Friday, June 08, 2012

Darwinian Sustainability: Ehrlich versus Ridley

"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."

That is the first paragraph of Paul Ehrlich's book The Population Bomb, first published in 1968.  I was reminded of that book when I noticed that Ehrlich is back in the news with an article in the latest issue of Nature (June 7, 2012), with new warnings about the approaching Malthusian Apocalypse.  There are many other articles in this same issue of the journal with similar warnings, which are to prepare us for the upcoming Rio Earth Summit.  The newspaper coverage of these articles suggests that we will see another wave of hysterical predictions about the gloomy future of the Earth, comparable to those initiated by Ehrlich and others in the 1960s and 1970s.  This is what Anthony Barnosky and his coauthors in another article in Nature call "biological forecasting." 

The most amazing feature of all of this writing is the silence about the failure of the "biological forecasting" of people like Paul Ehrlich.   When Ehrlich's Population Bomb was published in 1968, the world population was three and one half billion.  Today, the population has just passed seven billion.  This was not supposed to happen.  Ehrlich predicted that mass starvation in the 1970's would cause a collapse of world population to bring it down to the "carrying capacity" of the Earth. This is the logic of Thomas Malthus:  human population grows until there is not enough food to feed everyone, and then the population drops dramatically through famine, war, or disease until the balance with limited natural resources is restored.  While many people have starved in many parts of the world over the past 50 years, the average human life-span and per capita wealth have increased around the world. 

If scientific research is to be judged by falsifiable predictions, then the science of those like Ehrlich has been refuted by their record of falsified predictions.  In contrast to Ehrlich, Julian Simon argued that population growth was good as long as free markets and free trade allowed human entrepreneurial and inventive genius to find new ways to turn natural resources to productive uses.  To prove his point, Simon challenged Ehrlich to a bet.  In 1980, Ehrlich could pick a list of five commodity metals.  If Ehrlich was right, he would predict that by 1990 these metals would be so scarce that their prices would have risen.  If Simon was right, their prices would drop.  Ehrlich lost the bet.  The prices in 1990, adjusted for inflation, had dropped, just as Simon predicted. 

In 1989, I was on a year-long sabbatical at Stanford University doing research on "Darwinian natural right," and I audited some of the classes in the "Program in Human Biology" at Stanford.  Ehrlich is a Stanford biologist, and he lectured to some of the classes.  The students and faculty treated him with awe.  I was astonished that he was never challenged for his embarrassing failures.  In 1990, he lost his bet.  But he also received the "genius award" of the MacArthur Foundation!

Ehrlich is not a complete fool.  He has learned from his mistakes.  What he has learned is that he should never again make any predictions that are precise enough to be falsifiable.  So now he predicts an eminent "turning point" in the history of the Earth that will be catastrophic.  But he will not give us exact dates as he did in 1968.

So what's going on here?  It's the debate between Darwinian pessimism and Darwinian optimism.  It is well known that reading Thomas Malthus's book on population inspired Darwin in formulating his theory of evolution by natural selection in the "struggle for life."  It is possible, then, to infer that the natural evolution of life on earth is a history of population growth followed by mass starvation or conflict leading to a population decline falling back within the limits of scarce natural resources necessary for sustaining life.  Thus, "sustainability" is identified with limits to growth.

But, as I have indicated in some recent posts, it is also well known that reading Adam Smith inspired Darwin to see how human beings used social cooperation to achieve a dominance over the Earth.  Moreover, Darwin had some intimation of the importance of trade or exchange in allowing human beings to increase the productivity of their labor through specialization, just as Smith saw in The Wealth of Nations.  In The Rational Optimist, Matt Ridley has developed this as the theme of all human history--the ever-increasing productivity of human life spurred by exchange and specialization--to explain human progress.  The critical turning point came with the Industrial Revolution--starting in England and Scotland during the lifetime of Smith--when human population and prosperity exploded to unprecedented levels.  The logic of Malthusian boom and bust was overturned, so that Darwinian pessimism could be replaced with Darwinian optimism.

Notice that in this new journalistic coverage for Ehrlich's Malthusian pessimism, there are no references to the arguments of people like Simon and Ridley.  Even in the articles in Nature, the scientists are careful not to mention the historical record supporting Darwinian optimism.

But don't we have good reasons to be pessimistic about the future?  If we continue using scarce resources (like fossil fuels) at the present rate, and if we continue to promote global warming at the present rate, can't we foresee catastrophe sometime in the near future?

For example, consider the following sentence in the article by Barnosky et al.: "A decrease in this extra energy budget, which is inevitable if alternatives do not compensate for depleted fossil fuels, is likely to impact human health and economics severely" (54).

But notice the conditional language--"inevitable if."  This points to what Ridley identifies as the fundamental fallacy of Malthusian pessimism--extrapolationism.  Extrapolate present trends into the indefinite future and catastrophe becomes inevitable.  Assume that the future will be a continuation of the present with no novel adaptations.  That was Ehrlich's mistake in 1968.

In The Population Bomb, he has a few pages on the possibility that new high-yield varieties of food grains might increase productivity to the point of feeding world population without any mass famines.  Ehrlich dismissed this as unlikely.  But that's exactly what happened.  Norman Borlaug's "green revolution" allowed countries like India to produce so much food in the 1970's that they actually become exporters of grain; and now India has become one of the more prosperous countries in the world.  India and China are the two most populous nations in the world, and they also have the greatest stockpiles of food grains.

Ridley draws the lesson from this:
The pessimists are right when they say that, if the world continues as it is, it will end in disaster for all humanity.  If all transport depends on oil, and oil runs out, then transport will cease.  If agriculture continues to depend on irrigation and aquifers are depleted, then starvation will ensue.  But notice the conditional: if.  The world will not continue as it is.  That is the whole point of human progress, the whole message of cultural evolution, the whole point of dynamic change--the whole thrust of this book.  The real danger comes from slowing down change.  It is my proposition that the human race has become a collective problem-solving machine, and it solves problems by changing its ways.  It does so through invention driven often by the market: scarcity drives up price; that encourages the development of alternatives and of efficiencies.  It has happened often in history.  When whales grew scarce, petroleum was used instead as a source of oil.  (As Warren Meyer has put it, a poster of John D. Rockefeller should be on the wall of every Greenpeace office.)  The pessimists' mistake is extrapolationism: assuming that the future is just a bigger version of the past.  As Herb Stein once said, 'if something cannot go on forever, then it will not.'" (281)

But what about global warming?  Doesn't that bring the insurmountable limit to human population and economic growth?  Ridley's response is prudent.  He accepts the evidence for global warming as a product of human activities.  But then he asks us to consider the most reasonable response to this.  If we accept the projections of the Intergovernmental Panel on Climate Change (IPCC), we can still be Darwinian optimists, Ridley argues, because the pessimistic assumptions about future global warming coming from the IPCC depend on optimistic assumptions about growing wealth, because it's the expansion of economic growth around the world that's likely to have the greatest effects on global climate.  Consequently, we should see that "the richer people get the less weather dependent their economies will be and the more affordable they will find adaptation to climate change" (333).  "In short, a warmer and richer world will be more likely to improve the well-being of both human beings and ecosystems than a cooler but poorer one" (341).  Those like Ehrlich argue just the opposite: a cooler but poorer world, with fewer human beings, would be better for us and for the Earth.

Darwinian optimists see a general trend in human history that is progressive--especially in the last 200 years--towards greater peace, prosperity, and population.  Steven Pinker's Better Angels of Our Nature surveys the evidence for declining violence in history leading to the "liberal peace" of the present.  Ridley's Rational Optimist surveys the evidence for growing prosperity and population.  Both support a Darwinian liberal progressivism based on the idea that classical liberal ideas--liberty, commerce, tolerance, limited government, bourgeois virtues--have promoted a course of cultural evolution that has cultivated the "better angels" of our evolved human nature.

It is not clear, however, that Darwinian thinking promotes a cosmic optimism.  After all, a Darwinian explanation of the place of human life in the cosmos would seem to indicate that the extinction of all life, including human life, is inevitable, and the most we can do is to slow the inevitable decline of Earthly life into entropy. 

That's a question for a future post.


Anthony Barnosky, et al., "Approaching a State Shift in Earth's Biosphere," Nature, 486 (7 June 2012): 52-58.

Paul Ehrlich, The Population Bomb (New York: Ballantine Books, 1968).

Paul Ehrlich, Peter Kareiva, Gretchen Daily, "Securing Natural Capital, and Expanding Equity to Rescale Civilization," Nature, 486 (7 June 2012): 68-73.


David said...

The influence of population waves on history is quite interesting. Gregory Clark, for instance, has shown that the Medieval lower classes in England barely reproduced. The upper classes reproduced at a 2:1 rate over the lower classes, which resulted in a downward mobility of people and their genes. This phenomenon probably resulted in lower violence and an increased average IQ for the English. This trend -- over the upper classes repopulating a society -- was probably happening all over Europe, as a few upcoming studies will show.

The problem with the coming population bomb is as follows:

In short, overpopulation is bad for the environment and bad for living conditions. People shortages can result in labor shortages, which increase the standard of living. The highest standard of living seen by Medieval Europeans was after the Black Death.

Troy Camplin said...

The evidence actually shows that we can absorb quite a bit of population so long as we have good institutions. Bad institutions make even low population density areas overpopulated. It's all about institutions.

We see per person wealth increasing the world over even as population grows. What does that tell us?

Greenish said...

Great post. The only thing I found somewhat disturbing is Steven Pinker's enduring popularity. Pinker is the guy who denies empirical evidence about intelligence differences in human populations with long-ago-debunked gouldite pseudo-reasonings because, you know, it's too un-PC to be touted out there. He's the guy who in order to support Better Angels' main claim, simply puts aside 250 million of violent deaths only in the 20th century or the role of nuclear weapons in the so-called "peace" of the Cold War.

In "Better Angels" he supports a notion of lightning-like speed in human change in the last centuries. But elsewhere he explicitly states that differences between nordic europeans --I don't remember right know the precise country-- and bushmen is negligible (his example).

I can't respect Pinker. It's impossible.

Larry Arnhart said...


As indicated in my long sequence of posts on Pinker's BETTER ANGELS, I am more supportive of his argument.

He actually makes use of intelligence testing to argue for a "moral Flynn effect."