1. B-6.6: Explain how human activities (including population growth, technology, and consumption of resources) affect the physical and chemical cycles and processes of Earth.
Human Impact

2. “4 Minutes” by Madonna (with Justin Timberlake)
“There is a sense of urgency… that we are living on borrowed time essentially and people are becoming much more aware of the environment and how we’re destroying the planet.” – Madonna interview with MTV
Madonna wrote the song
“4 Minutes” because she
felt a sense of urgency
to save the planet from
destruction

3. Activity
Working with a partner, your task is to solve some of the world’s toughest problems
Each group is only responsible for 2 to 3 issues.
You only have 4 minutes to save the world!!!

4. Humans and the Ecosystem
Humans play a role in ecosystem and cycles
People depend on resources and cycles of Earth to provide clean water, breathable air, and good soil
Human activities are affecting the cycles and Earth processes:
Population growth
Technology
Consumption of resources

5. Carrying capacity
Carrying capacity: maximum population size that can be supported by the available resources
Various factors determine the carrying capacity of humans
Energy
Water
Oxygen
nutrients

6. Sustainability
Sustainability  meeting the needs of humans to survive indefinitely
Needs to be a balance between Earth’s resources and carrying capacity, needs of humans, and needs of other species on Earth
Factors that affect sustainability: population growth, technology, consumption of resources

7. Population Growth Grown exponentially
Prediction: will continue to grow at a rapid rate
Natural slowing of population growth as it nears its carrying capacity is due to increase in death rate and decrease in birth rate due to:
Food and water shortages
Pollution
diseases

8. Population Growth - water
Increasing population affects amount of water produced
If clean water is being depleted at a greater rate than it can be purified, it is not considered renewable in our lifetime

9. Population Growth - waste
An increasing population can affect amount of waste
There are mechanisms to control the disposal of waste products, but more waste is produced than can be managed
Some waste products require complicated and costly means of removal

10. Population Growth – fertile soil
An increasing population can effect amount of available fertile soil for food resources (agriculture)
Soil is often lost when land is cleared, making land unsuitable for agriculture
Worldwide demand for land (agriculture or habitation) has led to deforestation
Forests cut down, less carbon dioxide absorbed leading to increase in global warming
Deforestation can increase rate of erosion (wind and water) and decrease rate of soil generation

11. Worldwide, about ½ of the area once covered by forests is now cleared
Compare the before and after for Asia

12. Human population growth
When these resources become scarce, many natural processes are affected
Water cycle
Carbon cycle
Nitrogen cycle
Physical processes of soil regeneration

13. Technology Technology used to find solutions to problems
Technology has been a benefit but also contributed to: pollution of air, water and land
For sustainability, technology has provided cleaner energy sources, safer ways to deal with waste and better methods for cleaning up pollution
Technological advances in agriculture, industry, and energy can have a positive or negative impact on Earth

14. Agricultural technology
Improve ability to grow crops to sustain growing population
Help conserve fertile soil and reduce soil erosion
Farm machinery consume renewable resources and can contribute to erosion and air pollution
Addition of substances (fertilizers, pesticides, fungicides, livestock waste) to environment can alter composition of soil and have a negative/positive effect on water, carbon or nitrogen cycles

15. Industrial technology
Lead to developments in communication, transportation and industry
Development of certain chemicals (CFCs) contribute to depletion of ozone layer (increasing UV rays reaching Earth)
CFCs: chlorofluorohydrocarbons, used in producing foam packing materials, cleaning electronics, and refrigeration chemicals

16. The Greenhouse Effect

17. Industrial technology
Technological advances revolutionized communication industry; however disposing of outdated or damaged equipment is a concern

18. Industrial Technology – burning fossil fuels
Burning fossil fuels increases sustainability of growing population, however,
It increases greenhouse gases, which increases temperatures which affects sea levels, climate and atmospheric composition
It produces acid rain
Acid rain decreases pH of soil and nutrients can leave soil
Acid rain changes pH of aquatic ecosystems

19. Acid Rain

20. Industrial technology – alternative energy technology
Using natural renewable energy sources decreases burning of fossil fuels and increases quality of atmosphere
Renewable resources: wind, water, geothermal, or solar energy
Using nuclear energy provides alternative energy that does not impact atmosphere
However, there is a concern about nuclear energy waste

21. Nuclear Energy

22. Consumption of Resources
As population increases and technology expands, demand for earth’s resources increases
Limited supply of these resources to sustain population
Some resources are renewable resources (production = consumption)
Food, clean water, and timber
Some factors limit their production
Example: grain is limited by amount of land available, fertility, etc.

23. Consumption of Resources
Some resources are nonrenewable resources (consumption > production)
Fossil fuels
Demand for minerals, metals and ores increases for industry but are decreasing in availability
Minerals are nonrenewable resources because mineral deposits can be extracted are formed so slowly
Sustainable use of resources can be accomplished by reducing consumption, reusing products rather than disposing of them or recycling waste to protect the environment