Section 6.1 & 6.2 A changing Landscape

Section 6.1 & 6.2A changing Landscape

Human Population and Natural Resource Use• With increased human population, we are using more

and more of the Earth’s natural resources.

• Two types of Resources are:−Renewable resources : resources that can be

regenerated, regrown, or replaced.Examples: fresh water, air, soil, trees, sunlight

−Nonrenewable resources – resources that cannot be replenished by natural processes.

Examples: oil, coal, natural gas, old growth trees

Natural Resources• Sustainable use – a way of using natural resources at a rate that does not deplete

them and cause long-term harm.

- Examples of Sustainable Use:

• Reusing paper and plastic supplies.

• Recycling paper, plastics, metals.

• Using solar or wind power for electricity.

• Riding a bike or walking.

• Buying locally grown foods and other local products

• Upgrade electronic devices less often and RECYCLE your phone!!!

• Turning off the water while you brush your teeth!

Soil and its Importance• Many objects you use daily rely on soil

(your food, wood for construction, paper).

• Healthy soil supports agriculture and forests.

• Good topsoil allows water to drain and retains moisture.

• Topsoil is a renweable resource if it is managed properly, but it can be damaged or lost.

Soil erosion: the movement of soil by wind or water.

• Soil erosion is often worse when land is plowed and left barren between plantings.

• When soil is eroded, organic matter and minerals that make it fertile are often carried away with the soil.

Desertification – turning fertile land into deserts• This happened in the Great Plains in the 1930s.

Threats to soil resources

• Deforestation – removal of all trees from land for logging, agriculture, and grazing.

- In less than 40 years, we have destroyed over 50% of our tropical forests.

• Effects of deforestation- Severe soil erosion (esp. on mountainsides)

- Decreased rainfall and soil fertility

- Decrease in oxygen and increase in carbondioxide in the atmosphere.

- Loss of habitat for wildlife.

Threats to soil resources

What can we do?• Leaving stems and roots from the previous year’s crop

in the ground or by growing a cover crop can help keep soil in place.

• Rotating crops each year can help soil because different crops take different nutrients from the soils.

• Only harvest some of the mature trees in a forest.• Protect the quality of soil by limiting pollution and the

use of chemicals.

Water and its Importance• Humans depend on fresh water and freshwater

ecosystems for drinking water, recreation, industry, transportation, energy and waste disposal.

• Only 3% of the Earth’s water is fresh water and most of it is locked in ice at the poles.

• When we burn fossil fuels, we release nitrogen and sulfer compounds into the air. When those compounds combine with water vapor in the air they form acid rain.

• Acid Rain has a lower pH than normal rain (pH of 4-6).

• Effects of Acid Rain • Destruction of forests• Fish and other aquatic

organisms die• Changes in water and soil pH

• These compounds are considered pollutants which are harmful materials that can enter the biosphere through land, air, or water.

Threats to Water Resources

What Can We Do?Protect our natural water filters: • Example: As water runs through wetlands,

plants absorb excess nutrients and filter out certain pollutants so keeping our soils clean will allow our water to stay clean as water flows under ground and is filtered by the rocks and soil.

Atmosphere (air) and its importanceFor most if the Earth’s history, the quality of the Earth’s atmosphere has been naturally maintained by the Earth’s cycles of matter.

If these cycles become disrupted, or if we overload the atmosphere with pollutants, the effects on its quality can last a very long time.

Atmosphere (air) resourcesWe rely on the Oxygen in our atmosphere for cell respiration. The quality of our atmosphere has direct effect on our health.

Ozone is a form of Oxygen that is found in the upper atmosphere. The ozone absorbs harmful ultraviolet radiation from the sun. Ozone also protects our skin from damage that can cause cancer.

• Ozone DepletionHuman activities have been partly

responsible for removing a layer of ozone gas (O3) in our atmosphere.

- The ozone layer protects us from the sun’s harmful UV radiation.

- Ozone depletion is caused by chemicals used in aerosols, plastic foams like styrofoam, and refrigeration coolants.

• Effects of Ozone DepletionIncrease in global temperatureIncrease in skin cancer rates.

Threats to Air Resources

Atmosphere (air) resourcesThe Greenhouse Effect – when gases in the atmosphere trap heat energy and maintain the Earth’s temperature range. Without these gases, the Earth would be about 30 degres Celcius cooler than it is today.

Greenhouse Effect:Because humans are releasing greenhouse gases into the atmosphere, more heat is being trapped in our atmosphere and may be causing global warming and climate change.

• Effects of Climate Change• Rise in sea levels• More frequent severe storms

and weather disturbances.• More frequent droughts and

floods. • Changes in geographic

distribution of species.

Threats to Air Resources

• Air Pollution: • Smog – a mixture of chemicals that occurs as a gray-brown

haze in the sky.

The U.S. alone releases 700,000 tons of air pollutants each day!

Threats to Air Resources

• Using wood stoves that are certified by Oregon (they add less particles into the air!)

• Composting leaves instead of burning them!

• Planting trees and other plants.

• Driving a vehicle that uses less fuel…

• or better yet, BIKING or WALKING!

• Keeping our homes insulated so you save energy heating and cooling it.

• Using organic fertilizers in our yards. Chemical fertilizers pollute the air and water.

What Can We Do?