DEMOGRAPHICS REVEALED

Washington, DC – Africa, the world’s poorest region, will record the largest amount of population growth of any world region between now and 2050.

Africa’s population is expected to more than double, rising from 1.1 billion today to at least 2.4 billion by 2050. Nearly all of that growth will be in the 51 countries of sub-Saharan Africa, the region’s poorest.

The Population Reference Bureau’s 2013 World Population Data Sheet and related material, including an interactive map and infographic, will be online at 10 a.m. (EDT) on Sept. 12, 2013. The Data Sheet offers detailed information on 20 population, health, and environment indicators for more than 200 countries.

We are hosting a webinar on Friday, Sept. 13, 2013, 11 a.m.–noon (EDT). To receive an invitation to the webinar, send an e-mail to Tyjen Tsai .

The Population Reference Bureau informs people around the world about population, health, and the environment, and empowers them to use that information to advance the well-being of current and future generations.

AN EYE-OPENING MEASURE: THE VITAL INDEX

by Carl Haub, senior demographer, PRB

The vital index, the annual number of births per 100 deaths, is a simple measure but can often be eye-opening. Only a few countries publish the index on a regular basis. While that may not sound exciting at first, the measure can teach us a lot about population dynamics. Recently, the index did receive some national news: when the number of deaths of non-Hispanic whites in the United States exceeded births, for the first time in history.

In the table, we can see that the current level of the total fertility rate (TFR), or the average number of children per woman,  does not necessarily show where a country stands with regard to births and deaths. The present vital index is a result of a number of factors: how recently the TFR declined to a low level; the proportion of the population in the older ages; the number of young people who have moved into childbearing ages; and the effect of immigration, which normally consists of workers and their families who are themselves in the childbearing ages. All of these factors play into the vital indices in the table in different ways.

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WHAT REALLY IS MY LIFE EXPECTANCY?

by Carl Haub, senior demographer, PRB

As compelling a concept as it may be, life expectancy is an often-misunderstood demographic measure. Frequently, it is life expectancy at birth that receives the most attention, although we’re all aware we’re “living longer.”

Life expectancy results from life tables, sometimes referred to as actuarial tables. In a sense, a life table summarizes the mortality experience of a population in a given time period, often a year. Death rates are low for young people and naturally rise with age. But what matters is how much or how little these rates change and at what ages. As an example, consider life expectancy in the United States in 1940.

A TALE OF FOUR PYRAMIDS

by Carl Haub, senior demographer, PRB

There has been quite a bit made in the media and in blogs about low birth rates in industrialized countries. Quite correctly, many people (and countries!) are concerned that unprecedented aging and a dearth of younger people are leading to serious pressure on national budgets from a rising burden of support for the elderly because of  a declining group of tax-paying workers. But the situation is far from equal everywhere, and less is written about that.

The contrast between the age structures of the two country pairs below is striking, to say the least. All four countries have rather stable birth rates. If they stay that way, the demographic future of all four seems quite clear but in very different ways. These differences have profound implications for the future. Sharp shifts to an aging population will result in growing budgetary constraints, less ability to provide aid, and limited foreign policy options.

Populations of France and Germany, by Age and Sex

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WERE THE POPULATION ALARMISTS RIGHT OR WRONG?

by Carl Haub, senior demographer, Population Reference Bureau

Articles proposing that past alarm over world population growth is now completely wrong have appeared quite frequently over the past 10 years or so and seem to be gathering momentum. Such writings express the view that low birth rates, not high ones, are the world’s problem, voiding the long-held fears of overpopulation. Paul Ehrlich, author of the (in)famous 1968 book  The Population Bomb, is a common target of this criticism, although concern about rapid growth predated his book by many years. The concern over rapid population growth decades ago had a very sound basis. Birth rates in developing countries—where the concern was by far the greatest—were quite high and the use of family planning unknown. There really did seem to be no end in sight.

“EXPONENTIAL” DOES NOT MEAN “FAST”!

by Carl Haub, senior demographer, Population Reference Bureau

I’ve seen many occasions where writers have stated that a particular population is growing “exponentially.” That term seems to have evolved to mean “fast.”  The exponential rate—as opposed to percentage increase—is the one usually used to measure population growth. So let’s take a look at what it really means and, honestly, I’m definitely not being picky here. Exponential growth simply means that something, be it money in the bank or the population of Egypt, grows continuously. Compounding continuously is another way of saying it.

HOW TO WRITE ABOUT THE BIRTH RATE

by Carl Haub, senior demographer, Population Reference Bureau

No demographic subject captures writers’ imaginations like a country’s birth rate, be it baby “booms” or “busts,” or record highs or lows. But what measure should you use when you’re writing about the birth rate? Yes, there’s more than one—there are three: the crude birth rate, the general fertility rate, and the total fertility rate. In this blog post, I want to clear up the confusion.

First, we’ll take the crude birth rate (CBR), which is simply the number of births in a year per 1,000 population. Rates have a numerator (in this case, births) and a denominator (the country’s total population). The fact that the denominator is the total population of all ages is the reason why the CBR is labeled “crude.” In 2011, the CBR in the United States was 12.7 births per 1,000 population. But the CBR can be significantly affected by age structure, so that a population with a high proportion of elderly will tend to have a lower rate than one with a younger population. Why bother to report it? Because the CBR is one of three essential parts of the national population growth rate, since populations grow or decline based on the number of births, deaths, and net immigration—the balance of people moving in and out.

WRITING ABOUT POPULATION PROJECTIONS: BEWARE

by Carl Haub, senior demographer, Population Reference Bureau

It’s quite common to see reports such as “The United Nations projects that world population will be 9.3 billion in 2050,” a perfectly true statement. Many readers will most likely take that at face value and move on. But they should be asking questions! There are over 200 countries in the world with birth rates from 1.1 children per woman (in Taiwan) to 7.6 (in Niger). In most of those countries, it is the future course of the birth rate that will largely determine population size. The projection of 9.3 billion is just the sum of all the country-level population projections. What should those readers ask? For starters: What does the United Nations assume will happen to all those birth rates over the next few decades?