This document discusses human population carrying capacity and factors that influence it. It notes that while the concept of carrying capacity applies to other species, it is difficult to define for human populations due to variables like technology, resource use, and trade. The document also summarizes Malthusian and Boserup theories on population growth and food production. It introduces the concept of ecological footprint and compares footprints of different countries. Finally, it discusses environmental value systems and perspectives like ecocentrism, technocentrism, and anthropocentrism.

1. Topic 8
Human Systems and Resource Use
8.4 Human population carrying
capacity

2. Human Population Growth
• Carrying Capacity
– The maximum number of individuals of a species that
can be sustainably supported within a habitat. It occurs
when birth rate is equal to death rate
• But does this really apply to human populations?
• Do human populations actually have a carrying
capacity?
• Well, there are many examples of direct and
indirect effects of drought, famine and war which
act to reduce populations when they grow too
large

3. Human Population Growth
• Size of population isn’t the only factor which
impacts on natural resources
• Other factors include:
– Wealth (MEDC or LEDC)
– Resource desire
– Resource need (or use)
– Age distribution
– Rural or urban populations
– Time (it is dynamic)
20% of the world’s population lives in MEDCs where birth rate is falling (or negative,
e.g.Japan)
80% of the world’s population lives in LEDCs where birth rate is increasing

4. Human Population Growth
• It is very difficult to assess a carrying capacity for
a human population (or even if one exists):
– We produce non-biodegradable waste which can
cause environmental degradation and reduce the
ability of an area to provide resources
– The resources we use are far more varied and there
are necessities and luxuries to take into account
– Human populations have the capacity to move goods
around the world – we can import food from another
region if there isn’t enough where we live
– We employ technology to change the environment

5. Malthusian Theory
• Malthus believed that human populations
grow exponentially, but resources only
grow arithmetically (limited by land
availability and existing technology)
• Food production can only therefore
increase to a certain level
• Above this level, soil erosion and
decreasing soil fertility cause productivity
to decrease
• A natural check on population occurs
Thomas Malthus

6. Boserup Theory
• An increase in population will simply stimulate
scientists to come up with ideas to increase food
production
• “Necessity is the mother of invention”
• Productivity has been increased by:
– Reclaiming land from the sea
– Selective breeding and cross breeding
– Developing high-yield plants
– Genetic modification
– Terracing
– Hydroponics
– Greenhouses
– Irrigation
– Artificial fertilisers
– Switching to new crops (e.g. soya)
– Fish farming
Norman Borlaug

7. Environmental Demands of Human
Populations
• An ecological footprint (EF) is the hypothetical
area of land needed by an individual, group or
society to fulfil its resource needs and
assimilate all waste
• An ecological footprint is not necessarily
sustainable. It may refer to an unstable
equilibrium
Mathis Wackernagel

8. Ecological Footprint
• A country with a total ecological footprint
greater than its available land is in theory living
beyond its means (It has an ecological deficit)

9. Factors affecting ecological footprint
• A large footprint could be caused by:
– Reliance on fossil fuels
– Increased use of technology (depending on its use)
– High levels of importation
– Large production of carbon waste
– High food consumption
– Meat-rich diets
• Footprint could be reduced by:
– Reduced resource consumption
– Recycling and reuse of resources
– Improved efficiency of resource use
– Reduced pollution
– Exportation of waste
– Use of technology (to increase carrying capacity and efficiency of land use)
– Reduced population

12. Approximate Ecological Footprints (2003)
• USA – 10.3 ha cap-1
• Australia – 9.0
• Canada – 7.8
• Germany – 5.3
• UK – 5.2
• Switzerland – 5.1
• Mexico 3.0 (2007 data)
• China – 1.6
• India – 0.8
In 2003, there were approx. only 1.8 ha available per person (including
productive marine areas). Therefore many of us are living beyond the Earth’s
ability to sustain the population
Which country do you think currently has the largest ecological footprint?

13. Calculations
• Ecological footprint is usually calculated in hectares
• 1 hectare = 10 000m2
• This is aproximately the size of a football field (0.6-0.8 ha)
or the field inside a 400m athletics track (about 1.2 ha)
• The 2 basic calcs usually carried out are
1. Per capita land (and water) required for food consumption
2. Per capita land (and water) required for carbon waste
absorbtion
• They are are added together to give the total footprint

14. Calculations
Per capita land requirement for food production (ha cap-1)
= per capita food consumption per year (kg cap-1 yr-1)
mean food production per hectare per year (kg ha-1 yr-1)
Per capita land requirement to assimilate carbon waste (ha cap-1)
= per capita CO2 emission per year (kg cap-1 yr-1)
total CO2 fixation by vegetation per year (kg ha-1 yr-1)
+Food given as kg equivalents of grain

15. The 6 components of a national
footprint
• Footprint of built-up land
– Infrastructure, housing, paved land – produces CO2 and in many
cases unable to recycle waste
• Footprint of national fishing grounds
– Estimated area of primary production at sea and in fish-farms
on land
• Footprint of forestry
– Estimated land required to produce paper pulp, timber for
wooden products and wood for fuel
• Footprint of grazing land
• Footprint of cropland
• Carbon uptake footprint
– Estimated green area required (other than areas of ocean )to
absorb the CO2 produced by the other five components

16. Problems with the Calculation
• It doesn’t consider the effects of pollutants
other than CO2
• It doesn’t consider land (or water) needed to
assimilate wastes other than CO2
• It doesn’t consider land lost through
urbanisation
http://wwf.panda.org/how_you_can_help/live_green/footprint_calculator/

17. MEDCs vs LEDCs
more/less economically developed countries
1. Which has the higher ecological footprint?
2. Why does North America have a particularly high
per capita grain equivalent consumption?
3. Which are more dependent on fossil fuels?
4. Which has higher CO2 fixation and why?
5. Use the data to calculate per capita footprints:
Area Per capita grain
consumption kg
cap-1 yr-1
Grain
production
kg ha-1 yr-1
Per capita CO2
emissions
kg cap-1 yr-1
Net CO2 fixation
by vegetation
kg ha-1 yr-1
Africa 300 6000 200 6000
North America 600 300 1500 3000

18. Environmental Value Systems (EVSs)
• A set of paradigms which shapes the way individuals or societies
perceive and evaluate environmental issues
• This is affected by:
– Cultural concerns
– Religious concerns
– Economic issues
– Whether a society belongs to an MEDC or an LEDC
• As with any system, they have
– INPUTS (e.g. education, media, religious doctrines)
– OUTPUTS (e.g. environmental mediation)
– PROCESSING (e.g. political decisions)
– FEEDBACK LOOPS (e.g. scientific advice)
Rather than being based on energy and/or matter, environmental value systems
are based on the flow and processing of information

19. Environmental Value Systems
• Since EVSs vary, different cultures, societies, and special-
interest groups often come into conflict over them
• e.g. The U.N. moratorium on whaling is seen very
differently in Japanese society compared to European
nations
• e.g. The oil lobby in the U.S. sees attempts to switch to a
greener economy differently to environmental groups

20. Environmental Value Systems
• There are 3 general categories:
– Ecocentric (centred on the environment)
– Technocentic (centred on technology)
– Anthropocentric (centred on humans)
ecocentrism anthropocentrism technocentrism

21. Ecocentrism
• Ecocentrists are likely to distrust technology
• They would stand against large-scale production and
corporations
• They would view nature as having control over human
society rather than the other way round
• They would view the world as having very finite natural
capital which should be protected rather than exploited
• They believe that ecology is too complex for humans to
fully understand and therefore be able to manage it
• Some believe that nature has more value than humanity
(an extreme view referred to as “deep-ecology”)

22. Technocentrism
• Technocentrists trust in technological advances to
solve environmental problems
• They trust in the resourcefulness of humans
• They believe that humans are able to control nature
• They believe that scientific thinking and scientific
research is important in making public policy
• Extreme technocentrists are referred to as
‘cornucopians’. They believe that the world has
infinite resources to support a growing population
and that this is achievable through a free-market and
reliance on technology

23. Anthropocentrism
• Anthropocentrists would include aspects of both
ecocentrism and technocentrism and in their
worldview
• They would view humans as managers rather than
controllers of nature
• They believe that population control is as important
as use of natural capital
• They believe that government has an
important role to play in regulating
human action in relation to the
environment
Silent Running, 1972

24. Religion
• The Abrahamic religions (Christianity, Islam and Judaism)
set out a concept of ‘dominion’ and ‘stewardship’ of nature
in the Book of Genesis
• This is an extreme version of anthropocentrism in which
nature has value in terms of its usefulness to humans and
the pleasure and profit it can provide
• However, a belief in creationism also endows the
responsibility on humans to look after God’s creation
• It could be argued that this is a religious responsibility
rather than a moral one

25. Deep-Ecology
• A school of philosophy (ethics) founded
by Norwegian intellectual Arne
Næss(1912-2009)
• He believed humans should do nothing
unless they are fully aware of the
outcomes of an action and can take
responsibly for it
• He was profoundly influenced by Gandhi
and the book ‘Silent Spring’ by Rachel
Carson

26. Deep-Ecology
• The tenets of deep-ecology are:
– The well being of human and non-human life has no value in
itself which is independent of the usefulness of the non-human
world to humans
– The richness and diversity of life contributes to these values
– Humans have no right to reduce this richness and diversity
except to satisfy vital needs
– For human (and non-human) life to flourish a substantial
reduction in human population is required
– Human interference with the non-human world is excessive
– A substantial change in world policy is needed in terms of
economics, technology and ideology
– Humans should appreciate the quality of life rather than aspire
towards higher standards of living
– People with ecocentric views need to constantly work to make
these changes to improve the well-being of the Earth

27. Can Carrying Capacity Change?
• If we cut down on our use of natural resources
• It may be achieved by:
– Recycling (reprocessing materials into new
products)
– Re-use (returning materials to the manufacturer
of processor, or finding new uses ourselves)
– Reduction (using less energy or resources)
– Substitution (switching to renewable resources
from non-renewable)
https://www.youtube.com/watch?v=E8dkWQVFAoA