It’s often hard to think in very large numbers. Suppose, for instance, the US government spends around $100 million on developing, using and analyzing climate models per year. (I believe this is about right.) That sounds like a big number! Much too big perhaps? Well, if you are an average American, it’s thirty three cents out of your pocket every year. Is that a good deal? Too much? Too little? It is easier to think about the thirty-three cents than the hundred million.
Numbers like $450 billion (the annual Pentagon budget) and $100 million tend to overflow most people’s abilities to think substantively. Dividing them out into a per capita basis puts them into perspective.
I have been thinking about this in the context of the big question of our time, which as Jeffrey Sachs points out, is not about terrorism or islamo-fascism or even oil or climate. It is about whether all of us can fit comfortably on this planet. It is a big population and a big planet, so thinking quantitatively is daunting.
Fortunately, to make matters more palpable and less mathematical, per capita thinking can put matters into a more familiar perspective.
The St Exupery World
Consider the world of The Little Prince by St. Exupery.
If you haven’t read it yet, by all means go and do so. Someone somewhere is probably violating copyright to put the whole thing on the web in English.
(Harcourt is enforcing their copyright with respect to web postings. I think this is foolish as many of the people who read the story will be sufficiently entranced to buy a nicely bound and illustrated copy. I have two, one in English and one in the original French, and I recommend owning one. If you want to “steal” a look without driving down to Borders Update: Barnes & Noble (sigh) where you can easily read it in its entirety over a cup of coffee, Google on some distinctive phrase from the book.)
The Little Prince of the story is a child living alone on a small spherical asteroid, his only companion a single flower. He consoles himself by the fact that it is always a short walk to a sunrise or a sunset.
Somehow the asteroid remains habitable. The damage done to physics and biology to make an atmosphere, reasonable gravity, and an orphan prince are neglected for purposes of storytelling.
Let’s tell a slightly different story with a similar asteroid, a per capita world. Instead of being one of six billion people on a big planet, let’s suppose you were alone on a comparable planet. We’ll give you your six-billionth share of the surface area, your six-billionth share of each of the major landmasses and biomes, your own six-billionth scale Africa, your own little Australia. In other words, you will have the resources available to you that is exactly the average resource ownership of everyone on earth.
Your St. Exupery asteroid has a six-billionth of the earth’s total surface area. It is a sphere with a radius of 82 meters, and with a surface area of about 85000 square meters. That, depending on how you prefer to think about it, is almpst exactly 21 acres, or 8.5 hectares. In more urban terms, that is 19 American football fields, about 12 English football (professional soccer) fields.
Just over 70% of this is covered by salt water, so you cannot really walk around it. If it were to freeze over, though, you could walk from any point to any point at a leisurely pace in under ten minutes. Your world’s ocean covers fifteen acres and the land surface covers six acres.
A vast variety of soils and climates are arrayed about your 6 dry acres. According to the CIA, the area under cultivation is a bit under 5% of the total land area, or a bit over a third of an acre. If you push matters to less valuable soil, you might be able to grow things on as much as an acre, but most of your 6 dry-land acres are desert or tundra or rocks. You even have some substantial ice sheets on your land. There is also the problem that you have built your house, your workshop, your garage, your driveway and all your industrial outbuildings on the best farmland.
About a third of your land under cultivation is irrigated, much of it using depletable ground water. Some of the ground water is being contaminated by some of your industrial processes. To a lesser extent your soils are also being contaminated, but a bigger problem is that as you till them for food they erode much faster than the natural rate of replenishment.
You also like to eat fish, but most of your ocean does not naturally support large fish. From the few areas that do, you have been eating the fish faster than they reproduce. This would astonish your great grandparents, but of course they lived on a larger world. (Their per capita share was bigger with a smaller population.)
Still, you live much better than your great grandparents on your smaller planet, because you have found ways to dig up fossil fuels and use them to power heavy machinery to do your bidding. Some of your machines are very advanced, but some of them are crude and nasty. All your raw materials are dug out of the ground and refined. You produce a fair amount of industrial waste along with household waste, but you do not attend to it very carefully.
You currently use a bit over a ton of fossil fuel per year, producing 4 tons of CO2. (This is based on world average; note that the typical North American emits about five times this much!) It seems from direct measurement that about half of this (two tons per year) stays in the atmosphere, with the rest ending up in the ocean and the soil. While this is a fairly small fraction of your atmosphere’s total mass of 880,000 tons, you are wondering whether this has anything to do with a certain slushiness you are seeing in your ice sheets.
Thinking about the Asteroid
This is a model of the sustainability problem. In some ways it is a fantasy, but the scales and constraints are the real ones, expressed not as huge global numbers but as per capita quantities. You are using fuels that are not replaceable. We can come up with some numbers for ground water reserves and fuel reserves on the same basis. Your world is smaller than your ancestors’ but larger than your descendants’. Your use of resources is more intensive than your ancestors, and habitually increasing. At some point your descendants will not be able to keep up.
Most importantly, there is no replacing your six acres, no frontier to advance in order to replace them. No amount of human ingenuity will make the Earth’s surface bigger.
Is the world big enough to sustain us indefinitely? Are we on the edge? Are we past the point where we are doing permanent damage from which no amount of future cleverness can recover?
Some argue that we can we make up for our problems by increasing energy intensiveness. Indeed, some of our problems can be solved with more power. We can desalinate sea water, for instance. However, more energy use puts demands on other parts of the system, causes other problems.
Opinons (and they are usually barely more than intuitions) differ on this question, but it is a sure thing that every year the sustainability question posed this way is getting worse. There are no major trends that indicate the contrary. Increasing wealth doesn’t make our asteroid any bigger; indeed it seems only to create more byproducts that we have to put somewhere. Meanwhile the little asteroid keeps shrinking (representing your declining average share of the land as a result of the real world’s population increases).
Whether by design or by circumstance, sooner or later we will run up against limits. Whether than moment is still approaching or is long since past is debatable, but it is impossible to argue that we can avoid big changes forever, all the while becoming wealthier. If we don’t have foresight we will eventually end up in a situation where our little one acre of farm will be eroded, our well run dry, and our fisheries ruined beyond recovery. Some say we are already at that point or near it.
As you contemplate your little asteroid, keep in mind that the intensiveness described there is a worldwide average, including many poor people who have much smaller impact than almost everyone who will read this. Most of the world’s population aspires to at least a European standard of living. If progress fails, the political climate of the world becomes very unstable. If it succeeds, the demands we place on our asteroid go up about fourfold, even as its are shrinks by a third.
Economists will dislike the St Exupery world model, since economics has been totally factored out.
Scientists will understand that this is a useful simplification. Here is an economics-free geopolitcis-free view of sustainability that the tiny asteroid brings into focus. No matter how clever our advances, we will never have more than an acre to feed us. (I was actually rather surprised, in composing this article, to find out how small my fair share is.)
Whether we have enough food and water is limited by factors that are not conventionally dominant in economic thinking. Economics only complicates matters and seems to be a constant distraction from the baseline question: can we continue to provide, indefinitely? The fact that the planet is finite can’t be treated as a minor factor in that crucial question.
Can we sustain ourselves, meaning a modern society with billions of members, and if so, how well?
Optimists will argue that progress will prevail. Pessimists will argue that progress is an illusion. I find myself on a less popular middle ground, which says that progress is possible, but not automatic. We can prevail, but we will have to be very clever about how we do it, and can’t rely entirely on individuals acting in self-interest without very careful collective attention to how we set up the reward stucture.
Like the Little Prince, we find ourselves rather lonely imagining this solitary little world. Our relationships to each other are crucial to our circumstances, and in the end economics and politics can’t be ignored. So in a future essay I will consider a different way of scaling the problem, to the village level rather than the individual level. We will reconsider everything scaled to a village of six thousand people on a larger asteroid. We will have to deal with rather larger numbers, but we will be able to consider human relationships as part of the model.
Image used by kind permission of the artist, Oleg Pikhurko