by me) that has adjusted the spatial size of countries based upon their total CO2 output. 

Generally speaking, developed nations, not developing nations, produce far more CO2 levels. Now that is just total output. So we see China is a bigger culprit than the US. But what about per capita CO2 levels, which better reflect the actual consumption? Here is another color coded map clearly showing even more that developed nations share far more blame for global CO2 levels. 

In fact, US per capita CO2 emissions are at global levels. If you look at the Middle East, you see some countries, like Saudi Arabia, the United Arab Emirates, etc., with remarkably high levels. These levels have increased since the 1970s and, though I am not informed on this, are likely connected to the creation of OPEC in the 1960s.

Clearly, demography can’t be overlooked as a variable in global deterioration, but the processes of degradation, population, economy, and politics are far too complex and multi-scalar to simply equate everything to population. Doing so ignores history. Doing so is scientifically spurious. Doing so places the blame on the wrong shoulders.

Boserup, E.
1965 The Conditions of Agricultural Growth: The Economics of Agrarian Change under Population Growth. Aldine, New Brunswick. 

Diamond, J.

2005 Collapse: How Societies Choose or Fail to Succeed. Penguin, NY.

Hardin, G.
1968 The Tragedy of the Commons. Science 162:1243-1248.

Harris, M

1966 The Cultural Ecology of India's Sacred Cattle. Current Anthropology 7:261-276.

Kolbert, E.

2006 Field Notes from a Catastrophe: Man, Nature, and Climate Change. Bloomsbury. 

Malthus, T.
1798 An Essay on the Principle of Population, as It Affects the Future Improvement of Society
with Remarks on the Speculations of Mr. Godwin, M. Condorcet, and Other Writers. Electronic
Scholarly Publishing Project, http://www.esp.org.

Netting, R. M.
1993 Smallholders, Householders: Farm Families and the Ecology of Intensive, Sustainable
Agriculture. Stanford University Press, Stanford.

Robbins, P.
2004 Political Ecology. Wiley-Blackwell, Malden, MA.

Sen, A.
Poverty and Famines: An Essay on Entitlement and Deprivation. Clarendon Press, Oxford.

Steward, J. H.
1949 Cultural Causality and Law: A Trial Formulation of the Development of Early
Civilizations. American Anthropologist 51:1-27.

Wittfogel, K. A.
1957 Oriental Despotism: A Comparative Study of Total Power. Yale University Press, New
Haven.