Can Growth Continue Forever?
The Economy That Ate the Planet: Why GDP Has a Physics Problem
Every economic model ever built assumes we can have more tomorrow than we have today — but the planet did not get the memo.
The Idea
Mainstream economics treats growth as the default state of a healthy economy. GDP goes up, living standards improve, problems get solved. The implicit promise is that this can continue indefinitely, and that technology will always find a way to decouple prosperity from resource consumption. It is a seductive idea. It is also, at a fundamental level, in tension with thermodynamics. The concept doing the heavy lifting here is called the biophysical critique of growth — the argument that the economy is not a self-contained system floating above the physical world, but a subsystem entirely embedded within it. Economies consume energy and materials, transform them into goods and services, and emit waste. The laws of physics are not suggestions: you cannot recycle energy back into useful work, and you cannot dematerialise an economy all the way to zero while it continues to do things in the physical world. This does not mean growth is finished tomorrow. But it does mean that the standard assumption — that we can perpetually grow GDP while somehow reducing our physical footprint — faces a hard ceiling that no amount of clever engineering fully dissolves. Efficiency gains are real, but they consistently unlock new consumption rather than reducing total throughput. Economists call this the Jevons Paradox: make something cheaper to run, and people use more of it. The gains get absorbed. The pie just gets eaten faster.
In the World
In 1972, a team of researchers at MIT published a report for the Club of Rome called The Limits to Growth. Using a computer model they called World3, they simulated the interactions between population, food production, industrialisation, pollution, and resource depletion across a century. Their base-case scenario — business as usual, no dramatic policy shifts — showed global industrial output and population peaking somewhere around the 2040s before declining sharply. The report was attacked ferociously by mainstream economists, who argued that markets and technology would always find substitutes for depleted resources. For decades it was largely dismissed as doomist overreach. Then, in 2008, a researcher named Graham Turner at Australia's Commonwealth Scientific and Industrial Research Organisation went back to the original data and compared it against fifty years of real-world figures. His conclusion was striking: actual data on population, food production, industrial output, pollution, and resource use was tracking almost precisely along the base-case collapse trajectory the 1972 model had projected. Turner updated the analysis in 2014. The fit remained uncomfortably close. More recent independent assessments — including work published in Yale's Journal of Industrial Ecology — have reached similar conclusions: the world is not on a path that diverges happily from the Limits to Growth's central warning. The model was not perfectly right. But it was not wrong in the ways its critics assumed.
Why It Matters
None of this requires you to become an economic pessimist or a degrowth activist. But it does invite a more honest question about what we are actually optimising for when we cheer a rising GDP number. Growth in what, exactly? GDP counts hospital visits and oil spills as positively as it counts education and clean water. A country that clear-cuts its forests and sells the timber looks, on paper, like it is thriving — right up until it isn't. On a personal level, the biophysical critique is a useful lens for reading financial news and policy debates. When a politician promises that growth will pay for climate action, or that green technology will let us have everything we currently have plus more, you now have a sharper tool for evaluating that claim. Not to dismiss it, but to ask: where does the energy come from, and what happens to the waste? The most important insight is not that growth must end, but that treating it as automatically self-sustaining is a choice — a political and philosophical one — dressed up as economic common sense.
A Question to Ponder
If the goal of an economy is human wellbeing rather than growth itself, what would you actually measure to know if things are getting better?
Get a new one of these every morning.
Start learning with Thinkable