Human

Chapter 6

PopulatIOn

How has human population grown?

• Slowly over time• Scarce food and incurable disease• Death rate high• Families had many children

• 500 years ago• Rapid growth• Why?• Agriculture, industrial; revolution, better food supply, shipping methods improved,

improved sanitation, healthcare, improved medicine• Led to expanded human growth

Science Behind Human Population

• Thomas Malthus• English Economist• Human population cannont grow exponentially

• Limits: Famine, disease, war

Malthus's controversial theory on population growth, in terms of the concept of "moral restraint"

• Thomas Malthus warned that population growth would exceed resource growth, leading to catastrophic checks on overpopulation.

• population grew exponentially while food supply grew arithmetically.• Without population control, the population would be reduced by catastrophes such as famine or

war (Malthusian catastrophes) according to Malthusian theory.

• As a solution, Malthus urged moral restraint: people must practice abstinence, sterilization, and have criminal punishments for those who have more children than they can support.

• These Malthusian catastrophes have not taken place on a global scale due to progress in agricultural technology. • many argue that future pressures on food production, combined with threats such as global

warming, make overpopulation a still more serious threat in the future.

• Overpopulation- population of a species exceeds the carrying capacity of its ecological niche

• Underpopulation- having a low population rate

• Optimum population- size of a population that produces the best results according to chosen end targets.• End Targets include:

ecological sustainability, economic output and philosophical or ethical ends-in-themselves.

Science Behind Human Population• Esther Boserup

• Danish agricultural economist• a seminal theory of population to

rival Malthus• pioneering work on the role of

women in human development

• population is reaching the point when the food supply is reaching exhaustion Malthus says, the extra people have to die, BUT

• Boserup says that you just have to upgrade the productivity of the food supply. • Under pressure of numbers, with more mouths to feed, people put more labor and more intense

effort into feeding themselves, and find ways to get more food production out of the land. • They cultivate the land more intensively, • they add extra manure, • extra fertilizer, • extra water• improve their crops.

• They invent their way out of the Malthusian crisis

• Malthusian trap may even drive the development of technology. • Boserup developed her ideas in connection with traditional farming systems in South East Asia, but her

ideas have been applied to global agricultural patterns.• Perhaps a Malthusian crisis drove our ancestors to cease hunting and gathering and take up

farming. As Chairman Mau maintained,

“each mouth comes with a pair of hands.”

If Boserup is right, then the most advanced agricultural technology should be found in places which are closest to a Mathusian crisis. High-tech agriculture only be found in places with large populations of near-starving people. the places with the food shortages tend to have low-tech agriculture the high-tech parts of the world tend to have high living standards and plenty of food.

• There are some who argue that Boserup can't work indefinitely. • At some point, the population may get so huge that they can't be fed no matter how inventive they are.

?) Can the environment really sustain this kind of pressure in the long run?

• You probably don't have to choose between Boserup and Malthus. • Malthus is talking about the potential for a population to face environmental limits.• Boserup is talking about overcoming those limits through culture and technology.

Demography

• Scientific study of human population• Study a variety of social and economic factors that effect human population• Examines characteristics of human population and attempts to explain how

and why human population changes over time

•3 Factors that influence Population Sizes:• Birth rate • Death rate• Age structure

Demographic Transition

Dramatic change in birth rates and death ratesLow Death rate, High Birth rate

From 1760 to 1910Society modernizes

Increase level of educationRaise standard of livingFamilies have fewer children

Birth rate decreasesPopulation growth slowsDemographic transition complete when:

Birth rate falls to meet death rate and population growth stopsOnly complete in a few countries

India and China high birth rate

Age Structure

• Population depends partly on how many people of different ages make up a population• Age-structure diagrams• Population profiles used to predict future population growth• Show population of a country broken down by gender and age group

Age structure in US• Equal # of people in each age group• Slow and steady growth rate for near future

Age Structure in Nigeria • More young children than teenagers• More teenagers than adults• Population will double in 30 years

Controlling Human Population• India• Compulsory sterilization

• China• Family planning program

• Benefits and bonuses• Forced abortions

Slowing Human Population Growth

1.Reduce poverty through ECONOMIC DEVELOPMENT & universal primary education

2.Elevate the status of women 3.Encourage Family Planning & Reproductive Health care

Predicting Future Population Growth

• Many factors• Age structure of countries• Prevalence of life threatening diseases

• By 2050• 9 billion• Growth will level off or decrease if countries growing rapidly go through

demographic transition

•Lower growth rate means population growth is slowing by it is STILL growing•How does this effect environment?• Ecologists predict that if this growth does not slow even

more there will be Serious damage to • Environment• Global economy

•Other ecologists predict that science, technology, and changes in society will control those negative impacts on economy and environment