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In the News...



January 9, 2003

From the Desk of
Patrick Burns, Director
Population & Habitat Program, Audubon

Betting the Farm…Carefully

Yesterday, I posted a short piece about "Long Bets," Stewart Brand's newest brain child (see

The idea here is to get people to think a little deeper about the future.

As a point of history -- and as a form of education -- I note that "long bets" have not always been good for our side.

Back in the 1980s, Julian Simon bet Paul Ehrlich that the price of any five minerals Ehrlich chose to name would go down. Ehrlich chose five minerals whose value had gone up steadily from 1950 to 1975, and Simon sold Ehrlich an option to buy an amount of each mineral worth $200 in 1980 (i.e. total wager of $1,000 minus the actual costs of the minerals). Inflation was taken into account, so that the payoff would be in 1990 dollars corresponding to whoever's predictions were more accurate.

The price of all five minerals went down (see table below), and Ehrlich sent Simon a check for $576.07.

Mineral Quantity 1980 price 1990 price
Copper 196.56 lbs $200 $163
Chrome 51.28 lbs $200 $120
Nickel 65.32 lbs $200 $193
Tin 229.1 lbs $200 $56
Tungsten 13.64 lbs $200 $86

Simon offered Ehrlich an opportunity to recover his money by making another bet, this time on the future price of any set of commodities to be named by Ehrlich. Ehrlich declined this bet (a good thing too -- see world commodity prices at:

Five years later Simon expanded his offer, saying he would bet that "any trend pertaining to material human welfare" would be positive over a 10-year time period.

Ehrlich and a compatriot, Stephen Schneider, took up the challenge, and offered Simon their bet on a "take-it-or-leave it basis."

Simon declined their bet, saying the Ehrlich-Schneider trends were not "direct" measures of human welfare such as life expectancy, leisure time, and purchasing power, but merely a bet on the way certain indicators might go -- often with only a tenuous link as to why this change might be meaningful to humans in the long run.

A look at the proposed Ehrlich-Schneider bet (stakes were to be $1,000 per trend, and their were 15 trends) suggests Ehrlich and Schneider would have won their gamble, but it also explains why Simon did not consider these trends very good metrics for gauging "material human welfare."

bulletEhrlich wanted to bet that the average temperature between 2002 to 2004 would be warmer than the average temperature between 1992-1994. The bet offered no estimate of how much temperature would rise. In fact, global temperatures have risen one degree Fahrenheit in the 20th Century (see ), and the actual temperature rise over the 1,000-year mean is just over half a degree. This seems to me somewhat short of having had an impact on "material human welfare" - Simon's point. This is not to say that the potential for global warming is not a legitimate concern -- it certainly is. The good news, however, is that rapid steps are being taken to reign in greenhouse gas emissions. A recent analysis of China's greenhouse gas outputs, for example, shows that overall carbon dioxide emissions in that country fell by 7.3 percent between 1996 and 2000, and that overall methane emissions declined by 2.2 percent between 1997 and 2000. See

bulletFive of Ehrlich's 15 questions dealt with global warming. Along with the one already enumerated (see above), Ehrlich wanted to bet on whether four greenhouse gases would go up or down: carbon dioxide, nitrogen, ozone and sulfur dioxide (this last one only for Asia). No amount of increase was specified. In fact, Ehrlich would have won this bet, but once again it is not clear how this rise in gases was supposed to have had an impact on "material human welfare" over the 10-year life of the bet.

bulletEhrlich wanted to bet that per capita fertile cropland would decline, but did not link this bet to world or regional food outputs (i.e. commodity availability or prices). Ehrlich would have won this bet, but the number would have had no real meaning in terms of "material human welfare." In fact, as we have shown here in the U.S., it is possible to have an increase in total farm production AND take more and more land out of production (see Conservation Reserve Program map at, AND have a declining amount of per capita farmland AND have a tremendous growth in urban sprawl -- all at the same time.

bulletEhrlich wanted to bet that there would be less rice and less wheat grown per person. Note that Ehrlich could have bet on the future price of rice and wheat (both are commodities), but he declined. In fact, wheat and rice production have declined, but not because the potential for production has evaporated, but because the world market is glutted with cereals and production expansion has slowed as a consequence. Though Ehrlich's first book predicted massive famines, the Ehrlich-Schneider bet of 1995 does not offer to bet on per capita calorie intake (which has increased even in the less developed world), or to wager on an increase in the gross number of malnourished people in the world (it has gone down). For more information, see Professor Tim Dyson's National Academy of Sciences paper on grain production at, FAO data on calorie consumption and malnutrition at, IFAD/World Health Organization data on malnutrition at, and UNICEF data on malnutrition at

bulletEhrlich wanted to bet that "In developing nations there will be less firewood available per person in 2004 than in 1994," and that "the remaining area of tropical moist forests will be significantly smaller in 2004 than in 1994." Ehrlich would have won both these bets. That said, it's worth noting that per capita firewood availability is not a very good metric of either forest health or human health. The reason: as more and more people switch to natural gas, the amount of real forest can stay the same (what wildlife really cares about), while a declining percentage of people suffer from the health aspects of cooking over a wood fire (what humans really care about). In fact, this is more or less what is happening. Global forest data can be seen at From 1990-2000, total world forest cover declined by 0.22 percent per year.

bulletEhrlich wanted to bet that per capita oceanic fishing would decline. It has, and Simon was smart not to take this bet. Ehrlich could have bet Simon on fish prices however, and that would have been interesting, as per capita fish consumption has gone up in the world thanks to aquaculture which now provides 22% of the world's fish. Aquacultural output has been growing at 11 percent a year for the past decade, making it the fastest growing sector of the world's food economy. About 85 percent of fish farming is in developing countries (mostly carp in China, but also other kinds of fish in countries such as India, Bangladesh, Indonesia, and Thailand). Pond yield is climbing rapidly too. In China, for example, pond production increased from 2.4 tons of fish per hectare in 1990 to 4.1 tons per hectare by 1996 (a 70 percent per-acre production increase in just six years). If current trends continue, aquaculture production could exceed beef production (by weight) within the next 5 years.

bulletEhrlich bet Simon that there would be fewer plant and animal species extant in 2004 than in 1994. If the bet had been limited to vertebrates and vascular plants, I think Simon might have won, depending on how the bet was actually operationalized. Every year about as many previously "extinct" species are "found" as are added to the list. Recent examples include the Pale-headed Brush-Finch, the Coontail Plant, the Uinta Mountain Snail, the Golden-crowned Manakin, the Ventura Marsh Milkvetch, the San Fernando Valley Spineflower, the Los Angeles Sunflower, the Bavarian Pine Vole, and Gilbert's Potoroo. The IUCN notes that "In the last 500 years, human activity has forced 816 species to extinction" (see, yet the IUCN also make regular announcements about formerly "extinct" species being refound (see The question of what to do with animal and plant species that are "created" or "recreated" also muddies the water somewhat. Selective breeding is bringing back the extinct Burchell's Zebra and Quagga, for example (see while hybridization is occurring so often between plant and animal species that species creation of some kind is clearly occurring at a very rapid rate. If we are willing to declare the Asian Lion a separate species teetering on the edge of extinction even though "the [genetic and visual] difference is less than that found between different human racial groups" (, why not count the fertile progeny of lion and tiger crosses as a new species as well (ligers and tigons)? Bird and plant crosses are so frequent that they are almost impossible to list and document.

bulletEhrlich wanted to bet that more people would die of AIDS in 2004 than they did in 1994. Ehrlich would have won this bet, but it was a no-brainer; millions of people with HIV in 1994 were sure to degenerate into full-blown AIDS (especially in Africa) by 2004. Ehrlich could have looked at a very robust gross metric of overall human health - infant mortality rates or life expectancy at birth, for example, but he declined.

bulletEhrlich wanted to bet that between 1994 and 2004, sperm counts of human males would continue to decline and reproductive disorders would continue to increase (ostensibly due to chemicals in the environment). What research I can find does not give a good base line on sperm counts (it seems to go up and down all over even within countries, but I note that New York City residents are doing particularly well for some reason :-). In fact, sperm count decline may be due to increased iodine in salt; a dietary supplement added to stimulate the thyroid to produce chemicals vital to brain development (see

I raise these issues to provoke thought, and to point out how artfully predictions are written when dollar-amounts are actually attached to them -- one of the lessons of the Simon-Ehrlich bets.

A lot of times metrics are being used that are not particularly valuable in illuminating what is going on. Sometimes the metrics illuminate one aspect of the problem, but obscure other points. Sometimes, the bet is very carefully worded so that it suggests a causal relationship when one does not, in fact, exist.

Simon's bet with Ehrlich suggests that everything in the world can be summarized by a dollar price -- i.e. that humans are the only reference point, and that price encapsulates all values.

The bet proposed by Ehrlich and Schneider to Simon is most illuminating for what it excludes. Ehrlich and Schneider clearly do not want to bet on simple human-welfare indexes like life expectancy, economic growth, malnutrition, infant mortality, literacy, or the percentage of people with access to something as simple as electricity and a refrigerator. Nor do they want to wager on simple (and wildlife-meaningful) environmental indexes like the water quality of rivers and streams or total global (or even regional) forest cover. Instead, one-third of their proposed bet deals with greenhouse gases -- a phenomenon that has had no clearly quantifiable impact on human life or wildlife to date (though it may 20 or 30 years out from now).

I would be interested in hearing what population and habitat predictions folks would bet if they had $5,000 to wager. Would you bet on a human index, a habitat index, or a wildlife index? Would you make one big bet or five small ones? Why do you think you could win your bet? How does your bet relate to human population growth -- and how might family planning make a difference over time?