The InterDependent

As a still mostly genteel battle rages among demographers and environmentalists over how concerned we should be about a growing global population – on the brink of reaching 7 billion people, up a billion in little more than a decade – the United Nations Population Division has issued warnings about regions where life could become unmanageable.

“Although the rate of population growth has been declining since the late 1960s, the doubling of the world population between 1950 and the late 1980s has meant that, over the past half century, each additional billion has been added more rapidly than at any other time in history: the last two in a record 12 years each,” the population division reports in World Demographic Trends, a study prepared for a mid-April meeting of the UN Commission on Population and Development (http://www.un.org/esa/population/cpd/cpd2011/cpd44.htm).

The rate of population growth is different from the numbers of growth. The disconnect between the reality of a decreasing rate of fertility – the number of children a woman is expected to bear in a reproductive lifetime – and global population growth is central to the population division’s projections, which confirm that most of the numerical growth will take place in the poorest nations. There, an already large number of women of childbearing age will be followed by many more in the “youth bulge” generation now coming to maturity. Both children and the elderly are also healthier and living longer, increasing the numbers at both ends of the spectrum.

The richest nations, where fertility rates are very low (except the United States) are beginning to see declining or shrinking populations, which are arguably a manageable problem. European countries, Japan and a few Latin American nations have already started policies supporting women who may want to have more children or have any children at all. In a few cases, there are calls to discourage or even end family planning programs.

In the developing world, fertility levels will have to fall (and family planning become more accessible) to ensure a sustainable future, the report says.

“The additions to world population are increasingly being concentrated in the developing regions of the world and particularly in Africa,” the report says, while “the share of population growth in the developed regions has declined markedly and is expected to decline further as a rising number of developed countries experience population declines. These trends are producing population imbalances that will increasingly underpin development prospects and condition long-term sustainability.”

Unicef/NYHQ/Pirozzi

Newborn twins in Niger, one of the poorest countries on earth. A new UN study warns that the rapidly increasing rate of population growth will wreak havoc mostly in developing countries.

A big question mark hangs over India, soon to be the world’s most populous nation, already home to the largest number of the world’s poor. “The large and diverse population of India, for instance, may continue to have large segments with high fertility that could counterbalance the fertility declines in other segments,” the population division predicts. “Furthermore, other populous countries, such as Egypt, Nigeria, the Philippines or Pakistan, still have moderate to high fertility.”

The population division’s report projects six possible scenarios for population growth, from the next few decades to 2300 – the most distant ones called “what ifs.”

One example: in the medium scenario – somewhere between current and reduced fertility and other factors – population could peak at 9.4 billion by 2070 and start to decline, but only if fertility rates decline significantly in developing countries. That is by no means a given.

Statistically, a replacement fertility rate that would level growth is 2.1 children. In many developing countries, the rate is considerably higher and would have to fall below replacement to slow growth before leveling out. “Even with significant fertility reductions, Africa’s population will likely increase by 150 percent by 2100,” the report suggests, “and many of its countries will see their populations increase four-fold or more.”

Worldwide, countries as diverse as Brazil, China, Iran and Thailand have lowered fertility rates to replacement levels or below. But they are the exceptions. The overall prognosis of the population division is challenging, even dismal.

“The rapid population increases in recent decades are occurring on a planet that is increasingly showing signs of strain,” the report says. “If a population that adds a billion new inhabitants every 12 or 15 years is to be averted, global fertility must eventually reach and maintain replacement level. The reduction of fertility may be inevitable, but considerable effort is still required to make it a reality over the next few decades.”