12. The greenhouse effect is caused by human activities
which produce the greenhouse gases; carbon dioxide,
methane, nitrous oxide and fluorocarbons.
Carbon dioxide is the main greenhouse gas and is
produced by fossil fuel burning power plants, heating
systems, factories, and modes of transportation that burn
fossil fuels.
Methane is another greenhouse gas produced by human
use of land, including the livestock we use and such
agricultural objects as rice fields, wetlands and marshes.
Nitrous oxide is produced by the exhaust of cars, human
disposal of waste and human use of nitrogen-based
fertilizers.
Fluorocarbons are gases which are emitted when humans
use their refrigerators and their air conditioners
Causes
13. Affects
• Global warming will affect human health in a
number of different ways
• The spread of infectious diseases will be
affected
• Agriculture will be affected
• Extreme weather patterns will be affected
• The amount of smog near the ground will be
affected
• The supply of freshwater available to humans
will be affected
• Coral reefs
• The polar ice caps