Human Impact on the Human Impact on the EnvironmentEnvironmentChapter 43Chapter 43

PollutionPollution Pollutants are substances Pollutants are substances

that ecosystems have no that ecosystems have no natural experience with natural experience with and cannot adapt to.and cannot adapt to.

Air PollutionAir Pollution Smog – a gray or brown haze Smog – a gray or brown haze

found in major cities. found in major cities. Develops from the burning Develops from the burning

of coal and fossil fuels for of coal and fossil fuels for manufacturing, heating, and manufacturing, heating, and making electric power.making electric power.

Acid DepositionAcid Deposition Factories emit sulfur oxides, Factories emit sulfur oxides,

and the burning of fossil and the burning of fossil fuels emit nitrogen oxides. fuels emit nitrogen oxides.

Both dissolve in atmospheric Both dissolve in atmospheric water and fall to the earth water and fall to the earth as acid rain. as acid rain.

Ozone ThinningOzone Thinning The ozone layer is The ozone layer is

essential for preventing essential for preventing damaging UV radiation damaging UV radiation from reaching the earth. from reaching the earth.

CFCs (chlorofluorocarbons) CFCs (chlorofluorocarbons) are major problems in are major problems in ozone depletion. ozone depletion. CFCS are found in CFCS are found in refrigerators and air refrigerators and air conditioners as coolant, conditioners as coolant, in plastic foams and in plastic foams and other solvents.other solvents.

DeforestationDeforestation Removal of all trees from Removal of all trees from

large tracts of land for large tracts of land for agriculture, logging or agriculture, logging or grazing. grazing.

The forests are important The forests are important for regulating water flow. for regulating water flow.

As the forests are cut down, As the forests are cut down, the water is uncontrolled, the water is uncontrolled, causing soil erosion, causing soil erosion, flooding, and the flooding, and the accumulation of sediment accumulation of sediment that clog rivers, lakes, or that clog rivers, lakes, or reservoirsreservoirs

DesertificationDesertification The conversion of large tracts The conversion of large tracts

of natural grasslands to more of natural grasslands to more desert like conditions. desert like conditions.

About 200,000 square About 200,000 square kilometers are being converted kilometers are being converted annually. Overgrazing of annually. Overgrazing of livestock is the main cause.livestock is the main cause.

Water CrisisWater Crisis The Earth has a great The Earth has a great

supply of water, but most supply of water, but most of it is too salty.of it is too salty.

Desalinization is not an Desalinization is not an answer, due to the answer, due to the extreme cost and resulting extreme cost and resulting mountains of salt.mountains of salt.

Water PollutionWater Pollution Increases the problem of water Increases the problem of water

shortage. Inputs of pollution shortage. Inputs of pollution have made much water have made much water undrinkable. undrinkable.

Water treatment is only used Water treatment is only used on 70% of water, the rest is put on 70% of water, the rest is put back into waterways untreatedback into waterways untreated. .

Solar-Hydrogen EnergySolar-Hydrogen Energy Sunlight can be trapped Sunlight can be trapped

in photovoltaic cells and in photovoltaic cells and produce an electric produce an electric current that splits water current that splits water into oxygen and hydrogeninto oxygen and hydrogen

Considerably cheaper Considerably cheaper than using fossil fuelsthan using fossil fuels. .

FusionFusion Condensing atomic nuclei Condensing atomic nuclei

into fusing and releasing into fusing and releasing power. power.

Researchers are able to Researchers are able to mimic this and release mimic this and release some energy. some energy.

Currently, not much Currently, not much power can be released power can be released this way, but work is this way, but work is being done to increase being done to increase the amount of energy the amount of energy released. released.