geos2: population patterns and processes

demography

the statistical study of human populations: number of people; their characteristics; their geographic distribution; past trends and future projections

pessimist perspective

• population growth is bad for the environment

• earth is nearing it’s capacity in terms of supporting the human population

  • the earth’s regenerative capacity can not keep up with the human population

"population growth is the single most significant threat to the natural environment, indeed to the future of life on Earth" (Paul Ehrlich)

"we (Australia) should reduce its population to its ecological carrying capacity of around 6-10 million" (Tim Flannery)

optimist perspective

• we will also find a solution to curb the challenges associated with resource scarcity

• more people on earth equals more innovative minds to implement ways we can coexist with nature as a growing population

“population is a source of ingenuity that will resolve all problems. we have the technology to cater for an ever growing population, forever” (Julian Simon) 

“Australia should aim for a population of around 50-60 million” (Malcom Fraser)

principle of population

• exponential population growth will cause societal collapse

• supplies are finite and grow at a slower rate than population growth

  • if population growth outstrips our supply chain famine, wars and epidemics can occur

• [context] was written after the French Revolution; Malthus was concerned with rapid population growth among the lower echelons which could potentially threaten the balance of power in England

Malthusian trap

a point (on the graph) where the rate of population growth intersects and overtakes the rate of food production

how does a country accommodate population growth?

• migration

• industrialisation → increased production of food

• imports → resources from other countries

myth

there is no association between population growth and economic growth

neo-malthusian

• the idea that there was too rapid population growth in developing countries in the 1940s-60s

• concerns about the environment

• rapid population growth would be checked (positive) by the limits on finite resources (food, energy or water)

• contraception was regarded as a preventative check

I = f (P, A, T)

the environmental impact equation:

I = environmental impact

p = population

a = affluence

t = technology

*sometimes written as I = f (P, C, T) where C = consumption

the graph reveals that population growth is slowing

fertility policies

• fertility policies are usually unsuccessful because:

  • it is very difficult to make fertility levels to return to their prior levels

  • higher levels of education means people are partnering later in life

  • historically children were an economic asset; now children are a cost liability

the five stages of the demographic transition (dt)

a model that describes why rapid population growth is a temporary phenomenon

(dt) stage 1

• birth rate: high

• death rate: high

• natural increase: stable or slow increase

(dt) stage 2

• birth rate: high

• death rate: falls rapidly

• natural increase: rapid increase

(dt) stage 3

• birth rate: falling

• death rate: falls more slowly

• natural increase: increase slows down

(dt) stage 4

• birth rate: low

• death rate: low

• natural increase: falling and then stable

(dt) stage 5

• birth rate: yet to be seen (possibly falling further or rising again)

• death rate: low

• natural increase: little change

most population growth this century will occur in Africa

transition from a young, rural, fluctuating population through a period of rapid growth towards an old, urban population that is stable or in decline

P^t+n = P^t +(B-D)

the basic demographic equation:

P^t+n is population at time t plus n years

P^t is population at time t

B is births occurring between t and t + n

D is deaths occurring between t and t + n

*I represents gains from immigration, O represents losses through emigration

the crude death rate (CDR)

• number of deaths per year divided by the population (per thousand population)

• not great for comparative purposes

  • this figure does not take into account differences in age and how this alters to frequency of death in certain countries with an aging population

why do we have more deaths in developed countries?

developed countries have a higher proportion of older people who are most likely to die

infant mortality rate (IMR)

• number of infant deaths per year divided by the population (per thousand population)
  

• when mortality conditions decline , infant mortality goes down first

  • when hygiene becomes better children benefit the most because they are more prone to infectious diseases

• thus, a good measure of where a country is situated in the demographic transition model

life expectancy at birth (LEB)

the average number of years a person can expect to live according to current mortality conditions

• it can be reported for any ages

• it is a figure often reported at birth (but can be reported at any age)

*note progress is not linear

• (30 years) Neanderthals

  • food scarcity

  • hunting accidents

  • transition of disease from animals to humans

• (38 years) Neolithic

  • life expectancy increased because people settled down and started agriculture

  • more secure food supply

  • causes of death started to change

  • as humans startled living together we see transition of diseases among humans (e.g. cholera)

• (35 years) classical Greece and Rome

  • dense urbanisation

    • increased rate in the propagation of diseases amongst humans

    • this is an example of why progress is not linear (urbanisation does not necessarily mean better life expectancy)

  • violent conflict

• (48-38) Medieval period

  • urbanisation

  • plague

  • crop failure

• (80) post WW2

  • vaccines to protect against infectious diseases increased life expectancy

major pandemics and mortality events

• 1347 to 1351 Black Death

  • killed ~15% of global population (~30% of Europeans)

• 1845 to 1849 Irish potato famine

  • decline of ~25% of population

• 1918 to 1920 Influenza epidemic

  • killed ~30 million (~2% of global population)

• • on)