Four Out of Five Scientists Agree: Population Matters

Robert J. Walker

Does population growth matter? Of course it does. It would be silly to suggest otherwise. We live on a finite planet with finite resources, and while humans may one day inhabit other worlds, less than .00001 percent of those living on Earth have a realistic chance of ever residing on another planet. The rest of us are stuck. So let’s face it, we are not getting out of this world alive, and today’s world, quite frankly, is not what it used to be.

A poll released this year by the Pew Research Center revealed an overwhelming majority of American scientists (82 percent) regard population growth as a major challenge, almost as many as those who believe climate change is mostly due to human activity (87 percent). The poll also discovered that a clear majority of Americans (59 percent) are concerned there won’t be enough food and resources to accommodate a growing world population, though the level of concern in the scientific community, as with climate change, is noticeably higher.

On one level, at least, the results are not surprising. For decades, scientists have warned that humanity is overusing planetary resources and inflicting dangerous harm on the environment. Earlier this year, eighteen scientists authored a paper in the journal Science warning that humanity is encroaching on nine “planetary boundaries” and has already crossed four: deforestation, the extinction rate for plant and animal species, the level of carbon dioxide in the atmosphere, and the runoff (from fertilizer) of nitrogen and phosphorous into the ocean. Their warnings are built upon an ever-growing indictment of what humanity is doing to the planet.

There is no shortage of jaw-dropping factoids to choose from. Here are a few worth pondering:

• About half the world’s tropical forests have been cleared already. The United Nations (UN) estimates that eighteen million acres of forest are lost every year, an area roughly the size of Panama.

• The rate of plant and animal extinction is about one thousand times higher than the natural rate. Scientists are calling it the “sixth mass extinction” in Earth’s history.

• For most of Earth’s recent history, our atmosphere has contained about 275 parts per million (ppm) of carbon dioxide (CO2). Today, we are at 400 ppm and climbing, a level that essentially locks in significant climate change.

• It is not just the atmosphere; we are also changing the chemistry of the oceans. The increase of CO2 in the oceans is, in terms of magnitude and rate, the highest it has been in about twenty million years, and no one really knows what that means for ocean life.

• Coral reefs support an estimated 25 percent of all marine creatures, but pollution, global warming, and other human-driven factors are expected to kill 30 percent of existing reefs in the next thirty years.

• About 90 percent of the ocean’s population of large fish has been wiped out by overfishing and other human activity.

• The Global Footprint Network, which promotes the concept of the “ecological footprint,” tracks our use of renewable resources and estimates that we are overusing our renewable resource base by about 50 percent; by 2030, it estimates that we will need two Earths (which we don’t have) to sustain us for the long haul.

Given the levels of scientific concern about these and other indicators of planetary overshoot, it is remarkable that more scientists are not talking publicly about population. When it comes to climate change, there is no shortage of scientists willing to speak out about the need to reduce greenhouse gas emissions. So if humanity is breaking “planetary boundaries” and imperiling, in the process, humanity’s future, why aren’t more scientists speaking publicly about the population trajectory and its implications?

Good question. The answer, I suspect, is many scientists do not want to “intrude” into decisions regarding how many children women should have. Very few scientists, I suspect, believe that women should be coerced into having fewer children. Most scientists, simply put, do not want to trample on reproductive rights. Good for them. Women should be able to decide, free from coercion, how many children they will have and when.

In reality, however, many pregnancies are unintended, unplanned, or unwanted. Even in the United States, where we consume a disproportionate share of the world’s resources, almost half of pregnancies are unintended. In developing countries, where large family size is a major contributor to hunger, poverty, and environmental degradation, many women have little or no control over how many children they will have. Population growth in many developing countries is largely propelled by gender inequality and antiquated child-marriage practices that effectively deny women the freedom to make informed reproductive choices.

There is, quite simply, a vast amount that can be done about global population that is fully supportive of the reproductive health and rights of women. In this country, we can stop the harebrained political assaults on family planning clinics and increase the number of women eligible for contraceptive services under state Medicaid laws. There are, unfortunately, plenty of reasons why my own organization’s recent fifty-state report card on reproductive health and rights gave fifteen states a failing grade of F and another nine a D. Despite recent declines in the teenage pregnancy rate, America still has one of the highest rates in the industrial world, yet many states continue to rely upon “abstinence-only” curricula, which research has shown to be highly ineffective in preventing teen pregnancies.

Overseas, there is much that can be done to expand and improve contraceptive options for women in developing countries. At the same time, far more needs to be done to advance gender equality, including the education of girls and the elimination of child-marriage practices. In addition to combating hunger and poverty, empowering girls and women in developing countries would do much in the long term to reduce water stress and environmental pressures.

To be fair, the scientific community has not been entirely silent on population. Twenty-three years ago, the Royal Society of London and the U.S. National Academy of Sciences issued a powerful joint statement on population growth and resource consumption. Three years ago the Royal Society published a compelling follow-up report, People and the Planet. Still, if more than four out of five U.S. scientists believe that population growth poses a major challenge with respect to food and resources, the public should be hearing a lot more from the scientific community about the need to do something.

Just as there are climate deniers, there will always be population deniers who refuse to acknowledge the impact population growth has on the planet. But that should not deter scientists from speaking out. Population, in one form or another, touches a whole host of scientific concerns, including climate change. Recent studies indicate slowing population growth could make a major contribution to slowing and ultimately reducing greenhouse gas emissions. Indeed, if world population grows, as currently projected, from 7.2 billion to 9.6 billion over the next thirty-five years, it is hard to imagine that we will succeed in meeting the ambitious targets that must be achieved to avoid the worst effects of climate change.

The unwillingness of scientists to talk about population is shared by other professions. Many of those working overseas to alleviate poverty and hunger are similarly reticent to speak about population. The evidence, however, is clear: high fertility rates serve to perpetuate poverty, exacerbate food security and water scarcity, accelerate d
eforestation, and make it more difficult to improve living standards. Population growth, in other words, is a challenge multiplier, and for many developing countries, the challenges are formidable.

By some measures, Niger is the poorest country in the world, yet its population could easily triple over the next thirty-five years. Chronically afflicted by severe drought and heavily dependent upon emergency food assistance for survival, no one really knows how Niger will feed its projected population growth.

Similarly, Yemen has been described as a hydrological disaster. Experts say Sanaa, the capital, will run out of water within the next ten to fifteen years when the underground aquifer that supplies drinking water to the city goes dry. Take into consideration the never-ending conflict that afflicts Yemen, and it is all too easy to understand why a growing number of observers classify the country as a “failed” state. Yet despite its manifest difficulties, Yemen’s population continues to grow and could easily double over the next fifty years.

Some people, even the well-informed, desperately want to believe that population is no longer a problem. Citing the rapid decline in fertility rates during the past half-century, some observers breezily dismiss population concerns and warn, to the contrary, that the world is facing a “birth dearth.” In reality, however, world population continues to grow; according to the “medium variant” projection published by the United Nations Population Division, world population, currently 7.2 billion, will likely reach 9.6 billion by 2050 and nearly 11 billion by the end of the century. That estimate, however, assumes that fertility rates will continue to fall. If fertility rates remain at current levels, the UN says world population will grow to 27 billion by 2100.

Others, while acknowledging these population projections and their implications, still insist that it is wrong to talk about population and fertility. They argue that access to family planning and reproductive health is a basic human right—end of story, nothing more need be said. Similar arguments are made about the education of girls and the empowerment of women. They believe we should be doing those things because they are good for women; there is no need to point out that they are also good for their families, communities, and entire countries.

In truth, however, we are not doing enough to improve access to contraception or to remove the cultural and informational barriers to contraceptive use. An estimated 222 million women in the developing world want to avoid pregnancy but are not using modern methods of contraception. That is about the same number as fifteen years ago. Unless we develop a greater sense of urgency, that number will not change. Put quite simply, we are not doing enough.

We need to bring a greater sense of urgency to the task. The right of women to determine how many children they will have and when is not just a moral imperative, it is a global imperative. A great deal hangs in the balance, including what kind of world our children and grandchildren will inherit.

Experience has shown that reproductive rights and gender equality, in combination with access to modern contraception, promote smaller families. In doing so, they also boost educational attainment, fight poverty, improve food security, reduce pressure on water and other resources, and even help preserve plant and animal habitats. It is a “win-win-win” proposition: good for women, their families, and the world around them.

Let’s talk about population.

Further Reading

Funk, Gary, and Lee Rainie. “Chapter 3: Attitudes and Beliefs on Science and Technology Topics.” In Public and Scientists’ Views on Science and Society, Pew Research Center, 2015. Accessed March 11, 2015.

O’Neill, Brian C., et al. “Global Demographic Trends and Future Carbon Emissions.” Proceedings of the National Academy of Sciences of the United States of America, October 21, 2010.

Population Institute, “The State of Reproductive Health and Rights: a 50-State Report Card.” January 2015. Accessed March 11, 2015.

The Royal Society. People and the Planet. April 26, 2012. Accessed March 11, 2015.

Steffen, Will, et al. “Planetary Boundaries: Guiding Human Development on a Changing Planet.” Science, February 13, 2015.

United Nations Department of Economic and Social Affairs. “World Population Prospects: The 2012 Revision.” Accessed March 11, 2015.

Robert J. Walker is president of the Population Institute, which works to bring human population into balance with natural resources.

Robert J. Walker

Robert J. Walker is president of the Population Institute, which works to bring human population into balance with natural resources.