According to the United Nations Population Fund, the seven-billionth child is most likely to be a boy born in India or China, this week. However the trend of fertility or growth of population in the longer term is in a different direction toward slower population growth, says Dudley Poston, a professor of sociology and demographics at Texas A&M University.
For the first time ever, the human reproduction rate is slowing, in many places slowing significantly, and the slowing growth is not only happening in Europe and Japan, he said. “Once your fertility rates drops below two, it is very very hard to get it to go back up again,” he explained. “We now have 75 countries in the world where the fertility rate is below two,” meaning the average woman is having fewer than two children. That is far below the rate of 2.2 to 2.3 considered optimal to hold the population steady, factoring in the number of females who have no children or who don't live to reach childbearing age.
He added that Europe and the industrialized democracies of East Asia are the “poster children” for demographic shift, low birth rates are also being seen in Brazil, in China, and in the Islamic Middle East, where the fertility rate in the United Arab Emirates is 1.8. Poston added, “Japan is losing more people today than they're gaining… South Korea has an alarmingly low fertility rate, 1.1.”
In 1970, the average fertility rate worldwide was 4.5, leading to predictions of demographic doom. Poston says the fastest growth period in the history of the world was in the mid to late 1960s, which prompted the predictions. Poston says a combination of factors led to what may be the most significant demographic shift ever. In the industrialized West, improved methods of birth control and greater opportunities for women in the workplace and in society meant the end of 5,000 years of women generally being considered society's baby-makers.
In China, there has been aggressive enforcement of a 'one child' policy, drastically reducing population growth rates, and leading to a surplus of males. Worldwide, urbanization has reduced the need for large families beneficial in rural agricultural areas. “It is really only in the countries of sub Saharan Africa where fertility is still high...,” Poston said, “but even in several of these countries there have been fertility declines in recent years.”
Reasons for significant growth rate declines in places like Iran, where the rate has fallen from 7.0 in 1974 to 1.9, remain more of a mystery, but Poston says they probably can be traced to cultural changes that can be very difficult to reverse. “We have been growing very, very fast in the world and now we're starting to slow down.”
The fertility rate in Germany, Italy, Spain, Greece and many other nations is less than 1.5 children per woman, dramatically lower than the “replacement” rate of 2.1 children (the extra .1 accounts for children who do not survive to adulthood). Japan (fertility rate 1.4), South Korea (1.2) and China (1.5) are close to the target.
Poston said high fertility rates were effectively countered by high infant mortality rates, diseases, and nearly continuous warfare that generally cut down men at the height of their most active reproductive years. Now science led to a decrease in infant mortality and deadly diseases, and combined with a continued high fertility rate led to a huge population bloom.
Moreover, the warfare and constant societal violence that helped keep the population in check has retreated, Harvard University psychologist Steven Pinker says in his recent book “The Better Angels of our Nature.”
So Poston says while it took 12 years to reach Monday's seven billion mark from six billion, it will take 14 years to reach eight billion - the first time in history a billion milestone has taken longer to reach than the one before - and then 18 years to reach nine billion.
The U.N. says world food production per person today is 41 percent higher than in 1961, thanks largely to the “Green Revolution” in farming which brought higher yields not only to Western farmers, but brought traditional subsistence farming in Africa and Asia into the modern age. Food production per capita in India today is 37 percent higher than fifty years ago, according to the World Bank. “(Whether) the rate of farm production slow down or level off is uncertain… But right now there is no difficulty,” Poston said.
Only gray spot in this is that the human population is also graying with larger older age populations.
The pyramid, once with a tiny number of old folks at the peak and a broad foundation of children, is inverting. In wealthy countries, the graph already has a pronounced middle-age spread.
“There are many countries, more all the time, that are going to be looking at a population implosion, rather than a population explosion,” said Matthew Connelly, a Columbia University professor of history and the author of “Fatal Misconception: The Struggle to Control World Population.”
The aging of the world will change cultures in myriad ways. People may have to extend their working lives far beyond the traditional retirement age. Countries may start competing for immigrants. Vast numbers of people are already migrating across the planet, from high-fertility countries to those who need workers. For example Ethiopia and Germany have roughly the same population today, but Ethiopia’s is expected to more than double in the next four decades while Germany shrinks by 10 million people.
And America is a juvenile country compared with Japan, where, by mid-century, the 65-plus cohort will reach 40 percent of the population. There will be, if trends hold, just one-working-age person per Japanese retiree. “It’s a big, big social change. Lots of things are going to be disrupted,” said Ted C. Fishman, author of “Shock of Gray,” a 2010 book whose subtitle frames the issue comprehensively: “The Aging of the World’s Population and How it Pits Young Against Old, Child Against Parent, Worker Against Boss, Company Against Rival, and Nation Against Nation.”
Fishman points out that this isn’t all bad but rather is a challenge. “Longer life is what humans beings have wanted ever since we started talking to spirits and mixing herbs in bowls. And we worked at the top of our intelligence to get to this point of our life. It took almost the sum total of human history to get it. And now we have to work at the top of our intelligence to solve the social challenges that come with longer life and aging societies,” he said.
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