The Human Population

Challenge: From “Population

Bomb” to “Demographic Crisis”

Lecture Series in Quantitative

Sustainability

by

Toni Menninger MSc

http://www.slideshare.net/amenning/ toni.menninger@gmail.com

The Human Population

Challenge: From

“Population Bomb” to

“Demographic Crisis”

Sept 2011 Global and US population

Population clock: http://www.census.gov/popclock/

Sept 2012 Global and US population

Jan 2014 Global and US population

Population clock: http://www.census.gov/popclock/

US Population

• 315,218,420 January 29, 2013

• 317,444,010 January 29, 2014

• In one year 2,225,590 increase

• 0.7% annual growth rate

Decennial Census: http://2010.census.gov/

Global Population 2012: 7 billion

Growth rate is currently 1.1%

Doubling time = 70 / growth rate = 64 years

Annual increase about 77 million per year

• US Census International Programs

• UN Population Division

• National Geographic Magazine: The World at

seven billion

The Human Population Challenge

0

1,000,000,000

2,000,000,000

3,000,000,000

4,000,000,000

5,000,000,000

6,000,000,000

7,000,000,000

1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000

Global population since AD 1000

Exponential growth?

The Human Population Challenge

0

0.5

1

1.5

2

1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000

Global population percent growth rates, AD 1000 to present

1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000

Global population since AD 1000

0

0.5

1

1.5

2

1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000

Global population percent growth rates, AD 1000 to present

• Population growth has been 0.1% or less for most of human history

• Sharp increase after 1750 (Industrial Revolution) and especially after WWII (Green Revolution)

• Growth rates of past century are historical anomaly

Population growth rates worldwide

United Nations population growth rate estimates for the period

2005–2010 (wikipedia)

China

World Population Cartogram

World Population Atlas: Country areas scaled to population size

Census

year

China India USA

1990 1,134 847 249

2000 1,266 1,029 281

2010 1,340 1,210 309

The Human Population Challenge:

Demographic terms and concepts

Group work (2-3 students)

China, India and USA are the world’s most populous countries. In 2010, they each completed a decennial population census. The table shows the census results since 1990, in million:

Population change China India USA Sum

1990-2000

2000-2010

Fractional change in % China India USA

1990-2000

2000-2010

The Human Population Challenge:

Demographic terms and concepts China, India and USA are the world’s most populous countries. In 2010, they each completed a decennial population census. The table shows the census results since 1990, in million:

Approx. what percentage of global population do these 3 countries account for?

Approx. what percentage of global population increase do they account for?

What can you conclude about population growth in the 2000s compared to the 1990s: increased - stayed the same - decreased?

Complete the table:

Census year China India USA World

1990 1,134 847 249 5,263

2000 1,266 1,029 281 6,070

2010 1,340 1,210 309 6,972

Census year China India USA World

1990 1,134 847 249 5,263

2000 1,266 1,029 281 6,070

2010 1,340 1,210 309 6,972

Population change China India USA Sum

1990-2000 132 182 32 346

2000-2010 74 181 28 283

Fractional change in % China India USA

1990-2000 11.6 % 21.5 % 12.9 %

2000-2010 5.8 % 17.6 % 10.0 %

Demographic terms and concepts

China, India and USA are the world’s most populous countries. Last year, they each completed a decennial population census. The table shows the census results since 1990, in million:

Approx. what percentage of global population do these 3 countries account for? 41%

Approx. what percentage of global population increase do they account for? 37%

What can you conclude about population growth in the 2000s compared to the 1990s?

Fractional growth rate declined in all countries

Absolute rate of increase declined dramatically in China, less so in USA, and reached a plateau in India

Note: growth rates in table are per decade. To annualize percent rates, use logarithmic formula. E. g. ln(1.215)/10=1.9% for India during 1990s.

What causes birth rates to fall?

The Demographic Transition

Demographic terms and concepts

The Demographic Transition

Demographic terms and concepts

Births per woman since 1960

Iceland

China

Mexico

USA

The Demographic Transition

Total Fertility Rate (TFR): average number of children per woman

Replacement-level fertility: an average fertility of slightly more than 2

children per woman

The Demographic Transition

Growth rate = birth rate – death rate + net migration

Components of annual population change in the USA

Natural increase = growth rate – death rate

Demographic terms and concepts

World population growth rate:

• World Birth rate 2013: 18.9/1,000 per year

• World Death rate 2011: 7.9/1,000 per year

How to calculate growth rate?

Demographic terms and concepts

World population growth rate:

• World Birth rate 2013: 18.9/1,000 per year

• World Death rate 2011: 7.9/1,000 per year

How to calculate growth rate?

Birth rate – death rate =

(18.9-7.9)/1000 =

11/1000 = 1.1% (per year)

Demographic terms and concepts

Why are death rates higher in developed countries?

Demographic terms and concepts

Demographic terms and concepts

Why are death rates higher in developed countries? => Age structure

Source: United Nations, World Population Prospects: the 2002 Revision (2003), found at http://www.flatrock.org.nz/topics/money_politics_law/boom_moves_along.htm

Expansive vs. constrictive age structure

Age structure histograms

Demographic terms and concepts

Age structure histograms: expansive

Example: West Africa

Demographic terms and concepts

A rapidly growing

population has a large

proportion of pre-

reproductive and

reproductive individuals

and relatively few older

people.

Almost one third (1.8 billion) of the world’s population is

under 15 years; in Africa, 42% are under 15 years.

Age structure histograms Mexico Canada Sweden

Age structure histograms

Mexico: highly expansive, rapidly growing

US: somewhat expansive

Germany: constrictive,

starts shrinking

WWII

Demographic terms and concepts

0-4

5-9

10-14

15-19

20-24

25-29

30-34

35-39

40-44

45-49

50-54

55-59

60-64

65-69

70-74

75-79

80-84

85-89

90-94

95-99

100

0 200000000 400000000

World population histogram 2009

Female Popula-

tion

A rapidly growing population has a large proportion of

pre-reproductive and reproductive individuals and

relatively few older people.

Almost one third (1.8 billion) of the world’s population is

under 15 years; in Africa, 42% are under 15 years.

Age structure histograms: expansive

Demographic terms and concepts

A stationary or

shrinking population

has a small

proportion of children

and a relatively large

proportion of older

people.

Age structure histograms: constrictive

Demographic terms and concepts

Japan's demographic transition http://www.stat.go.jp/english/data/handbook/c0117.htm#c02

84 million 128 million 97 million (projection)

Age structure histograms: expansive to constrictive

0-4

5-9

10-14

15-19

20-24

25-29

30-34

35-39

40-44

45-49

50-54

55-59

60-64

65-69

70-74

75-79

80-84

85-89

90-94

95-99

100

0 100000000 200000000 300000000 400000000

World population histogram 2009

Female Popu-

lation

0-4

5-9

10-14

15-19

20-24

25-29

30-34

35-39

40-44

45-49

50-54

55-59

60-64

65-69

70-74

75-79

80-84

85-89

90-94

95-99

100

0 100000000 200000000 300000000 400000000

World population histogram 2050 (projected)

Female Popu-

lation

Source: U.S. Census Bureau International Data Base (IDB)

A global demographic transition?

0-4

5-9

10-14

15-19

20-24

25-29

30-34

35-39

40-44

45-49

50-54

55-59

60-64

65-69

70-74

75-79

80-84

85-89

90-94

95-99

100

0 100000000 200000000 300000000 400000000

World population histogram 2009

Female Popu-

lation

Total Fertility Rate (TFR): average

number of children per woman

Replacement-level fertility: an

average fertility of slightly more than

2 children per woman

Population stabilization requires a

reduction in TFR to 2.1. This will in

the medium run eliminate population

growth.

However, in the short term

population will continue to grow

because of population inertia (e. g.

China). Many fertile females.

A global demographic transition?

Factors favoring population growth

• Children are needed in agriculture

• Children are needed to support ageing parents

• Many children can be a symbol of high status

• Demographic transition not yet completed in LDC

→ Sustainable economic development will,

in the opinion of many experts, induce the

completion of the demographic transition

via social change and economic improvement

Factors favoring population growth

• Contraceptives not available/too expensive

• Family planning not considered due to cultural/religious reasons

• Unequal social and economic status of women

• Education, employment opportunities for women

lacking/denied

• Lack of reproductive rights

→ Development experts, organizations and (some)

governments promote the empowerment of women

as a means to stabilize population

International Conference on Population and Development

(ICPD) Cairo, 1994

Fourth World Conference on Women, Beijing 1995

The Human Population Challenge –

so what?

• Sustainability requires

stabilization of both

population and (per capita)

consumption

• Zero population growth will

eventually happen –

hopefully by benign means

rather than through disease,

war and famine.

• There is no scientific

agreement on what the limit

of earth's carrying capacity

might be – estimates range

from 0.5 to 50 billion.

• The closer we get to the

limit, the more difficult it will

be to achieve sustainability

and decent living standards.

The Human Population Challenge –

so what?

At the local and regional level, especially in

poor countries, rapid population growth creates

or exacerbates social, economic and

environmental problems and destabilizes

communities (e. g. Congo, Haiti, Pakistan).

Social institutions and vital infrastructure such

as school and health care systems are

overwhelmed, jobs for young adults are lacking,

adequate housing is lacking, natural resources

are overexploited.

The Human Population Challenge –

social implications of rapid growth

Population growth highest in poor countries

The Human Population Challenge –

beware of oversimplification

• It is simplistic to blame population

growth as the root of global

environmental problems, as some

environmentalists have done (e. g.

Paul Ehrlich, “The Population Bomb”,

1968). Example for Malthusianism

• Equating hunger with overpopulation

is also simplistic. Hunger is in most

cases caused by poverty and

economic inequality, not lack of food

supply.

• Resource overuse, climate change and other global

environmental crises are overwhelmingly caused by

an affluent minority. There is extreme global inequality.

• However, raising the living conditions of the world's

poorest implies an increased environmental footprint

for billions. The greater the numbers, the more difficult

it will be to balance development and sustainability.

• E. g. China: per capita CO2 emissions one fourth that

of U.S., total emissions now equal to U.S.

The Human Population Challenge – a

complex issue

It is simplistic to blame population growth as the root

of global environmental problems.

Reading assignment

George Monbiot 2009: "around one sixth of the world’s

population is so poor that it produces no significant

[greenhouse gas] emissions at all. This is also the

group whose growth rate is likely to be highest.“

• I=PAT: Total environmental impact equals population

times affluence times technology

• I=CAT: Impact = consumers times affluence times

technology

The Human Population Challenge –

over-population or over-consumption?

What is "overpopulation"?

→ Term is often used unscientifically. There are no

generally accepted criteria.

Population density

• Many advanced countries (esp. Western Europe and Japan) have

high population density.

• Many poor countries have low population density, with notable

exceptions (e. g. Bangladesh, Haiti).

Again, high population density can exacerbate social and environ-

mental problems in an underdeveloped, rapidly growing country - but it

is rarely the direct cause of such problems (exception: small islands).

The Human Population Challenge – a

complex issue

Population density (people per km²) by country, 2006 (wikipedia)

The Human Population Challenge Japan over 1000 people per square km

The Human Population Challenge

While some environmentalists warn of “overpopulation”, there is an opposite viewpoint – frequently present in the media - that European and Asian countries with low birthrates are facing a “demographic crunch”.

These dire predictions usually refer to countries like Germany, Italy, Japan and South Korea but there have even been warnings of a “looming demographic crisis” (Washington Post, February 28, 2010) or an “underpopulation crisis” (Slate, March 7, 2006) threatening China, the world's most populous nation.

The Human Population Challenge – a

demographic crisis?

→ Western Europe and East Asia are already densely populated.

Demographic stabilization in these regions should be welcomed.

The Human Population Challenge – a

demographic crisis? Japan > 1000 people per square km

A typical example of the “demographic crisis” argument:

“The building blocks of Japan's future are collapsing, in the view of many economists. Japan has fewer children and more senior citizens as a percentage of its population than any country in recorded history, but the government does little to encourage childbirth or enable immigration.” Washington Post, February 3, 2010

The Human Population Challenge – a

demographic crisis?

• Japan is the 10th most populous nation (127 million people).

• It has a population density 10 times higher than the United States (873 per square mile).

• Japan's workforce is highly educated and highly productive.

• An increase in the share of senior citizens is an unavoidable consequence of the demographic transition (unless life expectancy declines). The alternative would be to continue growing indefinitely, which is impossible.

The Human Population Challenge – a

demographic crisis?

A demographic crisis due to aging population?

• More retirees need to be

supported through the inter-generational contract.

• Fewer children → in general more resources are available for each child

• The working age share of Japan's population is now greater than it was 60 years ago, despite aging.

• In 40 years, one economically active person might have to support one additional person on average (current ratio 2:1). Increased productivity, full employment and possibly a higher retirement age will likely compensate for the increased burden.

• The main challenge is arguably on the level of social values rather than material resources.

“Demographic crisis”: is Japan facing a labor shortage?

The economic problem of every society is to provide (i. e. produce and distribute) the goods and services required by that society. In every society, there are members that are economically productive and those that are not (because they are too young, too old, sick, unemployed, etc.) The term Demographic crisis expresses concern that ageing populations with low birthrates see their share of retirees increase and the share of economically productive members decline. So the burden of providing for society's economic needs placed on the economically active population becomes heavier and heavier.

Is the demographic crisis concern valid?

The potential economic product of a society roughly speaking depends on three factors: age structure, labor force participation rate, and labor productivity. The cohorts between the ages of 15 and 65 are generally considered the economically active population from which the work force is recruited. The work force (labor force) participation rate is the percentage of the economically active population that is actually engaged in economic activity (by some definition). Labor productivity is the average economic product per worker ("worker" here includes anybody engaging in productive economic activity).

In the example of Japan, the economically active population share has actually increased between 1950 and present despite ageing. Labor force participation rate has generally increased since WWII in industrial societies due to increased participation of women. Labor productivity has increased exponentially since WWII.

It is projected that Japan's economically active population share will somewhat decrease over the next decades. It doesn't follow that there will be a labor shortage. Increased productivity and/or an increase in the labor force participation rate can easily compensate for the demographic change. Increasing demand for labor will lead to increased wages which will lure people into the workforce who might otherwise choose not to work. Some workers will choose to retire later if they feel well compensated and well respected.

Most societies today are suffering from high unemployment and a surplus of labor. There is no evidence that Japan or any other country is facing a looming labor shortage.

"For three years running, South Korea has had the world's lowest birthrate... The no-husband, no-baby trend has become a demographic epidemic in East Asia...

Collapsing birthrates are alarming East Asian governments, which in coming years will face a demographic crunch as the proportion of pensioners rises and the number of working-age adults declines."

Washington Post, March 1, 2010

The Human Population Challenge – a

demographic crisis?

“Demographic crunch” in South Korea?

→ South Korea – population 48 million - has 15

times the population density of the USA.

Economist Dean Baker (CEPR) comments:

“In standard economic theory, a smaller labor force will lead to a higher capital to labor ratio, which will increase productivity. If productivity is higher, workers can both enjoy higher living standards and be able to support a larger population of retirees.”

The Human Population Challenge –

popular demographic misconceptions

"Germany also faces a demographic challenge, managing a population that is not only graying but shrinking. Last month the government announced that the population dropped below 82 million for the first time since 1995. That means fewer people trying to pay off a growing national debt, with a projected budget deficit of $118 billion this year."

New York Times, February 11, 2010

→ Statement is a non sequitur: the capacity to pay back the national debt has nothing to do with population growth, unless the economy is understood as sort of a “Ponzi scheme”.

The Human Population Challenge –

popular demographic misconceptions

"We are living in an age of reverse-generativity. Far from serving the young, the old are now taking from them. First, they are taking money. ... the federal government now spends $7 on the elderly for each $1 it spends on children." David Brooks: The Geezers’ Crusade, New York Times, February 1, 2010

The Human Population Challenge –

popular demographic misconceptions

Class discussion

http://reason.com/archives/2012/07/23/generational-warfare

Generational

contract or

Generational

warfare?

"the federal government now spends $7 on the elderly for each $1 it spends on children."

David Brooks, NYT

→ The federal government doesn't fund schools. Most public spending targeted at children is at the state and local level.

→ Social Security is funded by a dedicated payroll tax. Retirees have contributed to the fund throughout their working lives. It is inaccurate to imply that this money is somehow taken away from children.

→ Old age provision systems such as Social Security are based on the inter-generational contract. Modern society arguably cannot function without, or retirees would have to rely on family support (which would favor large families).

The Human Population Challenge –

popular demographic misconceptions

"400 Million People Can’t Be Wrong"

With a fertility rate 50 percent higher than Russia, Germany, or Japan, and well above that of China, Italy, Singapore, South Korea, and virtually all of Eastern Europe, the United States has become an outlier among its traditional competitors, all of whose populations are stagnant and seem destined to eventually decline.

With the mobilization of our entrepreneurs and supportive government policies, the United States should be able to exploit its vibrant demography to assure its preeminence over the next four decades.

Joel Kotkin, Newsweek, April 16, 2010

The Human Population Challenge –

popular demographic misconceptions

“The United States has become an outlier among its traditional competitors”

The Human Population Challenge –

popular demographic misconceptions

"400 Million People Can’t Be Wrong“?

“Mercantilists [the school of thought that dominated Europe from the 16th through the 18th century] and the absolute rulers who dominated many states of Europe saw each nation’s population as a form of national wealth: the larger the population, the richer the nation. Large populations provided a larger labor supply, larger markets, and larger (and hence more powerful) armies for defense and for foreign expansion. Moreover, since growth in the number of wage earners tended to depress wages, the wealth of the monarch could be increased by capturing this surplus. In the words of Frederick II the Great of Prussia, “the number of the people makes the wealth of states.” Similar views were held by mercantilists in Germany, France, Italy, and Spain. For the mercantilists, accelerating the growth of the population by encouraging fertility and discouraging emigration was consistent with increasing the power of the nation or the king. Most mercantilists, confident that any number of people would be able to produce their own subsistence, had no worries about harmful effects of population growth. (To this day similar optimism continues to be expressed by diverse schools of thought, from traditional Marxists on the left to “cornucopians” on the right.)” Encyclopedia Britannica

A cornucopian is a futurist who believes that continued progress and provision of material items for mankind can be met by similarly continued advances in technology. Fundamentally they believe that there is enough matter and energy on the Earth to provide for the ever-rising population of the world. Looking further into the future they posit that the abundance of matter and energy in space would appear to give humanity almost unlimited room for growth. The term comes from the cornucopia, the "horn of plenty" of Greek mythology, which magically supplied its owners with endless food and drink. The cornucopians are sometimes known as "Boomsters", and their philosophic opponents—Malthus and his school—are called "Doomsters" or "Doomers."

Cornucopianism versus Malthusianism

The Human Population Challenge –

popular demographic misconceptions

"400 Million People Can’t Be Wrong“?

• The idea of strength through numbers, and of a “war of the cradles” between competing nations, was popular among 18th century mercantilists.

• Is such a view still appropriate in the 21st century?

• Is there really a connection between birth rates and the competitiveness of a modern industrial society in a globalized economy?

Summary: The Human Population Challenge:

Demographic terms and concepts • World population as of 2013: 7.1 billion

• Birth rate, death rate (mortality), natural change, net migration, growth rate

• Population Growth rate = Birth rate - death rate + net migration

• World Birth rate 2013: 18.9/1,000 per year

• World Death rate 2011: 7.9/1,000 per year

• World population growth rate: (18.9-7.9)/1000 = 1.1% per year

• Age structure diagram (“population pyramid”)

• Cohorts

• Expanding (expansive) – stationary – contracting (constrictive)

• Total Fertility, Replacement Fertility

• Maternal age, birth spacing

• Population Inertia

• Life expectancy, infant mortality, child mortality

• Demographic transition

• Economically active population, labor force, labor force participation rate

• Generational contract, Social security

• Carrying capacity

• Malthusianism, Cornucopianism

• Zero Population Growth

• I=PAT, I=CAT