AQA · GCSE · Chemistry
Course version: 8462 · Version from Sept 2018
Some human activities increase the amounts of greenhouse gases in the…
Full specification wording
Human activities which contribute to an increase in greenhouse gases in the: Some human activities increase the amounts of greenhouse gases in the atmosphere. These include: carbon dioxide methane.
Greenhouse gases absorb outgoing infrared radiation, warming the atmosphere.
Checked against the AQA 8462 specification (opens in a new tab) on .
- Point 1 of 6
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
Greenhouse gases absorb outgoing infrared radiation, warming the atmosphere. Human activities raise their concentrations. Carbon dioxide increases mainly by burning fossil fuels such as coal, oil and natural gas, and by deforestation, because trees remove carbon dioxide during photosynthesis. Methane increases through livestock farming, especially cattle and sheep, rice paddy fields, landfill sites and anaerobic digestion of waste. For example, a coal-fired power station releases carbon dioxide, while a cattle farm releases methane. These gases trap heat, so higher concentrations strengthen the greenhouse effect. You should link each activity to the gas it releases and explain the mechanism briefly.
What earns the marks
- Carbon dioxide is released by burning fossil fuels such as coal, oil and natural gas in power stations, factories and vehicles.
- Deforestation reduces photosynthesis, so less carbon dioxide is removed from the atmosphere, increasing its concentration.
- Methane is released by livestock farming, particularly cattle and sheep, through digestion and waste.
- Methane is released from rice paddy fields, landfill sites and anaerobic decomposition of organic waste.
- Greenhouse gases absorb infrared radiation emitted by the Earth, so increasing their concentration strengthens the greenhouse effect.
Common mistakes and how to put them right
Confusing the gases released by different activities, such as saying cattle release carbon dioxide.
Put it right by linking livestock to methane and fossil fuel combustion to carbon dioxide.
Thinking deforestation directly releases carbon dioxide only.
Put it right by explaining that it also removes fewer trees, so less carbon dioxide is absorbed.
Describing the greenhouse effect as a human-made process.
Put it right by stating it is a natural process strengthened by human activities.
Exam tips
- When asked to name activities, give specific examples such as burning coal or rearing cattle rather than vague terms like pollution.
- Link each activity to the correct greenhouse gas in the same sentence to secure both marking points.
- Use the term infrared radiation when explaining how greenhouse gases warm the atmosphere.
Try the lesson
The start of the Human activities which contribute to an increase in greenhouse gases in the: Some human activities increase the amounts of greenhouse gases in the atmosphere. These include: carbon dioxide methane. lesson, made from checked teaching notes for this specification point.
Have a go first
Which two gases are named as greenhouse gases whose amounts in the atmosphere are increased by some human activities?
Listen
Greenhouse gases absorb outgoing infrared radiation, warming the atmosphere. Human activities raise their concentrations. Carbon dioxide increases mainly by burning fossil fuels such as coal, oil and natural gas, and by deforestation, because trees remove carbon dioxide during photosynthesis. Methane increases through livestock farming, especially cattle and sheep, rice paddy fields, landfill sites and anaerobic digestion of waste. For example, a coal-fired power station releases carbon dioxide, while a cattle farm releases methane. These gases trap heat, so higher concentrations strengthen the greenhouse effect. You should link each activity to the gas it releases and explain the mechanism briefly. A strong answer earns marks for these points. Carbon dioxide is released by burning fossil fuels such as coal, oil and natural gas in power stations, factories and vehicles. Deforestation reduces photosynthesis, so less carbon dioxide is removed from the atmosphere, increasing its concentration. Methane is released by livestock farming, particularly cattle and sheep, through digestion and waste. Methane is released from rice paddy fields, landfill sites and anaerobic decomposition of organic waste. A common slip: Confusing the gases released by different activities, such as saying cattle release carbon dioxide. Instead, linking livestock to methane and fossil fuel combustion to carbon dioxide. Exam tip: When asked to name activities, give specific examples such as burning coal or rearing cattle rather than vague terms like pollution.
Key words
Say what each word means before you turn the card.
Greenhouse effect
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Carbon dioxide sources
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Methane sources
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Human impact on climate
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See every definition
- Greenhouse effect
- Greenhouse gases absorb infrared radiation emitted by the Earth, so increasing their concentration strengthens this effect.
- Carbon dioxide sources
- Burning fossil fuels such as coal, oil and natural gas, and deforestation, which reduces photosynthesis so less carbon dioxide is removed from the atmosphere.
- Methane sources
- Livestock farming, particularly cattle and sheep, rice paddy fields, landfill sites and anaerobic decomposition of organic waste.
- Human impact on climate
- Some human activities increase the amounts of greenhouse gases in the atmosphere, and these gases trap heat.
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