Case study: China’s one-child policyCase study: China’s one-child policy

1980

Human population growth: 7 billionHuman population growth: 7 billion

Human population growth: 7 billion

A few milestones that lead to our present population:

• 10,000 bc agriculture• 1500 new crops from Americas reach

Europe • 1798 vaccinations• 1850 sewers were separated from drinking

water, which was filtered and chlorinated• 1884 contraception• 1930 better nutrition, sanitation, health care• 1960 Green Revolution

The human population is still growing rapidlyThe human population is still growing rapidly

Agricultural Revolution Industrial Revolution

1350

Hunter/Gatherer

Increasing our carrying capacity

Result of Large Populations

pollution

starvationReduction in biodiversity

Greater need for resources

World population has risen sharply

• Global human population was <1 billion in 1800.

• Population has doubled just since 1963.

• We add 2.5 people every second (79 million/year).

“baby boom”

United States birth rate (births per 1000 population)

Baby boom 1946-1964

1909 1919 1929 1939 1949 1959 1969 1979 1989 1999 2009

1939-1945 WWII

Rates of growth vary from region to regionRates of growth vary from region to region

At today’s 1.2% global growth rate, the population will double in 58 years

Global Variation in Fertility RateGlobal Variation in Fertility Rate

Is population growth really a Is population growth really a problem?problem?

Population growth results from technology, medical care, sanitation, and food.

– Death rates drop, but not birth rates.

Some people say growth is no problem.– New resources will replace depleted ones.– But some resources (i.e., biodiversity) are

irreplaceable.

Quality of life will suffer with unchecked growth.– Less food, space, wealth per person

Population and the Environment• Population growth can lead to environmental

degradation.

Overpopulation in Africa’s Sahel region has led to overgrazing of semi-arid lands.

Affluence and the environment• Poverty can lead to environmental

degradation…

BUT

• wealth and resource consumption can produce even more severe and far-reaching environmental impacts.

Population (Billions), 1999

Energy Use/ Year (1999)

Developed 1.2 7.4 kW

Developing 4.6 1 kW

Population vs. Energy Use

Demography studies human Demography studies human populationspopulations

• Demography: the application of population ecology to the study of human populations– Population size – Density and distribution– Age structure, sex ratio – Birth, death, immigration,

and emigration rates

Population size and densityPopulation size and density

Predictions of population size depend on different assumptions about fertility rates.

Population density and Population density and distributiondistribution

Population size: National populations

Age Pyramid United States 2012

• The United States’ “baby boom” is evident in age bracket 40–50. U.S. age structure will change as baby boomers grow older.

Age structure: Age pyramids

Age structure: “Graying Age structure: “Graying populations”populations”

• Demographers project that China’s population will become older over the next two decades.

Age structure: “Graying Age structure: “Graying populations”populations”

• China’s aging population will mean fewer working-age citizens to finance social services for retirees.

Figure 7.11c

China’s natural rate of change has fallen

China’s rate has fallen with fertility rates. It now takes the population 4 times as long to double as it did 25 years ago.

Sex ratiosSex ratios 100 females born to 106 males China: 100 females born to 117 males

Population growth depends Population growth depends on various factorson various factors–Birth –Death –Immigration –Emigration

• Technological advances led to dramatic decline in human death rates.– Widening the gap between birth rates and

death rates resulting in population expansion

Factors affecting total fertility rate

• Urbanization decreases TFR.– Access to medical care– Children attend school and impose

economic costs • With social security, elderly parents

need fewer children to support them.• Greater education allows women to

enter the labor force, with less emphasis on child rearing.

Worldwide, total fertility Worldwide, total fertility varies widelyvaries widely

Family planning and TFR

• Family planning, health care, and reproductive education can lower TFRs.

A counselor advises African women on health care and reproductive rights.

Poverty and population growth are Poverty and population growth are correlatedcorrelated

The Earth can’t support our consuming The Earth can’t support our consuming lifestylelifestyle

Humanity’s global ecological footprint surpassed Earth’s capacity to support us in 1987.

The wealth gap and population growth The wealth gap and population growth cause conflictcause conflict

LongevityLongevity• Lowest: Africa (55 years) and developing Oceania (64) Lowest: Africa (55 years) and developing Oceania (64)

years)years)Mortality Rates in Long-Lived Populations

Age Adjusted Death Rates (per 100,000 people)

Rank* Location Life Expectancy

Eating Pattern CHD** Cancer Stroke All Causes

1 Okinawa 81.2 East-West 18 97 35 335

2 Japan 79.9 Asian 22 106 45 364

3 Hong Kong

79.1 Asian 40 126 40 393

4 Sweden 79.0 Nordic 102 108 38 435

8 Italy 78.3 Mediterranean 55 135 49 459

10 Greece 78.1 Mediterranean 55 109 70 449

18 USA 76.8 American 100 132 28 520

* Average life expectancy world rank** Coronary Heart Disease