On the 50^thanniversary of Garrett Hardin’s influential essay about the 'freedom to breed,' the director of the CU Population Center contends he missed the mark

“Freedom to breed will bring ruin to all.”

The ominous statement reads more like a line from a dystopian novel than a peer-reviewed journal article. But it is, in fact, the punch-line of one of the most influential scientific essays to date.

Published in Science in December 1968 by the late University of California ecologist Garrett Hardin, the 6,000-word Tragedy of the Commons has been cited more than 38,000 times and informed policies on everything from climate change to intellectual property to digital content. 

Its bold assertion that, left unchecked, population growth will inevitably outpace the earth’s resources helped ignite a zero-population fervor in the 1970s, was often used to justify China’s now-defunct one-child policy, and is still conjured today in op-eds about immigration, Front Range overpopulation and fertility planning in the developing world. 

But on the 50^thanniversary of its publication, a new CU Boulder-led paper published this month in the journal Nature Sustainability argues that Hardin’s theories about overpopulation were “simplistic” and “underdeveloped” and run the risk of leading to ill-informed policy.

“Pointing fingers at people who live in Tanzania and have large families or people who migrate here from elsewhere is not going to solve our environmental problems,” contends lead author Lori Mae Hunter, director of the CU Population Center at the Institute of Behavioral Science. 

“It distracts us from looking at the way we live our own lives, our own consumption patterns and the way we build our own transportation and energy systems.”

Selfish herdsmen, a growing flock, and climate change

Hardin’s parable centers around a flock of hypothetical herdsman who, if given access to a communal pasture, will increase their herd size until they collectively degrade the pasture. “Ultimately, the commons collapses, hence the tragedy,” summarizes Hunter, who also chairs the sociology department.

The metaphor is most often conjured in the context of environmental protection: The global atmosphere is the “commons.” Owned by no one, used by everyone, and left unregulated it, like the pasture, is doomed to be overexploited and ruined.

That prediction has been debated for years, with one challenger, the late Elinor Ostrom, winning a Nobel Memorial Prize in Economic Sciences for her elucidation of a more optimistic real-life scenario—one in which small communities around the globe have managed to devise ways to successfully manage common resources like grazing land, forests and irrigation waters.  

But Hardin’s second argument—the overpopulation argument—has not received the same critical attention. 

That’s the task that Hunter and co-author Aseem Prakash, a political scientist at University of Washington, set out to do.

“It’s time to move past Hardinesque population alarmism … in order to develop better-informed policy,” they write.

Relinquishing the freedom to breed

In his essay, Hardin bluntly applies the “tragedy of the commons” idea to parenting, suggesting that the availability of food and other resources as part of the “welfare state” drives people to procreate and overpopulate:

“If each human family were dependent only on its own resources; if the children of improvident parents starved to death; if, thus, overbreeding brought its own punishment to the germ line—then there would be no public interest in controlling the breeding of families. But our society is deeply committed to the welfare state,” he wrote. His solution: Mandated population control:

“The only way we can preserve and nurture other and more precious freedoms is by relinquishing the freedom to breed.” 

That argument had ripple effects, notes Prakash, indirectly fueling heated arguments within the Sierra Club over whether population control, including stronger checks against U.S. immigration, should be a central pillar of their environmental agenda. (It is not).

“Even today, with all the discussions of the border wall, in the back of the mind is Hardin’s overpopulation thesis again. That if you have too many resources, people will in-migrate and procreate,” said Prakash. “What we are pointing out is that is much more complex than that.”

They note that while the birth rate in the United States is at its lowest in 30 years, 51 percent of people here still believe the population is growing too fast.

Meanwhile, they add, in the places where the population is truly growing rapidly, carbon emissions per capita are minuscule compared to those in the West. For instance, U.S. residents emit 16.49 tons per capita in carbon emissions, while in Tanzania, per capita emissions run around 0.22 tons.

The complex reasons women get pregnant, or don’t

While Hardin drew a simple conclusion—that availability of resources drives procreation—Prakash and Hunter also point to a complex web of factors, including social values, cultural norms and local reproductive health policies, that contribute to family planning.

For instance, in Nepal, where resources are scarce, women tend to want to have more children to help them to gather those resources—such as firewood and food for their animals.

In Rwanda, which had notoriously high fertility levels prior to 2005, fertility rates have declined a stunning 25 percent—from 6.1 to 4.6 children per woman—not due to a shrinking of the “welfare state” but due to a national prioritization of family planning and a greater exposure to mass media, which shifted male attitudes about birth control. Together, that led to a huge boost in contraceptive use.

“People don’t just procreate because they know they can feed their family,” says Prakash. “We shouldn’t take these simplistic notions—a la Hardin—and use them to support misinformed policies.”

Instead, he and Hunter suggest, policymakers and others concerned about overpopulation should consider the key role sociocultural factors can play in fertility decisions and take steps to empower women to control their own family planning.

And when it comes to the environment, they argue, they should stop pointing fingers at large families, and take a close look at their own house.

“We would not argue that population doesn’t matter at all when it comes to the environment. Of course it matters,” said Hunter. “But simply pointing a finger at others and saying you shouldn’t be here obscures all the other things we should be thinking about.”