In a recent email exchange, my correspondent wrote, “they say if everyone consumed like the US, we would need 2.5 earths.” That sort of claim is commonly made and readily accepted as true. A June 2015 BBC magazine article titled “How many Earths do we need?” begins with the claim “that if everyone on the planet consumed as much as the average US citizen, four Earths would be needed to sustain them.”
Those types of claims are half-truths, and like most half-truths, they confuse rather than clarify. Fortunately, a little bit of reasoning and checking the facts are sufficient to get closer to the truth.
Earth is an Open System
The undeniable fact is that the earth is finite, which means nothing on earth — soil, water, minerals, etc. — is infinite. But for all practical purposes what we need is virtually infinite. The reason for virtual infinity in a finite earth is that the earth is not a closed system.
If you have some content in a finite box, that content has to be finite too. If you can neither add anything to the box or take anything out of the box, it is a closed system. Conversely if you can add or remove stuff from the box, it’s an open system.
The earth is an open system because it receives energy from the sun. That makes an enormous difference in that it enables material to be recycled. A simple example of that is water. We never “use up” the water we use. Though the amount of water is finite, the amount of rainfall on earth is unbounded because of the hydrological cycle: the sun’s energy continually evaporates water into the atmosphere and that falls back to earth as rain. This cycle has been going on for billions of years and will continue for the indefinite future. We cannot “use” up the limited water because it gets naturally recycled.
Another important cycle is the carbon cycle. Nearly all life on earth depends on that cycle. For instance, plants “eat” the carbon from atmospheric CO2 in the presence of sunlight, and release oxygen into the atmosphere; we and other animals eat plants, and use oxygen from the atmosphere to generate energy and release CO2 back into the atmosphere. The net amount of carbon on earth is finite but it gets endlessly recycled. CO2 goes from the atmosphere into plants and animals and then back into the atmosphere. Life on earth is “carbon neutral” since the amount of CO2 living things release into the atmosphere is exactly the amount they take from the atmosphere.
We have a finite number of trees on earth at any particular instance of time but trees are a renewable resource since they grow on their own given sunlight, land and water. At a reasonable rate of harvest, we can harvest an indefinite number of trees.
In finite systems, infinite cycles are possible provided it receives energy from outside the system.
The fact is that nothing can actually be used up. This is due the fundamental law of nature called the “conservation of mass and energy.” Matter cannot be created or destroyed; it can only change form. At the purely chemical level, matter does not get used up; matter just changes from one configuration of atoms to another configuration. Given the required energy and the appropriate knowledge (technology), you can have an infinite variety of materials and endless cycles.
Matter can be converted to energy and vice versa. That involves nuclear (fission and fusion) reactions. That is allowed by conservation laws of physics.
The summary conclusion from the above is that while the earth is finite, we are in no danger of running out of water, or carbon, or iron, or oil, or whatever else you care to name. A little understanding of how the world works is sufficient to dispel the fear that “we are running out of resources.” The sun will supply the energy and the human mind will invent the technology (create knowledge) that will keep the system improving indefinitely.
This conclusion is contrary to common sense but it is true nonetheless.
How many people can the earth support? The answer is a surprising “as many as you wish.” How many people and at what level of consumption per capita can the earth support? The answer is again a surprising “as many as you wish and at whatever level of consumption you choose” provided you have the energy and the appropriate level of technology — both of which are possible and even probable.
Let’s go back to 10,000 years before the present. Could the earth have sustained nearly 8 billion humans then as it does today? No, because even simple agricultural technology did not exist then. People lived by foraging as hunter-gatherers in small groups. That mode of survival could only support a few million people.
Human population expanded when people moved to agriculture but life continued to be hard and short. It was the Malthusian era — more food production led to more people to the point where everyone was back to just barely subsisting, and when occasionally food production fell, the population contracted too.
Energy and Technology
Only in the last 250 years or so, there has been both an increase in population and an improvement in the quality of life. It’s all thanks to technology. Agricultural productivity has increased, which means that more food is produced using less land and less labor than before. The increase in agricultural production required more energy and better technology.
In the year 1950, the population of the US was 150 million. Using 1950s technology to support 330 million Americans (the population of the US in 2020) at the 1950 level of consumption would use up 120% more resources than was used in 1950. Supporting 150 million Americans at the 2020 level of consumption given 1950 technology would require more than one earth’s resources. Supporting 330 million Americans at 2020 levels of consumption given 1950 technology would require several earths.
The world population was 2.5 billion in 1950, of which 60% or 1.5 billion lived in extreme poverty. In 2020, there are over three times as many people on earth as in 1950. Yet the per capita consumption has gone up — to the point that less than 10% of the world live in extreme poverty today. What made that tremendous improvement possible? Technology.
Technology made more and cheaper energy available, which increased productivity in every area of human enterprise — agriculture, manufacturing, transportation, mining. More food is grown today using less land than 20 years ago, and the trend will continue. Forest cover has increased 15% in the last 20 years. Every indicator of human flourishing is trending upward.
We Create Wealth
The amount of wealth in the world has increased monotonically all throughout human existence (which is estimated to be around 250,000 years.) We take all the things around us for granted, as if they are provided unbidden by nature. However in reality, wealth is created by humans. Our thinking is limited because we believe that there is only so much stuff on earth, and once we have used up that limited stuff, we would be done. But that is patently not true because we created the wealth we have.
None of the wealth that exists today was there even a mere 10,000 years ago. No farms or factories, no roads, no cars, no trucks, no ships, no airports, no jetliners, no hospitals, no shopping malls, no schools, no universities, no radios, no TVs, no computers, no internet — no nothing. We have a lot now but we will have an unimaginable more in the future. The future is open-ended.
The future is open-ended because there is no limit to how much knowledge can be created, and how much energy we can produce for our use. We started with just muscle power for energy, and then added wood, wind and water energy (which is actually solar energy), and then fossil fuels (stored solar energy), and then nuclear fission, and in the near future we will have nuclear fusion energy.
The story of civilization is also the story of ever greater use of energy.
We are creating knowledge at an ever more accelerating pace. There are tens of millions of people today — more than the population of the earth just 10,000 years ago — engaged in creating knowledge in research institutions because they don’t have to work to create the stuff they need for survival (food, clothing, shelter.) That knowledge creation leads to an increase in the creation of wealth ever more efficiently.
Here’s something to marvel at. Around 40 years ago, there used to be supercomputers at the most prestigious institutions in the most advanced industrialized nations. They were housed in huge buildings; they required an army of highly trained technicians to build, operate and maintain; they cost hundreds of millions of dollars; and the energy they used cost thousands of dollars per month.
If you had claimed in 1980 that in 2020 everyone would privately own a supercomputer, the first argument against you would be this: a supercomputer uses 30 metric tons of material. So 5 billion supercomputers would require 150 billion metric tons of material, and of course more than 60,000 times the energy to operate them than was being produced globally in 1980, and around 100 billion trained technicians (assuming only 20 of them per supercomputer) to operate them.
You would be asked: Are you stupid and retarded, or are you merely insane for suggesting that in just 40 years there would be 5 billion of 1980 supercomputers on earth?
In reality, humans figured out how to design and manufacture faster, cheaper, smaller integrated circuits that used orders of magnitude less energy than before, and packaged them into little portable devices we use without a thought. Now the equivalent computing power of those supercomputers is available in devices that cost a few hundred dollars, that use only a few cents worth of energy, that people carry in their pockets, and even people who cannot afford indoor plumbing routinely use “supercomputers” in their daily lives.
Oh the Waste
Ah but, the objection would go, what about all the waste that gets generated in the process of manufacturing all the stuff we use and then dump in landfills? Will we not eventually run out of the materials?
Actually, no we will not run out of anything. We will not run out of any material for a couple of reasons. The first reason is that everything can be recycled. Just as nature recycles water and CO2, humans can recycle matter — provided there is sufficient need to do so. If it is cheaper to recycle, that’s what we will do.
Take gold. It’s a precious metal and highly valued for its aesthetic and industrial properties. Gold has been mined for thousands of years. Nearly all of the gold that has ever been mined is still around in use because gold is easily recycled and rare. We will never “use” up gold. We will only add to the stock of gold that we have.
Once upon a time, aluminum was more precious than gold. Napoleon III, Emperor of France 1852 – 1870, would serve his more important guests on aluminum dinnerware, and his lesser guests would have to make do with gold dinnerware. The Washington Monument, the 555-foot obelisk completed in 1888, is capped with a 6-lb pyramid of aluminum — then the largest piece of cast aluminum. Today, we toss empty aluminum soda cans without a thought. It is a wonder metal that no one had ever seen before 1825.
The second reason for not running out of something is that when the available stock of something runs low relative to the demand for it, the price goes up. When the price goes up, people put in the effort to discover substitutes. And oftentimes the substitute is better than the original. That is the story of whale oil. (I will expand on this later.)
People fear that we will run out of petroleum. This fear is justified by noting that there is only so much oil in the ground, and once we have extracted and used some oil, that bit is gone forever. Unlike trees, oil is not renewable. There is no “recycling” of oil that has been burnt. So when the last bit is used up, we are out of luck. But that fear is actually not justified. We will never run out of oil because long before we deplete our world oil reserves, we will have discovered or invented substitutes. (More on this later.)
But, the next objection would be, where will we grow all the food that would be needed in a world of 11 billion people (the peak predicted population in a few decades) and how will the earth cope with people eating more animal protein? It takes umpteen hundreds of gallons of water to get one kilo of meat and another umpteen acres of land to grow the animal feed for just one animal? Isn’t a meat-based diet a recipe for environmental disaster?
The answer is two-fold. First, to grow food, you don’t have to do traditional agriculture that requires huge expanses of land. Vertical farming is a soon-to-be viable alternative. It uses only a tiny fraction of the land used by traditional farming, it recycles water in a closed-system, it uses little or no pesticides, and uses very little labor. The inputs to that would be energy — which will be orders of magnitude cheaper than what it is today because of fusion technology. Cheap energy implies cheap food. No one needs to starve.
Second, traditional animal protein will be replaced by artificial “animal protein.” That’s just around the corner. It will be vegetarian in origin and no animals will be harmed in the production process. The artificial stuff will not only be healthier but it will be cheaper and tastier than the real stuff. So in a couple of decades, we will be using less land and consuming whatever kind of food we prefer without inflicting untold cruelty on innocent sentient beings.
Yeahbut, what about global warming and CO2 and climate change? Isn’t the world going to hell in a handbasket? How on earth will we survive climate change, eh?
The climate is changing. It has always changed. Ocean levels have risen and fallen. Temperatures have risen and fallen. Deserts have advanced and retreated. And all through that humans have not just survived but prospered. The best part of the story is that humans are getting ever better at meeting the challenges the world throws at us. How? By getting better at generating knowledge that enables us to solve the problems.
Our knowledge is finite and our ignorance is infinite. Our planet is finite but given the right knowledge, infinite cycles are possible in a finite world. The physicist David Deutsch argues that if we fail in doing something that is not forbidden by the laws of physics, it is because we have failed to create some knowledge. We are forever pushing the boundaries of what we are capable of. The future is open-ended and unimaginably vast.
 The BBC magazine article has an interesting infographic produced by science write Tim De Chant in 2012 which answers the question “How much land would the world’s 7 billion people need to live like the people of these countries?” The data is from 2012. So I would expect that if the whole world were to live like the Chinese do today, then instead of 1.1 earths, we’d probably need 3 earths; Bangladesh, India and Uganda would still be less than one earth.
 See this article on Why Napoleon III Served Dinner On Aluminum Instead Of Gold.