Limits to physical and economic growth

Article author: 
Thomas W. Murphy Jr
Article publisher: 
Nature Physics
Article date: 
Friday, July 22, 2022
Article Body: 

Across the world, decisions on investment and policy are made under the assumption of continuous economic expansion. Fundamental physical limits may soon put an end to this phase of development, as foreshadowed by the 1972 report The Limits to Growth.

Quantitative economic growth, in which inflation-adjusted wealth continues to rise, has been reasonably reliable for generations and is deeply woven into modern societal structure. The promise of a tomorrow that is "bigger" than today fuels investment, innovation and dreams. Growth is imagined to offer a solution to inequality between developed and developing nations: redistribution today is unnecessary if growth will eventually address the problem by growing the pie. Interest rates, bank loans, home mortgages and pension plans rest on the assumption of growth. The funding of social safety nets such as Social Security and Medicare in the United States is predicated upon both economic growth and growth of the labour pool...

Physical limits

A finite world of finite resources will not support indefinite growth in the extraction of those resources. In the case of non-renewable resources such as mined minerals and fossil fuels, whose stocks are finite, we obviously cannot continue extraction indefinitely: we simply run out of materials. But even for renewable resources such as solar power, the rate of replenishment is set by nature and cannot grow arbitrarily large, not to mention that building the technology to harvest such flows also requires consumption of non-renewable resources....

Because Earth has never hosted 8 billion humans with an unprecedented and continuously growing per-capita demand, we cannot base projections for future resources on the fact that they have not yet failed us....

In a continued progression, we would exceed the total solar power incident on Earth in just over 400 years, the entire output of the Sun in all directions 1,300 years from now, and that of all 100 billion stars in the Milky Way galaxy 1,100 years after that. This last jump is made impossible by the fact that even light cannot cross the galaxy in fewer than 100,000 years. Thus, physics puts a hard limit on how long our energy growth enterprise could possibly continue....

At present, the waste heat term is about four orders of magnitude smaller than the solar term. But at a growth factor of ten per century, they would reach parity in roughly 400 years. Indeed, the surface temperature of Earth would reach the boiling point of water (373 K) in just over 400 years under this relentless prescription....


An end to quantitative economic growth need not translate to an end to innovation or other forms of qualitative development and improvement. But growth as we have known it will no longer be able to drive the way civilization operates....

Thomas W. Murphy Jr. is a professor of physics at UC San Diego in La Jolla, California.


Understanding Exponential Growth - an interactive tutorial

Why Understanding Limits Is the Key to Humanity's Future, by Richard Heinberg, Resilience, 19 January 2021:

... Limits exist everywhere in nature. Physics, chemistry, biology, geology, astronomy—pick your field, dig into the literature, and you'll soon be struck by how everything in the universe is defined by limits of temperature, weight, volume, density, number, power, frequency, speed, and more...

All these developments together [fossil fuels, artificial fertilizers] enabled population growth at rates that far outstripped historic trends: human numbers expanded from one billion to eight billion in a mere two centuries. We were, in effect, stretching existing constraints on population and consumption to the point that it was difficult for many people to see that boundaries still existed at all...

It turns out that fossil fuels suffer from a couple of serious drawbacks: depletion and pollution... We've already extracted all the easy stuff, and beyond a certain point it will take more energy to obtain the remaining fuels than they will yield when burned...

As we've grown our population and our per capita consumption rates, we've been taking habitat away from other organisms. As a result, nature is in full retreat. Vertebrate and invertebrate animal species have suffered average population declines of 70 percent in the past 50 years, and thousands of plant species are endangered as well...

Not only are most people apparently willing to ignore the loss of Earth's biodiversity as long as the industrial economy can continue to keep them fed, clothed, housed, and entertained, but they are also largely unaware of the exhaustion of the materials that feed the industrial machine...

Altogether, civilization's survival dilemma in the 21st century is best described by a concept from population ecology—overshoot. This refers to the situation where a crucial resource temporarily becomes more abundant, thereby enabling a group of organisms to grow its population beyond levels that can be sustained over the long run...

Wisdom says: embrace limits even as they snap back, knowing that, in the long run, everything moves toward balance...


Book: Overshoot: The Ecological Basis of Revolutionary Change, by William R. Catton, 1982.

Overshoot and the work of William R. Catton Jr.

Book: Blip: Humanity's 300 Year Self-Terminating Experiment With Industrialism, by Christopher O. Clugston, 2019.

Book: GeoDestinies, by Walter Youngquist.

Book: Living within Limits: Ecology, Economics, and Population Taboos, by Garrett Hardin.

5 minute video: What's Wrong with Wind and Solar? by Mark Mills, Prager U, 14 September 2020.

What's Wrong with Wind and Solar?


The green revolution has won a temporary success in man’s war against hunger and deprivation; it has given man a breathing space. If fully implemented, the revolution can provide sufficient food for sustenance during the next three decades. But the frightening power of human reproduction must also be curbed; otherwise the success of the green revolution will be ephemeral only.”
- Norman Borlaug, winner of 1970 Nobel Peace Prize


Al Bartlett, Professor Emeritus in Nuclear Physics at University of Colorado at Boulder. Watch Arithmetic, Population and Energy - a celebrated lecture by Al Bartlett. "The greatest shortcoming of the human race is our inability to understand the exponential function."

Are there no limits? The crisis of overpopulation, mass immigration, and overconsumption, The Social Contract, Summer 2018.

Living Within Limits - The Enduring Relevance of Garrett Hardin, The Social Contract, Spring 2019.

The future of an unsustainable planet, The Social Contract, Fall 2007.

Facing our geo-destiny: honoring the work of geologist Walter Youngquist, The Social Contract, Spring 2005.

'The Limits to Growth' - honoring the memory of Donella Meadows, The Social Contract, Summer 2001.

Garrett Hardin: an introduction and appreciation, The Social Contract, Fall 2001.

Population growth and resource depletion, The Social Contract, Summer 1999.

Growth, smart growth, and sustainability

The Weight of Mass Immigration