Some columns hit a nerve. A recent interview with Phillip Longman about his book, "The Empty Cradle," did just that. It brought a torrent of mail.

Much of it was abusive.

About 80 percent of the letters protested that we already had too many people on the planet. That it was too crowded. That over-consumption wasted irreplaceable resources. That Longman was wrong because population was rising. That I had "failed to study Thomas Malthus." That Longman and I both should watch "Soylent Green." That it was all due to abortions. That no one should be promoting larger families.

This is clearly an area where emotions make communication difficult. So hang with me, please. Let's consider three important words. Demography. Care. Nurture.

It is true that world population is rising and will continue to rise for more than half a century. It is also true that we, collectively, will be hard pressed to provide adequate resources for the increased population. Water is a particular concern. So is energy. I have written about both even though my beat is personal finance.

Demography isn't a quick-change subject. If it were a boat, demography would be an aircraft carrier, not a jet ski. In demography, 25 years is statistical noise. Fifty years starts to look meaningful. A century can be telling. Decisions made today will only see their full ramifications in 75 years. Here are some figures.

•  According to recent United Nations figures, the total population of the more developed regions of the world was 1,193.8 million in 2000. It will reach 1,219.7 million by 2050. The population appears flat because the rising U.S. population covers the declining population of Europe and Japan.

•  United States population is rising but what the Centers for Disease Control and Prevention in Atlanta calls our "intrinsic rate of natural increase" has been negative for over 30 years--- and this applies to both white and black women.

•  The population of Europe will decline by nearly 96 million people over the next 50 years, reaching an estimated 632 million. The population of Japan will fall from 127 million to 109.7 million. Since the United States, Europe, and Japan account for most of the consumption in the world, the pressure on some natural resources won't be as great as it would be if developed world population was rising rapidly.

•  The population of Russia will virtually collapse, falling from 145.6 million to 101.5 million by 2050.

•  The population of China will continue rising to 2030, peaking at 1,450.5 million--- but will decline to 1,395.2 million by 2050.

•  About one-third of the expected population growth will occur in Africa--- except that estimates are revised downward year after year to reflect the downward spiral of HIV/AIDS and political anarchy.

•  Even areas of sustained population growth have rapidly falling birth rates. In India the birth rate fell by one-third between 1981 and 1997.

Phillip Longman directs his concern to the unsung hero of human societies: the family. Most economists treat families as mere tools for consuming the output of business or the purported benefits of government. In fact, no business or government institution can replace the functioning of a family. Without that functioning, society would cease to exist. (Skeptics should check what it costs to institutionally care for an abused child or a parent with Alzheimer's disease.)   Longman sees a birthrate that is literally verging on extinction (nearly half the required rate for replacement) in Europe, Japan, and Russia. And he asks questions few are asking.

Those questions turn on two words.

Care. It will become more difficult in such a rapid population shift. Longman points out that there will be 35 million fewer children in the world by 2050--- but 1.6 billion more elderly people. We can measure that by asking what portion of the population will be at least 60 years old in 2050, remembering that in most of human history it has been less than 5 percent. In forever-young America, the figure will hit 26.9 percent, the lowest of any of the developed economies. In Italy and Japan it will be 42.3 percent. In Germany it will be 38.1 percent.

These are massive changes. They will absorb the lifetime work of millions of younger people. It will strain--- or completely destroy--- institutional systems of retirement income and health care that depend on transfers from younger workers. It will put devastating strain on younger households who may have to care for aging parents and stepparents.

Nurture.   This is what adult parents do for the next generation. Nurture will be increasingly problematic as young couples confront the competing demands of caring (or paying) for the elderly, paying off education debts taken on to be competitive in the job market, and paying for expensive housing in the shrinking number of school districts where quality public education can be obtained.

Many underestimate the pressure on today's young people. They should read books like "The Two Income Trap: Why Middle Class Mothers and Fathers Are going Broke" (Warren and Tyagi) and "The Price of Motherhood: Why the Most Important Job in the World is still the Least Valued" (Crittenden).

This is about the human condition. I pray that we can find as much concern for human beings, as a species, as we can find for whales and birds, as species.

United Nations population projections

United Nations: World Population Aging: 1950-2050, population figures

United Nations: World Fertility Patterns, 2003

United Nations: World Fertility Rate Map  

United Nations: World Fertility Patterns, by region

Sunday, August 22, 2004: A Bearish Birthrate Outlook

The Two-Income Trap: Why Middle Class Mothers and Fathers Are Going Broke

The High Cost of Motherhood: Why The Most Important Job in the World is still the Least Valued