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8.4 Human population carrying capacity - Coggle Diagram
8.4 Human population carrying capacity
Maximum number of individuals of a given species that an area's resources can sustain indefinitely without significantly depleting or degrading those resources.
Determining/quantifying for humans is hard as:
range of resources used is much greater than other species
when resources become limited humans develop new technology always around limitations.
resource requirements vary according to lifestyle which develops over time eg stone arrows in the Stone Age v fossil fuels now
humans regularly import resources from outside their immediate environment = they can grow beyond the boundaries set by their local resources hence increase current capacity
Humans
Thomas Malthus suggested that the growth of the human population would outstrip the ability of the earth to provide sufficient food resources for the population.
Esther Boserup up created the phrase "necessity is the mother of invention". She believed humans would adapt and overcome the limitation causing the current capacity to continuously increase.
growing crops in greenhouses
use new resources like shale gas
increased use of fertilizers and irrigation.
The optimistic POV = caring capacity will be increased with technological improvements e.g. fertilizers, GM food. Pessimistic POV = the earth is a finite resource that can only sustain a certain population size
Ecological footprint
Area of land and water required to support a defined human population at a given standard of living.
The measure takes account of the area required to provide all resources by the population and all waste.
The flows of energy and matter to and from any defined economy and converts these into the corresponding land/water area required for nature to support these flows.
It's able to provide a quantitative estimate of human carrying capacity = the inverse of carrying capacity = area required to sustainably support a given population rather than the population that a given area can sustainably support.
Increased by
greater reliance on fossil fuels
increased use of technology and energy (but technology can also reduce the footprint)
high levels of imported resources (which have high transport costs)
large per capita production of carbon waste (high energy use, fossil fuel use)
large per capita consumption of food
Decreased by:
reducing use of resources
recycling resources
reusing resources
improving efficiency of resource use
reducing amount of pollution produced
transporting waste to other countries to deal with
It provides a way round the dilemma of human CC. Instead of focusing on an environment and calculating the CC it focuses on a given population
Calculating EF
An approximation can be calculated using per capita food consumption and per capita CO2 emissions
Total land requirements can then be calculated as the sum of both formulas multiplied by the total population.
It is able to provide a quantitative estimates of human carrying capacity.
UNITS = hectares or global hectares
If it is GREATER than the land area available, the population is unsustainable = exceeds CC
LEDCs v MEDCs
There is an increase in EF with each stage of the DTM. How is the word countries mean I'll be reducing EFSC through energy efficiency strategies however. However usually greater wealth leads to higher consumption of goods and natural resources like water
In stages 4 and 5 more goods are imported and transportation/ travel increases. Hence there are more pollutants = carbon emissions. There is also greater production of domestic waste
People in later stages of the DTM often consume more meat.
In MEDCs twice as much energy is provided by animal products than LEDC's
EF for meat eaters is likely to be larger than that of vegetarian as production of meat requires greater energy than growing crops.
Degradation / consumption / population growth
As population growth and standards of living increase the consumption of resources increases. This increases pollution, degradation of the environment which could limit future population growth. The demand for consumer goods has dramatically increased in the last three years putting the worlds resources under great pressure.
Technology is a threat to CC as it promotes the use of the most technologically advanced resources. EG in MEDCs like China the use of cars or computers has increase = increased demand for energy.
If human populations don't live sustainably, they will exceed CC and risk collapse.
Once demand exceeds the sustainable yield of these natural systems, additional demand can only be satisfied by consuming the resource base itself = overfishing, overgrazing, overpumping...