Environmental Issues Human Impact on the Environment.

Environmental Issues

Human Impact on the Environment

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• Humans did not set out to ruin the biosphere (area of planet that sustains life)

• Some choices we have made have had negative effects on the environment and we need to address them

Acid Rain• SULFUR introduced into the

atmosphere by smokestacks from factories can combine with water vapor to produce SULFURIC ACID

• Sulfuric acid is carried to the earth’s surface in acidified precipitation called ACID RAIN

• Acid Rain has a pH that falls below 5.0

Ozone Depletion• The decrease in the earth’s

OZONE LAYER allows more UV rays to reach the earth’s surface.

• This has caused an increase in SKIN CANCER (which has nearly doubled since 1980)

• CFC’S (CHLOROFLUOROCARBONS) cause ozone depletion

Global Temperature• The global temperature has been increasing rapidly

for more than a CENTURY• Global WARMING is followed by centuries of

COLD• Human activity contributes to global warming• Warmer temperatures raise sea levels (by melting

more ice) and decrease agriculture output (by affecting weather patterns).

Greenhouse Effect• Bonds in CO2 absorb solar

energy

• This traps HEAT within the ATMOSPHERE

• The INCREASE in carbon dioxide (CO2) is from the burning of fossil fuels

DeforestationDeforestation• Clear-cutting of forests causes erosion, flooding, and changes in weather patterns.

• The slash-and-burn method of clearing forests for agriculture increases atmospheric CO2, which contributes to the greenhouse effect.

Effects of Chemical Pollution• Pesticides such as DDT have

been used to control insects• The chemicals end up in the

water supply• As molecules pass up the

TROPHIC levels, they become more CONCENTRATED

• This is called BIOLOGICAL MAGNIFICATION, or biomagnification

Human Introduction of Organisms• Nonnative plants and animals that are

introduced into a habitat where they harm or endanger native plants and animals are invader, invasive, exotic, or alien species

Human Population• The number of

humans inhabiting the Earth is rising exponentially– Longer life spans– Better food/medicine– Technology

• When will we run out of space?

• When will we run out or resources?