Human Population Growth Through Time Current world population: 7.35 Billion (Nov. 2016) http://www.worldometers.info/world-population/ 2012 7 billion 1999 13 years 12 years 1974 1927 1804 13 years 14 years 33 years 123 years Tens of thousands of years
Birth and Death Rates Birth rate is reported as the number of births per people Death rate is reported as the number of deaths per people Calculating Population Change Immigration Emigration Population Change = { Births + } {Deaths + } zero population growth (ZPG) occurs when factors that increase and decrease population size are in balance.
Population Change Birth rates are higher in nations (highest on the continent) Annual rate of population increase is expressed as a percentage.
Country A has a birth rate of 12 per 1000 in 2000, and a death rate of 9 per 1000 in the same year. What is its rate of growth in the year 2000 (assuming no net immigration or emigration), as a percent? Since the birth and death rates are given per 1000, need to convert the difference to a percent. Doubling time of a population can be calculated by the rule of 70: Doubling time = 70/percentage growth rate If a population of howler monkeys increases by 3.5% per year, how long will it take the population to double?
Fertility Rates Replacement Fertility: Number of children a couple must have to replace themselves. in developed nations in developing nations (due to higher infant mortality) Total Fertility Rate (TFR): Average number of children a woman will have in her child-bearing years. Global average: Developed nations: Developing nations: National Geographic: Population density map http://www.nationalgeographic.com/earthpulse/population.html http://metrocosm.com/history-of-cities/ https://ourworldindata.org/fertility/#total-fertility-rate-from-1950-to-2015
Population Momentum Although the average fertility rate has gone down dramatically in the past few decades (from 5 in 1950 to 2.5 in 2015), because of the large number of people (esp. below the age of 15) the population is still greatly increasing, due to the between birth and age of Singapore:
Global Population Growth Through Time World human population is now starting to show growth instead of exponential growth Highest rates of growth increases above per year were seen briefly during the Growth rate peaked at in 1963, and declined to 1.1% by 2009. Annual births have reduced to 140 million since their peak at 173 million in the late 1990s Deaths number 57 million per year and are expected to increase to million per year by. Current projections show a continued increase of (but a steady decline in the population ) with the population to reach between 7.8 and 10.8 billion by the year 2050.
Factors That Can Decrease Fertility Rates greater availability of reliable greater availability of legal change in religious beliefs, traditions, & cultural norms away from encouraging. increased ; higher average ; increased of raising & educating children; infant mortality (larger families if infant death common) increase in average level of education & ; increased educational & employment opportunities for ; greater availability of private & public ; decrease in importance of ;
Two Primary indicators of overall health of a country 1. (higher in developing nations) 2. (lower in developing nations)
Birth & Death Rates Over Time Death rates have decreased substantially during the past 100 years, due to: Improved (Green Revolution) and birth rates have also decreased, but not as fast as death rates the increasing difference between birth & death rates is what has led to population growth In countries decreases in death rates are being accompanied by decreases in birth rates over time. In countries decreases in death rates have not been accompanied by as large of decreases in birth rates over time, leading to major population increases.
Demographic Transition Model 1) Preindustrial Stage: both birth & death rates are relatively, the population does not, & the population size is small. 2) Transitional Stage: rate drops due to industrialization, increased food production, & improved health care; birth rates remain relatively, the population. Many nations are in this stage.
Demographic Transition 3) Industrial Stage: rate drops & eventually approaches a balance with death rate, leading to a population growth. 4) Postindustrial Stage: birth rate & death rates approximately balance, population growth is attained, & the population stabilizes at a size much than the preindustrial size; if birth rate declines below death rate population growth may even be attained. http://www.cbsnews.com/news/italys-birth-dearth/
Population Age Structure Age structure refers to the proportion of the population in each age class: Examples: Examples: Guatemala USA Saudi Arabia Australia Examples: Spain Finland Examples: Italy Male Female Russia Rapidly growing populations: pyramid shaped age structures, with large numbers of individuals. Slower growing populations: more even age distribution. Pre-reproductive Age 0-14 Zero population growth: nearly proportions of prereproductive & reproductive individuals; Reproductive Age 14-45 Post-reproductive Age > 45 Negative growth: proportion of reproductive than pre-reproductive individuals.
Population Age Structure Developing countries are expected to continue to have a pyramid shape through the year 2025, although the age structure will become somewhat more evenly distributed. Populations of developed countries are expected to have an increasingly even age distribution through the year 2025.
India vs. Japan India: developing nation, so a wide base = fast-growing population Japan: developed nation, narrow base = negative population growth Japan
World Population Pyramid: Past, Present and Future Projections http://www.worldlifeexpectanc y.com/world-populationpyramid Case Studies: United States Census Stats: 2010: 310 mill (+8.4%) 2000: 286 mill (+13%) 1990: 253 mill (+9.8%) 1980: 231 mill (+11.43% 1970: 203 mill (+13.37%) 1960: 179 mill
U.S. Immigration History Immigration in the U. S.: as fertility, immigration has become a major source of population in the U.S.; The arrival of new immigrants and the births of their children and grandchildren account for of the U.S. population increase from 1965 to the 2015 (Pew Research Center) increasing levels of legal & illegal immigration have been happening since the 1960 s working immigrants boost the national in the long run; but states often bear most of the cost
Total Fertility in the United States Total fertility (TFR) in the United States had a major increase during the "baby boom" (1946 64) & is now hovering near. Baby Boom TFR of major racial groups in the US, 1980-2010
Baby Boom Generation Population age structure of the United States continues to show a bulge as the baby boom generation ages. As the generation leaves the workforce, there will be less competition for, but there will be an increased demand for for the elderly (i.e. Social Security and Medicaid).
Demographic Change in the United States By 2050, the US will see a more youth population, and the disappearance of the Baby Boom generation, which was largely US Dept of Human and Health Services
Case Studies: India Early efforts at lowering population growth were unsuccessful because of poor planning, inefficiency, low status of women, extreme poverty, and lack of funds Large regional differences exist in population and TFR. Issues include gender imbalance, high poverty, pollution issues see text and movie questions. India s total fertility rate fell to 2.3 in 2013, a significant slowdown in population growth, compared to 3.6 in 1991. Large divide: women in villages have a fertility rate of 2.5, while that of urban residents is 1.8. Large population Projected to surpass China before.
Case Studies: China The One Child Only policy was implemented in 1979 to control growth. At the time, the population was 970 million. Part of the reason for this was a massive that started in the late 1950 s. Incentives or rewards for families who adhered to the policy included better employment opportunities, higher wages and government assistance. Those who don t were subjected to, and less access to government assistance, and. There have been some exceptions to the policy since the 1980 s. China s current population is almost billion (2015) The one child policy is believed to have prevented up to births. By 2030, China population is expected to reach its maximum, around billion
Case Studies: China By 2050, China is projected to have population growth Projected population in 2050: 1.41 billion In October, 2015 China relaxed the policy so all couples can now have children One reason for relaxing the policy is the of China s population. By 2030, 25% of China s population will be over 60. Many couples in cities are not expected to have a second child, due to the high cost of raising children in urban areas. Gender imbalance: One of the unintended side effects of the one-child policy is that China is now one of the most gender-imbalanced countries in the world due to a preference for male offspring. This has resulted in the practice of couples opting to abort female fetuses. Abortion is legal in China, although sex-selective abortion is not. The gender ratio in China reached as high as boys for every 100 girls born, although this trend seems to be reversing.
Case Studies: Nigeria High TFR due to infant mortality Religion (Muslim and Catholicism Cultural Norms: Large families signal prosperity and importance use <20% Many cities, such as Lagos, are very overcrowded with poor living conditions High level of youth unemployment can foster rise of militant groups and civil strife.
Case Studies: Russia Russia s population peaked in the early 1990 s at 148 million and is now 142 million By 2050, it is projected to be only million Causes of decline: Low fertility rate (1.6) High death rate (15/1000; world average = 9/1000; US = 8/1000), One factor: high alcoholism rate average life expectancy of males is 59 years, 72 years for women
Case Studies: Russia Causes of Decline (cont d) High abortion rate: mosnews.com reported that in 2004, 1.6 million Russian women had abortions, while 1.5 million gave birth, BBC news reported that 13 abortions for every 10 live births Low immigration rate: mostly former Russians moving back from the former republic Government measures to slow population decline: supporting foster families, developing preschool education, promoting a healthy lifestyle, and incentives to have more than one child (a Day of Conception, and about $9,200, ~$36,112 relative to US standard of living). Public information campaigns
Population Statistics of Case Study Countries Country Population (2016) Median Age k (%) Fertility Rate China 1.37 Billion 37.1 0.43% 1.6 India 1.27 Billion 27.6 1.19% 2.45 United States 324 Million 37.9 0.81% 1.87 Nigeria 186 Million 18.3 2.44% 5.13 Russia 142 Million 39.3-0.06% 1.61
The Effect of AIDS While the number of people infected with HIV continues to grow, the number of people with AIDS, and the number of people dying from AIDS is slowing down.
An Aging Population The global population is getting older: The # of people 65 and older is projected to by 2050, from 531 million in 2010 to 1.5 billion in 2050. Seniors in the US is expected to slightly more than double, from 41 to 86 million. Trading young for old: Most countries, including the US are projected to see the share of their population that is 65 and older the share that is younger than 15 by mid-century.
An Aging Population and a shift to Africa World compared to US A population shift to Africa Pressure on workers: working-age people in the world may have to support more dependents, while workers in nations will likely have to support fewer dependents.
The Future: UN 2015 World Population Prospects 2015 2050 2100 World Population 7.3 bill 9.7 bill 11.2 bill Median Age Europe LDC s* 30 42 20 36 46 26 42 47 36 Population >60 0.9 bill 2.1 bill 3.2 bill Life Expectancy 70 77 83 Global TFR 2.5 2.25 2.0 Good News: *LDC = Least Developed Country Life expectancy increased by yrs from 2005 to 2015 Impact of AIDS in the last decade: Life expectancy in Africa was 62 in 1995, 52 in 2005, and is now 57 in 2015 mortality fell from 71/1000 in 2005 to 50/1000 in 2015
More than half this growth is expected to be in Africa LDC s (Least Developed Countries) projected to grow from 954 million to 1.9 billion in 2050 to 3.2 billion in 2100 46% of World s Population in 2015 lived in countries with TFR Future Projections for Population less than replacement Fertility Rates are dropping world-wide, with a slight increase in Europe Net migration to High Income countries in 2000-2015 was 4.1 million Net migration will account for 82% of growth in High Income countries from 2015 to 2050.