What is the significance, if any, of being briefly alive and aware in the early twenty-first century?

The immediate focus of this question is on our time right now; but in imagining this significance, it is essential to place ourselves in the context of history, beginning with the creation 13.8 billion years ago, out of an unknown nothingness, something we call our universe and within it a ticking clock embodying time and thus the possibility of history, the trace time leaves in space. This history has many aspects: the early physical aspect involving the creation of forces, fields, and particles; the coalescing of particles into simple atoms as the primordial plasma cools and transparency ensues; the accumulation of hydrogen, helium and a trace of lithium into stars. Following is the area of cosmology, the story of star generations with their life and supernova deaths creating complex atoms beyond the first three kinds and their galaxies revolving around massive black holes. Then comes geology, considering the ages of our planet with the creation of life, stratigraphy, continental drift, and various eras as life becomes complex and finally the accident of early forms of pre-humans. Then anthropology studies the evidence left by early forms of humanity until ultimately writing develops and traditional history begins.

Traditional history has countless themes, all possible subjects of future consideration: the wars, the technology, the growth of culture, the empires, the human urge to create art and music, the understanding of how it was in the past; and finally, that we are here looking back at all of this history, knowing the wonder of the whole story, but knowing also that we are still fundamentally animals with our emotions controlling our formidable intellects. Perhaps the significance of our time is that the universe could throw up a being whose very existence could be, for us, anyway, an event of significance in the universe.

As a first example of our human story and its possible significance I’ll consider how we humans have used our inventive brains to increase the carrying capacity of our environment to the extent that the environment itself becomes endangered by our very numbers and activities. In considering how any animal’s population fluctuates in response to changes in the ecosystem in which it lives one encounters many simplified stories of overpopulation, followed by a crash, followed by a recovery and a new overpopulation. Such life stories of a single species are actually the exception, however. And even in a so-called typical case one is apt to find that there is a complexity within the apparently simple story. The bio-sciences are not as straightforward as the physical sciences I’m more accustomed to, which is, in fact, to me one of their main attractions. Thus, it is not surprising that the story of human population growth is not simple. Even a broad-brush narrative such as I am giving here, has its somewhat paradoxical wrinkles. I’ll start this account by considering an interesting book. In this part of hoalablog I will often make a practice of bringing up and talking about books I’ve read, not so much reviewing them as using them as a launching pad for discussion or as a source of relevant ideas.

When I first began to write this piece, I remembered reading this book, but I had completely forgotten the name of the author or the title of the book. The book concerned the story of the early industrial revolution, invention, and the steam engine which was its centerpiece. It was a readable book and I knew it would be relevant. In a “what-the-hell” moment I googled “industrial revolution”, in what seemed to me a futile quest. To my surprise one of Google’s featured books was The Most Powerful Idea in the World: A Story of Steam, Industry and Invention by William Rosen. I read a review or two in Amazon, and upon dipping into the book via Amazon’s “look inside” feature, it became clear that this was indeed the book I was trying to remember. Idle curiosity then led me to figure out when I had read it. I checked out the Bend Library and it wasn’t there. I didn’t own it and it wasn’t in my Kindle library so I must have found it in the Eugene library and read it before 2013, the year we moved to Bend. The book was published in 2010, so this thought is plausible.

The main theme of Rosen’s book is the story of how humanity escaped what has been called “the Malthusian Trap”. This phrase refers to the theory expounded in Robert Malthus’s influential book, An Essay on the Principle of Population, published in 1798. Malthus’s idea is that population growth is inherently exponential while food supplies will only increase linearly. The result is that any increase in food supply is overwhelmed by population growth which means that a large portion of the population will always be on the brink of starvation. (An example of exponential growth is a doubling series – 1, 2, 4, 8, 16, 32, … while the corresponding linear series is – 0, 1, 2, 3, 4, 5, … .) I remember learning about Malthus as I sloughed through Stanford University’s famous course A History of Western Civilization¹ in the academic year 1947- 48. At that time, I was lazy and bored by history so I skipped most of the reading and simply took notes and paid close attention in class to the young, charismatic professor, managing to pass the course and come away with some knowledge. Besides Plato’s Phaedo, one selection I did read was an excerpt from Malthus’s book. His idea was new to me and I was impressed by his logic.

Going back to the early history of homo sapiens, starting some 2 to 3 hundred thousand years ago I suspect that Malthus’s ideas don’t apply to our situation as hunter-gatherers during that era. In a hunter-gatherer society the population is kept under control, more or less, in the same manner as for any other animal. We have abundance and starvation, war with other tribes and always accidents and disease, keeping a largely static population and an undisturbed environment. We did cause a few environmental problems during this era; notably the extinction of some megafauna, but though this is probably regrettable, these extinctions posed no massive environmental threat. With the advent of agriculture some 6 or 7 thousand years ago we gained control of our food supply and fell into a Malthusian trap. Rosen estimates that in the 7600 years between 6000 B.C and 1600 A.D world population increased from 5 to 500 million, with a doubling every thousand years or so. Although this population increase is large in absolute terms, the annual fractional increase is only about 0.000606. (I won’t get into the details of how one comes up with that number. God forbid that one brings serious math into history; or, for that matter, history into physics, chemistry or engineering. However, see a brief appendix at the end of this piece for details.) During this era of agriculture being the dominant economic activity, there was a food supply that could support a slowly increasing population. Although life was miserable for most people as per Malthus, a surplus of food, unevenly distributed, gave rise to occupations besides farming. Over these thousands of years, the food surplus allowed technology and culture to grow. Finally, in the west the scientific revolution occurred during the late 16th century onwards. However, this revolution did not allow us to escape the Malthus dictum. Life for most remained marginal and precarious.

Rosen’s Most Powerful Idea goes into the history of the steam engine in great detail telling of Thomas Newcomen’s first commercially successful engine of 1712 used for pumping water from coal mines, followed by decades of incremental improvements until in 1764 James Watt made a huge breakthrough which brought on the industrial revolution’s full flower. The engine was used in factories and most notably in steam locomotives, enabling railways to spread in England, the United States, and the Continent. Still later in the century steam largely replaced sail on ocean vessels. Rosen considers that the “most powerful idea” of the times during which the steam engine was developed and applied, was the patent system which democratized invention, adopted in England during the mid-1700’s. With the patent system both the incentive and the mechanism were in place for anyone to reap the rewards of invention. According to Rosen it was the flourishing of invention which lay behind the industrial revolution and ultimately expanded the economy, breaking us out of the Malthusian trap.

It should be noted that this breaking of the trap was not immediate. In the early years of the 1800’s as textile factories replaced skilled workers with the less skilled who could produce more under miserable working conditions with lower wages, the Luddite movement arose. Later, after parliament passed a reform act in 1832 which did not extend voting rights to those without property, the chartist movement came into being. Nevertheless, as the nineteenth century wore on, a tremendous number of new niches appeared in the ecology of the economy and a significant middle class arose in Europe and America. Between around 1860 to 1940 while the population grew rapidly, this growth did not seriously impact the environment. I can recall the life my parents lived in the late 1930s, a time, at least in Hawaii, when a peak was reached in enlightened employment practices. My Dad went to work as an accountant in the morning at 8 am. He had a half-hour off for lunch and finished the day at 4 pm, giving him ample time to swim at Waikiki for an hour or so before dinner with his wife and kids. He and my mother could afford to build two homes before the war came to us on Dec. 7, 1941. Around 1944 in school, I learned that the world population was now 2 billion, so there had been a substantial increase during the 344 years since1600 when the population was around 500 million.

Of course, after the war there was a population explosion and by now in 2024 there are numerous worrisome environmental impacts. We can summarize human population growth in a “big picture” way by saying that after the agricultural revolution, human numbers grew slowly with numerous ups and downs for 7000 years or so, subject to Malthus’s Law. The histories of this period neglect the miserable condition of the great mass of humanity, concentrating on the wars, the culture, and the innovations of a small fraction. With the industrial revolution, at least in the West, there was a breakout from the Malthusian Trap, which allowed a better life for many within a rapidly increasing population, driven by invention, but without the danger of the imminent extinction of humanity if not all of life. After World War II, the population grew frightfully fast with an increasingly better life for those in “first world” countries; but with the invention of the atomic bomb and the sheer numbers of people threatening the environment we now do face threats of extinction.

Some numbers substantiate the story above. I’ve already pointed out that during the agricultural era the world population increased from 5 to 500 million with an average doubling time of 1000 years and a fractional growth rate of 0.000606 per year. From 1600 to 1944 the world population increased from 500 million to 2 billion. Population doubled twice in those 344 years, giving a doubling time of 172 years and an annual fractional rate of increase of 0.00402. Finally, in the 80 years since 1944, population has again doubled twice, reaching 8 billion in 2023, giving a doubling time of 40 years and an annual rate of 0.017. To obtain an annual percent increase, commonly found in contemporary studies of population growth, one simply multiplies these annual fractional rates by 100.

Fortunately, the situation is not quite as dire as the last figures would suggest. It seems that one assumption made by Malthus is incorrect: as people’s affluence increases in a modern society, the extra wealth does not result in population growth. Instead, the cost of raising children goes up, the child mortality rate goes down, and birth control becomes available. There is also in many areas the possibility of abortion. As a result, the rate of population growth has gone negative in many first world countries and even in many third world countries the rate, though positive, is going down. The situation since WWII has been extensively considered and one can find many results on the internet. For example, the link

https://www.macrotrends.net/global-metrics/countries/WLD/world/population-growth-rate

has graphs of world population and the percentage growth rate from 1950 to 2024 and projections into the future. According to the year-by-year growth rate, the highest growth of 2.2% occurred in 1963, while in 1991 the decreasing rate dropped below the average, 1.7%, I calculated. The current growth rate, according to this study, is 0.9%.

Projections into the future are, of course, controversial. This particular estimate is about average for the few studies I’ve looked at. It projects the growth rate for the world to go negative in 2086 with a maximum world population of 10.43 billion at that time.

This study and others however, neglect the numerous threats our current times provide. A recent New Yorker article (June 10, 2024) examines a University of Chicago course entitled “Are we Doomed?”, which considers various scenarios of disaster. After many guest lectures and discussions, students in the course considered that the most serious threat would be the break-out of nuclear war. Climate change they concluded had the main effect of increasing the risk of nuclear war. There are many other threats. I’ve just read an interesting book, The Blue Machine: How the Ocean Works, by Helen Czerski, a physicist turned oceanographer. Most of the book simply considers the workings of the “blue machine” as far as we know them; but the last chapter considers the threats oceans face, using the knowledge explored earlier. Collapse of ocean life support systems, however, is only one of many environmental threats. I could doubtless write an entire piece about threats to our existence using Czerski’s book as a touchstone as well as another favorite, The Ministry for the Future by Kim Stanley Robinson. Perhaps I will.

It seems clear to me that the story of human world population growth, which I’ve told here, is indeed one matter of significance for an aware person of the early twenty-first century.

Appendix – Calculating Population Growth Rates

The basic equation for annual population growth is

P_{next year} = (1 + r) times P_{this year},

Where the P’s are population numbers and r is the rate of annual increase per year.

This equation has to be applied hundreds or thousands of years at a time when one considers population growth over long periods of time. The calculation is similar to that of investing when one wants to know the compound interest rate, knowing what one’s principal amount is at the beginning and end of a time period. With interest, one compounds daily and uses an Excel spread sheet with its automated repeat feature. With the population equation above, the built-in compounding time is one year.

Fortunately, there is a simple highly accurate approximation in any case of compound growth; namely, the exponential growth equation

P_{time t} = P_{time 0} e^rt

Where P is the population, r is the rate, t is the time period and e the base of nature logarithms with a value of 2.718… . Note that the quantity rt is dimensionless, r being a rate and t being a time; e.g. a rate is a fraction per year and t is a time in years. One can, in fact argue that the exponential growth rate equation defines r rather than the equation at the top.

To use the growth equation, make an algebraic rearrangement and then take the natural logarithm, ln, of both sides, obtaining

            rt = ln (P_t / P_{t zero})

In our first calculation the ratio of the P’s is 100 with a natural log of 4.605.  (In one’s calculator turn it sideways to bring up the ln function.) Enter 100 and tap ln. Then divide by 7600, the number of years to get an r of 0.000606. Back to Top

1. See Post History I ↩︎