This presentation identifies the major Greenhouse gases and where they come from

1. What are our Greenhouse
gases and where do they
come from?

2. Carbon Dioxide
• Animals take in Oxygen and give off Carbon Dioxide
when they breathe. Plants/trees, on the other hand,
take in Carbon Dioxide and give off Oxygen.
• Deforestation results in an increase in Carbon Dioxide.
• Carbon Dioxide is also released by combustion of
fossil fuels (coal, oil and natural gas) especially in
factories and cars.
• Forest fires, whether natural or man made can make
significant contributions.
This Photo by Unknown author is licensed under CC BY-SA-NC.

3. Water Vapour
• This occurs naturally as water is evaporated by
the energy of the sun.
• Man helps to increase the amount of water
vapour through everyday activities as cooking
and cleaning.
• Man's industrial activities can cause large
amounts of water vapour to be released to the
atmosphere. This occurs during industrial
processes involving heat and water such as the
iron and steel industry, an also food processing.
Water is also used to cool down hot
equipment (during which evaporation takes place
as the water also becomes heated).
This Photo by Unknown author is licensed under CC BY.

4. Nitrous Oxides
These found in the environment from natural
fertilizers or may be introduced by man.
It can be added through the combustion of
fossil fuels.
Nitrous oxides are emitted from farms through
fertilizers (nitrogen enriched) and animal
droppings.
Nitrous Oxide is emitted from wastewater that
contains nitrogen-based organic materials, such
as those found in human and animal waste.
This Photo by Unknown author is licensed under CC BY-SA.

5. Chlorofluorocarbons
(CFCs)
• CFCs are chemical compounds made up of
chlorine, fluorine and carbon.
• CFCs are used in:
- aerosol sprays (as propellants)
- styrofoam manufacture
- refrigerators and air conditioning units
(they are used as coolants, but leak
out eventually if the unit is not
disposed of properly at the end of use)
This Photo by Unknown author is licensed under CC BY-SA.

6. Methane
• Methane is a naturally occurring gas but can be influenced by human activity. It can be
found:
- where there is decomposition of plant matter (in the natural
environment and especially in swamps). Decaying matter in
Landfills also contributes Methane to the atmosphere.
- in natural gas (often released into the atmosphere during
extracting, processing and distribution).
- in farms. Some animals, especially cattle, sheep and goats,
produce Methane through their digestive process, which is released
to the atmosphere as they pass gas. Large scale farming in places
such as the mid-west USA contribute significant amounts of Methane
to the atmosphere.
This Photo by Unknown author is licensed under CC BY-ND.

7. Indirect Greenhouse
Gases
• Indirect Greenhouse Gases do not directly trap heat but
assists by influencing the production of Direct Greenhouse
Gases (those that trap heat). This includes:
- Carbon Monoxide – derived through
combustion. This gas helps to increase the
global warming potential of gases like
Methane.
- Sulphur Dioxide – derived through combustion of
fossil fuels and naturally from volcanoes.
This gas assists in the formation of aerosols
in the atmosphere, which can trap heat.
This Photo by Unknown author is licensed under CC BY.