World Population Dynamics

The Population Explosion

The Population Explosion

Population Explosion—a recent event Last 200 years or less for MDCs Industrial Revolution Improvement in sanitation and medicine Last 50 years or less for LDCs Transfer of technology, i.e. medical, agricultural (Green Revolution)

Frequency of Vital Events: The Population Clock http://www.census.gov/main/www/popclock.html Vital Events (per time unit) http://www.census.gov/cgi-bin/ipc/pcwe The global population reached 6 billion in fall of 1999 The global population is reached 7 billion in October 2011 Currently @7.2 billion

Rates of Global Pop. Change use: International Data Base http://www Rates of Global Pop. Change use: International Data Base http://www.census.gov/ipc/www/idbnew.html, then Online Demographic Aggregation CBR (crude birth rate) = number of births per 1000 population 1990: 24 Today: 19.4 CDR (crude death rate) = number of deaths per 1000 population 1990: 9 Today: 7.89 growth rate = birth rate - death rate (often in %) 1990: 1.5% Today: 1.2% growth rates have come down

Special Kinds of Fertility and Mortality Rates TFR (total fertility rate) = number of children born to a woman during her reproductive years (or life time) 1990: 3.1 2014: 2.36 IMR (infant mortality rate) = infant deaths per 1000 live births (infant < 1 yr) 1990: 62 2014: 43 (1900: 200)

Population, population change, growth rates Population: number of persons Population change: increase in the number of persons (per year) Growth rates: rate of change (per year)

Doubling Time Number of years in which a population reaches twice its size doubling time can be approximated using growth rates doubling time = 69 : growth rate rate: 1.4 doubling time: 49 rate: 2.0 doubling time: 34.5 rate: 0.5 doubling time: 138 rate: -0.5 doubling time: ????

Population Pyramids Graphic device: bar graph shows the age and gender composition of a region horizontal axis: gender male: left-hand female: right-hand absolute number of people or % vertical axis: age 5-year or 10-year age groups

The Demographic Transition

Five Stages of the Demographic Transition birth rates, death rates and growth rates systematically change through time as societies change: modernize, urbanize gain access to technology

Stage 1 high birth rates, high (at time erratic) death rates, low growth rates stage for much of human history, traditional societies practically no country today

Stage 2 high birth rates, declining death rates, rising growth rates improvements in sanitation (water) and medicine in Europe during Industrial Revolution in developing countries since the 50s/60s much of Africa today, some countries of Asia (Afghanistan, Nepal, etc.)

Stage 3 continued decline of death rates, declining birth rates, growth rates decline from high to lower levels change in behavior: adaptation to lower death rate, in particular infant mortality rate economic change: urbanization (incentive to have fewer children) Mexico today

Stage 4 & 5 Stage 4: low birth rates, low death rates, low growth rates United States today Stage 5: low birth rates, rising death rates, declining growth rates (if birth rates drop below death rates: negative growth rates) Western Europe, Japan

Population Pyramid with young cohorts

Population Pyramids Population Pyramids on the Web http://www.census.gov/ipc/www/idbpyr.html

Population Pyramids and Demographic Stages characteristics shapes of ‘pyramids’ wide base (true pyramid) wide middle (bulge), somewhat wider base urn- or bottle-shaped reversed pyramid different shapes--different dynamics

Population Pyramid and Demographic Transition Stage 2: wide base

Population Pyramid and Demographic Transition stage 3: wide middle

Population Pyramid and Demographic Transition stage 4: slender

Population Pyramid and Demographic Transition stage 5: narrow base

Demographic Transitions in China

China Population Pyramid 2005

Why does this matter?

Why does this matter? In 1900, Europe accounted for 20 percent of the world's population. Today, this figure is down to 12 percent. By 2050 it will drop to 7, by the end of the 21st century to 4 percent. Today, India and China together account for 37 % of the world’s population.

Population and Energy China: 2000-2005: 8 % of Global oil consumption but 27 % of growth in global consumption. World’s second largest consumer and third largest producer of primary energy. Meets 90% of needs with domestic supplies, mostly coal. India: World’s 5th largest consumer. By 2030 expected to become 3rd largest, overtaking Japan and Russia. India has only 0.4 % of the world’s proven oil reserves and is expected to run out of coal