Human Impact on the Environment

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Matt Baker

Human Impact on the Environment

I. Human Population and Industrialization 

A. By-products of industrialization

1. Industrialization is driven by energy consumption from coal, petroleum, and natural gas

a. Fossil fuels were formed by decomposition and pressure on remains of plants and animals millions of years ago

b. Oil is the fuel most widely used, both as starting material for making gasoline and for other products

2. Pollution is any environmental change that adversely affects the lives and health of living things

a. Burning fossil fuels results in hydrocarbons, carbon, nitrogen and sulfur oxides, particulates

b. Automobiles consume one-third of the world's production of oil and are the chief source of air pollution

c. Some estimate there will be four times more automobiles in the world in 2025

d. These sources are considered nonrenewable since they are in limited supply

3. Sources of energy that are relatively nonpolluting exist

a. Solar energy does not add additional heat to the atmosphere; solar panels absorb and move rooftop heat

b. Photovoltaic (solar) cells produce energy directly from sunlight

c. Falling water is used to produce electricity in hydroelectric dams

d. Geothermal energy derived from heat in the earth's core heats water to heat buildings, generate electricity

e. Wind power can pump water or generate electricity

f. These sources are all considered renewable since they are replenished by physical means

II. Global climate change 

A. Climate Fluctuation

1. Earth's climate fluctuates; we are currently between ice ages, and today's climate was last seen 130,000 years ago

2. Some scientists are concerned that global climate will warm at a rate ten times faster than in the past

a. In 1850, atmospheric CO2 was about 280 parts per million (ppm); today, it is about 350 ppm

b. This increase is due largely to burning of fossil fuels and clearing of forests

c. Oceans currently absorb half of the CO2 emitted or else the atmospheric level would be higher

d. Methane given off by oil and gas wells, rice paddies, cows, etc. is increasing by one percent a year

e. Greenhouse effect -  warming of lower atmosphere caused by accumulation of certain greenhouse gases that allow rays of the sun to pass through, but then reflect or reradiate heat to the earth

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f. Greenhouse gases:

1) carbon dioxide (CO2), produced by fossil fuel and wood burning

2) nitrous oxide (NO2), produced by fertilizer use and released from decomposition of animals wastes

3) methane (CH4), produced by bacteria (especially in animal guts), in sediments, and in flooded rice paddies

4) chlorofluorocarbons (CFCs), in particular Freon (a refrigerant)

III. Acid precipitation (rain)

A. Rainfall pH 

1. Pure water has a pH of 7; dissociation of H2O produces equal numbers of H+ and OH- ions

2. Atmospheric CO2 combines with water to produce a weak carbonic acid and an increased number of H+ ions

3. Rain normally has a ...

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