IT would be truly foolish if the world brought an end to population growth - and still lost the habitat for much of its wildlife. Unfortunately, that looks likely in the wake of September's population conference in Cairo.
The world may be able to limit its population to as few as 8 billion to 9 billion people. Donor countries will almost certainly provide the $17 billion Cairo laid out for expanded family-planning programs. Affluence is spreading fast in the third world, which helps reduce births, too.
But there doesn't seem to be much public support for research on high-yield farming - and that's dangerous. High-yield farming is the only way to keep wildlife habitat from being plowed under when those 8-to-9 billion people demand cooking oil, meat, and milk in the year 2035.
Agricultural research centers in the third world, which brought us the ``green revolution'' and its high-yielding varieties of rice and wheat, are facing a funding crisis. Thousands of the research workers have been laid off. The World Bank has temporarily covered a $50 million shortfall in the tiny $270 million budget for international farm research.
Money can't be the reason we're starving the agricultural research budget. It's a mere 2 percent of what we're pledging for contraceptives. It must be that agricultural research now is politically incorrect. Fighting famine is no longer popular.
Has the world's fear of being overcrowded brought us to a lurking suspicion that additional food production will simply encourage more births? If so, we can set our minds at rest. The evidence shows that higher-yield farming encourages fewer births. Countries with the most progress in raising crop yields also have made the most progress in lowering birth rates. For example:
* Indonesia's rice yields are up 160 percent since 1950, against population growth of 142 percent. The fertility rate of the mostly Muslim population is down from 5.5 births per woman to 2.4. (Zero growth is 2.1.)
* India's rice yields have risen 135 percent, and its wheat production has soared from 6 million tons to 55 million. That has covered the food needs of a 149-percent population increase. India's births per woman have fallen from 5.8 to 3.1.
* Chile's corn yields are up four-fold, easily accommodating a population increase of 130 percent. Births per woman in this Roman Catholic country are down from 4 to 2.1.
* Zimbabwe has increased its village corn yields four-fold, matching its population increase. Births per woman have fallen to 3.5, less than half the peak of 7.7.
The truth is, unsuccessful farming leads to more births. Strange as it might seem, the countries with less success in raising grain yields have also kept the highest birth rates:
* Rwanda's corn yields have risen only about 25 percent, while its population has increased 250 percent. Births per woman have come down from 7.8, but are still 4.9. (Does that increase tribal frictions?)
* Ethiopia's grain yields have risen 120 percent but the population has grown 178 percent. The fertility rate increased from 5.8 births per woman in 1960 to 7.5 in 1992.
* Ghana's rice yields have risen only 24 percent since 1950, while the population has shot up more than 300 percent. Fertility is a still-high 5.4 births per woman, down from 6.7.
It is reasonable that grain yields should be a leading indicator of lower birth rates. High-yield farming directly raises living standards in largely rural countries. It helps give parents confidence that their first two or three children will live, and that the parents will be cared for in their old age. High-yield farming also produces a marketable food surplus to support cities, and urban populations have sharply lower birth rates than rural ones.
The lesson is clear. Cutting off farming research and discouraging the use of fertilizer will slow, not hasten, our progress toward zero population growth.
Low-yield farming also poses a major threat to the world's wildlife. Naturalists are urgently concerned that it will take too much land to produce food for our 21st-century population. (They aren't much worried that today's narrowly targeted and rapidly degrading farm chemicals will kill off large numbers of wild creatures; they're worried about people clearing and plowing under huge tracts of wildlife habitat.)
The concern is valid. High-yield farming is already saving 10 million square miles of wildlife habitat worldwide. But it will take more farming resources per capita to supply the affluent populations of the future. Humans have a hunger for high-quality protein. China's meat consumption is rising by 3 million tons per year, requiring 15 million tons more feed grain. India's Hindus are drinking 2 million tons more milk per year, while Indonesians are eating more poultry. These high-protein calories take two to five times more resources to produce than calories from cereals.
Indonesia and India are already risking environmental assets to produce meat and milk. Without higher crop yields, we might finally plow under the 10 million square miles of wildlife preserve that we've saved.
A recent analysis of population trends by the Winrock Foundation points to the low-growth scenario produced by the United Nations as the most likely. It shows population growth slowing rapidly in the first quarter of the next century, peaking at 8 billion around 2035 and trending down for the rest of the 21st century.
If so, the world's major environmental risk is illustrated by Indonesia, which is clearing tropical forest to grow low-yield soybeans ... for chicken feed.