To the Last Breath: Population Growth, Superabundance, and the Problem of Oxygen on the Earth and Beyond the Earth

While I am in my office this morning before dawn thinking about the mind's dependence on oxygen in the Earth's atmosphere, I hear my 94-year-old mother-in-law in her bedroom a few steps away from my office struggling against death as she labors to breathe. 

I am reading a new book by Marian Tupy and Gale Pooley--Superabundance: The Story of Population Growth, Innovation, and Human Flourishing on an Infinitely Bountiful Planet.  Tupy and Pooley challenge the common belief of many people throughout history that there must be an inverse relationship between population growth and available natural resources, so that as population grows, resources become increasingly scarce.  In his 1798 book Essay on the Principle of Population, Thomas Malthus presented the most influential statement of this idea:  while population grows geometrically (1, 2, 4, 8, 16, . . .), food production grows arithmetically (1, 2, 3, 4, 5, . . .), and consequently growing population must eventually outstrip food production, and many people must then starve to death.  The modern ecological and environmentalist version of this argument is that the unprecedented growth of world population, which recently surpassed 8 billion people, has long ago exceeded the supply of natural resources necessary to support this huge human population: such a population growth is "unsustainable."  For example, the Global Footprint Network has developed the Ecological Footprint as a measurement of human demand for natural resources.  They estimate that the world currently needs the resources of 1.75 Earths to satisfy the human demand for natural resources, and by 2030, this could rise to 2 Earths.  Obviously, they insist, since we have only 1 Earth, this proves that Malthus was right, because we have now gone beyond the Malthusian limit to human population growth; and to avoid ecological collapse, we must either severely reduce the human population, or we must severely reduce our high modern standard of living that is depleting the Earth's natural resources.

Tupy and Pooley argue that this is not really true.  Over the 225 years since the publication of Malthus's book, there has been a stunning increase in the global human population--from about 900 million in 1800 to over 8 billion today--and yet the Malthusian prediction of apocalyptic catastrophe from unchecked population growth has not come true.  The mistaken thinking in the Malthusian argument became clear in the debate between Paul Ehrlich and Juian Simon.

I have written previously about this debate and how it confirms the evolution of human progress through the Liberal Enlightenment.

THE HUMAN MIND AS THE ULTIMATE RESOURCE

In 1968, Ehrlich (a biologist at Stanford) began his popular book The Population Bomb with this paragraph:

"The battle to feed all of humanity is over.  In the 1970's the world will undergo famines--hundreds of millions of people are going to starve to death in spite of any crash programs embarked upon now.  At this late date nothing can prevent a substantial increase in the world death rate, although many lives could be saved through dramatic programs to 'stretch' the carrying capacity of the earth by increasing food production.  But these programs will only provide a stay of execution unless they are accompanied by determined and successful efforts at population control.  Population control is the conscious regulation of the numbers of human beings to meet the needs, not just of individual families, but of society as a whole" (11).

Ehrlich's Malthusian prediction of catastrophe from unchecked population growth did not come true. Norman Borlaug's development of new high-yield varieties of food grains--the "green revolution"--allowed high-population countries like India to produce so much food in the 1970s that they actually became exporters of grain.  And while the world population in 1968 was three and one half billion, the world population today is over 8 billion, and yet the rate of global famine and poverty is much lower today than in 1968.

This confirms the prediction of Julian Simon--in contrast to Ehrlich--that population growth does not lead to a shortage of resources, because a growing population means not only more labor but also more people with more ideas about how to solve our problems, and as long as there are the incentives of a free market economy, people will make resources more plentiful through more efficient uses of resources, increased supply, and the development of substitutes.  Consequently, Simon argued, a growing population creates not scarcity but abundance!

In 1980, Simon challenged Ehrlich to make a bet with him.  Ehrlich could select a basket of raw materials that he expected would become less abundant and consequently more expensive over some designated time period.  At the end of that time period, the inflation adjusted price of those materials would be calculated.  If the price was higher, Ehrlich would win the wager.  If the price was lower, Simon would win.  Ehrlich chose copper, chromium, nickel, tin, and tungsten; and he chose 1980 to 1990 as the time period.  By 1990, the world population had increased by 873 million from 1980, but all five of the commodities that Ehrlich had selected had declined in price by an average of 57.6 per cent.  Ehrlich mailed Simon a check for $576.07.

Some of Ehrlich's supporters have tried to argue that Simon was just lucky, because if they had selected a different time period, Ehrlich could have won the bet.  But in 2016, some economists pointed out that in 2015 Ehrlich's five metals were 22.4 percent cheaper than they were in 1980.

Recently, Gale Pooley and Marian Tupy have developed a new way to measure the availability of resources, which confirms Simon's argument.  They have compiled the latest price data for 50 important commodities covering energy, food, materials, and metals.  They then have calculated the "time-price" of these commodities--in terms of the global average hourly income, the "time-price" is the amount of time that an average human has to work in order to earn enough money to buy a commodity.  By that standard, the real price of Ehrlich's minerals has declined in every year from 1980 to the present.  Pooley and Tupy also found that from 1980 to 2018, the real price of their basket of 50 commodities fell by 36.3 percent, and the time-price fell by 71.6 percent.  As compared with workers in 1980, workers in 2018 were able to buy some 252 percent more goods and services with their hours of work. Over that same period, population rose by 71.2 percent.  Thus, a huge increase in population brought not a scarcity of resources, as Malthus and Ehrlich would predict, but a huge increase in resources, which is what Pooley and Tupy call "superabundance" (1-2).

Their explanation for why Simon won his bet with Ehrlich is based on their Hayekian understanding of how the price system works to generate abundance:

"The relationship between prices and innovation is dynamic.  Relative scarcity leads to higher prices, higher prices create incentives for innovations, and innovations lead to abundance.  Scarcity gets converted to abundance through the price system.  The price system functions as long as the economy is based on property rights, rule of law, and free exchange" (5).

As long as the price system functions in a free society, the ultimate resource is not the material resources of the Earth but the intellectual resources of the human mind.  Increasing population means more minds with new ideas for solving problems, and the pricing system provides the incentives for people to try out their ideas, and the best ideas will prevail in the marketplace.

As I have argued in a previous post, this shows how classical liberals recognize that liberty promotes the growth of population.  Many thinkers of the Liberal Enlightenment in the 18th century saw this.

David Hume, for example, in his long essay on "Of the Populouness of Ancient Nations," criticized ancient nations for having a lower growth in population than modern nations, and he argued: "every wise, just, and mild government, by rendering the condition of its subjects easy and secure, will always abound most in people, as well as in commodities and riches. . . . if every thing else be equal, it seems natural to expect, that, wherever there are most happiness and virtue, and the wisest institutions, there will also be most people" (Essays, Liberty Fund, p. 382).  Hume believed that population was growing faster in modern nations than in ancient nations because there was more liberty in modern nations: "human nature, in general, really enjoys more liberty at present, in the most arbitrary government of Europe, than it ever did during the most flourishing period of ancient times" (383).  After all, the primary difference between the economic life of the ancients and that of the moderns was the practice of slavery among the ancients.  Like Hume, Etienne Damilaville, in his article on "Population" in the French Encyclopedia, edited by Diderot and d'Alembert, claimed that liberty fosters a growing population, because "it is under mild, limited governments, where the rights of humanity are respected, that men will become numerous" (Encyclopedic Liberty, Liberty Fund, p. 502).  It was this belief that growing population was a sign of human progress in a free society that was challenged by Malthus.

In his Foreword to Tupy and Pooley's book, George Gilder explains this Malthusian pessimism about population growth leading to a scarcity of resources as based on the "materialist superstition."

"The materialist superstition is this:  that wealth consists of things rather than thoughts, of accumulated capital rather than accumulated knowledge--that people are chiefly consumers rather than creators, mouths rather than minds."

". . . Thomas Sowell, expounding the argument that wealth is essentially knowledge, not material resources, wrote, 'The cavemen had the same natural resources at their disposal as we have today, and the difference between their standard of living and ours is a difference between the knowledge they could bring to bear on those resources and the knowledge used today.'"

What we need, Gilder observes, is an "economics of mind" that recognizes that wealth arises "not by accumulating matter but by replacing it with mind" (xvi-xvii).

This elevation of mind over matter as the source of wealth is only partially true, however, because it ignores the simple fact that minds depend on matter, and particularly matter as it exists in the biosphere of the Earth today.  It is not clear, therefore, that the "economics of mind" has any application to anywhere in the Universe beyond the ecological conditions of the Earth today.

THE ELEMENTS OF MATTER AND MIND

What I mean by "matter" is displayed in Charles Cockell's "Astrobiological Periodic Table of Elements":

To read this Table, you will need to enlarge it.

I should say here that I am speaking of "matter" in the ordinary sense, which ignores the Dark Matter hypothesized to exist by many scientists, which might be over 95% of the matter in the Universe.  This exotic form of matter has no direct relevance to life.

Mind depends on matter in the sense that mind can exist only through a particular combination and structure of these elements.  For example, the element oxygen with atomic number 8 is essential for the human mind.  If my mother-in-law is deprived of oxygen for more than a few minutes, she will die, and her mind will disappear, because her brain cannot function without a steady supply of oxygen.  For that reason, we have a tank of oxygen next to her bed, so that we can artificially increase her oxygen.  The elements sodium with atomic number 11 and potassium with atomic number 19 are also essential for the brain, because the sodium-potassium pump found in the membrane of all animal cells provides energy for the firing of nerve cells.  My mother-in-law's low levels of sodium and potassium have caused her to be mentally confused, and so we have been trying to increase her intake of those elements.

Studying the Astrobiological Periodic Table tells us a lot about the material basis of the human mind and life, and how the Earth's biosphere might be unique in the Universe as the one place adapted for supporting human intelligent life, if only for a few million years.

Except for the artificial elements that must be artificially created in laboratories, the other elements found in nature originate from the astrophysics of the Universe--from the Big Bang, low mass stars, high mass stars, supernovae, or cosmic rays.  Most of these elements can have some use in supporting some kind of life.  But six of them are essential in all known life--carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur (known by the acronym CHNOPS).  Carbon is the most versatile backbone of molecules, which is why we speak of "carbon-based" life.

That all of these elements supporting life are found throughout the Universe might suggest that life is pervasive in the Universe.  But actually life requires a structuring of these elements that seems unique to the Earth beginning about 3.5 billion years ago.  If there is any extraterrestrial life, it has yet to be found.  Even if it is found, it is likely to be limited to microbial life, because the conditions for multicellular plant and animal life are so difficult to achieve.

Even life on Earth is likely to endure for what will be only a brief moment in the history of the Universe.  From what we know about the evolution of stars, we can foresee that the Sun will turn into a Red Giant star several billion years from now, and the Earth will be a dead planet.  Even before then, the increasing luminosity of the Sun will extinguish all animals and then all plants.

As indicated in some previous posts, all animal life, including human life, depends on the energy derived from breathing the atmospheric oxygen generated by oxygenic photosynthetic organisms such as plants, algae, and cyanobacteria.    There was little oxygen in the atmosphere until about 2.4 billion years ago, when photosynthetic cyanobacteria began to raise the level of oxygen, and now oxygen is about twenty percent of the atmosphere. 

Electrons are the source of energy for all life.  Like other aerobic organisms, we eat organic carbon as the electron donor, and we breathe in atmospheric oxygen as the electron receptor.  The electron transport chain in the membranes of our cells forms ATP (adenosine triphosphate), which is the universal energy currency for life.  This all depends on photosynthesis creating organic carbon and atmospheric oxygen.

Only a few kinds of organisms can live independently of photosynthesis.  Methanogens (microorganisms that produce methane) live in the deep subsurface of the Earth.  They use hydrogen as an electron donor and carbon dioxide as both an electron acceptor and a source of carbon for making methane (one carbon atom bonded to four hydrogen atoms).  Methanogens might show us the evolution of the first metabolisms, and we might look for that on other planets.

If there were not enough carbon dioxide in the atmosphere, photosynthesis would shut down.  Right now, that doesn't seem to be a problem because human activity has been raising the level of atmospheric carbon dioxide over the past two centuries.  But scientists project that over the longer term--somewhere between a hundred million and a billion years into the future--this carbon dioxide will disappear, photosynthesis will then stop, and all the life that depends on photosynthesis on the planet will die.

If we're lucky, we can hope to prolong the life of our species and other species for a few more centuries or millennia.  But we cannot hope to prolong life forever, because we live in an evolving universe that does not care about us or for us, and the evolutionary conditions sustaining human life and all living beings are enduring but not eternal.  Eventually, everything we love and everything that lives will die, and the Earth will become just another dead planet.  That's what Leo Strauss identified as "the most terrible truth" of Lucretian evolutionary atomism.

But surely, we might hope, long before the extinction of life on Earth, human beings will have colonized other planets, perhaps even beyond the Solar System.  And if they establish free societies with pricing systems that reward innovative ideas for promoting a flourishing life on those planets, then they can generate the superabundance that sustains growing populations, and human life will proliferate in the Universe beyond the Earth.

THE PROBLEM OF OXYGEN AND THE POSSIBILITY OF EXTRATERRESTRIAL LIBERTY

But as we have seen, astrobiologists like Charles Cockell warn that achieving such extraterrestrial liberty will require that we solve the "problem of oxygen."  Cockell worries that the extreme conditions in the universe beyond the Earth's biosphere--especially, the lack of oxygen in a breathable atmosphere--will tend to promote tyranny, because those who control the technology for supplying oxygen and the other basic commodities necessary for life (such as water and food) will have tyrannical power over those dependent on this technology of life support.  To counter this tendency to extraterrestrial tyranny, he lays out proposals for how the liberal institutions for promoting liberty on Earth could be applied to the design of human settlements in space, particularly on Mars, the one planet most like the Earth.  As is characteristic of classical liberalism, he looks for ways to limit, divide, and decentralize power to protect liberty and avoid tyranny.

Consider how one might solve the problem of oxygen on Mars in a way that could promote liberty rather than tyranny.  Compared with the Earth, the atmosphere of Mars is very thin, and most of it--95%--is carbon dioxide.  It has only trace levels of oxygen (0.174%).  The Malthusian would conclude that such a severe scarcity of a natural resource necessary for human life must make human habitation on Mars impossible.

It is possible, however, to build machines that can extract oxygen from atmospheric carbon dioxide--by splitting carbon dioxide molecules into oxygen and carbon monoxide, so that the oxygen atoms combine to form gaseous oxygen.  NASA built such a machine--the MOXIE (Mars OXygen In-situ resource utilization Experiment) for the NASA Mars Perseverance rover.  On April 20, 2021, this machine successfully produced oxygen on Mars.  This demonstrated in principle that we could build personal oxygen machines for Mars that could be individually owned and mass produced.  A free-market pricing system with private property rights could create incentives for developing the most efficient machines.  And as long as the production and distribution of these machines is decentralized, there should be no central control of these machines that could be used for tyrannical power.

While this illustrates how mind depends on matter (the mind's need for oxygen), it also illustrates how mind creates innovative ideas about how to better secure those material resources such as oxygen, and how this can be done best through a pricing system that secures human life and liberty, and the growth of human populations, even on Mars.

Mars Isn't Turner's Frontier. But It Could Become Zubrin's Frontier of Innovation for Abundance.

Zach and Kelly Weinersmith have written an article for Foreign Policy--"Space Isn't the Final Frontier"--ridiculing "Mars fantasists" who "still cling to dreams of the Old West" on Mars.  The target of their ridicule is the American Frontier Thesis of Frederick Jackson Turner and the metaphorical extension of that thesis by people like Robert Zubrin who claim that space, and particularly Mars, is America's New Frontier.  

The Weinersmiths are partly right and partly wrong.  They are right in criticizing Zubrin's naive acceptance of Turner's frontier thesis and then applying it to Mars.  But they are wrong in not seeing that a revised version of Turner's thesis is defensible and supports Zubrin's anti-Malthusian idea of unlimited abundance created by the human mind and technology, which could be extended to Mars.

In 1893, Turner delivered a lecture to a meeting of the American Historical Association in Chicago entitled "The Significance of the Frontier in American History."  He began by quoting from a bulletin of the Superintendent of the Census for 1890, which announced that there was no longer a clear line of Western frontier settlement because the unsettled area was broken up by isolated bodies of settlement.  Turner observed: "This brief official settlement marks the closing of a great historic movement.  Up to our own day American history has been in a large degree the history of the colonization of the Great West.  The existence of an area of free land, its continual recession, and the advance of American settlement westward, explain American development."

From the time the European immigrants first settled on the Atlantic coast of America, Turner argued, there was always "free land" in the West, which attracted pioneer settlers who reverted to the original primitive conditions of human evolution and then advanced through all the universal stages of human social evolution: from the hunter to the trader to the rancher to the miner to the farmer and finally to the urban factory worker.

In their struggle to overcome the harsh conditions of life on the frontier and to build a new human civilization, the pioneers in the American West developed all the moral and intellectual traits of the uniquely American national character.  Turner explained: "That coarseness and strength combined with acuteness and inquisitiveness; that practical, inventive turn of mind, quick to find expedients; that masterful grasp of material things, lacking in the artistic but powerful to effect great ends; that restless, nervous energy; that dominant individualism, working for good and for evil, and withal that buoyancy and exuberance which comes with freedom--these are the traits of the frontier, or traits called out elsewhere because of the existence of the frontier."

But Turner also suggested that there had been a tragic turn in this epic story of the American frontier.  If the frontier was closed by 1890, that suggested that the vitality of the American character--its individualism, inventiveness, and love of freedom--would fade away if it were no longter nourished by the challenge of settling a frontier.  Surely, then, Americans needed to find a new frontier that would revive the old frontier spirit of the American West.  That would become a recurrent theme of American political rhetoric.

And, indeed, when John Kennedy was nominated as the Democratic candidate for President in 1960, he promised that if elected, he would lead Americans as pioneers into a New Frontier.  Speaking at the Democratic Party Convention at the Los Angeles Memorial Coliseum, he declared his new version of Turner's Frontier Thesis:

"I stand here tonight facing west on what was once the last frontier.  From the lands that stretch three thousand miles behind us, the pioneers gave up their safety, their comfort and sometimes their lives to build our new West.  They were not the captives of their own doubts, nor the prisoners of their own price tags.  They were determined to make the new world strong and free--an example to the world, to overcome its hazards and its hardships, to conquer the enemies that threatened from within and without."

"Some would say that those struggles are all over, that all the horizons have been explored, that all the battles have been won, that there is no longer an American frontier.  But I trust that no one in this assemblage would agree with that sentiment; for the problems asere not all solved and the battles are not all won; and we stand today on the edge of a New Frontier--the frontier of the 1960's, the frontier of unknown opportunities and perils, the frontier of unfilled hopes and unfilled threats."

. . .

"The New Frontier is here whether we seek it or not."

"Beyond that frontier are uncharted areas of science and space, unsolved problems of peace and war, unconquered problems of ignorance and prejudice, unanswered questions of poverty and surplus.  It would be easier to shrink from that new frontier, to look to the safe mediocrity of the past, to be lulled by good intentions and high rhetoric--and those who prefer that course should not vote for me or the Democratic Party."

"But I believe that the times require imagination and courage and perseverance.  I'm asking each of you to be pioneers towards that New Frontier. . . ."

Early in his presidency, in the spring of 1961, Kennedy explained that the "uncharted areas of science and space" in the New Frontier would include landing men on the Moon and returning them safely to Earth before the end of the decade.  That launched the "race to the Moon" that ended with the first landing of Americans on the Moon on July 20, 1969.

                                             Did the U.S. Go to the Moon to Beat the Soviets?

There have been no human beings on the Moon since the Apollo 17 crewed landing on December 7, 1972.  And the original NASA plan to land humans on Mars was never executed.

But then, in 1996, Robert Zubrin's The Case for Mars was published; and it revived interest in landing humans on Mars and even colonizing it.  Inspired by his reading of the book, Elon Musk founded SpaceX in 2002 with the goal of having a crewed landing on Mars within his lifetime.

Just as Turner had identified "The Significance of the Frontier in American History," Zubrin identified "The Significance of the Martian Frontier" (2019: 271-86; 2021: 323-34).  JFK's New Frontier would have to be extended to Mars: "Free societies are the exception in human history--aside from isolated pockets, they have only existed during the four centuries of frontier expansion of the West.  That history is now over.  The frontier opened by the voyage of Christopher Columbus is now closed.  If the era of Western humanist society is not to be seen by future historians as some kind of transitory golden age, a brief shining moment in an otherwise endless chronicle of human misery, then a new frontier must be opened.  Mars beckons" (2021: 332-33).

Against this, the Weinersmiths argue that the Turner frontier thesis is incorrect, and it's a bad model for space settlement rhetoric.  Professional historians no longer accept the Turner thesis, they insist.  And they quote the American West historian William Cronon who wrote back in 1987: "In the half century since Turner's death, his reputation has been subjected to a devastating series of attacks that have left little of his argument intact."  But the Weinersmiths ignore what Cronon said about the ultimate truth of a revised version of the Turner thesis that is similar to Zubrin's argument about the sources of American abundance in the human mind.

Cronon saw that historians had made two kinds of critiques of Turner's thesis.  The epistemological critiques noted the vagueness in Turner's use of the word "frontier."  It "could mean almost anything: a line, a moving zone, a static region, a kind of society, a process of character formation, an abundance of land" (Cronon 1987: 158).  The empirical critiques argued that the history of frontiers was far more complex--culturally, economically, and politically--than Turner recognized.  The frontier experience of French Canada, the Spanish Southwest, and South America was very different from that of Anglo-American settlements.  Even the Anglo-American frontiers did not conform to Turner's characterization.  For example, the rates of upward mobility in the West were not much different from those in the urban areas of the East.

And yet Cronon's final conclusion is that an improved revision of Turner's thesis is correct.  "Turner's notion of the 'frontier' may be so muddled as to be useless, but if Turner's 'free land' is a special case of Potter's American abundance, then the general direction of Turner's approach remains sound" (Cronin 1987: 175).  "Potter's American abundance" refers to David Potter's People of Plenty.  In that book, particularly in his chapter 7 on "Abundance and the Frontier Hypothesis," Potter argued that Turner had failed to see "that the frontier was only one form in which America offered abundance," and that "other forms of abundance had superseded the frontier even before the supply of free land had been exhausted" (Potter 1954: 156).  If we define "frontier" more broadly as "the edge of the unused," then we can see 

". . . that science has its frontiers, industry its frontiers, technology its frontiers, and that so long as Americans can advance their standards of living and maintain the fluidity of their lives and their capacity for change along these frontiers, the disappearance of the agrarian frontier is not at all critical.  In terms of abundance, Turner was correct in saying, 'Never again will such gifts of free land offer themselves,' but his implication that nature would never again offer such bounty is open to challenge, for the frontiers of industry, of invention, and of engineering have continued to bring into play new resources quite as rich as the unbroken sod of the western frontier" (1954: 157).

This confirms Zubrin's anti-Malthusian thesis about how abundance is created by human beings--by their ideas and their inventiveness in transforming natural raw materials into natural resources that can sustain an ever-growing human population enjoying ever-growing wealth.  This is what some scholars have called "superabundance":  in a free society--with private property, rule of law, and free exchange--there will be incentives for innovative solutions to human problems that will create new wealth, which has allowed the human terraforming of the Earth so that today it can support over 8 billion people.  

According to Thomas Malthus, this was supposed to be impossible, because as the human population grows, it must quickly exhaust the natural resources of the Earth for supporting human life.  But what Malthus failed to see, as Zubrin argues, is that natural resources are not inherently finite, because the capacity of the human mind to invent ways to transform natural raw materials into natural resources is infinite.  For example, for thousands of years, oil was worthless for human beings, until human minds discovered the technology for using oil as a fuel for machines.  And as oil becomes scarce, human beings devise ways to make the search for oil more efficient or to find substitutes for it.

Zubrin quotes this remark from two Malthusians--Paul Ehrlich and John Holdren--writing in 1971:

"When a population of organisms grows in a finite environment, sooner or later it will encounter a resource limit.  This phenomenon, described by ecologists as reaching the 'carrying capacity' of the environment, applies to bacteria on a culture dish, to fruit flies in a jar of agar, and to buffalo on a prairie.  It must also apply to man on this finite planet" (Zubrin 2019: 313).

But when they wrote this, the population of the world was about 3.7 billion.  Now, it has more than doubled.  Isn't this far beyond the "carrying capacity" of a "finite planet"?

Zubrin observes: "so long as humanity is limited to one planet, the arguments of the Malthusians have the appearance of self-evident truth" (2019: 305).  But notice that there is only the "appearance" of truth.  In fact, Zubrin insists, the Earth is "a world of unlimited resources" as long as human beings are free to create those resources (314).

So, for Zubrin, the reason for humans going to Mars is not to escape "this finite planet" of Earth, but to turn Mars into "a world of unlimited resources" like the Earth.  And just as life has terraformed the Earth, we will have to terraform Mars.  

To do that, human beings on Mars will have to be inventive in using technology to turn raw materials into productive resources that generate abundance.  But it's hard to see that this has anything to do with Turner's American frontier.

For example, Zubrin foresees that "Martian frontier farming will need to deal with a shortage of land, water, and labor," and he compares this with how the labor shortage on "the American frontier" created a need for "frontier agricultural technology focused on labor-saving machinery."  He anticipates that Martian agricultural technology will rely on genetically engineered crops to satisfy "humanity's demand for food."  And thus, in combination with other technologies, "Martian civilization will open the way to unlimited material resources for all of humanity, forever" (Zubrin 2024; 220-25).  But the technology of genetically engineered crops emerged in late-twentieth century America, long after the closing of Turner's American frontier in 1890.  So, despite Zubrin's talk about "Martian frontier farming," this example of American inventiveness in using technology to create abundance has nothing to do with the American frontier.

Zubrin's appeal to Turner's frontier thesis is an unnecessary distraction from his fundamental argument for how human innovation can create superabundance--on Earth and perhaps potentially on Mars. 

REFERENCES

Cronon, William. 1987.  "Revisiting the Vanishing Frontier: The Legacy of Frederick Jackson Turner."  Western Historical Review 18: 157-186.

Potter, David M.  1954.  People of Plenty: Economic Abundance and the American Character.  Chicago: University of Chicago Press.

Weinersmith, Zach, and Kelly Weinersmith.  2024.  "Space Isn't the Final Frontier."  Foreign Policy (January 21).

Zubrin, Robert.  2019.  The Case for Space: How the Revolution in Spaceflight Opens Up a Future of Limitless Possibility. Amherst, NY: Prometheus Books.

Zubrin, Robert.  2021.  The Case for Mars: The Plan to Settle the Red Planet and Why We Must.  25th anniversary edition.  New York: Free Press.

Zubrin, Robert.  2024.  The New World on Mars: What We Can Create on the Red Planet.  New York: Diversion Books.