Climate & Social Justice

7 Billion and Counting: That’s a Lot of People

Can the planet sustain mankind’s growing numbers? Depends on whom you ask.


The global population is closing in on 7.2 billion — a mere 15 years ago it was at 6 billion. (istock)

Since the start of the Industrial Revolution some 250 years ago, the widespread use of chemical fertilizers and pesticides that began about a century and a half later, and the atomic half-life of the past seven decades, humans have developed and doused land and dammed and diverted water. These practices have left a wound that continues to fester as the human population swells.

Artificial fertilizer and the commercialization of industrial nitrogen changed the world significantly, according to author Alan Weisman, who was a panelist at The Nature Conservancy’s first forum in its 2014 “Future of Nature Boston Speaker Series.”

“Forty percent of us wouldn’t be here without it,” he said.

The global population is closing in on 7.2 billion — a mere 15 years ago it was at 6 billion. Earth’s human population is expected to exceed 9 billion by 2050. While global population growth must be part of the conversation about sustaining the planet, it’s seldom discussed. The issue is largely ignored at our own peril.

Some 40 years ago, human population was at the forefront of many discussions, because it was seen then as a barrier to economic growth, said Andrew Foster, director of the Population Studies and Training Center at Brown University. Today, environmental concerns associated with population growth don’t have the same place on the global agenda, he said.

Roger-Mark De Souza, director of population, environmental security, and resilience at the Washington, D.C.-based Wilson Center, said there is another reason the population conversation has been muted.

“Politically it’s a third-rail issue in D.C.,” he said. “Touch it and you’re dead. It’s the easy way out to avoid a needed conversation.”

To help push this conservation from the fringes, The Nature Conservancy hosted a panel discussion in late April at the Boston Center for the Arts entitled “7 Billion and Counting: Population and the Planet.” De Souza and Weisman, author of “Countdown” and “The World Without Us,” were two of the four panelists.

The panel, which also included Caroline Crosbie, senior vice president of Pathfinder International, and Peter Kareiva, chief scientist for The Nature Conservancy, spent 90 minutes discussing the impacts of human population growth.

The media packet distributed at the event included a few questions the panelists would discuss: Does human population growth affect other species and the planet as a whole? What about families already struggling to find food, water and health care? Can empowering women make life more sustainable for people and nature? Can conservation and technology support the planet’s ability to provide food, water and other benefits to a growing human population?

Each panelist addressed the topic differently. Weisman was the most pessimistic; Kareiva the most optimistic. But there’s little disagreement globally that humankind’s rapidly growing numbers are stressing the planet’s finite natural resources.

Peak water
More than 90 percent of all fresh water used worldwide is for agriculture. Fewer than 15 percent of the world’s rivers now run freely to the ocean. This allocation of water comes with a steep price.

By overpumping aquifers and misusing rivers, humans are using water faster than it can be naturally replenished, according to Peter Gleick, president and co-founder of the Pacific Institute. The MacArthur “genius” fellow has said the world is in danger of reaching “peak water.”

By 2025, according to the Wilson Center, nearly 2 billion people will be living in countries with scarce water supplies, and two out of three people will be living in conditions of water stress.

The Waterkeeper Alliance has estimated that within a decade 3.5 billion people will face water shortage issues.

Land grab
An average of nearly 25 acres of forest were lost every minute from 2000 to 2010, according to the Wilson Center. Most of this lost forestland was cleared by humans for agriculture and timber.

The loss of vital forestland to the stress of human population isn’t lessening. For example, the energy demands of some 2 billion people who depend on wood for cooking and heating is devastating rainforests, according to the Food and Agriculture Organization of the United Nations.

The prodigious reach of humanity’s growing numbers doesn’t just impact Third World countries and places hard to locate on a map. Southern New England has felt and is feeling the stress caused by population growth.

Rhode Island has lost 80 percent of its farmland since 1945, and only about 40,000 acres remain in production — less than 7 percent of the state. In Newport, there are 40 hotels on less than 10 square miles of land.

In Massachusetts from 1999 to 2005, land was developed at a rate of 22 acres a day, converting some 40,000 acres of forest and farmland into residential development.

About 14 percent of the region’s vital Narragansett Bay watershed — 60 percent lies in Massachusetts; 40 percent in Rhode Island — is under streets, roofs, driveways, and parking lots. Impervious cover by municipalities in this 1,754-square-mile area ranges from 3 percent to 40 percent.

Besides knocking down carbon-sequestering forests and covering open space with asphalt and concrete, humans have been dousing much of the world’s land with synthetic toxins every day since the 1940s. In 1947, for instance, the United States manufactured 124 million pounds of pesticides. Sixty years later, in 2007, the United States alone produced 1.1 billion pounds.

“We’re chemically force-feeding the land and all this poison is no good for the soil or water,” Weisman said. “We don’t want to play Russian roulette with the one ecosystem we have.”

Hunger games
About 40 percent of the planet’s land is farmed to produce food. Yet, the United Nations has estimated that nearly one in eight people is food insecure. The U.N.’s Food and Agriculture Organization has reported that food production will need to increase 70 percent by 2050 to be able to feed another 2-3 billion more people.

Locally, we rely on the rest of the world to feed us. For example, about 65 percent of the produce consumed in Rhode Island comes from out of state. In fact, only 1 percent of all farm products sold in the state are from Rhode Island. These percentages are similar in both Massachusetts and Connecticut.

Worldwide, we are relying more and more on genetically modified organisms (GMOs) and genetic engineering to feed us. In the United States, more than half of all farmland is used to grow GMO crops, most notably soybeans and corn.

This growing practice, largely controlled by multinational corporations worth billions, has both supporters and detractors. Proponents say GMO crops are the best way to feed a growing population. They claim GMOs improve crop yield and enhance the nutritional value of said crops.

Opponents say that in the past three decades only a few commercial successes have been produced by the corporations that manufacture GMO food. Since most of these crops are immune to herbicides, they claim hundreds of millions of pounds more of weed-killer are now being used. They say building up and supporting local food systems is the best way to sustainably increase the world’s food supply.

Others, like Weisman, believe we already produce enough food to feed the planet; we just need to be more equitable with the bounty.

Mass extinction
“Everyone one of us has felt the crush of the growing human population,” The Nature Conservancy’s Kareiva told those gathered inside the Boston Center for the Arts’ Wimberly Theatre two months ago.

Virtually every other species on the planet — animal, plant, insect — also has felt the growing crush of humanity. Every hour, 24 hours a day, 365 days a year, three species become extinct, and humans’ growing presence is a huge factor in these disappearances.

As the the number of humans has increased, we have become more adept at altering ecosystems for our own purposes, according to Laurie Mazur of the Wilson Center. Centuries of alterations have transformed diverse habitat into less-resilient monocultures.

In fact, according to research, human population density is an excellent indicator of biodiversity loss. About half of the human population lives on less than 3 percent of the planet’s habitable land, and most of us live at densities between 100 and 1,000 people per square kilometer, according to the Wilson Center.

Some 330,000 tons of lead are released into the environment annually as a result of human activity, compared to just 28,000 tons happening through natural processes. For a growing number of materials, we are now scaling beyond the planet’s natural rhythms.

What’s the plan?
Besides the shrinking number of climate-science deniers, few would argue that billions of people riding in planes, trains, and automobiles, pushing snowblowers and lawnmowers, and wielding leaf blowers, chain saws, and weed wackers hasn’t altered the planet’s landscape. Simply cutting a hayfield changes the environment, so damming rivers, clear-cutting forests, and paving over open space most certainly has scarred the third rock from the sun.

Humans are geoengineering the planet to sustain our expanding and unsustainable numbers. But can our efforts actually sustain the planet? Depends on whom you ask.

The Nature Conservancy’s chief scientist believes we’re looking too far into the future to deal with the issue.

“We tend to frame things as business as usual … but there are global trends and we can ride those trends to solutions,” Kareiva said. “These are real problems, but it’s a terrible idea to be thinking that far ahead. We need to identify pathways to solve these problems. Take definitive actions today that improve our quality of life for the next year. That’s how you address long-term problems.”

About 200 years ago, English scholar Thomas Malthus published “An Essay on the Principle of Population.” In this book he noted that human population tends to grow geometrically, while the resources available to support it tend to grow arithmetically. Under these conditions, he wrote that human population will inevitably outgrow the supply of food. He predicted that population growth would lead to degradation of the land, and eventually massive famine, disease, and war.

Improvements in agriculture and the Industrial Revolution postponed the disaster Malthus thought was imminent, but two centuries later many don’t believe we can again geoengineer our way out of the numerous impacts a growing human population creates.

“A million people being added to the planet every four and a half days is not sustainable,” Weisman said, “and we need to do something.”

But what? As has been noted, simply discussing the issue is frowned upon, and many of the conversations that are held inevitably veer toward population control and China’s since-lax one-child policy.

That isn’t the conversation that is needed. There’s another topic — also largely hushed and certainly underfunded, especially in the United States — that needs to play a central role in any discussion about human population growth: family planning.

Empowering women by improving their access to education and health care is an effective and relatively inexpensive way to address this challenging issue, according to De Souza.

“We need to think about the impact we are having on the planet,” he said. “We need to talk to communities at the local level about public health and population. We need to talk about and understand reproductive health.”

Up until the early 1980s, however, family planning was illegal in many countries, said Crosbie of Pathfinder International. In 1984, around the time President Ronald Reagan was re-elected to a second term and some countries began to embrace the importance of family planning, the United States began scaling back on funding such services here and abroad.

“The U.S. government is becoming more conservative when it comes to family planning,” Crosbie said. “The rest of the world is becoming more progressive. Government commitment is needed, like in Thailand and Bangladesh.”

Or in Iran, where a voluntary family-planning program helped drop the highest rate of population growth in the country’s history to replacement level a year faster than China’s compulsory one-child policy.

Individual countries are learning that smaller families makes more sense economically and environmentally, Brown University’s Foster said. He noted during a recent interview at his office on Waterman Street in Providence that the global fertility rate is falling, except in some places such as sub-Sahara Africa.

In remote villages on the shore of Lake Tanganyika in Tanzania, for example, women there, on average, give birth to more than seven children. In Niger, with the world’s highest fertility rate, each woman bears an average of nearly eight children.

Despite the fact fewer cultures are now marrying off their young daughters right after they have their first period, 15 million girls between the ages of 10 and 14 in developing countries (one in nine) were still forced into marriage in the past decade. Some 220 million women in developing countries wish to delay or stop having children, but aren’t using any method of contraception, according to Pathfinder International.

Family planning must play a critical role in addressing these issues, but the idea, especially in the United States, is seemingly held hostage by the fiercely divisive topic of abortion.

“The issue of abortion colors the family planning debate more than it should,” Foster said. “The abortion issue gets in the way of a more proper discussion about family planning.”

He used Planned Parenthood as an example. The organization provides access to birth control, offers breast and cervical cancer screenings, and tests and treats for sexually transmitted diseases, but it’s often marginalized because it also provides abortions.

At The Nature Conservancy’s panel discussion, De Souza noted that there is a positive when it comes to the issue of family planning. “Younger generations understand population concerns better than past generations,” he said. “They understand reproductive health. They realize it’s important to understand population dynamics when addressing reproductive health and climate change.”

The concentration of heat-trapping carbon dioxide in the atmosphere has risen from about 315 parts per million in 1960 to 401 this past April, according to the Scripps Institution of Oceanography.

Carbon concerns
U.S. carbon dioxide emissions from the consumption of fossil fuels — coal, natural gas, and petroleum — had been declining since a record high in 2007 and were 12.5 percent lower in 2012 than they had been five years earlier. Not anymore.

The decline in U.S. carbon dioxide emissions has ended, according to the U.S. Energy Information Administration. Carbon emissions increased by 2.4 percent in 2013 compared to 2012, and for the first two months of this year, they increased by 7.5 percent compared to the same period in 2013.

While consumption by developed nations is the largest contributor to greenhouse-gas emissions, population growth also plays a big role in fueling climate change. In fact, slowing population growth by 2050 could produce a 16 percent to 29 percent reduction in carbon emissions, according to the National Center for Atmospheric Research.

Besides producing more heat-trapping atmospheric emissions, however, our postwar population explosion has led to ocean acidification. The world’s oceans are a third more acidic than they were in 1800, and by the end of this century they likely will be 150 percent more acidic than they were at the start of the Industrial Revolution, according to an article written by Daniel Smith in the May 2014 edition of Harper’s Magazine.

Just as the burning of fossil fuels alter the chemical composition of the atmosphere, this practice also transforms the composition of the world’s oceans, Smith wrote. About 1 of every 3 tons of carbon dioxide spewed into the air is absorbed by the sea — this 2.5 billion tons of annual carbon dioxide dissolves and forms carbonic acid.

“The world’s environmental problems stem from us,” Weisman said. “But environmental groups don’t like to touch the question of human population. Up until the nineteenth century, when we passed one billion, the population barely grew. Then in the 20th century the population exploded. These crowds aren’t what it’s supposed to be.”

Magic number
In his latest book, “Countdown,” Weisman traveled to 21 countries to ask four questions that experts agreed were probably the most important on Earth. One of those questions was: “How many people can the planet sustain?”

There is no definitive answer. Expert estimations of the planet’s carrying capacity range from 1.5 billion people to 10-plus billion.

Both Weisman and Foster said the answer will ultimately depend on how humans decide to address greenhouse-gas emissions.

“Carbon dioxide is a big problem,” Weisman said. “The seas are the basis of life on this planet.”

While Weisman mentioned studies that say 2 billion people — the world’s population in 1930 — could be the high end of the planet’s carrying capacity, Foster believes the Earth could support up to 10 billion, if society is willing to make some hard choices. He said the world’s collective mindset is more critical than sheer numbers.

“Do we have the societal will to make changes to reduce emissions?” he asked. “It’s less about how many people and more about how they think. Are we willing to make some sacrifices?”

For example, are we willing to live in smaller houses? Are we willing to live in more dense communities? Are we willing to eat less meat? Are we willing to invest in public transportation? What state or country is willing to lead the way and take serious measures to protect the environment?

Foster said the value placed on the environment is a tricky issue to quantify, because it varies so widely from individual to individual and from one region of the planet to another.

“If I ride my bike to work every day, the impact on the environment will be negligible,” he said. “But if everyone in Rhode Island biked to work, the world most certainly would be a better place.”

To address carbon emissions, he said, a number of political hurdles have to be cleared — i.e., is there an economy that can prosper with a shrinking population? — and “we have to be willing to tax carbon in some way.”

“There’s a lot of natural environment left out there, but more people certainly means less open and wild space,” Foster said. “I think we are willing to make better choices.”

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  1. Thanks for even raising the issue.
    The environmental movement has been missing in action on this despite the looming extinction of so many species losing habitat as humanity spreads, despite the mathematical fact that
    total emissions = average emission per person TIMES the number of people,
    and despite the fact that efforts to reduce population growth are being increasingly undermined in such diverse places as Iran, Israel, India, Egypt, even China is loosening pressures to hold down population growth, and now the US government is being taken over by ideologs who want to undermine access to birth control, both in the US and worldwide.
    Its true in a perfect world, and in a world where people agreed to give up meat, much of our driving, flying, use of AC, and such, we could sustain a lot more people, but even then the numbers cannot keep growing indefinitely.
    Both the political left and right and the environmental movement are hurting our global prospects by ignoring population in deference to the religious zealots of all types who oppose reproductive freedom and/or the many self-appointed ethnic spokesmen who consider their populations should be free to grow without limits. Of course in all the religions the men make the rules, (often made by men afraid of female sexuality) but women bear the major burden.
    Its not that hard to be proactive, working to explain the math of exponential growth, working to ensure access to birth control for all who want it, working to improve contraceptive methods, working to empower women in society, these are all doable solutions, but leaving that to a handful of increasingly beleaguered organizations like Planned Parenthood is clearly so inadequate.
    I no longer contribute to enviro groups that don’t take on population too, I hope others will too as all environmental issues are ultimately lost causes unless this is adequately addressed.
    This is especially bad as there is a

  2. since you wrote the population has increased to over 7.73 billion, it is still being irresponsibly neglected by the environment community despite the increasing loss of biodiversity and natural habitat. I no longer contribute to national environmental groups that won’t recognize the underlying population issue

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