Human Population Growth Problems

• The world population explosion including the United States. What about Pennsylvania?

• Different population growth rates in developed and developing nations.

• Consequences of exploding populations.

• Dynamics of population growth.

The Human Population Explosion

9,000 human beings added to the planet every hour

Why the explosion of over the past 100 yrs, or more?

• Improved sanitation, medicine, and nutrition.• Reduced mortality, especially infants and children.• Increased longevity – we grow older.• High total fertility rate remained high initially.• Increased technology facilitates migration and

better coping with environmental adversity.• No longer in dynamic equilibrium, i.e. biotic

potential has overcome aspects of environmental resistance (e.g. less disease).

“Black Death”:Yersinia pestis

World Population Growth (1.34%) and Absolute Growth

Population Growth Rate = percent increase from one year to the next.

Absolute Growth = increase in the number of people from one year to the next.

Although growth rate is declining, population continues to increase.

What about the United States; or more specifically Pennsylvania?

US growth rate 1.28%

PA growth rate 0.32%

Nations with Different Incomes:

Rich

• High-Income (Rich): industrialized and highly developed; 20% pop. but 80% wealth; USA, Canada, Japan, Europe, Australia; average per capita of $25,510.

• Middle-Income: moderately developed; Latin America, northern and western Africa, eastern Asia, and former USSR countries; average per capita of $2,950.

• Low-Income (Poor): under-developed countries; eastern and central Africa, central Asia, and India; average per capita of $520.

• Middle and low income countries represent 80% pop. but only 20% wealth.

Developing Vs. Developed Countries

Consequences of Growth?

• Smaller farms that are overexploited; leads to erosion, desertification, decreased food production.

• Clearing forest for new agricultural lands; land not ideal for sustainable agriculture; loss of habitat, biodiversity and ecosystem functions.

• Rural resident emigration to cities; hope for employment and social services; often results in poor unsanitary living condition, i.e. slums.

Growing Cities

UN project 2 billion living in slums by 2030.

Consequences of Growth?

• Increase in illicit activities; drug farming, urban crime; poaching of exotic animal and plant life (role of the affluent consumer). Tyranny!

• Emigration to developed countries where consumption per capita is higher – no solution, it make matters worst globally.

Environmental Impact

=Population size x Consumption

Stewardship

Consequences of Exploding Populations in Developing World

MORE

LESS

deforestation wetlandsfisheriesdesertificationbiodiversitydisease (drug resistance)population migrationcrimecultureeducation

The Meaning of Absolute PovertyIt’s not a choice, but rather a condition of too few resources

being available to go around to all people.

• Malnutrition• Illiteracy• Disease• Squalid

surroundings • High infant mortality• Low self-esteem• Low life expectancy

17 million children under 5 years old die each year.

Population ProfilesGive age structure and used to make population

projections (forecasts) into the future.

Population Forecasting Projections of future population size also require

assumptions of fertility rate and death rate.

Fertility Rate> 2

Fertility Rate< 2

Fertility Rate and Income

Projected World Population: Three Different Fertility Scenarios

Note the affect of a fertility transition (i.e. shift to lower birth rates).

Population Projections for

the United States

• The 1989 forecast was based on fertility rate of 1.8.

• The 1992 forecast is based on fertility rate of 2.1.

What will happen in developing nations with assistance in health care and food aid without a cultural shift to reduced fertility rate?

Population Projections: Developing Nations

The epidemiological transition (lower death rate) needs to be countered by a fertility transition (lower birth rate).

The Demographic Transition

Shift from primitive stability to modern stability.Crude rates refer to total births or deaths per 1000 per year.

Demographic Transition Comparisons

What should be done to promote demographic transition in developing countries?