Growth: From Microorganisms to Megacities
By Vaclav Smil
The MIT Press, Cambridge, Massachusetts, 2019
People used to think growth was a good thing. Politicians, economists and business leaders brag
about healthy or robust growth in jobs, GDP, and profits. But that’s changing. These days, growth is often described as
excessive, uncontrollable, and unsustainable.
In her speech
to the United Nations Climate Action Summit in New York on September 23, 2019,
Swedish activist Greta
Thunberg scolded world leaders with these words:
“We are in the beginning of a mass extinction, and all you can talk about is money and fairy tales of eternal economic growth. How dare you!”
Growth’s reputation has become tarnished.
Can the world economy keep growing as it has for the past
two hundred years? Can we transition to
a more sustainable form of growth? How do
we enable people in developing regions to enjoy the comforts and consumption that
typically come with economic growth? Can
we do any of these things while living within planetary
Into this debate, Vaclav Smil drops a 600-page tome, Growth: From Microorganisms to Megacities.
Vaclav Smil might be the most important scientist you’ve
never heard of. He is Distinguished
Professor Emeritus at the University of
Manitoba in Winnipeg,
Canada. He’s a multidisciplinary scholar
with interests in environment, population growth, food, economics and public
policy. But he’s mainly known as one of
the world’s foremost thinkers about energy in all its forms, uses and
To give you an idea of Smil’s influence, Bill Gates says, “There is no author whose books I look forward to more than Vaclav Smil.”
Growth is his latest book, his 40th. From the outset, Smil sets himself a gargantuan task; to examine the nature of growth in living organismsms, human-made artifacts and complex systems. Literally, growth from microorganisms to megacities.
He looks at the growth trajectories of individual specimens
and whole populations. He tries to take
a long term view, looking back as far as he can within the limits of available
high quality data. In some cases he also
makes projections, extrapolating from historical trends, but he is careful to provide
a range of possible outcomes. He is
deeply skeptical of anyone predicting revolutionary change on time scales not
supported by historical evidence, for example, rapid replacement of fossil
fuels with renewable energy sources.
Above all he avoids making rigid prescriptions. But the takeaway message of his book is clear:
“… before it is too late, we should embark in earnest on the most fundamental existential (and truly revolutionary) task facing modern civilization, that of making any future growth compatible with the long-term preservation of the only biosphere we have.” [p. xxv]
Growth has six chapters. In the first, Smil looks at the types of
growth, their trajectories and outcomes.
It’s essentially the mathematics of growth.
Chapter 2 covers the growth of living matter:
microorganisms, crops, forests, animals, and humans.
Chapter 3 is about energy – Smil’s special area of expertise
– and how it is both the source and object of growth. It seems like a digression, but it’s key to
the remainder of the book.
In Chapter 4, Smil examines the growth of human-made artifacts. First, he looks at improvements in their performance characteristics such as the growth over time in the lifting capacities of pullies and cranes. Second, he traces the adoption of tools and technologies, for example, the spread of smartphones around the world.
Chapter 5 is devoted to studying the historical growth of
our most complex structures: human populations, cities and economies.
Finally, in Chapter 6, Smil tries to forecast what comes after growth. What happens when growth in an organism, a technology, or an economy stops, plateaus or even collapses?
Rather than summarize each chapter, I’m going to focus on a
few of the topics and themes that I found most interesting.
Types of Growth
Growth is always measured over some time period be it days
There are two main types of growth; linear and exponential,
according to Smil. Linear growth occurs by
a constant amount in each unit of time and can be plotted on a graph as
a straight line. The growth of
stalagmites on a cave floor over centuries is typically linear. With exponential growth, the quantity
increases at the same rate in every unit of time. Graphs of exponential growth show a slow
gradual rise followed by a rapid upward-sloping “hockey stick” curve. Human
population growth since about 1800 has been roughly exponential.
Exponential growth is always temporary. Smil advises us to distrust any forecast that
includes an assumption of indefinite exponential growth.
There’s an intermediate form of growth which Smill calls “confined” growth or growth within limits. A graph of confined growth looks like an S-curve. (It’s technically called a logistic curve.) There’s a slow rise at the beginning, a period of temporary exponential growth followed by a leveling off to flat or slow growth again. Adoption of new technologies follows this pattern. When smartphones were first introduced, they were expensive and buggy and only technology enthusiasts bought them. Then they took off, especially after the introduction of the Apple iPhone. Now almost everyone has one. Further adoption of smartphones will be slower since the market is already saturated in most parts of the world.
Smil shows how this pattern of confined growth following a logistic curve occurs again and again throughout nature and throughout history. He warns repeatedly not to expect growth rates or growth patterns that are not supported by historical evidence. Don’t count on a sudden spurt in crop yields for example, when historical data shows linear growth.
Energy and Growth
Smil says that energy is the foundation for all growth.
Sunlight is of course the primary source of energy on Earth. Even fossil fuels are just sunlight stored millennia ago in plant matter. Every living organism converts sunlight, either directly or indirectly, into the energy it needs to survive and grow. Smil distinguishes between two types of energy “converters.”
Primary energy converters convert natural renewable energy
flows like sunlight, wind, water, plus fossil fuels, into more useful forms of
energy like thermal (heat), kinetic (mechanical e.g. rotational), light and
increasingly into electricity. Examples
of primary energy converters include waterwheels, windmills, steam engines,
internal combustion engines, photovoltaic cells, and nuclear reactors.
Secondary energy converters usually take electricity
and convert it into mechanical energy (electric motors) or lighting.
The growth of human civilization is essentially the story of
us getting better at converting more energy more efficiently into more useful
Smil traces the growth of human population from the first
emergence of homo sapiens about 190,000 years ago to today. Rapid population growth only began following
the adoption of agriculture at various times around the world, starting 11,000
– 12,000 years ago in the Middle East. Exponential
population growth really kicked off after 1850 following the Industrial
Ever since, population growth has been accompanied by dire
predictions of famine, most notably by the English scholar Thomas Malthus
who predicted that population growth would always exceed our capacity to produce
enough food for everyone.
Modern-day Malthusians such as the Club of Rome and Paul R. Ehrlich
predicted famines in the 1970’s leading to the deaths of hundreds of millions
“That was a spectacularly wrong prediction. Between 1968 and 2017 the world’s population more than doubled (from 3.5 to 7.5 billion) and yet by 2015 the total number of malnourished people had declined to fewer than 800 million or just below 13% of the world population compared to more than 23% a quarter century before …” [p. 315]
In fact, population growth rates peaked between 1962 and
1969 and began to level off in a typical S-curve pattern. This is because we’ve undergone a “demographic transition”
from high birth rates and high death rates with low overall population
increases to a new equilibrium with low birth rates and low death rates resulting
in low natural increase or even population declines in some places such as Japan
Still, our overall population is growing. How long will that last? When will population peak and at what level? Smil says that long range forecasting is an “inherently uncertain enterprise”. He cites projections for global population in 2100 that vary from 10 billion to 22 billion. Perhaps wisely, Smil does not say what he himself thinks the population will be at that time but he does warn:
“Malthus’s basic assumption is unassailable: the power of population growth is indeed much greater than the capacity to produce adequate subsistence – but that applies only when, as he correctly stated, the population growth is unchecked.” [p. 317]
Environmental Impacts of
There is no chapter or section of the book specifically dedicated
to the environmental impacts of growth, especially climate change, but it is a
Smil tells us that traditional economies relied on biomasss
for energy (burning wood, straw, charcoal, and dung) and on human and animal
labor supplemented by small amounts of water and wind power. We broke out of these energy constraints
during the Industrial Revolution through the burning of fossil fuels, starting
with coal and later adding petroleum and natural gas. He notes the irony of escaping the limitations
of consuming the products of photosynthesis by consuming “stockpiles” of past
These new sources of energy enabled the advances of the past
200 years, but at considerable cost to the environment including deforestation,
soil erosion, biodiversity loss, and of greatest concern, climate change. Since
1850, Smil says, we have emitted almost 300 Gt (that’s 300 billion metric tons)
of fossil carbon into the air, driving atmospheric concentrations of CO2 from
225 ppm to 415 ppm at the end of 2017. [p.
We have made some progress though. The US has reduced CO2 emissions faster than
Germany primarily by switching from coal to natural gas for electricity
generation, for example. And we’re making
more stuff with less raw materials, a phenomenon known as “dematerialization.” However,
“… there is no doubt that since 1973 (when the unprecedented period of rapid post-WWII growth ended) the world economy has become impressively more energy efficient and relatively less material-intensive – while continuing population growth, further increases of consumption in affluent countries, and fast economic advances in Asia in general, and in China in particular, have translated into relatively strong absolute global growth in both energy and material requirements.” [p. 496]
In other words, the tide has not yet turned.
A Post-Growth World?
Many people believe that in order to stop the most harmful
effects of climate change we must fundamentally restructure our societies and
especially our economies. They believe
we need to put an end to our obsession with growth, that sustainability and
growth are fundamentally incompatible, and that we need to live and work, produce
and consume in ways that do not depend on growth.
Smil looks at this question towards the end of the
book. He’s not very encouraging, mainly because
we have so little past experience to go on.
“… no modern society has been taking any thoughtful, effective steps to find its way to deliberately very low or no growth even in settings where a relatively high level of average affluence and obviously excessive levels of consumption and waste are all too evident.” [p. 498]
Japan is a harbinger. Its population has already begun
declining. Smil predicts Japan will become
the first truly geriatric society. Yet
Japan’s economy is still growing slowly.
Economists are apparently not much help because economic model
assume continuous growth supported by technological innovation. And “techno-optimists”
believe that dematerialization will enable wealth creation to gradually
separate from demand for energy and materials.
Smil is deeply skeptical of any such claims. He acknowledges progress in relative dematerialization:
individual artifacts can be produced with less materials and energy. But as long as population keeps increasing
there will be no absolute dematerialization. Total demand for energy and materials will
He cites research that concludes:
“… growth in GDP ultimately cannot plausibly be decoupled from growth in material and energy use, demonstrating categorically that GDP growth cannot be sustained indefinitely.” [p. 492]
Smil refers to different economic thinking by economist Kenneth Boulding
who suggested we need to move from a “cowboy economy” where unlimited resources
can be recklessly exploited towards a “spaceman economy” where the earth is s
spaceship with no unlimited resources.
Of course it is impossible to predict how long we can
continue on our present path, or what exactly the outcome will be.
“Ultimately it comes down to the biosphere’s capacity to support an expanding population consuming at higher rates.” [p. 502]
But, echoing Greta Thunberg, Smil says,
“Continuous material growth, based on ever greater extraction of the Earth’s inorganic and organic resources and on increased degradation of the biosphere’s finite stocks and services, is impossible.” [p. 511]
Good life within planetary boundaries is possible, he says,
but not without a fundamental restructuring of how we produce and consume. And we have no time to waste. Smil concludes the book with:
“I believe that a fundamental departure from the long-established pattern of maximizing growth and promoting material consumption cannot be delayed by another century and that before 2100 modern civilization will have to make major steps towards ensuring the long term habitability of its biosphere.” [p. 513]
Growth was a long and difficult book (leading to a
long and difficult review – thanks for sticking with me!). As you can probably tell from the quotes, Smil’s
writing is dry, dense and academic, although he does get a little snarky once
in a while.
Growth is at heart an academic work. It’s a magnum opus on the subject of growth. I’m in awe of the breadth of its scope and the depth of its scholarship. The book is insanely well-researched. Practically every paragraph in its 513 pages contains one or more academic citations. The References section runs an additional 100 pages.
I did not read every word of it. I skimmed over topics that I was less
The overall message of Growth is sobering, especially
for a “techno-optimist” like me. Indefinite
exponential growth is impossible. We cannot
predict when or how growth will come to an end, only that it will end if we
continue on our present trajectory. We
have few guideposts and very little experience for how to move towards a low-
or no-growth civilization. But we must act
quickly to avoid catastrophic degradation of the biosphere.
These conclusions aren’t new or unique to Smil. So why did he write such a massive, sprawling
Perhaps Growth’s most important contribution is to shed light on recurring patterns that span the natural and human-made worlds. It’s an evidence-backed antidote for anyone proposing quick technical fixes or “this-time-it-will-be-different” forecasts.
But in the end it left me unsatisfied. Smil draws useful boundaries around how to
address the problem of growth but he doesn’t make specific prescriptions or even
suggest general approaches that he thinks might work or could be worth trying. Maybe he feels that’s not his job, or that he
would just be speculating. Still I found
this is the most disappointing aspect of the book.
Vaclav Smil: Growth must end — interview with Vaclav Smil in The Guardian