The Elephant in the Corner.

It is well established that environmental impact is determined by the number of people on the planet multiplied by their resource demands. Both factors contribute to total impact, roughly in a 1-to-2 ratio. Every day, we hear about reducing our resource demand—driving fuel efficient vehicles, eating less meat, and not watering your lawn. Nevertheless, for citizens in the developed world, deciding to have one less child reduces the emissions of greenhouse gases to the atmosphere about 20-fold compared to deciding not to own a car.

Advocates on the population side of the argument are curiously silent. This silence may stem from the Judeo-Christian ethic to be fruitful and multiply, from our roots in Darwinian evolution to maximize reproductive fitness, from a fear that Uncle Sam may pull open the window shades and peer into our bedroom, or from the inherent pleasure that young children bring to many parents. This silence seems destined to increase our environmental impact on a finite planet and thus make life miserable for a vast number of people.

Currently the world population is increasing at a rate of approximately 1.1 %/year, projected to carry us to 10 billion fellows by mid-century. Those who are silent on the problem of population growth like to point out that the rate of growth has slowed dramatically recent years, ignoring the fact that any rate above zero increases the total number of people. Each year the Earth adds 80 million more people—equivalent to adding a new Germany or two Californias to our resource demands. Roads and land clearance for housing progressively reduce natural habitat.

Population growth is not just a third-world problem—it’s a global problem. Population displacements from climate disruption, poverty, and conflict are likely to cause mass movements of people worldwide. Solving the problem is about the empowerment of women globally through education, opportunity, and access to family-planning options.

Solving the problem starts at home. We should speak out against the beliefs that allow children to increase the number of exemptions on IRS form 1040, that economic growth will be stymied without a growing number of consumers, and that a younger working generation is the only way to support Social Security for the rest of us.

I would argue that reliance on population growth is a hollow and blunt instrument to ensure economic growth, relative to innovation and improved efficiency that can ensure a better life for all by reducing our use of the Earth’s resources. Environmental scientists cannot be silent on this issue any longer. We will not see a sustainable biosphere with a rising human population.

Remember, the child that is not born has no environmental impact.



Ehrlich, P.R. and J.P. Holdren. 1971. Impact of population growth. Science 171: 1212-1217.

Schlesinger, W.H. 2015a.

Schlesinger, W.H. 2015b.

White, L. 1967. The historical roots of our ecologic crisis. Science 155: 1203-1207.

3 thoughts on “The Elephant in the Corner.

  1. In the US of the 1960s this commentary would have been unexceptional. LBJ said publicly that family planning in foreign aid saved $20 for every dollar put into it. Now, in an age of better education and communications, it’s rare even for NPR to mention family planning or limits to growth. Rather, the quest is for more economic growth, a suicidally deluded answer to the World’s problems.

    What caused the change? As LBJ predicted, the Civil Rights Movement caused the White South to become Republicans. The GOP began a march to the right, gathering as it went ever more racist, fundamentally religious, and poorly educated constituents. It grew increasingly dogmatic and belligerent, producing the corresponding shift from Nixon to Reagan to young Bush to Trump. It became easier to control the Senate and House, thereby shifting US politics and policy ever further to the right. US foreign policy followed by downplaying and reducing funding for population control.

    Democrats, now more consistently liberal, were forced to choose between their preferences and what would be necessary for election. Among those compromises has been to beware of abortion, sex education, family planning, and government involvement in social planning, all of which offend the more fervent conservatives. Liberal media have also shifted, for the same reasons. Little political discourse is devoted to the onrushing destruction of the ecosphere.

    What can be done about it? Lots; most of it not easy. The Blue Wave reaction to the excesses of the Trump era is beginning to turn the tide somewhat; no one knows how successful it will be in the long run. Climate change will also move the needle leftward, but too late to avoid enormous damage. The momentum of population growth, increased per capita consumption, and misapplied technology will cause great additional harm, including large-scale extinction, to the ecosphere. And the turmoil brought on by the ecological, economic, and political stresses of the population-resource imbalance will increase authoritarianism and undermine democracy, as it has been doing for years. Science can offer solutions great and small, but as a rational process it has to compete with powerful fears and feelings rooted in human evolution. There are hundreds of useful things that can be done on a local level; they need to be meshed with appropriate national and international efforts.

    The elephant in the room is giving us a choice: show respect, or get trampled.

  2. Hey there Dr. Schlesinger,

    I’ve always found the global population fear to be a bit antiquated. Why do you feel that advocating developed countries, most of whom have birth rates below 2 (2 being neutral since 2 children replace 2 parents), to have fewer children still is a proper way to address sustainability concerns? The U.S. has a birth rate of 1.886 ( and all European nations are below 2, with the highest, Ireland and France, having 1.98 and 1.973, respectively. In fact, many developed countries (Japan most apparently) are having huge demographic crises because of these declining birth rates. In a decade hence, if immigration were stripped out of the equation, it’s quite reasonable to predict that all of these countries would have fewer people – not more.

    I’m not arguing against your point directly. It’s apparent that the environmental impact of a developed country’s citizen far exceeds that of a developing country’s citizen. But I don’t think that there’s a rising population problem in these developed countries. If anything, there’s evidence to the contrary. What do you make of that?


    1. The largest part of the problem lies in the developing world, which has both high birth rates and a widespread desire to achieve “western lifestyles.” And, the population growth in many of the developed countries is higher than you suggest due to immigration of peoples from the developing world as a result of climate change, social unrest (including war) and limited food.

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