1. Quiz Friday – chapter 25 and the biosphere
Warm-up
What two human activities are thought to cause global warming?
Quiz Friday – chapter 25 and the biosphere

2. Earth Resources
Chapter 25

3. What are resources?
Natural Resources – resources provided by the Earth including land, air, water, living organisms, nutrients, rocks and minerals.

4. What are resources?
Renewable Resources – natural resource that can possibly be used indefinitely without reducing the available supply.
Ex. Living things, sunlight, fresh air, water.

5. What are resources? Renewable Resources
Can be replaced through natural processes at a rate equal to or greater than the rate they are used
Careful management is often necessary

6. What are resources?
Sustainable Yield – replacement of resources at same rate at which they are consumed

7. What are resources?
Nonrenewable Resources – resources that take hundreds of millions of years to form and cannot be replaced within our lifetime.
Fossil fuels (oil, coal natural gas), diamonds

8. What are resources?
Nonrenewable Resources – The US consumes approximately 30% of the total global consumption of mineral/energy resources (with 6% of the global population)

9. Land Resources Protected Land
42% of the US is public land (forests, parks, wildlife refuges)
Protect timber, grazing areas, minerals and energy resources

10. Land Resources
Soil
It can take 1000 years to form a few centimeters of topsoil
Topsoil is eroding faster than it is formed on 1/3 of Earth’s croplands

11. Land Resources Ore – a natural resource that can be mined at a profit
Material left after ore is extracted may release harmful chemicals into groundwater or surface water

12. Air Resources
Pollutants – substances that can affect the survival, health or activities of organisms.
Air pollution – pollutants in air at levels harmful to human health and the environment

13. Air Resources Sources of Air Pollution
Natural sources – volcanic eruptions, forest fires
Human sources – burning fossil fuels (cars and power plants)

14. Air Resources Sources of Air Pollution
Some pollutants are carried downwind from source
Depends on wind direction and speed, topographical features, altitude of pollutants
Beijing, 2013

15. Air Resources
Sources of Air Pollution

16. Water Resources
Only 0.003% of the Earth’s water is available to humans

17. Water Resources Why is water important?
High boiling point and low freezing point
Heat-storage – can store lots of heat without a high increase in temperature (high specific heat)

18. Water Resources Why is water important?
Solvent – can dissolve wide variety of compounds
Solid less dense than liquid (ice floats)

19. Water Resources Managing Freshwater Resources
Dams – control flooding downstream
Reservoirs – water can be released for irrigation, home use, hydroelectric power production

20. Water Resources Reducing Freshwater Use
Trickle irrigation, use of recycled water by companies, low-flow toilets, fixing leaky pipes and faucets at home