What the controversial 1972 ‘Limits to Growth’ report got right: Our choices today shape future conditions for life on Earth

Image of Earth’s city lights, created with data from the Defense Meteorological Satellite Program. NASA/Newsmakers via Getty Images

by Matthew E. Kahn, USC Dornsife College of Letters, Arts and Sciences

The 1970s launched an environmental reckoning across the U.S. Spurred by rising public concern, corporations and national leaders pledged to protect resources, and created new laws and agencies to lead that effort.

Amid these discussions, a group of researchers at MIT tackled a far-reaching question: How long can humanity keep growing and consuming at its current rate?

Using computer modeling, they came up with an ominous answer:

“If the present growth trends in world population, industrialization, pollution, food production, and resource depletion continue unchanged, the limits to growth on this planet will be reached sometime within the next one hundred years. The most probable result will be a rather sudden and uncontrollable decline in both population and industrial capacity.”

Their report, “The Limits to Growth,” generated widespread controversy when it was published in 1972. It was an intellectual extension of biologist Paul Ehrlich’s thesis in his 1968 bestseller “The Population Bomb,” which predicted that aggregate world demand for resources, driven by population growth, would lead to future starvation. Some predictions in “The Limits to Growth” were impressively accurate, while others proved to be way off.

As an environmental economist, I tend to be skeptical that any one model can explain how the global economy operates at a single point in time, let alone predict global conditions in 2100.

Nonetheless, I believe “The Limits to Growth” got a larger point right: Humans must limit and soon reduce their aggregate production of greenhouse gas emissions. The authors anticipated the potential for the world’s economy to shift to cleaner sources of energy, noting that “If man’s energy needs are someday supplied by nuclear power instead of fossil fuels, this increase in atmospheric carbon dioxide will eventually cease, one hopes before it has had any measurable ecological or climatological effect.”

Graph showing world growth declining radically
A figure from ‘The Limits to Growth,’ with consumption continuing at the 1970 rate. Depletion of nonrenewable resources leads to a collapse of industrial production, with growth stopping before 2100. YaguraStation/Wikipedia, CC BY-SA

Extrapolating resource use

The MIT research team that produced “The Limits to Growth” focused on five basic factors that they claimed determined, and therefore ultimately limited, growth on Earth: population, agricultural production, natural resources, industrial production and pollution.

They hypothesized that a growing economy eventually devours its finite supplies of natural resources. If aggregate demand for resources such as wood, oil, rubber, copper and zinc increases as the world’s population grows and per capita income rises, they forecast that the world will eventually run out of these precious resources.

At its heart, this is an extrapolation exercise. If developing nations such as India catch up by the year 2035 to the U.S level of average income in the year 2000, the argument goes, then the average person in India in 2035 will consume the same quantity of natural resources as the average American did in 2000. This approach assumes that we can foresee a developing nation’s future consumption patterns by looking at consumption patterns in a rich country today.

World map showing nations' GDP per capita in 2020
Wealth per capita varies widely around the world. Richer nations have much higher per capita resource consumption. Our World in Data, CC BY-ND

Economists respond

Economists have tended to be more optimistic that ongoing economic growth can slow population growth, accelerate technological progress and bring about new goods that offer consumers the services they desire without the negative environmental consequences associated with past consumption.

The Limits to Growth mindset implicitly assumes that our menu of consumption choices does not really change over time. Consider the vehicle market: In the year 2000, one could not buy a Tesla or Chevy Volt to get around without consuming fossil fuel.

A typical economist would argue that Elon Musk invested in Tesla because he anticipated rising demand for high-quality electric vehicles. In this sense, the belief that we could run out of oil helps us to adapt to expected scarcity by accelerating innovation.

Why? If the Limits to Growth hypothesis is correct, then future gas prices will soar as aggregate demand devours our finite supply of resources. And as gas prices rise, so will future demand for electric vehicles.

This point applies to more than cars. In a 1992 reassessment of “The Limits to Growth,” Nobel laureate William Nordhaus argued that rising aggregate demand for natural resources traded in markets, such as oil, wood and copper, will lead to rising prices. This scarcity signal will encourage buyers to substitute other products for increasingly expensive resources.

Economists tend to be optimistic that we can always find substitutes for resources that are becoming increasingly scarce. “The Limits to Growth” implicitly assumed that such possibilities were limited.

For-profit firms constantly design new products to attract consumers. Some goods, such as smartphones, may deplete natural resources. But others have smaller environmental footprints than the products they replace, and those eco-benefits can help attract customers.

For example, affluent people today are choosing to eat less red meat to improve their health. Innovative firms are designing “fake meat” to cater to those consumers. If more consumers substitute fake meat for meat, then the perverse environmental impacts of global caloric intake decline.

“The Limits to Growth” emphasized population and income growth as key determinants of resource collapse. But worldwide, as people move to cities and their earnings rise, they tend to marry later and have fewer children. Nobel laureate Gary Becker argues that choosing to have fewer children represents prioritizing quality over quantity of children. Such household choices help to reduce aggregate population growth and defuse the “population bomb.”

Copenhagen offers a model for sustainable urban development, with a goal of carbon neutrality by 2025.

The limits that matter today

Today, scientists and policymakers widely agree that climate change is an overriding challenge worldwide. But the risk isn’t running out of resources. Rather, it is warming Earth drastically enough to produce heat waves, wildfires, floods and other impacts on catastrophic scales.

The standard economic policy prescription for cutting greenhouse gas emissions that drive climate change is adopting a carbon tax. This gives consumers an incentive to use less fossil fuel and businesses an incentive to produce better low-carbon technologies, such as electric vehicles and green power.

If every nation enacted a carbon tax that rises over time, then economists would be confident that we could avoid the most severe negative effects of global economic growth. Why? A great race would unfold, with carbon emissions per dollar of global gross domestic product declining faster than economic growth would rise and global emissions declining.

The vast majority of economists believe that economic growth is essential for improving the lives of billions in the developing world. As people invest in their education and urbanize, economic logic predicts that population growth will slow. And energy efficiency will increase if energy prices are rising over time, due to induced innovation.

Children stand in line in a slum, carrying large plastic jugs.
Children stand in line to receive free water distributed by the Kenyan government in Nairobi, April 7, 2020. Gordwin Odhiambo/AFP via Getty Images

Climate scientists are analyzing how much nations must reduce their aggregate emissions to avoid climate change on a catastrophic scale. Ideally, climate mitigation policies can be fine-tuned to balance ongoing global per capita income growth while staying within the aggregate emissions constraints prescribed by climate science research.

Since the full costs of runaway climate change aren’t known, many economists have embraced the idea of reducing carbon emissions as insurance against extreme climate risks. Call it a “limit to carbon growth.” Ongoing efforts to invest in climate change adaptation, and nascent efforts to explore the potential of geoengineering, provide humanity with additional strategies for coping with the consequences of our past carbon growth.

Matthew E. Kahn, Provost Professor of Economics and Spatial Sciences, USC Dornsife College of Letters, Arts and Sciences

This article is republished from The Conversation under a Creative Commons license. Read the original article.

What happens when cities say no to growth

Read the full story in the Washington Post.

Housing costs skyrocket and shortages can negatively affect everything from education to diversity.

As Seas Rise, Americans Use Nature to Fight Worsening Erosion

Read the full story from Climate Central.

Centuries of dredging, diking and development have replaced wetlands throughout the U.S. with more than 10,000 miles of rocks, concrete and metal. For every seven miles of coastline in the Lower 48, scientists in North Carolina calculated that about one mile is hardened with a seawall, bulkhead or other hard structure to protect land and property.

Rising costs from flooding and erosion are prompting Americans, military bases and government agencies to opt for more natural alternatives. State and federal governments are changing permitting rules and taking other steps to encourage the switch, which can improve water quality, support fisheries and protect against storms and rising seas.

Rethinking Urban Sprawl: Moving Towards Sustainable Cities

Download the publication.

This report provides a new perspective to the nature of urban sprawl and its causes and environmental, social and economic consequences. This perspective, which is based on the multi-dimensionality of urban sprawl, sets the foundations for the construction of new indicators to measure the various facets of urban sprawl.

The report uses new datasets to compute these indicators for more than 1100 urban areas in 29 OECD countries over the period 1990-2014. It then relies on cross-city, country-level and cross-country analyses of these indicators to provide insights into the current situation and evolution of urban sprawl in OECD cities.

In addition, the report offers a critical assessment of the causes and consequences of urban sprawl and discusses policy options to steer urban development to more environmentally sustainable forms.


Chicago’s vacant Sears stores create new opportunities for mixed-use redevelopment

Read the full story at Curbed.

The shuttered Sears facility at the intersection of Chicago’s North and Harlem avenues is poised to get a new lease on life as a development containing both retail and loft-style apartment components.

The preliminary plan for the vacant North Side site straddling the Galewood neighborhood and Elmwood Park was announced Wednesday by Tucker Developer and Seritage Growth Properties—a spin-off of Sears’ former real estate arm.

The Tucker/Seritage joint venture also revealed plans to redevelop the Six Corners Sears at border of Chicago’s Old Irving Park and Portage Park neighborhoods. Sears announced in April that it would be closing the 4730 W. Irving Park Road facility—its last in the city.

Scientists just showed what building new suburbs does to the atmosphere

Read the full story in the Washington Post.

A team of scientists this week reopened the debate over suburbs vs. city centers, with new research showing that carbon dioxide emissions increased as suburban areas developed to the southwest of Salt Lake City in the past decade — while comparable population growth in the center of the city did not have the same effect.

Fish and Wildlife Service retracts concerns about massive housing plan

Read the full story from the Center for Investigative Reporting.

The U.S. Fish and Wildlife Service last month lifted its longstanding objections to the construction of a city-sized development that threatens the last free-flowing major river in the arid Southwest.

The San Pedro is a vital resource in the parched Sonoran Desert, sustaining some 400 species of migratory birds. The agency twice in recent years had warned that a key federal permit to build 28,000 homes, golf courses and other amenities near the San Pedro River in southern Arizona would have “appreciable” effects on wildlife. It cited substantial scientific research warning of risks to rare species such as the jaguar and yellow-bellied cuckoo.

Density Is The Best Way To Reduce A City’s Carbon Footprint

Read the full story at Fast Company.

Ending sprawl could be even more important than applying the latest energy-saving technologies as cities look to incorporate more energy-efficient buildings.

Boomtown, Flood Town

Read the full story from ProPublica and the Texas Tribune.

Climate change will bring more frequent and fierce rainstorms to cities like Houston. But unchecked development remains a priority in the famously un-zoned city, creating short-term economic gains for some while increasing flood risks for everyone.

Attracting Infill Development in Distressed Communities

Many communities across the country have been revitalizing their older neighborhoods, traditional downtowns, and central business districts. However, economically distressed communities have been less able to attract this kind of infill development and attain the accompanying economic, environmental, health, and quality of life benefits.

EPA’s new report, Attracting Infill Development in Distressed Communities: 30 Strategies, can help these communities determine their readiness to pursue infill development and identify strategies to better position themselves to attract infill development.

  • It presents strategies and case studies to establish priorities, policies, and partnerships and change public perceptions, which can help make infill development more feasible.
  • It discusses innovative strategies to help finance infill development and replace aging infrastructure.
  • It includes comprehensive self-assessment questions communities can answer to determine if they are ready to pursue infill development and if particular strategies are appropriate for their context.

Many of the strategies in this publication stem from work in Fresno, California, that was part of the Strong Cities, Strong Communities (SC2) Initiative, which provides intensive technical assistance and capacity building to economically distressed cities. EPA and the state of California partnered with the city to convene a task force of experts in development finance, law, public policy, planning, and business to identify strategies to promote infill that were feasible in Fresno’s challenging economic and fiscal environment. EPA developed this publication based in part on the task force’s work.