WHEN it comes to our planet's ecological future, the lovable old cartoon character Pogo said it all: ``We have met the enemy, and he is us.'' The ``critical thing'' in the destruction of Earth's life-support systems is the impact of human population, says Stanford University human ecologist Paul Ehrlich. Unprecedented overpopulation and its continuing growth ``are major factors in problems as diverse as global warming, African famines, acid rain, the threat of nuclear war, the garbage crisis, and the danger of epidemics,'' he explains.
Professor Emeritus Nathan Keyfitz, a Harvard University sociologist, has noted that some economists have taken to ``viewing population as the ultimate resource and science as infinitely and immediately able to supply technological solutions.'' He calls that view ``the result of a narrow disciplinary perspective that treats economics in isolation from its real-world setting.''
Concerned ecologists such as Drs. Ehrlich and Keyfitz warn that we are depleting the capital resources on which human life depends. Especially in the poorest areas ``the `scissors effect' of poverty and increasing population is slicing away at their ability to sustain human life,'' says Nafis Sadik, executive director of the United Nations Population Fund. Dr. Sadik points up her concern with a few startling numbers. Tropical forests shrink by 27 million acres a year. Some 26 billion tons of topsoil slip away annually. New deserts appear at a rate of about 15 million acres a year. Tropical developing countries have seen roughly 400 million acres of upland watershed ``grossly degraded'' over the last three decades.
In addition, users in many areas are consuming groundwater faster than nature replaces it. Also, something like half the world's croplands are troubled with waterlogging and salt buildup. In fact, Sadik says, reviewing the situation in the United Nations magazine Update, ``The amount of land available for agriculture may be shrinking even as numbers and needs grow.''
In industrially advanced regions, relatively fewer people make relatively larger demands on resources. ``The birth of a baby in the United States, given our lifestyle support system, is 100 times the ecological disaster that the birth of a baby in Bangladesh represents,'' says Ehrlich to dramatize this point.
It's hard to quantify population impact. Ehrlich suggests looking at rates of energy use. Sadik notes that ``the industrialized countries contain less than 25 percent of the world's population, yet they consume 75 percent of the energy used, 79 percent of all commercial fuels, 85 percent of all wood products, and 72 percent of all steel production.''
This does not mean that massive overpopulation and its growth in many developing countries is any kinder to the planet. Keyfitz has observed that ``it's possible to debate this issue [of lifestyle versus sheer numbers] endlessly.''
In his institute's publication Options, he explains: ``What we call traditional good farming or good forestry practice is maintaining the land in such condition that it will keep producing indefinitely .... But tradition is not everywhere a protection: The loggers of Nepal, like the cattle-raisers of the Sahel, have improvident traditions. They do not seem about to change their practices; indeed, they are too poor to risk any change at all - and the more of them there are, the more quickly they destroy their resource base.'' He sums up by saying, ``The least one can say is that every aspect of the problem [of human impact] is eased by having fewer rather than more people.''
As things stand now, having fewer people is not the direction of global population trends. The current growth rate is about a billion people every 11 years, mostly in developing nations. That's an extra 94 million people a year - roughly the population of Britain Ireland, Iceland, Belgium, Denmark, Norway, Sweden, and Finland combined.
There is a consensus among ecologists that such a trend can't go on. If it is not dealt with rationally, through birth control, they warn that nature - famines, pestilence, plague, war - will adjust things brutally. Writing in the recent US National Academy of Sciences publication Global Change and Our Common Future, former Environmental Protection Agency administrator William Ruckelshaus observes that nature will go on even if it means dispensing with the human species. ``Attractive animals and even particular ecosystems may be vulnerable, but Nature herself is not . . . . We are talking about a self-regulating system the size of a planet 3 billion years old,'' he notes.
What the experts seem to be saying is that it is time to face the much-discussed issues of population control squarely because they are central to humanity's future. As Ehrlich notes, this will not be easy because these issues are viewed in a variety of cultural, ethnic, national, and religious perspectives. This is why they have been peripheral to the concern about the environment.
Curbing population growth will take global cooperation. Rich nations must help poorer countries with birth control and with the associated economic problems, ecologists say. Developing countries must take charge of their population destinies if such help is to be effective. But little will happen until there is a global consensus for action. ``We need to decide what we [humanity] want out of life,'' Ehrlich says.
He likes to quote George Bush on this point. In the introduction to the book World Population Crisis (1973), Bush wrote: ``Success in the population field may determine whether we can resolve successfully the other great questions of peace, prosperity, and individual rights.'' He added, ``One fact is clear . . . major world problems like population . . . will have to be handled by large complex organizations representing many nations and many different points of view.''
Ehrlich says hopes that now-President Bush will take a lead in tackling this challenge.