8.4 Carrying capacity and ecological footprints Flashcards
carrying capacity definition
the maximum number of species or ‘load’ that can be sustainably supported by a given area
what factors determine general carrying capacity?
- resource availability (food, water, shelter)
- interactions between species (presence of predators, availability of prey, competition for food resources)
- enviornmental factors (temperature, rainfall patterns, soil fertility)
define optimum population
the number of people who, when using all the available resources, will produce the highest per capita economic returns
- population has highest standard of living/quality of life
- if the size of the population increases or decreases from the optimum, the standard of living will fall
(dynamic concept that changes with time as techniques improve, population tools and structures change, and as new materials are discovered)
define over-population
too many people relative to the resources and technology locally available to attain the optimum standard of living eg. Bangladesh
define under-population
when there are far more resources in an area (eg. food production, energy, minerals) that can be used by the people living there to reach the optimum population eg. Canada
what factors define human carrying capacity?
- rate of energy and material consumption
- level of pollution
- interference with enviornmental life-support systems
Malthus approach to population growth and food resources
population will grow faster than food supply, and will eventually overtake
Boserup approach to population growth and food resources
humans will come up with innovations to solve food shortage because only as population grows, new techniques for intensive farming are adopted
- resource increase is adaptable due to human ingenuity
- carrying capacity isnt fixed
- limiting factors can change
Malthus criticisms
since his time (beginning of industrial revolution about 1700s), people have increased food production through:
- draining marshlands
- fish farming
- making artifical fertiliser
- growing crops in greenhouses
- using more sophisticated irrigation techniques
Boserup criticism
are innovations sustainable?
why is it difficult to estimate the enviornmental carrying capacity for human populations?
- variety of resources is too great
- humans can substitute one resource for another when the first becomes depleted
- lifestyle affects resource requirement
- technological developments change resource required and available
- resources can be imported
ecological footprint definition
the hypothetical area of land and water required to support a defined human population at a given standard of living. the measures takes into account of the area required to provide all the resource needed by the population, and the assimilation of wastes
difference ef and carrying capactiy
ef: theoretical area
cc: real area
= inverse of eachother
ef general concept explanation
a country with ef of 2.4 times its own geographical area is consuming resources and assamiliting waste on a scale that would require a land are 2.4 times larger than the actual size of the country to be sustainable
what factors increase ef?
- meat-rich diet
- greater reliance on fossil fuels
- high reliance on technology > uses a lot of energy (technology can also decrease ef)
- large per capita co2 waste (eg. energy use)
- large per capita food consumption
- large amount of imported resources (uses fuel, releases co2)
what factors decrease ef?
- reducing amount of resource use
- recycling
- reusing
- improving efficiency of resource use
- reducing amount of pollution production
- transporting waste to other countries
- improving technology/ using available technology to increase carrying capacity (eg. using GM crops to increase yield on same amount of land)
- importing more resources from other countries (“offloads” EF)
- reducing population to reduce resource use
- using technology to intensify land use
factors used in a full ecological footprint would include:
- bioproductive land: land used for food and materials like farmlands, gardens, pastures, managed forests
- bioproductive sea: sea area used for human consumption (often limited to coastal areas)
- energy land: the area of biologically productive land required to produce energy sustainably or to absorb the carbon dioxide emissions resulting from energy use -> depends on energy generation (larger for fossil fuels) + difficult to estimate for whole planet
- built land: used for developments like roads and buildings
- biodiversity land: for example desert, subtraction from total land available.
simplified ef calculation ignores:
- land or water required to provide any aquatic and atmospheric resources
- land or water needed to assimilate wastes other than co2
- land used to produce materials imported into the country to subsidise arable land and increase yields
- replacement of productive land lost to urbanisation
pros of EF
- a lot of data points = anaylsis, patterns
- easily comparable
- tailored to different scales (individual, national)
- since 1961 -> compare trends -> predict -> mitigate
- easy to understand (can be used for education and campaigns to the public)
- holistic view links local decisions with global impacts
cons of EF
- estimates = a degree of uncertainty in data
- oversimplification (only looking at one moment in time) (model)
- doesnt regard all aspects of sustainability (economic, social)
- deep ocean area and atmosphere are ignored -> do they hold resources? do they absorb carbon?
Compare/contrast 2 national EF’s: Peru data
low EF: 2.1 g/ha person
high biocapacity: 3.5 gha/person (rainforests, mountains etc., large land mass)
= ecological surplus
- low consumption, limited industrialisation
- gov./international aid reduce deforistation and pollution
- sustainability threathend: declining biocapacity and deforistation
Compare/contrast 2 national EF’s: UAE data
high EF: 8.9 gha/person
low biocapacity: 0.6 gha/person (desert, small land mass)
= ecological deficit
- high consumption > wealth, rapid urbanisation, tourism
- imports 80% of food (investing in hydroponics and vertical farming)
- gov.-lead sustainability initiatives
Compare/contrast 2 national EF’s similarities
- gov. efforts to reduce EF
- face long-term sustainability challenges
Compare/contrast 2 national EF’s differences
Peru: surplus biocapacity, UAE: deficit biocapacity
Peru: low EF due to low development, UAE: high EF due to high development
Peru: reducing EF through aid, natural resource use, conservation efforts, UAE: reducing EF through technology
