IDEAS : Doomsayers of Overpopulation Sound a New Jeremiad : Fears are voiced that human numbers will outstrip the means of subsistence. The focus now is less on survival than on the quality of life.

Maybe it’s because eerie new diseases are cropping up to foil the finest medical minds. Maybe it’s because nations are unraveling and hurling legions of refugees around the world. Or worries of forests falling, deserts spreading, species disappearing, ozone vanishing and cities bursting at the seams.

Maybe it’s a periodic fad for the intellectual nail-biters. Or maybe, now, the Jeremiahs of doomsday are right.

Whatever the reasons, an old fear is emerging anew: Calamitous global overpopulation.

“The most important question in the world is whether human beings are wise enough to see what’s coming,” says Denis Hayes, organizer of the original Earth Day in 1970.

Today, as executive director of the environmentalist Bullitt Foundation in Seattle, Hayes is among a growing number of credible public figures sounding the alarm. And this time the argument is less about human survival than the quality of life.

“Today’s global population cannot ever be sustained at anything approaching the current lifestyles of the United States or Europe or Japan,” Hayes says.

Two hundred years ago, Englishman Thomas Malthus crystallized the population argument for Western intellectuals: “Population, when unchecked, increases in a geometrical ratio. Subsistence only increases in an arithmetical ratio.”

Ever since, population doomsayers have been known as Malthusians.

Almost a century later, Charles Darwin joined the case. “Man tends to increase at a greater rate than his means of subsistence; consequently he is occasionally subjected to a severe struggle for existence.”

Nearly 100 years after that, Paul Ehrlich foretold of impending calamity in his highly charged 1968 book, “The Population Bomb.”

But each time, after furious debate, popular concern waned. And the world’s population continued to grow--from 2.5 billion people in 1950 to 5.6 billion today, on the way to 6 billion in the year 2000 and perhaps 9 billion by 2025 or 2030.

Powerful social forces work against serious public consideration of overpopulation. Religion for one. For another, overpopulation implies the need for population limitations. And that raises the impossible question: For whom?

Today, more than 90% of the population growth is occurring in the developing world. At the same time, industrialized nations gobble some 80% of the world’s production. Between these two numbers lies the inevitable formula for ethnic, racial and cultural strife.

Maybe just as significantly, overpopulation suggests that human ingenuity itself has limits, an idea that so far has not taken deep hold. Improvements in agriculture and technology have disproved previous doomsday prophecies. Why won’t they always?

Over the decades, a good many experts on both sides of the issue found themselves settling on an uneasy consensus: Prosperity was the root problem, not population. Once a nation’s standard of living rose, its population rate would decline--just look at the industrialized nations, which have stable or even dropping rates of reproduction.

Make people rich and they will lower the birthrate.

But that consensus is being challenged by those who would turn the prosperity argument around. Overpopulation, they contend, is the foremost barrier to universal well-being.

Last month, a Cornell University team led by ecologist David Pimentel published an exhaustive study of the world’s cropland, water, energy and consumption. The study concluded that the world can support only 2 billion people at a universal standard of living now enjoyed by industrialized nations.

“As human populations continue to grow, prosperity and quality of life can be expected to decline,” Pimentel said. The report suggests that these changes can be seen already, even in the United States.

The findings are by no means unique. In 1992, 1,600 scientists--including more than half of the living Nobel laureates in science--signed a declaration to the world’s leaders: “No more than a few decades remain before the chance to avert the threats we now confront will be lost and the prospects for humanity immeasurably diminished.”

Former Colorado Sen. Timothy E. Wirth will represent the United States at the United Nations population conference in Cairo this fall. And he already has made his position clear:

“Overpopulation growth is the overwhelming issue of the 21st Century. Overpopulation will overwhelm all our political institutions, all our economic institutions; it will destroy the environment around us and erode any opportunities that we have to provide quality of life to the people in the world.”

There are some signs that everyday citizens are reaching the same conclusion. In recent years demographers have noticed that, contrary to the accepted axiom, population rates are decreasing in some countries even though prosperity is not rising.

“This is a rather profound situation and is not well understood,” Hayes says. He attributes the change to the increasing status of women in the world and the spread of more efficient birth control. Even when confronted with cultural taboos, these women are “making trade-offs between having more kids and having some degree of comfort.”

“If we all want to live like peasants, there is room for 20 times more people than if we want to live like the luckiest of us today,” Hayes says. “You and I and the rest of us can say what we want, but the people who will determine the future are the tens of millions of girls age 12 to 18 around the world.”

The Global Impact

Even if world economies could comfortably sustain the rising population, the toll on resources would be tremendous. Developed nations consume resources at a rate far out of proportion to their populations.

Heavy Users

* Super consumers: Each American consumes 23 times more goods and services than the average Third World citizen.

* Richer diet: Americans consume 570 pounds of dairy products per year, compared with a worldwide average of 170 pounds.

* Indirect consumption: Feed grains for food-producing animals are consumed at a rate of 1,460 pounds per capita in the United States, compared with 255 pounds for the rest of the world.

Projected Growth

The discrepancies in growth between developed and undeveloped nations is apparent in projections for the United States and the western African nation of Guinea.

Current Projected Years it will take population (millions) to double, at (millions) 2010 2025 current rate WORLD 5,607 7,022 8,378 43 U.S. 261 300 338 98 GUINEA 6 9 13 28

*

Adding a Billion People to the World Year 1st billion: 1800 2nd billion: 1930 3rd billion: 1960 4th billion: 1975 5th billion: 1987 6th billion: 2000 7th billion: 2008 8th billion: 2019 9th billion: 2030 10th billion: 2050 11th billion: 2082 *

BIRTHS PER . . . (Based on mid-1994 population) Year: 141 million Month: 12 million Week: 3 million Minute: 268 Second: 4.5 *

DEATHS PER . . . Year: 51 million Month: 4 million Week: 990,000 Minute: 98 Second: 1.8 Sources: Population Reference Bureau, Cornell University report titled Natural Resources and an Optimum Population

Researched by DOUG CONNER / Los Angeles Times