6.7 Billion Humans and Counting - Where is World Population Going?

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Dr. James R. Carter, Geography-Geology Department
Illinois State University, latest revision 2008

One of the great stories is the growth of world population over the last century and where this is going to go in the next few years. In 1900 there were 1.6 billion persons in the world. When I started high school in 1950 there were 2.5 billion persons in the world. By 2008 there are about than 6.7 billion persons. Population around the world almost quadrupled in a single century. Why did population grow so rapidly and when will it stop growing?

The Equation for Population Growth

For the world, population grows when births exceed deaths. Ultimately, everyone dies but at any give time births may exceed deaths. With few exceptions world population has been growing continuously over the past 2 millennia. The following numbers come from Paul Harrison, Third Revolution, Penguin Books, 1993, with more recent numbers from the Population Reference Bureau.

  Historic Rates of population growth

0 AD - 800        0.03% per year

  • 800 - 1700        0.11%
  • 1700 - 1950      0.57%
  • 1950 - 1980      2.05%
  • 1980                  1.74%
  • 1997                  1.50%
  • 2000                  1.4%
  • 2007                  1.2%

The great increase in population numbers reflects our success in lowering the death rate and improving the human condition. As civilization has advanced we have modified the environment to make it more comfortable and productive for humans. We have drained wetlands to reduce malarial infections, we have developed water supplies and sewage systems, we have public health programs, we vaccinate children, we have eliminated diseases, we substitute the use of machines for human labor, we use refrigeration to preserve food and have better cooking methods, we are able to produce and distribute nutritious food, we have useful medical services, etc. All of these steps have contributed to prolonging life and lowering the death rate. For this we can be proud.

There is plenty of evidence that the growth of world population is not sustainable, that is we cannot continue to grow as we have in the past.  In fact, many contend that we already have exceeded the carrying capacity of Earth.  But, when we look at the numbers we see that the world will continue to grow.  For how long and to what size depends on many factors, some of which we can influence.

And, we must recognize that growth is uneven around the world.  In places like Italy and Russia the population is declining. Japan is concerned because they have so few children.  And, now with the outbreak of HIV/AIDS, some countries are experiencing a great loss of young adults.  It is a mixed message but one that everyone should know.

What we see in much of the world today has its antecedents in western Europe. A hundred to two hundred years ago European populations were booming.  They had great problems with teaming masses.  Many people had no jobs, there was no more land to farm and the forests were cut over.  Women kept having children.  It was during that time that many people left Europe and migrated to the Americas.  Most of the U.S. is populated by descendents of those persons who migrated from Europe.

Populations in any place appear to go through what is called the Demographic Transition.  This is based on the experience of western Europe.  The basic idea is that in natural situations people have many children, generally as many as the woman can bear.  Many of these children will die.  Mothers die as do fathers.

Then, with advancements in an area Death Rates drop.  But couples keep having children because that is the natural thing to do.  The consequence is that population grows rapidly.  With time Birth Rates drop, for many good reasons.  At some time it is likely that Birth and Death Rates will come into balance to achieve a stable population.  There are considered to be four stages to the Demographic Transition.

Stages in the Demographic Transition

  • Stage 1 - High BR and High DR, little change in population
  • Stage 2 - DR falls, BR remains high, large growth in population
  • Stage 3 - BR begins to decline, DR remains low, slowing growth in population
  • Stage 4 - Low DR and Low BR, little change in population

Below is data on Birth and Death Rates over time for Finland, a northern European country.  This data seems to be the best example of the Demographic Transition in a particular country.  This data is cited frequently to illustrate the Demographic Transition.  It comes from the Population Reference Bureau

Demographic Transition in Finland

1785 - 1790 

Birth Rate = 38/1000 

Death Rate = 32/1000

Natural Increase = 0.6%< /p >

1825 - 1830

Birth Rate = 38/1000

Death Rate = 24/1000

Natural Increase = 1.4%< /p >

1910 - 1915

Birth Rate = 29/1000

Death Rate = 17/1000

Natural Increase = 1.2%< /p >

2000

Birth Rate = 11/1000

Death Rate = 10/1000

Natural Increase = 0.1%< /p >

Will the Demographic Transition play out in the rest of the world the way it did in Europe?  Today there are no new continents to migrate to as the Europeans did to the Americas.  Yet, the U.S. and Canada continue to be recipients of immigrants and/or temporary workers from many parts of the world.

As the economies of the more developed countries are booming, they need workers. So, we see many people moving from the less developed countries to the more developed countries.  Many people from Turkey are moving to Germany, and that is creating some tensions.  Italy is now seeing many people from Albania and north Africa, as are other European countries.  It was noted recently on CNN that there is a mosque in Tokyo to serve the many immigrants there from elsewhere in the world. That program noted that Japan needs to import 600,000 persons per year to meet job needs.  Around the world we hear about "snake heads" who make a living smuggling poor people into the wealthier, developed countries.

There is also a suggestion that not every area, or country, will move toward lower fertility rates.  We have seen that in most countries the number of children a woman will have in her lifetime has been declining.  This number is known as the Total Fertility Rate, or TFR. A TFR of 2.1 is considered to be the replacement rate.  The replacement rate has to be slightly greater than 2.0 because a few young people will die or be killed before they get to their reproductive years.

Today we find most European countries with TFRs well below the replacement rate. Italy, long known for its large families, now has a TFR of 1.4.  Germany is only 1.3, as are Poland and Russia.  The Demographic Transition has been very dramatic in Europe as populations boomed and are now stabilized or declining.

In much of the rest of the world we have been observing that TFRs are declining.  It has been assumed that the rest of the world would follow in the footsteps of Europe. But, in 2000 the Population Reference Bureau, PRB, reported that the fertility rates for women in Bangladesh and Egypt appear to be no longer declining.  They seem to be stuck at slightly more than 3 children per woman.  In 2007 Egypt had a TRF of 3.1 while Bangladesh was 3.0. With such high TFRs population will continue to grow.  So, perhaps the Demographic Transition that Europe experienced will not apply to the rest of the world.

But, in the same article, PRB noted Argentina has long maintained a TFR of about three children per woman, well above the replacement level.  In their 2007 World Data Sheet PRB reported a TRF of 2.5 for Argentina, showing that fertility rates are declining in some parts of the world, following the European model. 

So What?

There are many different interpretations about what is happening in the world. Occasionally, someone will warn of the coming population boom. I contend the bomb has already gone off and we are currently in the boom.

Some people argue that the explosion is already over, and things are settling down. Ben Wattenberg, a popular social scientist, contends the population boom is a myth. He looks at Italy and Japan and says they have problems because they are not growing.  I agree that some countries have or will have problems because their populations are declining but in some places population is still booming.

The ‘Cornucopians’ argue that the world is better off with more people because they represent more minds and more capabilities. Many people would like to see the developed countries of the world increase their birth rates and start growing.

For the world population will continue to grow by about 70 to 75 million person per year. That growth will come about in the lesser developed countries of Africa, Asia and South America. It will happen because on the average these people are early in the Demographic Transition and have TFRs of 3 to 6 children per woman.

Even if these peoples were to bring their TFRs to 2 children per woman, populations will continue to grow for many decades because there are so many young people. These young people want to have their own families.

Below is a table of data by major regions of the world. These numbers are from the Population Reference Bureau World Population Data Sheet 2007. There is a lot of information in these numbers but focus on the proportion of the population that is under age 15 and over age 65.

In the developed countries of the world the percentage of the population under age 15 is only slightly higher than that over age 65. In many regions of Africa about 45 percent of the population is under age 15. All of these kids are potential parents. As they come into their reproductive years, they will want to have their own families, as they should. But, because there are so many young people population will grow rapidly, even if each woman has only 2 kids. It is likely women will have more than 2 kids in many parts of the world.

Selected data from the Population Reference Bureau 2007 World Data Sheet

 

Popl

Crude

Crude

Total

Rate of

Percent

Percent

2007

Birth

Death

Fertility

Natural

under

over

Rate

Rate

Rate

Increase

Age 15

Age 65

(millions)

(/1000)

(/1000)

(children

(%)

per woman)

Northern Africa

195

26

7

3.1

1.9

35

5

Western Africa

283

42

15

5.7

1.9

44

3

Eastern Africa

294

41

15

5.5

2.5

44

3

Middle Africa

118

46

18

6.3

2.8

46

3

Southern Africa

55

24

16

2.8

0.8

33

4

North America

335

14

8

2.0

0.6

20

12

Central America

148

23

5

2.7

1.8

33

5

Caribbean

40

19

8

2.5

1.1

28

8

South America

381

21

6

2.4

1.5

29

6

Western Asia

223

26

6

3.4

2.0

34

5

South Cent Asia

1,662

25

8

3.0

1.7

34

5

Southeast Asia

574

21

7

2.5

1.4

29

5

East Asia

1,550

12

7

1.6

0.5

19

8

Northern Europe

98

12

10

1.8

0.2

18

16

Western Europe

187

10

9

1.6

0.1

16

17

Eastern Europe

295

10

14

1.3

-0.4

15

14

Southern Europe

153

10

9

1.4

0.1

15

18

Oceania

35

18

7

2.1

1.0

25

10

World

6,625

21

9

2.7

1.2

28

7

 

In those areas where 30% or more of the population is under age 15, how do you provide schools and services for young people? Where do the funds come from to pay for the schools?

On the other hand, in places like Southern Europe where the proportion of the population over 65 is larger than the proportion under age 15, who will pay for the care of the older, retired persons?  These are tough questions that we are addressing poorly.

Based on these numbers we know world population will continue to grow for many years.

"Development is the best contraceptive" is a term often given to explain human behavior with respect to reproduction. As people become better educated and are more financially secure, they choose to have fewer children. They delay the age when they get married, if they ever marry. They delay starting families. Many find it expensive and disruptive to have children. And, these educated people know how to not have children, they have alternatives to pregnancy after pregnancy.

So, to address the ever-growing population we need to see development around the world. Sorry to say development is coming very slowly to far too many areas.

One approach to addressing population growth is to give women a say in their reproduction. In many cases the woman has little power in a relationship. Another dimension of this is to provide education to girls, as well as boys. When girls become educated, they delay the age when they have their first child and generally have fewer children. In many places money is spent educating boys, because they are expected to be the wage earner.

Empowering women is quite controversial. We are still fighting this issue in the U.S. It is a tougher fight in many of the lesser developed parts of the world. It has cultural and religious dimensions.

And discussion of population growth must now include a consideration of HIV/AIDS. This problem is most dramatic in Africa but is a growing problem in many other parts of the world. In some of the African countries, more than 20% of the adult population is infected. Death rates are going up. In these areas the HIV/AIDS is creating a great number of orphans.

We have little idea what impact HIV/AIDS will have on the patterns of population growth in those countries where large portions of the populations are infected. Part of the problem is that few people want to face the reality of HIV/AIDS. It is not something to be proud of. So, if you preach high standards of morality and abstinence you can rise above the problem or so many leaders think.

Some people hope that the HIV/AIDS fight will force people to address sex and reproduction issues openly. If condoms are used openly to fight the spread of Sexually Transmitted Disease, then they are likely to have an impact on conception and birth rates. However, there is great opposition to be openly discussing these issues in many places, including in the U.S.

There are many NGOs addressing population issues. One of my favorites is PCI media impact, formerly known as Population Communication International.  The approach of this organization is to produce socially responsible soap operas that educate as well as entertain. If you want to educate and empower women, what is more effective than a soap opera on the radio or TV?

Coconut Bay is the name of a recent production airing in the Caribbean. This soap opera is a joint effort with an organization dedicated to protecting biological diversity.

I am a member of the Normal Rotary Club, of Normal, Illinois.  I also support the Rotary Action Group for Population and Development.  The title of this unit under Rotary International makes the link between population and development.  As I noted above, we recognize that 'development is the best contraceptive.'  Reportedly, there are more than thirty thousand life-time members in RFPD.  Obviously, many share my concerns.

Conclusion

World population will continue to increase by tens of millions for many years. Demographers have issued three projections for world population in 2050. Remember, we have more than 6.7 billion person today and the average TFR for the world is 2.7 children per woman.

The Projections of Population in 2050

If average TFR declines to 1.6 children per woman, then population will peak and decline slightly to 7.3 billion persons in 2050

If average TFR declines to 2.0 children per woman, then population will be 8.9 billion persons by 2050 and will continue to grow.

If average TFR declines only to 2.5 children per woman, then population will grow to 10.7 billion persons in 2050 and will keep on getting ever larger.

In terms of the environment, an ever-increasing population will make it harder to achieve a sustainable way of life. I firmly believe we must move toward greater sustainability.

Many people ask when we will reach the Carrying Capacity of Earth?  Some think we have already reached it and passed it.  Others reject the idea that there is a finite Carrying Capacity.  This subject deserves consideration, but that will have to be done another time in another place.

In closing it should be noted that if we really want to stop, or reverse, population growth, we can increase the death rate.  All we have to do is let people starve, die from toxics and pollutants, abandon safety practices, have more accidents, and have more and bigger wars. I do not find this to be an appealing alternative.  Hopefully, you do not like this alternative either.

   ============================== 

This paper was written originally for presentation at part of a series on Health of the Global Environment, ISU, Normal, Illinois, Spring Semester 2001 and has been updated regularly. As of 2021 it is quite dated in terms of population numbers but the message resonates.

For comments, contact me at:  [email protected]