The Human Population Chapter 7

Human Population and Carrying Capacity Current population ~6.8 billion a. due to: - improved sanitation - agriculture output - better living conditions Carrying Capacity - initially exponential until the limit is reached - limiting resources Every 5 days the global human population increases roughly by a million lives each day (1.8 million infants are born and 800,000 people die.

Factors Driving Population growth Variables in Population Size - immigration v. emmigration - Crude Birth Rate (CBR) * # of births per 1,000 people per year - Crude Death Rate (CDR) * # of deaths per 1,000 people per year - migration is not a factor (we don’t leave Earth) Immigration and emmigration Inputs to population greater than outputs: positive growth rate Outputs greater than inputs: negative growth rate

B. Changes in Population Size - Global Population Growth Rate [CBR – CDR] 10 example: [20 – 8] = 1.2 percent - National Population Growth Rate [(CBR + immigration) + (CDR + emmigration)] * We divide by ten in order to represent the value as a percentage since it is based off of 1,000 people

- Doubling Time. based on constant growth rate - Doubling Time * based on constant growth rate * rule of 70 example) population grows at a 2 percent per year 70/2 = 35 years

C. Fertility - total fertility rate (TFR) C. Fertility - total fertility rate (TFR) * estimate of the average number of children each woman will have during her childbearing years - replacement-level fertility * TFR required to offset the average number of deaths in a population so that the current population can remain stable * depends on country’s economic status (developed v. developing) Used to have a better understanding about the roles the births play in population growth RLF a. typically it is just over 2 children Developed – high levels of industrialization and income (replacement is 2.1) Developing – low levels of industrialization and income, higher mortality among younger children

D. Life Expectancy - average number of years that an infant born can be expected to live - depends on: * healthcare * sanitation * living conditions * aging * disease (HIV) - infant mortality * # of deaths of children under 1 per 1,000 live births Disease According to WHO, infectious diseases are the second biggest killer worldwide right after heart disease HIV – btwn 1990-2007, it killed more than 22 million adults and children - infects people aged 15-49 - has had a significant impact on infant and child mortality, population growth and life expectancy

E. Age Structure - 5-year increments - total area of all bars  size of whole population - population pyramid Demographers use data on age to predict how rapidly a population will increase Used to describe how its members are distributed across age ranges Population pyramids: Widest at the bottom and narrow at the top – typical of developing countries (venezuela and india) - population momentum -> it takes time for actions that attempt to reduce birth rates to catch up with a growing population therefore this is the reason why populations continue to grow despite the efforts Little difference between younger and older individuals (looks like a column from age 0-50) – slow growth or zero growth – US, many developed countries Inverted pyramid – TFR below 2.1 (China is on its way here) http://blue.utb.edu/paullgj/geog3320/lectures/populationgeography.html

F. Migration - aids in population growth - not used in calculation of total population size - net migration rate * difference between immigration and emigration in a given yer per 1,000 people in a country A country with a low CBR but a high immigration rate may still experience population growth Negative migration rate and low TFR, the population will decrease over time Migration can create crowded, unsanitary conditions, food and water shortages

Theory of Demographic Transition As a country moves from a subsistence economy to industrialization, it undergoes a predictable shift in population growth. Phase 1: slow growth – CBR roughly equals CDR, high infant mortality rate due to disease and lack of health care and poor sanitation Phase 2 – rapid growth; death rates decline and birth rates remain high due to better health care, better sanitation, increased access to food (this is India today) Phase 3 – stable growth; this occurs as its economy and educational system improve, family income increases and number of births also decrease; since both birth and death rates are declining, the system returns to a steady state Phase 4 – declining population growth; fewew young people and higher population of older people; since there are fewer people in the workforce and more that are retired, it forces pension programs and social security services to put a greater tax on the younger generation; there can also be a shortage in health care workers since there are more elder individuals (Japan is an example; giving incentives for people to have more children) http://globalsoc.wordpress.com/2008/04/18/demographic-transition-theory/

Family planning a. as the education levels of women is increasing, the number of children they have is decreasing b. “regulation of the number of offspring through the use of birth control”

Economic development 9 out of the 12 most populous nations are developing countries Top 3 a. China b. India c. US

Impact = Population X Affluence X Technology IPAT Equation Impact = Population X Affluence X Technology Impact – overall environmental effect Population – direct effect on impact Affluence – created by economic opportunity Technology – can degrade or help environment Affluence – money, goods, property The more affluent a society or individual is, the greater the effect Technology Degrade – CFCs Help – hybrid cars

Local, Global, and Urban Impacts - locally produced materials * overuse * environmental degradation * erosion, habitat loss b. Global - agriculture * affects carbon cycle

c. Urban - consumes ¾ earth’s resources - New York City - presents environmental challenges, but also have smaller ecological footrprints (ie. Public transportation)

Gross Domestic Product (GDP) Measure of nation’s wealth Value of all products and services produced in a year in a particular country - consumer spending - investments - government spending - exports minus imports Correlates with pollution levels