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Original Essays

Too Many of the Dominant Animal?

by Paul and Anne Ehrlich
  1. The Dominant Animal: Human Evolution and the Environment
    $11.95 Used Hardcover add to wishlist

    The Dominant Animal: Human Evolution and the Environment

    Paul R. Ehrlich and Anne H. Ehrlich
    "Though hopeful that...widespread transformation is possible, the Ehrlichs contend that it's only the encroaching crisis that will inspire it — unless, that is, this fascinating, inspiring book gets the wide audience it deserves." Publishers Weekly
  2. The Stork and the Plow: The Equity Answer to the Human Dilemma
    $6.95 Used Trade Paper add to wishlist
    "This ambitious, enlightened handbook is a cornucopia of strategies and ideas for concerned citizens and policymakers." Publishers Weekly
  3. One with Nineveh: Politics, Consumption, and the Human Future
    $10.95 Used Trade Paper add to wishlist
    "The Ehrlichs manage to be both meticulous and witty as they suggest reforms and remind us that ours is an astoundingly adaptive species capable of making radical change once we're motivated." Booklist
  4. Human Natures: Genes, Cultures, and the Human Prospect
    $7.50 Used Trade Paper add to wishlist
    "I doubt whether anyone will write as good a book of this sort on [human evolution] for another two or three decades." Science
It's been four decades since The Population Bomb was published in May of 1968, and we've recently had occasion to revisit the topic of the human future. Writing our new book, The Dominant Animal: Human Evolution and the Environment, which tells where humanity came from and where we think civilization is currently headed, gave us the opportunity to reflect on how the human prospect has changed in the last 40 years.

While The Population Bomb was often credited with igniting the debate on overpopulation and raising the world's environmental consciousness, others have not seen it so positively. Leading political conservatives labeled it among the "most harmful" books of the last two centuries — along with Charles Darwin's The Origin of Species and Rachel Carson's Silent Spring.

It's an honor to be in such company, but in truth the Bomb was flawed; it was, overall, too optimistic about our future, as we detail in Dominant Animal. But it was too pessimistic in one area. In 1968, given high rates of population increase, agriculturalists feared population was outstripping food capacity and large-scale famine would result. Following their lead, we underestimated how quickly farmers in developing nations would adopt "green revolution" agricultural technologies. They increased production at least in the short term, and there were fewer deaths than anticipated. Nonetheless, at least 200 million people have died of hunger and hunger-related diseases since Bomb was written. Since then, the world's population has nearly doubled, from 3.5 to 6.7 billion people, an increase we thought unsupportable 40 years ago. Why, then, do we say we were too optimistic overall?

A quick look at today's headlines tells part of the story: accelerating climate change, dramatic increases in the prices of energy and essential food staples, growing conflicts over water, and much more. The Population Bomb may have not had the timing of future events exactly right, but its principal flaw was a failure to see how much trouble we were already in — a central issue we take up in Dominant Animal. When Bomb was written, carbon dioxide was the only greenhouse gas to be reckoned with (the roles of methane, nitrous oxide, and chlorofluorocarbons were not recognized until a decade later), and most climatologists thought the effects of climate change would take place over hundreds, perhaps thousands, of years. The book noted, however, that exploding human populations were adding vast amounts of gases and materials to the atmosphere and that the results "could be catastrophic." Now, as we show in Dominant Animal, global climate change is a far more immediate problem than we could have envisioned then.

World-renowned scientist James Lovelock, who invented the apparatus that allowed discovery of the threat to the ozone layer and saved civilization from collapse, recently stated: "We have grown in number to the point where our presence is perceptibly disabling the planet like a disease." Nevertheless, there have been some remarkable advances on the population front. Birthrates have fallen in most of the world, including both industrialized and developing regions, in the latter largely in response not only to economic factors but to government-sponsored programs providing education and opportunities (especially for women) and making contraceptive information and materials available.

The big exception to this is the United States, the leading center of overconsumption, which continues growing because of relatively high birth and immigration rates. The United States indeed has been in the peculiar position of hotly debating immigration policy without ever discussing population policy. Sadly, the United States has also been plagued by administrations, first under Ronald Reagan and George H. W. Bush, and then George W. Bush, that have encouraged high birthrates by refusing family planning aid to agencies that allow women access to safe abortion. Even so, the majority of developing countries have adopted population policies, and many have substantially reduced their fertility. Some high-consuming European populations have even started shrinking in size — ironically accompanied by complaints from the innumerate about "aging populations." That the change in age distribution is inevitable as population growth stops, and is often beneficial and easily managed, is ignored. So is the vast benefit of lessening pressure on our already battered life-support systems.

Thus, as we describe in Dominant Animal, a central goal of The Population Bomb, to encourage the adoption of policies that would gradually reduce birthrates and eventually start a global decline toward a population size that is sustainable in the long run, has been partially achieved. Rather than doubling the population in 35 years, as continued growth at the 1968 rate would have done, we may not reach that level, 7 billion, until 2013, 45 years later. If birthrates can continue being reduced, especially in very poor, rapidly growing populations in the developing world, an end to the population explosion may be in sight.

Despite this partial success, the importance of population growth in generating environmental and economic problems was largely forgotten after the initial drop in birthrates occurred in the early 1970s and is only gradually working its way back into public and political consciousness today. The depressing fact is that even with good news on the population growth-rate front, humanity may still add some 2.5 billion people to the population before growth stops and (we hope) a slow decline begins. Those additional people will have disproportionate negative impacts on our life-support systems. Our ancestors naturally farmed the richest land and used the most accessible resources first. Now people are increasingly forced to turn to marginal land to grow more food; and instead of extracting rich ores on or near the surface, deeper and much poorer deposits must be mined and refined, at ever greater environmental cost. Water and petroleum must come from lower-quality sources or deeper wells and be transported over longer distances. The environmental consequences of past and future population growth will haunt humanity for a long time, and the effects will be determined by how the present population and the future additions behave toward our common environment.

Although demographic trends are in the right direction, the list of new hazards that emerged after 1968 is alarming, all exacerbated by our species' large numbers. At that time Sherwood Rowland and Mario Molina had not discovered the end-of-the-world potential of CFCs. Norman Myers was a decade from calling world attention to the destruction of tropical forests, and even ecologists had not fully realized the impact of biodiversity loss on critical ecosystem services. Scientists had yet to discover the enormous threat posed by the distribution of novel hormone-mimicking pollutants, chemical compounds that may be more dangerous in trace than in high concentrations.

In recent years the connection between overconsumption and environmental deterioration has become increasingly clear, and many environmental scientists, including us, believe that overconsumption will prove much more difficult to cure than overpopulation. So far there are no consumption condoms or buying-spree morning-after pills. And, although Bomb discussed the increasing risk of novel epidemics associated with denser populations, malnutrition, and high-speed transport, AIDS, SARS, West Nile virus, and the like had not yet appeared, and the increasing failure of antibiotics due to the evolution of resistance in bacteria was not widely understood.

Today, the world is facing one of the most severe food shortages in modern history, and no second green revolution is in sight. Instead, humanity is paving over more farmland for "development" and converting staple grains to biofuels while climate change further undermines food production. And rapidly escalating demand for meat in countries such as China and India is putting further pressure on the capacity of humanity to produce and equitably distribute food. Loss of pollinators and natural pest-control services, the creation of oceanic "dead zones" by fertilizer runoff, and the effects of deforestation all imperil the quality of the human future. Indeed, the situation is circular: the single greatest threat from the climate change that agriculture is helping to cause is disruption of agricultural productivity as periods of more extreme droughts and deluges seem to be becoming the norm.

We face the very real prospect of more resource wars as ever larger populations struggle over dwindling supplies of oil and shifting patterns of water availability. The 1967 Arab-Israeli war was over water; the Iraq war was an attempt to keep oil flowing to our SUVs. The latter is particularly tragic, as petroleum is a resource we should be trying to stop using in an effort to avoid catastrophic climate change.

As scientists have repeatedly warned, we would need more than another Earth to support even today's population sustainably. There is simply no question that humanity has exceeded our only Earth's carrying capacity. While environmentally triggered collapses such as afflicted the Sumerians, the Classic Maya, and the Easter Islanders were once strictly regional, the potential today is for a worldwide catastrophe. As we explain in Dominant Animal, if we're to achieve a sustainable society we need to work much harder to end population growth and begin declining, to reduce wasteful consumption (especially of fossil fuels), and to basically reconfigure the human enterprise.

Global collapse is not a pretty prospect. Our very dominance as a species today threatens to be our own undoing. Only we can prevent that denouement.

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Paul and Anne Ehrlich are on the faculty of Stanford University. Their latest book is The Dominant Animal: Human Evolution and the Environment, just published by Island Press. More information is available at spacer

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