8.1 human population dynamics Flashcards
sustainability definition
a system continuing without collapse or radical change caused by its initial conditions
sustainability equation
(max sustainable yield / natural capital depletion) - human pop x demand
natural capital depletion
reduction in the capacity of an ecosystem to produce
e.g. coral reef bleaching –> baby fish don’t have a place to grow –> die –> less fish for consumption
wealth and demand
increase in wealth is linked to increase in demand –> a greater ecological footprint
demography
= study of populations of any organism
- the World Population Clock shows the current world pop, births, deaths, and pop growth for the day and the year
crude birth and death rate
CBR = number of births/1000/year
CDR = number of deaths/1000/year
CBR calculation
number of births / total pop x 1000
critical value for total fertility rate
critical value = 2.2 –> mean population will remain stable
- less than = pop will decline & more = it will increase
factors affecting birth and fertility rates
- role of children in labour force –> MEDCs may see kids as a burden and LEDCs see them as workers
- rates of urban living –> space is more limited, access to healthcare and family planning, access to education is better
- women’s status
- cultural norms (when to get married, how many children, etc)
- infant mortality rate and pension –> many LEDCs don’t have pension so make kids to look after them when old
- religious beliefs and traditions –> encourage large families & no artificial contraceptives
factors affecting death rates
- income –> high income = access to healthcare, food, education, shelter, electricity
- education/literacy –> better access to jobs and understanding of healthy diet
- access to food (balanced diet) –> MEDCs higher income and easy availability of food so poor diet (obesity & death), LEDCs lack basic vitamins and minerals (not enough calories)
- water supply and sanitation
- access to shelter and healthcare
- lifestyle –> MEDCs poor diet and driving everywhere
doubling time and natural increase rate
NIR = combination of fertility and mortality to determine pop size
- fertility higher than mortality = positive NIR but mortality > fertility = negative NIR
NIR calculation
(CBR - CDR)/10
doublign time calculation
NIR is used to calculate DT
DT = long long it takes for pop to double in size
calc: DT = 70/NIR
pop growth history
- hunters and gatherers so CBR and CDR balanced each other out (low growth rate)
- pop increased after agriculture emerged but fluctuated rapidly due to plagues, wars, famine, and invasions
- agricultural and industrial revolution in Europe caused death rates to fall (improved healthcare, introduction of vaccination, and better sanitation)
- 1700-1900 Europe pop quadrupled = beginning of exponential growth phase (economic development and improved public health)
the variants
- high variant = worst case scenario –> death rates fall but birth rates don’t
- median variant = most likely scenario –> projects current trends. into the future w/ math
- low variant = best case scenario –> death rates increasing
population momentum calc
- pop = 5000
- CBR = 5/1000/year
e.g. –> 5000 (pop) / 1000 x 5 (CBR) = 25
Thomas Malthus: Malthus’s Theory
Wrote an essay in 1798 predicting human pop to be exponential & the increase in food production to be arithmetic –> this would lead to human pop exceeding carrying capacity and pop growth outstripping food production
- Mathus saw the solution to be war and famine
- Mathus’s theory backed up by Paul Enrich in 1968
Ester Boserup
- Anti-Malthusian ideas
- he argued that advances in agriculture due to the Green Revolution had increased food production
impacts of overpopulation on the env
- agricultural land lost to residential and industrial developments (urbanization => deforestation)
- food riots in countries (e.g. 2007 West Bengal, India)
- water being withdrawn at increasing rates depleting aquifers faster than they can replenish
- topsoil depleted by overcropping
- depleting fish stocks by overexploiting oceans
population pyramids
- shows age and gender distribution of a pop
- left = males, right = females
- a snapshot in time –> helps predict future trends
- Triangle pyramid = high mortality rates, high birth rates balances by high death rates
- Tent triangles = falling birth rates, high life expectancy and lower death rates, suggests a growing pop (lots of people at reproductive age)
stages of demographic prediction models
- High stationary = preindustrial society
- high CBR & CDR cancel each other out so low NIR, high death rates caused by natural events (disease and famine), high BR due to lack of awareness of family planning & children contributing to income - Early expanding = Urbanising/Industrializing
- CBR remains high but CDR decreases causing significant increase in NIR & rapidly expanding pop due to improved food production (Green Revolution), improved food storage, better understanding of disease spread, vaccination discovery, access to healthcare & education - Late expanding = Industrial
- death rate continues to fall and birth rate starts to decline, highest NIR of all stages + large gap between CBR and CDR, fall in birth rates due to availability of contraceptives, improvement in women’s education and status, ban on child labor (parents put kids to school = child becomes financial burden) - Low stationary = Post Industrial
- both rates, death rates, and NIR are all low but pop is large (usually tent shape) - Declining
- death rates pass birth rates due to increase in unhealthy lifestyle (low exercise & high obesity cases causing cardiovascular disease), large aging pop (ppl from stages 1&2)
- problem = falling birth rate = few workers to support the growing aged pop
criticisms of DTM
- usually based on MEDCs –> different relationship in LEDCs between economic development and pop growth
- some LEDCs go through stages faster since medical advances, contraceptives, and education already exist
- doesn’t consider natural disasters, epidemics, wars, or migration
development policies
- country raising marriage age, birth rates fall
- introduction of state pension decreases fertility because the need for children to look after old ones is reduced
- gov introducing free compulsory primary education = decrease in birth rate because children are preferred to be used for free labor
direct policies: Pro and Anti-natalist
Pro-natalist policies increase fertility rates while Anti-natalist decrease it
anti-natalist strategies
TAXES: e.g. one child policy in China, larger families get increased tax
- charge for education & health for extra kids
- remove child-care facilities for families with too many kids
- taxing is generally effective at reducing BR & better for gov because decreased cost for providing schooling and health for kids
- negative impacts: problems for aging pop, selective abortions, abandonment of babies
emancipation of women
- educated women in workplace = less time for marriage and childbirth
pro-natalist policies
Tax/Welfare Incentives
- tax breaks to families w/ more than 1 kid
- education and healthcare free for all children
- free housing or upgrading existing housing for large families (used in Sweden)
- giving parents a child allowance
- increase maternity and paternity leave
- provide free public transport
These policies are rarely effective in the long run bc expensive for gov
