1. Humans and The Environment
3.7 Limits to Growth
3.8 Environmental Demands of Human Populations

2. Assessment Statements
3.7.1 Explain the difficulties in applying the concept of carrying capacity to local human populations.
3.7.2 Explain how absolute reductions in energy and material use, reuse, and recycling can affect human carrying capacity

3. 3.7.1 Explain the difficulties in applying the concept of carrying capacity to local human populations.
Carrying Capacity
The number of people (organisms) that can be supported by a given ecosystem, based on their consumption of natural resources.
Each species has requirements for survival and reproduction
water
food
space
shelter

4. REVIEW Label the following growth curve:
3.7.1 Explain the difficulties in applying the concept of carrying capacity to local human populations.
REVIEW
Label the following growth curve:

5. Why is Human Carrying Capcity (K) so difficult to determine?
We use a much wider range of resources than other species
Technology changes the amount and type of resources required.
(No other animals have value in uranium for nuclear power)
Humans can substitute one resource for another when the 1st resource becomes limited.
Lifestyle differences among humans mean different populations at different places and times have different needs.
(Maasai tribe vs. New York banker.)
Humans have developed transportation for bringing resources in from other ecosystems,
(artificially increases local carrying capacity…does not change the global carrying capacity).
3.7.1 Explain the difficulties in applying the concept of carrying capacity to local human populations.

6. The Question Is…
How do we control the harmful effects of human activity on the environment?

7. Start Simple: The 3 R’s Reduce: Use fewer resources
3.7.2 Explain how absolute reductions in energy and material use, reuse, and recycling can affect human carrying capacity
Start Simple: The 3 R’s
Reduce: Use fewer resources
Use less paper, food, water…
Reuse: Use more than once
Use water bottle multiple times
Ecobricks – plastic bottles for rebuilding in Nepal
Recycle: Use objects material again to manufacture a new product
Nike – tennis shoe soles  playground turf
Patagonia – jackets made from recycled plastic bottles

8. Energy Consumption (thousands of kilocalories)
Aluminum can, used once
Steel can used once
Recycled steel can
Glass drink bottle used once
Recycled aluminum can
Recycled glass drink bottle
Refillable drink bottle, used 10 times 8 16 24 32
Energy Consumption (thousands of kilocalories)

9. Reducing Resources Activity
Activity: How would changes in the following impact human carrying capacity? Where would the reductions come from (i.e. how could we accomplish them)?
energy use
material use
reuse of materials
(can’t reuse energy - why?)
recycling materials
What are the positives and
Negatives of each?

10. 3.8 Environmental Demands of Human Populations

11. Assessment Statements
3.8.1 Explain the concept of an ecological footprint as a model for assessing the demands human populations make on their environment.
3.8.2  Calculate from appropriate data the ecological footprint of a given population, stating the approximations and assumptions involved.
3.8.3  Describe and explain the differences between the ecological footprints of two human populations; one from an LEDC and one from an MEDC.
3.8.4  Discuss how national and international development policies and cultural influences can affect human population dynamics and growth.
3.8.5  Describe and explain the relationship between population, resource consumption, and technological development, and their influence on carrying capacity and material growth.

12. 3.8.1 Explain the concept of an ecological footprint as a model for assessing the demands human populations make on their environment.
Ecological Footprint
The area of land that would be required to provide a population with all resources and process all its wastes.
Also a quantitative estimate of carrying capacity (land area instead of population)

14. Calculate Eco. Footprint
3.8.2  Calculate from appropriate data the ecological footprint of a given population, stating the approximations and assumptions involved.
Calculate Eco. Footprint

15. Calculate Eco. Footprint
3.8.2  Calculate from appropriate data the ecological footprint of a given population, stating the approximations and assumptions involved.
Calculate Eco. Footprint
Calculate the per capita ecological footprint (food land and carbon dioxide absorption land only) for each region.
Population
Per capita grain consumption kg yr -1
Local grain productivity kg ha-1 yr-1
Per capita CO2 emissions from fossil fuels
kg C yr-1
Net CO2 fixation by local vegetation kg C ha-1 yr-1
Africa
300
6000
200
North America
600
1500
3000

16. Calculate Eco. Footprint
3.8.2  Calculate from appropriate data the ecological footprint of a given population, stating the approximations and assumptions involved.
Calculate Eco. Footprint
Population
Per capita grain consumption kg yr -1
Local grain productivity kg ha-1 yr-1
Per capita CO2 emissions from fossil fuels
kg C yr-1
Net CO2 fixation by local vegetation kg C ha-1 yr-1
Africa
300
6000
200
North America
600
1500
3000
𝑷𝒆𝒓 𝒄𝒂𝒑𝒊𝒕𝒂 𝒍𝒂𝒏𝒅 𝒉𝒂 = 𝒑𝒆𝒓 𝒄𝒂𝒑𝒊𝒕𝒂 𝒇𝒐𝒐𝒅 𝒄𝒐𝒏𝒔𝒖𝒎𝒑𝒕𝒊𝒐𝒏 𝒎𝒆𝒂𝒏 𝒇𝒐𝒐𝒅 𝒑𝒓𝒐𝒅𝒖𝒄𝒕𝒊𝒐𝒏 𝒑𝒆𝒓 𝒉𝒆𝒄𝒕𝒂𝒓𝒆
for food production
𝑷𝒆𝒓 𝒄𝒂𝒑𝒊𝒕𝒂 𝒍𝒂𝒏𝒅 𝑨𝒇𝒓𝒊𝒄𝒂 = 𝟑𝟎𝟎 𝒌𝒈 𝒚𝒓 𝟔𝟎𝟎𝟎 𝒌𝒈 𝒉𝒂∙𝒚𝒓
=𝟎.𝟎𝟓 𝒉𝒂
𝑷𝒆𝒓 𝒄𝒂𝒑𝒊𝒕𝒂 𝒍𝒂𝒏𝒅 𝑨𝒇𝒓𝒊𝒄𝒂 = 𝟔𝟎𝟎 𝒌𝒈 𝒚𝒓 𝟑𝟎𝟎 𝒌𝒈 𝒉𝒂∙𝒚𝒓
=𝟐 𝒉𝒂
Note: 1 ha =10,000 square meters

17. Calculate Eco. Footprint
3.8.2  Calculate from appropriate data the ecological footprint of a given population, stating the approximations and assumptions involved.
Calculate Eco. Footprint
Population
Per capita grain consumption kg yr -1
Local grain productivity kg ha-1 yr-1
Per capita CO2 emissions from fossil fuels
kg C yr-1
Net CO2 fixation by local vegetation kg C ha-1 yr-1
Africa
300
6000
200
North America
600
1500
3000
𝑷𝒆𝒓 𝒄𝒂𝒑𝒊𝒕𝒂 𝒍𝒂𝒏𝒅 𝒉𝒂 = 𝒑𝒆𝒓 𝒄𝒂𝒑𝒊𝒕𝒂 𝑪 𝑶 𝟐 𝒆𝒎𝒊𝒔𝒔𝒊𝒐𝒏 𝒏𝒆𝒕 𝒄𝒂𝒓𝒃𝒐𝒏 𝒇𝒊𝒙𝒂𝒕𝒊𝒐𝒏 𝒑𝒆𝒓 𝒉𝒆𝒄𝒕𝒂𝒓𝒆
for absorbing CO2 waste
From fossil fuel
𝑷𝒆𝒓 𝒄𝒂𝒑𝒊𝒕𝒂 𝒍𝒂𝒏𝒅 𝑨𝒇𝒓𝒊𝒄𝒂 = 𝟐𝟎𝟎 𝒌𝒈 𝒚𝒓 𝟔𝟎𝟎𝟎 𝒌𝒈 𝒉𝒂∙𝒚𝒓
=𝟎.𝟎 𝟑 𝒉𝒂
𝑷𝒆𝒓 𝒄𝒂𝒑𝒊𝒕𝒂 𝒍𝒂𝒏𝒅 𝑨𝒇𝒓𝒊𝒄𝒂 = 𝟏𝟓𝟎𝟎 𝒌𝒈 𝒚𝒓 𝟑𝟎𝟎𝟎 𝒌𝒈 𝒉𝒂∙𝒚𝒓
=𝟎.𝟓 𝒉𝒂

18. Calculate your Ecological Footprint
1.489 × 1010 hectares on the Earth
7.023 x 10 9 People live on Earth
Calculate the hectares per capita if everyone lived like you.
1 Hectare is about the size of a soccer field

19. Ecological Footprints by World Region
3.8.3  Describe and explain the differences between the ecological footprints of two human populations; one from an LEDC and one from an MEDC.
Ecological Footprints by World Region
The average American places at least 20 times the demand on Earth’s resources as does an average person in Bangladesh

20. Where are these countries “borrowing” from?
3.8.3  Describe and explain the differences between the ecological footprints of two human populations; one from an LEDC and one from an MEDC.
Where are these countries “borrowing” from?

21. Who has bigger feet? MEDC vs. LEDC
3.8.3  Describe and explain the differences between the ecological footprints of two human populations; one from an LEDC and one from an MEDC.
Who has bigger feet? MEDC vs. LEDC
MEDC : Large
2x energy in their diet (animal products)
Higher CO2 Production
LEDC: Small
Less animal consumed = lower grain consumption

22. U.N. Millennium Development Goals
3.8.4  Discuss how national and international development policies and cultural influences can affect human population dynamics and growth.
U.N. Millennium Development Goals
8 goals agreed upon by world leaders
Began Sept. 2000
Deadline this year
Includes GO’s, NGO’s, private businesses, foundations & research institutions

23. 3.8.4  Discuss how national and international development policies and cultural influences can affect human population dynamics and growth.

24. 3.8.4  Discuss how national and international development policies and cultural influences can affect human population dynamics and growth.

25. Policies that affect population growth
3.8.4  Discuss how national and international development policies and cultural influences can affect human population dynamics and growth.
Policies that affect population growth
Economic Welfare: Improve economy and birth rates will come down on their own
Education: Promotes birth control/ economic independence of women
Domestic development: Improve sanitation, agriculture…)
Decrease death rate, increase birth

26. Technology & E.F. Technocentric Viewpoint
3.8.5  Describe and explain the relationship between population, resource consumption, and technological development, and their influence on carrying capacity and material growth.
Technology & E.F.
Technocentric Viewpoint
Technology will develop at a rate to save us (increase K)
Some arguments in support of this idea:
Technological advances can lead to improvements in sanitation and health
Technology has improved farming methods to increase the productivity of crops
Technology may lead to new methods of cleaning up polluted environments
However, it is important to remember that technology itself uses resources and may have an ecological cost as well.