Current Human Population Growth

and Implications

Human Population History

Factors Contributing to Population Explosion

• Agricultural advances

• Advances in medicine

• Industrial revolution

Reasons for exponential growth of human population

• Increased food supply

• Improvements in medical and public health and technology

• Improvements in sanitation and personal hygiene

• Safer water supplies

Thomas Malthus

• Studied the decline of living conditions in 19th century England

• Blamed this decline on:– Too many children– Inability of resources to replenish at levels with

increased population– Irresponsibility of lower class

• Proposed regulating family size of lower class to limit it to a level they could support

Malthus continued

• He said “positive checks” like food shortages and disease kept population at appropriate levels

• He said population growth was exponential but food production could not keep growing exponentially.

• As of today, he was wrong due to GM foods.

Current Stats• World Population: 6.6 billion people• U.S. Population: 295 million people• Kentucky Population: 4.1 million people• Louisville Population: 500,000 people• The U.S. is only 5% of the world’s

population, but we use ~ 1/3 of the Earth’s natural resources!!!

Crude Birth Rate and CDR

• CBR= the number of live births per 1000 members of the population in one year.

• CDR= the number of deaths per 1000 members of the population in one year.

• When calculating population change you must take into account total population size when using CDR and CBR.

Population change= (CBR+ immigration) – (CDR + emigration)

• Example: If the population is 50,000 and the number of births is 14 per 1000 and the number of deaths is 5 per 1000, what was the population change assuming no net immigration or emigration?

Alarming Facts…

• The human population is currently growing at a rate of 260,000 people per day!

• Every 3 years, the global environment must support another 285 million people

As a result of rapid growth…

• 1.3 billion people are impoverished• 841 million people are chronically

malnourished• Supplies of water for irrigation are declining• Nearly half of the Earth’s land mass has

been changed by human activity• Ocean fish stocks are depleting• Species are going extinct faster than ever

Earth’s Carrying Capacity (2billion-30billion)

• Determined by– Food production– Living space– Waste assimilation– Resource availability

• Can be expanded through advances in– Agriculture– Industry– Medicine

AccomodationsTo accommodate greater populations, many

policies would have to be implimented:Massive recyclingDriving restrictionsRestrictions on the transport of foodProhibitions against cutting trees on one’s

propertyLimitations to burning of fossil fuels

Fertility rates

• Replacement level fertility (RLF)= having enough kids to replace yourself– Slightly higher than 2 (2.1) b/c some kids die

• Total fertility rate (TFR)= average number of children a woman will have in her lifetime– Many factors affect like urbanization, education,

contraceptives and abortion availability

Indicators of overall human health:

• Life expectancy

• Infant mortality rate

Other factors that affect population growth

• Policies to encourage immigration

• Environmental refugees

• Religious persecution

• Baby boom generation in US– Why they are waiting to retire– How their retirement will affect the rest of us

Demographic Transition

• Pre-industrial= little to no growth (African nations)

• Transitional= rapid growth (Mexico, Pakistan)

• Industrial= stable growth (china)

• Post-industrial= declining growth (Japan, Russia, Germany)

Why are developing countries like India not moving toward Industrial

stage?• Most people are poor. Money is kept to few

in the country.

Age Structures and what they tell us about future population growth:

• What would a stable population age structure look like?

• What would a declining population age structure look like?

Ways to lower population growth:

• Provide economic incentives for having fewer children

• Empower and educate women

• More education means more money for work which mean less children are needed to take care of parents

• More education usually means having children later in life which usually means having less children

Cont.

• Family planning including contraceptives, legal abortions

• Improve prenatal and infant health care (need less kids if they survive)

China and India as case studies on family planning

• What do you think of these interventions?

What do you think?

• What is the US’s role (thus the taxpayers role) in other country’s population control?