In 1980 an ecologist and an economist chose a refreshingly unacademic way to resolve their differences. They bet $1,000. Specifically, the bet was over the future price of five metals, but at stake was much more _ a view of the planet's ultimate limits, a vision of humanity's destiny. It was a bet between the Cassandra and the Dr. Pangloss of our era.
They lead two intellectual schools _ sometimes called the Malthusians and the Cornucopians, sometimes simply the doomsters and the boomsters _ that use the latest in computer-generated graphs and foundation-generated funds to debate whether the world is getting better or going to the dogs.
The argument has generally been as fruitless as it is old, since the two sides never seem to be looking at the same part of the world at the same time. Dr. Pangloss sees farm silos brimming with record harvests; Cassandra sees topsoil eroding and pesticide seeping into ground water.
But in 1980 these opponents managed to agree on one way to chart and test the global future. They promised to abide by the results exactly 10 years later _ in October 1990 _ and to pay up out of their own pockets.
The bettors, who have never met in all the years they have been excoriating each other, are both 58-year-old professors.
The ecologist, Paul R. Ehrlich, has been one of the world's better-known scientists since publishing The Population Bomb in 1968.
When he is not teaching at Stanford University or studying butterflies in the Rockies, Ehrlich can generally be found on a plane on his way to give a lecture, collect an award or appear in an occasional spot on the Today show.
He is the pessimist in the debate over humanity's fate.
The economist, Julian L. Simon of the University of Maryland, often speaks of himself as an outcast, which isn't quite true. His books carry jacket blurbs from Nobel-laureate economists and his views have helped shape policy in Washington, D.C., for the past decade.
But Simon has certainly never enjoyed Ehrlich's academic success or popular appeal.
On the first Earth Day in 1970, while Ehrlich was in the national news helping to launch the environmental movement, Simon sat in a college auditorium listening as a zoologist, to great applause, denounced Simon as a reactionary whose work "lacks scholarship or substance."
Simon took revenge, first by throwing a drink in his critic's face at a faculty party and then by becoming the scourge of the environmental movement. When he unveiled his happy vision of beneficent technology and human progress in Science magazine in 1980 it attracted one of the largest batches of angry letters in the journal's history.
In some ways Simon goes beyond Dr. Pangloss, the tutor in Candide who insists that "All is for the best in this best of possible worlds." Simon believes today's world is merely the best so far. Tomorrow's will be better still, because it will have more people producing more bright ideas.
He argues that population growth constitutes not a crisis but, in the long run, a boon that will ultimately mean a cleaner environment, a healthier humanity and more abundant supplies of food and raw materials for everyone.
And this progress can go on indefinitely because _ "incredible as it may seem at first," he wrote in his 1980 article _ the planet's resources are actually not finite.
Simon also found room in the article to criticize, among others, Ehrlich, Newsweek and the National Wildlife Federation.
An irate Ehrlich wondered how the article had passed peer review at America's leading scientific journal. In a rebuttal written with his wife Anne, also an ecologist at Stanford, Ehrlich provided the simple arithmetic: The planet's resources had to be divided among a population that was then growing at the unprecedented rate of 75-million people a year.
The Ehrlichs called Simon the leader of a "space-age cargo cult" of economists convinced that new resources would miraculously fall from the heavens.
For years the Ehrlichs had been trying to explain the ecological concept of "carrying capacity" to these economists. They had been warning that population growth was outstripping the Earth's supplies of food, fresh water and minerals.
Ehrlich decided to respond to an open challenge issued by Simon to Malthusians.
The bet is on
Simon offered to let anyone pick any natural resource _ grain, oil, coal, timber, metals _ and any future date. If the resource really were to become scarcer as the world's population grew, then its price should rise. Simon wanted to bet the price would instead decline.
Ehrlich formed a consortium with John Harte and John P. Holdren, colleagues at the University of California at Berkeley specializing in energy and resource questions.
In October 1980 the Ehrlich group bet $1,000 on five metals _ chrome, copper, nickel, tin and tungsten _ in quantities that each cost $200 in the current market. A futures contract was drawn up obligating Simon to sell the group these same quantities of the metals 10 years later, but at 1980 prices.
If the 1990 combined prices turned out to be higher than $1,000, Simon would pay them the difference. If prices fell they would pay him.
The contract was signed and Ehrlich and Simon went on attacking each other throughout the 1980s. During that decade the world's population grew by more than 800-million, the greatest increase in history, and the store of metals buried in the Earth's crust did not get any larger.
"Population, when unchecked, increases in a geometrical ratio. Subsistence increases only in an arithmetical ratio."
_ Thomas Robert Malthus, 1798
It is such an obvious proposition in a finite world: Things run out. The American Indians put it nicely in a proverb that has been adopted as a slogan by today's environmentalists: "We do not inherit the Earth from our parents. We borrow it from our children."
The counterargument has generally consisted of a simple question: Why haven't things run out yet? The ones asking this question now tend to be economists, which is a switch, since their predecessors were the ones who initiated the modern preoccupation with resource scarcity.
Economics was first called "the dismal science" in the last century because of Malthus' predictions of mass starvation. He had many successors.
But naturalists gradually replaced economists as the chief doomsayers. They dominated the conservation movement early this century and in 1948 two of them _ Fairfield Osborn, the president of the New York Zoological Society, and an ornithologist named William Vogt _ started a national debate by publishing popular books: Our Plundered Planet and Road to Survival respectively.
Both men warned of overpopulation, dwindling resources and future famines.
These books made an impression on Ehrlich when he was a teen-ager. In the mid-'60s Ehrlich started giving public lectures about the population problem. In 1968 he produced what may be the all-time ecological best seller, The Population Bomb.
A subsequent appearance on The Tonight Show made him famous.
"I went on and did basically a monologue," Ehrlich recalls. "I'd talk until the commercial and during the break I'd feed Johnny (Carson) a question and then I'd answer it until the next commercial."
The Tonight Show got more than 5,000 letters about Ehrlich's appearance. He has been deluged ever since with requests for lectures, interviews and opinions.
The Population Bomb began: "The battle to feed all of humanity is over. In the 1970s the world will undergo famines _ hundreds of millions of people are going to starve to death."
Six years later, in a book he wrote with his wife, The End of Affluence, he raised the death toll.
"Due to a combination of ignorance, greed and callousness, a situation has been created that could lead to a billion or more people starving to death," he wrote.
Ehrlich was right about one thing: The world's population did grow. It is now 5.3-billion, 1.8-billion larger than when he published The Population Bomb. Yet somehow the average person is healthier, wealthier and better fed than in 1968. The predicted rise in the world death rate has yet to materialize.
There have been famines in countries afflicted by war, drought and disastrous agricultural policies, but the number of people affected by famines has been declining steadily during the past three decades.
Experts generally agree that the average person in the Third World is betternourished today than in 1968. Food production has increased faster than population.
A salute to human ingenuity
After receiving a doctorate in business economics from the University of Chicago, Simon joined the faculty at the University of Illinois in 1963.
He had heard the grim predictions about overpopulation and in the late 1960s began publishing papers on using marketing tools and economic incentives to persuade women to have fewer babies.
But then he came across work by economists showing that countries with rapid population growth were not suffering more than other countries. In fact, many were doing better.
He also came across a 1963 book, Scarcity and Growth, which provided the empirical foundations of Cornucopianism. The authors, Harold J. Barnett and Chandler Morse, tracked the price of natural resources back to 1870 and found the price of virtually everything had fallen.
The average worker today could buy more coal with an hour's pay than he could in the last century, just as he could buy more metals and food. Things were actually getting less scarce as population grew.
The evidence inspired the boomster view of history, which was then refined by Simon and others, such as Charles Maurice and Charles W. Smithson. These economists, then at Texas A&M University, looked back at 10,000 years of resource crises and saw a pattern: Things sometimes became scarce, but people responded with innovations.
Often the temporary scarcity led to a much better substitute. Timber shortages in 16th-century Britain ushered in the age of coal; the scarcity of whale oil around 1850 led to the first oil well in 1859.
"Natural resources are not finite. Yes, you read correctly," Simon wrote in his 1981 manifesto The Ultimate Resource. The title referred to human ingenuity, which Simon believed could go on indefinitely expanding the planet's carrying capacity.
This idea marked the crucial difference between Simon and Ehrlich, and between economists and ecologists: the view of the world not as a closed ecosystem but as a flexible marketplace.
Simon's fiercest battle has been against Ehrlich's idea that the world has too many people.
Simon acknowledges that rising population causes short-term problems, because it means more children to feed and raise. But he maintains there are long-term benefits when those children become productive, resourceful adults.
Among academics, Simon seems to be gaining in the debate. But he is still far behind when it comes to winning over the general public.
This past Earth Day Ehrlich was still the one all over national television. In the weeks leading up to Earth Day, Ehrlich appeared on many talk shows promoting his new book The Population Explosion.
Speaking at an Earth Day weekend symposium of ecologists at the Smithsonian's National Museum of Natural History, Ehrlich praised a colleague who had advocated the idea of governments stopping economic growth by setting quotas on the amount of resources that could be used each year.
And he criticized the shortsightedness of economists. He got a laugh when he alluded to Simon's book: "The ultimate resource _ the one thing we'll never run out of is imbeciles."
That same day Simon spoke only a block away in a small conference room at a symposium sponsored by the Competitive Enterprise Institute, a group that explores free-market solutions to environmental problems.
He spoke of population growth representing "a victory over death," because the growth was due to the doubling of life expectancy since the Industrial Revolution.
"Human history has never shown any achievement to hold a candle to that. You'd expect lovers of human life to be jumping with joy at this incredible success. Instead, across the street we've got them lamenting that there are so many people alive."
Final settlement: $576
The bet was settled this fall without ceremony. Ehrlich simply mailed Simon a sheet of calculations about metal prices _ along with a check for $576.07.
Simon wrote back a thank-you note, adding that he would be willing to raise the wager to as much as $20,000, pinned to any other resources and to any other year in the future.
Each of the five metals chosen by Ehrlich's group, when adjusted for inflation since 1980, had declined in price.
Prices fell for the same Cornucopian reasons they had fallen in previous decades _ entrepreneurship and continuing technological improvements.
Prospectors found new lodes. Thanks to computers, new machines and new chemical processes, there were more efficient ways to extract and refine the ores for chrome and the other metals.
For many uses, the metals were replaced by cheaper materials, notably plastics, which became less expensive as the price of oil declined.
Is there a lesson here for the future?
"Absolutely not," Ehrlich said in an interview.
Nevertheless, he has no plans to take up Simon's new offer. "The bet doesn't mean anything .
. I still think the price of those metals will go up eventually, but that's a minor point .
"Look at the new problems that have come up: the ozone hole, acid rain, global warming. It's true that we've kept up food production _ I underestimated how badly we'd keep on depleting our topsoil and ground water _ but I have no doubt that sometime in the next century food will be scarce enough that prices are really going to be high even in the United States.
"If we get climate change and let the ecological systems keep running downhill we could have a gigantic population crash."
Simon was not surprised to hear about Ehrlich's reaction. "Paul Ehrlich has never been able to learn from past experience," he said, then launched into the Cornucopian line on the greenhouse crisis _ how, even in the unlikely event that doomsayers are right about global warming, humanity will find some way to avert climate change or adapt and everyone will emerge the better for it.
But Simon did not get far into his argument before another cheery thought occurred to him.
"So Ehrlich is talking about a population crash," he said. "That sounds like an even better way to make money. I'll give him heavy odds on that one."
John Tierney is a reporter for the New York Times and is writing a book on environmental crises. This is an excerpt from his story in the New York Times Magazine.
1990 John Tierney. Distributed by Special Features/Syndication Sales