Humans and The Environment

3.7 Limits to Growth

3.8 Environmental Demands of Human Populations

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

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

3.7.1 Explain the difficulties in applying the concept of carrying capacity to local human populations.

REVIEWLabel the following growth curve:

3.7.1 Explain the difficulties in applying the concept of carrying capacity to local human populations.

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.

The Question Is…

How do we control the harmful effects of human activity on the environment?

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

http://www.patagonia.com/us/patagonia.go?assetid=2791http://www.nike.com/us/en_us/c/better-world/reuse-a-shoehttp://www.ecobricks.org/

3.7.2 Explain how absolute reductions in energy and material use, reuse, and recycling can affect human carrying capacity

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

0 8 16 24 32

Energy Consumption (thousands of kilocalories)

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?

3.8 Environmental Demands of Human Populations

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.

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)

3.8.1 Explain the concept of an ecological footprint as a model for assessing the demands human populations make on their environment.

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

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

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 6000

North America

600 300 1500 3000

Calculate Eco. Footprint

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

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 6000

North America 600 300 1500 3000

𝑷𝒆𝒓 𝒄𝒂𝒑𝒊𝒕𝒂𝒍𝒂𝒏𝒅 (𝒉𝒂 )= 𝒑𝒆𝒓 𝒄𝒂𝒑𝒊𝒕𝒂 𝒇𝒐𝒐𝒅𝒄𝒐𝒏𝒔𝒖𝒎𝒑𝒕𝒊𝒐𝒏𝒎𝒆𝒂𝒏 𝒇𝒐𝒐𝒅 𝒑𝒓𝒐𝒅𝒖𝒄𝒕𝒊𝒐𝒏𝒑𝒆𝒓 𝒉𝒆𝒄𝒕𝒂𝒓𝒆

𝑷𝒆𝒓 𝒄𝒂𝒑𝒊𝒕𝒂𝒍𝒂𝒏𝒅 ( 𝑨𝒇𝒓𝒊𝒄𝒂 )=𝟑𝟎𝟎

𝒌𝒈𝒚𝒓

𝟔𝟎𝟎𝟎 𝒌𝒈𝒉𝒂 ∙𝒚𝒓

𝑷𝒆𝒓 𝒄𝒂𝒑𝒊𝒕𝒂𝒍𝒂𝒏𝒅 ( 𝑨𝒇𝒓𝒊𝒄𝒂 )=𝟔𝟎𝟎

𝒌𝒈𝒚𝒓

𝟑𝟎𝟎 𝒌𝒈𝒉𝒂∙ 𝒚𝒓

¿𝟎 .𝟎𝟓𝒉𝒂

¿𝟐𝒉𝒂Note: 1 ha =10,000 square meters

for food production

Calculate Eco. Footprint

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

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 6000

North America 600 300 1500 3000

𝑷𝒆𝒓 𝒄𝒂𝒑𝒊𝒕𝒂𝒍𝒂𝒏𝒅 (𝒉𝒂 )=𝒑𝒆𝒓 𝒄𝒂𝒑𝒊𝒕𝒂𝑪𝑶𝟐𝒆𝒎𝒊𝒔𝒔𝒊𝒐𝒏

𝒏𝒆𝒕 𝒄𝒂𝒓𝒃𝒐𝒏 𝒇𝒊𝒙𝒂𝒕𝒊𝒐𝒏𝒑𝒆𝒓 𝒉𝒆𝒄𝒕𝒂𝒓𝒆

𝑷𝒆𝒓 𝒄𝒂𝒑𝒊𝒕𝒂𝒍𝒂𝒏𝒅 ( 𝑨𝒇𝒓𝒊𝒄𝒂 )=𝟐𝟎𝟎

𝒌𝒈𝒚𝒓

𝟔𝟎𝟎𝟎 𝒌𝒈𝒉𝒂 ∙𝒚𝒓

𝑷𝒆𝒓 𝒄𝒂𝒑𝒊𝒕𝒂𝒍𝒂𝒏𝒅 ( 𝑨𝒇𝒓𝒊𝒄𝒂 )=𝟏𝟓𝟎𝟎

𝒌𝒈𝒚𝒓

𝟑𝟎𝟎𝟎 𝒌𝒈𝒉𝒂 ∙𝒚𝒓

¿𝟎 .𝟎𝟑𝒉𝒂

¿𝟎 .𝟓𝒉𝒂

for absorbing CO2 wasteFrom fossil fuel

Calculate your Ecological Footprint

• www.footprintnetwork.org/en/index.php/GFN/page/calculators/

• www.bestfootforward.com/footprintlife.htm• www.myfootprint.org/• 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

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

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?

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

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.

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

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

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

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

3.8.5  Describe and explain the relationship between population, resource consumption, and technological development, and their influence on carrying capacity and material growth.