Human Impact on the Environment Chapter 43

Pollution  Pollutants are substances that ecosystems have no natural experience with and cannot adapt to.

Air Pollution  Smog – a gray or brown haze found in major cities.  Develops from the burning of coal and fossil fuels for manufacturing, heating, and making electric power.

Acid Deposition  Factories emit sulfur oxides, and the burning of fossil fuels emit nitrogen oxides.  Both dissolve in atmospheric water and fall to the earth as acid rain.

Ozone Thinning  The ozone layer is essential for preventing damaging UV radiation from reaching the earth.

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

Deforestation  Removal of all trees from large tracts of land for agriculture, logging or grazing.  The forests are important for regulating water flow.

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

Desertification  The conversion of large tracts of natural grasslands to more desert like conditions.  About 200,000 square kilometers are being converted annually. Overgrazing of livestock is the main cause.

Water Crisis  The Earth has a great supply of water, but most of it is too salty.  Desalinization is not an answer, due to the extreme cost and resulting mountains of salt.

Water Pollution  Increases the problem of water shortage. Inputs of pollution have made much water undrinkable.  Water treatment is only used on 70% of water, the rest is put back into waterways untreated.

Solar-Hydrogen Energy  Sunlight can be trapped in photovoltaic cells and produce an electric current that splits water into oxygen and hydrogen  Considerably cheaper than using fossil fuels.

Fusion  Condensing atomic nuclei into fusing and releasing power.  Researchers are able to mimic this and release some energy.

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