Today I need to take care of some unfinished business which I first mentioned in The Limits Of Free Will In Human Action.
When I talk about exponential "growth", or talk about the "urge to grow" being built right into the human animal, what am I referring to? Many researchers focus on population growth alone, but at a fairly high level of generality, I've always viewed population and consumption as indistinguishable and equally weighted. In DOTE's final days, I was reminded that I wanted to address this important question by a recent article in The Guardian. Andrew Simms was reviewing the work of Stephen Emmott (and Danny Dorling) in We keep moaning about population, but ignore consumption habits. He quotes Fred Pearce.
Three years ago the science writer Fred Pearce, a knowledgeable and long-term observer of climate change and other natural resource issues, published a book called Peoplequake.
Although expecting population to grow (and level off later in the century), Pearce came to quite opposite conclusions. Future historians, he wrote, would look back on this period in history as marked by a, "dramatic decline in fertility and the transformation of the role of women in society." In recent years, writes Pearce, fertility rates have generally fallen off a cliff.
If there is an explosive problem, he wrote, it is to do with consumption, and it is a problem for a wealthy minority of humankind. The poorest three billion people on earth, short of half the world population accounted for about 7% of carbon emissions, while conversely, the richest 7% of people accounted for about half of all emissions.
Observations like this seem obvious enough— the rich people do most of the consuming because ... they're rich. The more interesting bit has to do with fertility rates, which we can think of simply as the average number of children women have during their child-bearing years. These rates are indeed falling, as The Economist made clear in this 2009 article.
SOMETIME in the next few years (if it hasn't happened already) the world will reach a milestone: half of humanity will be having only enough children to replace itself. That is, the fertility rate of half the world will be 2.1 or below. This is the “replacement level of fertility”, the magic number that causes a country's population to slow down and eventually to stabilise. According to the United Nations population division, 2.9 billion people out of a total of 6.5 billion were living in countries at or below this point in 2000-05. The number will rise to 3.4 billion out of 7 billion in the early 2010s and to over 50% in the middle of the next decade. The countries include not only Russia and Japan but Brazil, Indonesia, China and even south India...
Modern Malthusians tend to discount the significance of falling fertility. They believe there are too many people in the world, so for them, it is the absolute number that matters. And that number is still rising, by a forecast 2.4 billion over the next 40 years. Populations can rise while fertility declines because of inertia, which matters a lot in demography. If, because of high fertility in earlier generations, there is a bulge of women of childbearing years, more children will be born, though each mother is having fewer children. There will be more, smaller families.
Assuming fertility falls at current rates, says the UN, the world's population will rise from 6.8 billion to 9.2 billion in 2050, at which point it will stabilise [see chart 1 above].
The Economist can never waste an opportunity to bash Malthusians, but more to the point, why are fertility rates falling in the wealthy nations? I found another article at The Economist which explains the issue very well. It's called More or less, and asks the question Why, as people get richer, do they have fewer children?
One of the most significant phenomena of modern history is the demographic transition: as people get richer, they have smaller families. This slowing of reproduction with economic development is the reason why Thomas Malthus’s prediction of disaster, caused by the human population outstripping its supply of food, is unlikely ever to come true. In the short term, Malthusian doom has been evaded by innovations that increased the food supply. But in the long term it is likely to be a ceiling on demand [consumption] that helps to save humanity. The world’s population, now some 7 billion, is expected to level out at a little over 10 billion towards the end of the century.
Why the demographic transition happens, though, is obscure—for this reaction by Homo sapiens to abundance looks biologically bonkers.
Other species, when their circumstances improve, react by raising their reproductive rate, not curtailing it. And work just published by Anna Goodman of the London School of Hygiene and Tropical Medicine and her colleagues, in the Proceedings of the Royal Society, suggests what humans do is indeed bananas. Dr Goodman has shown that the leading explanation advanced by biologists for the transition does not, in the context of the modern world, actually deliver the goods.
Bear with me, it's worth getting into the details.
This explanation is that, according to circumstances, people switch between two reproductive strategies. One, known to ecologists as “r-selection”, is to produce lots of offspring but invest little in each of them. This works in environments with high infant mortality. The other, known as “K-selection”, is to have only a few offspring but to nurture them so that they are superb specimens and will thus do well in the competition for resources and mates, and produce more grandchildren for their parents than their less well-nurtured contemporaries. The demographic transition, according to this analysis, is a shift from r-type to K-type behaviour...
If the r/K interpretation is correct (the letters stand for the rate of reproduction and the “carrying capacity”, or resource richness, of the environment), then an advantage of some sort for the socioeconomically privileged should show up as the generations succeed one another. Dr Goodman’s analysis shows that it does, but in a way that is not translated into any obvious evolutionary advantage.
Reducing family size certainly creates what look, on the face of things, like more competitive descendants. Children, grandchildren and great-grandchildren alike get better marks at school, are more likely to go to university and have higher incomes as adults. What these competitive individuals do not do, though, is go on to compete in the one arena which matters in a Darwinian sense: reproduction. If anything, the tendency towards smaller, more socially successful families tends to feed back on itself over the generations, and the contribution of the K-selected to the gene pool therefore shrinks.
To biologists, this is all very puzzling. If K-type behaviour is not delivering the goods then it should never have come about in the first place. But there may be an explanation: that the psychological make-up which encourages K-type behaviour worked in the past but is not appropriate to modern circumstances.
Disregarding how these two strategies evolved, let's simply state the two rules.
In circumstances of high infant mortality and poverty, measured by GDP per capita, humans use r-selection and fertility rates are high.
As wealth grows, humans increasingly use K-selection and fertility rates fall.
The second rule baffles biologists, for no other animal behaves this way.
Homo sapiens is sui generis! No surprise there.
But as wealth grows, real consumption rates grow, even though (counterintuitively) fertility is falling. Fewer people consuming more. The Economist asserts that in the long term it is likely to be a ceiling on demand [consumption] that helps to save humanity, for if fertility and consumption were both growing at the same time, even these hopeless optimists realize that Homo sapiens would be well and truly fucked.
For optimists, K-selection is humanity's out, the fine print in the Human Contract with Nature which gets them off the hook. Writers at The Economist and Hans Rosling (video below) and many, many others expect to see a world of 10,000,000,000 wealthy people whose fertility rates are falling. They then turn around and wring their hands in despair about what will happen when the human population goes into permanent decline because everybody is so rich
The latest U.N. projection says there will be 9.6 billion humans on Earth in 2050. Presumably, most of them will be living high on the hog like Americans once did.
But let us leave these Fantasies behind, and return to the subject of "growth" as I laid it out at the beginning at this post.
Humans have advanced technology (e.g., birth control) and culture, including education. It seems to me that what makes humans unique among the animals, as expressed in this K-selection/wealth/fertility relationship, is that in humans, higher consumption, enabled by education, technology and culture, substitutes for (replaces) the biological (innate) satisfaction animals evolved to receive from child-rearing.
And as wealth and consumption grow, so does the evolutionary fitness of offspring, even if there are fewer of them. So humans do not simply pullulate (breed) like rabbits regardless of the circumstances. Consequently, when we talk about "growth" generally we might want to careful (or maybe not, depending on the circumstances) to include both population and consumption.
The 2nd rule above, the one that baffles biologists, is an example of what I call an emergent property or trait in the human animal. Such characteristics can be quite unpredictable based on known evolutionary principles, as the K-selection/wealth/fertility relationship suggests. You could not know that humans would behave this way until there was sufficient wealth for this newly found human characteristic to emerge.
You could not know that all large, complex human societies are characterized by great wealth and social inequality until you have large complex societies. Little in hunter-gather societies of the last 120 thousand years suggests that we would get the grotesque wealth distribution distortions we saw during the Chalcolithic and Bronze Ages (in various parts of the world) and thereafter, or that we see now in the 21st century. Thus we get the complex, interesting dance of technology and culture on the one hand, and biological determinism on the other.
Humanity's eventual comeuppance is in large part a byproduct of the fact that the biologically determined urge to grow is an implacable force. Will that comeuppance be due to population growth? Or is it due to consumption growth?
The answer is it is due to both, as discussed here.
I hope this post clears up some of my previous statesments about "growth" and humanity's fate.
Hans Rosling is always good for a laugh. Wait 'till the end...