Small proportions (less than 1%) of other gases e.g. carbon dioxide, water vapour and methane
Oxygen in the atmosphere
Essential for all living things to stay alive
Essential for the combustion (burning) of fuels
Carbon dioxide
A compound with the formula CO2
Carbon is trapped in rocks and sediments, is found in organisms and in the ocean/atmosphere
Carbon cycle
Carbon dioxide is released and taken in from the environment
Ways carbon enters the atmosphere
Respiration – all living organisms carry out respiration
Combustion – burning substances like fossil fuels releases carbon dioxide
Decomposition – when animals and plants die, microorganisms break down the organism which releases the carbon in the organisms into the atmosphere by respiration
Photosynthesis
Carbon dioxide + water glucose + oxygen
Ways carbon is transferred
Animals feed on plants passing carbon from the plant to the animal
This is then exhaled as carbon dioxide during respiration
Carbon sinks
Absorb and store large amounts of carbon
The plant and animal material may be fossilised over long periods of time and become fossil fuel for combustion
Natural changes to the atmosphere
Volcanic activity (releases carbon dioxide)
Lightening (leads to oxides of nitrogen being produced)
Man-made changes to the atmosphere
Burning of fossil fuels (releases carbon dioxide)
Deforestation (prevents carbon dioxide from being taken in)
Cattle farming and rice farming (release methane)
Methane levels are increasing in the atmosphere as humans are doing more cattle farming and rice farming
The carbon dioxide levels in the atmosphere are increasing due to human activity, specifically burning fossil fuels and deforestation
Carbon footprint
A measure of the amount of carbon dioxide released into the atmosphere as a result of the activities of a particular individual, organisation, or community
Greenhouse gases
Water vapour
Carbon dioxide
Methane
Greenhouse effect
1. Radiation from the sun is emitted and passes through the atmosphere to the Earth's surface
2. Some radiation is reflected by the Earth's surface and escapes back into space
3. Some radiation is absorbed by the Earth's surface and re-emitted as a different form of radiation
4. This radiation is absorbed by greenhouse gases to produce temperature increase
Enhanced greenhouse effect
Human activity has increased the amount of carbon dioxide and methane in the atmosphere, so more radiation is absorbed and less heat escapes into space, leading to temperature increases
Global warming is causing the world's climate to change
Effects of climate change
Ice caps melting causing rising sea levels
Agricultural problems
Extremes of weather (e.g. flooding, hurricanes etc)