1. Renewable and Nonrenewable Resources

2. Tragedy of the commons
English villagers grazed their cattle on shared pasture lands called commons.
Sometimes there were more cattle than the pastures could hold.
Pastures were overused.
Overgrazing pastures damaged the land so bad that the pastures could no longer support cattle.
Ecologists called this the “tragedy of the commons”.

3. Classifying Resources
Environmental goods and services may be classified as renewable and nonrenewable.
Renewable resources – regenerate if they are alive or can be replenished by biogeochemical cycles if they are non-living. Examples – fresh water, trees, pasture
Nonrenewable resources – cannot be regenerated by natural processes. Examples – coal, oil and natural gas take too long to form

4. Sustainable Development
Human activities can affect the quality and supply of renewable resources such as land, forests, fisheries, air and fresh water.
Sustainable development is the way of using natural resources without depleting them and of providing for human needs without causing long-term environmental harm.

5. Land Resources
Land provides space for human communities and raw materials for industry.
Soil can be a renewable resource if used properly and damaged if mismanaged.
Fertile soils consist of good topsoil, sand, clay and rock particles.
Good topsoil absorbs and retains moisture and lets excess water to drain.

6. Land Resources
Plowing the land removes the roots that hold the soil in place.
Soil erosion is increased.
A combination of farming, overgrazing, and drought has turned fertile soils into deserts – termed desertification

7. Sustainable development practices to preserve land resources
Farming practices like contour plowing reduces soil erosion.
Leaving stems and roots of previous crops to hold the soil in place.
Planting a field with rye to protect the soil from erosion.

8. Forest Resources
Forests are important for the products they produce and the ecological functions they perform.
Use wood for heating and cooking
“Lungs of the earth” – they remove carbon dioxide and produce oxygen
Store nutrients and provide habitats
Moderate climate and limit soil erosion

9. Forest Resources Can be considered renewable resources
Northeastern forests have been logged at least once before.
Northwestern forests (old growth forests) are non-renewable since it takes many centuries to produce old-growth forests

10. Forest Resources Effects of Deforestation – the loss of forests
Severe erosion since soil is exposed to runoff
Erosion washes away nutrients in the soil
Grazing or plowing can cause permanent changes to soils that can prevent the regrowth of trees

11. Forest Resources
Forest Management strategies for sustainable development
Selective cutting of trees to promote growth of younger trees to preserve the forest ecosystem.
Plant, manage, harvest, and replant tree farms
Geneticists are breeding new, faster-growing tree varieties for high quality wood

12. Fishery Resources Fish and other animals are a valuable food source
Overfishing
Harvesting of fish faster than they can replace by reproduction
A true “tragedy of the commons”

13. Fishing Resources Sustainable development
US National Marine Fisheries Service created guidelines for commercial fishing.
Regulations help fish populations to recover
Specified how many fish and what size could be caught in various parts of the oceans.

14. Fishery Resources Aquaculture
The raising of aquatic animals for human consumption
Could pollute water and damage aquatic ecosystems

15. Air Resources Air is a common resource that we all use.
Smog is a mixture of chemicals that occurs as a gray-brown haze in the atmosphere.
Smog is considered to be a pollutant.
Pollutants are harmful materials that can enter the biosphere through the land, air, or water.

16. Air Resources
The burning of fossil fuels can release pollutants that can cause smog and other problems in the atmosphere such as nitrogen and sulfur compounds.
If these compounds combine with water, then acid rain is formed.
Acid rain can kill plants by damaging their leaves and changing the chemistry of soils and standing water ecosystems.

17. Freshwater Resources
Water is a renewable resource but is in a limited supply.
Pollution threatens waters in many ways;
Discarded chemicals get into waterways
Sewage can get into the soils