How many children to have is an intensely personal matter, often a source of family debate. But the decisions made by Ramjee, Mamta and others their age will have repercussions far beyond their own families and villages.
They are members of the largest generation in history — more than 3 billion people worldwide under the age of 25. About 1.2 billion of them are adolescents just entering their reproductive years.
If they choose, collectively, to have smaller families than their elders did, the world’s population — now 7 billion — will continue to grow, but more slowly.
According to United Nations projections, the number will rise to 9.3 billion by 2050 — the equivalent of adding another India and China to the world.
That’s an optimistic scenario, one that assumes the worldwide average birthrate, now 2.5 children per woman, will decline to 2.1.
If birthrates stay where they are, the population is expected to reach 11 billion by midcentury — akin to adding three Chinas.
Under either forecast, scientists say, living conditions are likely to be bleak for much of humanity. Water, food and arable land will be more scarce, cities more crowded and hunger more widespread.
On a planet with 11 billion people, however, all those problems will be worse.
The outcome hinges on the cumulative decisions of hundreds of millions of young people around the globe.
The relentless growth in population might seem paradoxical given that the world’s average birthrate has been slowly falling for decades. Humanity’s numbers continue to climb because of what scientists call population momentum.
So many people are now in their prime reproductive years — the result of unchecked fertility in decades past, coupled with reduced child mortality — that even modest rates of childbearing yield huge increases.
“We’re still adding more than 70 million people to the planet every year — which we have been doing since the 1970s,” said John Bongaarts, a leading demographer and vice president of the nonprofit Population Council in New York. “We’re still in the steep part of the curve.”
Think of population growth as a speeding train. When the engineer applies the brakes, the train doesn’t stop immediately. Momentum propels it forward a considerable distance before it finally comes to a halt.
U.N. demographers once believed the train would stop around 2075. Now they say world population will continue growing into the next century.
In India, a country of 1.2 billion people, women have an average of 2.5 children each, and the birthrate is projected to fall to 2.1 by 2030. At that point, parents will merely be replacing themselves.
But even then, India’s population will continue to grow because of momentum. It is on track to surpass China’s and is not expected to peak until 2060, at 1.7 billion people.
Momentum isn’t the only factor in population growth. In some of the poorest parts of the world, fertility rates remain high, driven by tradition, religion, the inferior status of women and limited access to contraception.
Population will rise most rapidly in places least able to handle it: developing nations where hunger, political instability and environmental degradation are already pervasive.
The African continent is expected to double in population by the middle of this century, adding 1 billion people despite the ravages of AIDS and malnutrition.
Even under optimistic assumptions, the toll on people and the planet will be severe.
Today, about 1 in 8 people in the world lives in a slum. By midcentury, with the population at more than 9 billion, the ratio would be 1 in 3, assuming poverty and migration to cities continue at their current rates.
Now nearly 1 billion people are chronically hungry, according to the U.N. Food and Agriculture Organization, and at least 8 million die every year of hunger-related illnesses.
By midcentury, there will be at least 2 billion more mouths to feed, and no one can say where the food will come from.
It’s not just that the population will be larger. It’s that hundreds of millions of newly affluent people, mostly in Asia, will want to add dairy products and grain-fed beef and pork to their diets.
To meet the projected demand, the world’s farmers will have to double their crop production, according to calculations by a team of scientists led by David Tilman, a University of Minnesota expert on global agriculture.
William G. Lesher, a former chief economist for the U.S. Department of Agriculture, said the brightest minds in the field haven’t figured out the solution.
“We’re going to have to produce more food in the next 40 years than we have the last 10,000,” he said. “Some people say we’ll just add more land or more water. But we’re not going to do much of either.”
Gosh, I sure hope that global warming thing doesn’t pan out.
