We Already Number Too Many : Emotional or prudish public responses are impeding urgently needed, fact-based talk about curbing global population.

As nations gear up for a world population conference in Cairo in September, a Cornell professor has given them something to talk about. He says that the number of human beings, currently 5.6 billion and rising, really should be about 2 billion.

The professor, David Pimentel, is not a crackpot, and he did not make his statement quietly. He put it forth with press-release fanfare at the annual meeting of the American Assn. for the Advancement of Science--the largest, most media-attended gathering of U.S. scientists. He backs his claim with a number-crunching paper that will appear soon in a journal called Population and Environment. Rush Limbaugh has already ridiculed him.

The notion that there should be fewer of us is bound to trigger emotional reactions. Before we jump into those reactions, let me summarize what Pimentel says. He looks at global endowments of land, water and energy and recognizes not only that they are limited and diminishing given the way we are managing them, but that they are interdependent. We could cultivate more land but only by using more water. We could get energy from the sun, but only by using more land. The land could give higher yields, but only with more energy. Because he accounts for these interdependences, Pimentel comes up with lower supportable population estimates than those who look at one resource at a time.

At present we need about 100 million more acres of cropland each year just to feed that year’s additional population. Instead, we degrade and abandon 25 million acres a year. Assuming we stop abusing land and assuming we want to provide a good diet for everyone, it would be possible, says Pimentel, to feed a global population of 3 billion. If we also use land to provide renewable energy--as we will have to someday--and if everyone used roughly half as much energy as Americans now do, there would be enough productive land for a world population of 1 billion to 2 billion. By this reasoning, the United States, with a current population of 260 million, could support about 200 million sustainably and well. Pimentel is trying to calculate an optimal population, not a maximal one. “Does human society want 10 billion to 15 billion humans living in poverty and malnourishment or 1 billion to 2 billion living with abundant resources and a quality environment?” he asks.

He envisions not a sudden population reduction, but one that happens over a century, by greatly reducing birth rates. “Granted, a drastic demographic adjustment to 1 billion to 2 billion humans will cause serious social, economic and political problems, but to continue rapid population growth to 12 billion or more will result in more severe social, economic and political conflicts plus catastrophic public health and environmental problems.” Pimentel says that his proposition has produced virtually no scientific criticism. To the contrary, he is receiving letters saying, in effect: “His numbers may not be exact, but they’re in the right direction. But I wouldn’t dare say that in public.” Why not? Because of the emotional reactions.

You can’t tell me what to do in my bedroom. You can’t tell me to give up what I have earned, inherited or extracted from the Earth or from other people. The whole argument is Malthusian nonsense. With new technology we will make food out of air and fuel out of seawater. We can have 40 billion people all living like Donald Trump. I refuse to talk about the future until women are compensated for the 10,000 years of patriarchal oppression. Or until the poor are released from the prison of their poverty. Or until the rich renounce their greed and wastefulness. The scientific community quietly approves, but publicly ducks, a proposition raised by a responsible scientist in a scientific forum, and leaves him to the mercies of a rabble-rousing radio host.

Politicians plan a world population conference that will not ask the most obvious question: How many of us can be supported at what standard of living? We bury the idea that there may be too many of us because we are afraid to talk about it. We would have to talk about sex, sharing, power, greed, freedom and responsibility. Though most of us can imagine a tolerant, equitable world with fewer people and more resources, though we yearn to live in such a world, or at least to prepare it for our children, we will not do the first thing necessary to bring it about: talk about it, seriously, with civility and compassion and determined fairness.

David Pimentel has dared to talk about it. He deserves more than silent approval and public ridicule. He has served humanity and nature far more by raising the tough questions than anyone does by wishing those questions would go away.