Name the three main greenhouse gases.

The three main greenhouse gases are: Carbon dioxide (CO 2 ) Methane (CH 4 ) Water vapour These gases trap heat energy in the atmosphere and maintain temperatures needed to support life.

Describe the greenhouse effect in terms of radiation wavelength.

Short wavelength (UV) radiation from the Sun enters the atmosphere. It is absorbed by the Earth's surface, then re-emitted as longer wavelength (IR) radiation. Greenhouse gases absorb this IR radiation, trapping heat energy and warming the atmosphere.

True or False? Greenhouse gases work by reflecting radiation back towards the Earth's surface.

False. Greenhouse gases absorb the longer wavelength (IR) radiation re-emitted by the Earth. The words "reflected" or "bounced off" are explicitly not accepted by mark schemes.

________ wavelength radiation enters the atmosphere. It is absorbed by the Earth and re-emitted as ________ wavelength radiation. This is ________ by greenhouse gases, which ________ the temperature.

Short wavelength radiation enters the atmosphere. It is absorbed by the Earth and re-emitted as longer wavelength radiation. This is absorbed by greenhouse gases, which increase the temperature.

Which gas is not a greenhouse gas? Carbon dioxide Methane Nitrogen Water vapour

Nitrogen is not a greenhouse gas. Carbon dioxide, methane, and water vapour are all greenhouse gases. Nitrogen is the most common wrong answer when students are asked to name a greenhouse gas.

Why does increasing the concentration of greenhouse gases cause global temperatures to rise ?

More greenhouse gas molecules means more IR radiation is absorbed by the atmosphere rather than escaping into space. This traps extra heat energy , causing the average temperature of the Earth's atmosphere to increase.

Give two human activities that are increasing methane levels in the atmosphere.

Methane levels are increasing due to: More waste being sent to landfill sites (as the human population grows) Increased levels of farming (livestock and rice paddies produce methane).

How does deforestation contribute to rising CO 2 levels?

Trees absorb CO 2 during photosynthesis . Fewer trees means less CO 2 is removed from the atmosphere, causing levels to rise. Additionally, if trees are burned, the stored carbon is released directly as CO 2 .

True or False? Burning fossil fuels is the only human activity causing atmospheric CO 2 to rise.

False. Deforestation is also a major cause: fewer trees means less CO 2 is absorbed by photosynthesis. Both burning fossil fuels and deforestation are required for a complete answer.

What methods do scientists use to estimate historical climate conditions before accurate measurements existed?

Scientists analyse: Gas bubbles trapped in ancient ice cores Tree rings (ring width reflects climate conditions) The fossil record . These methods are less precise and less globally representative than modern instruments.

Methane levels are rising due to more ________ sites and increased ________ . CO 2 levels are rising due to burning ________ fuels and ________ .

Methane levels are rising due to more landfill sites and increased farming . CO 2 levels are rising due to burning fossil fuels and deforestation .

Why is peer review important for climate change evidence?

Peer review means other scientists check the results and conclusions for validity. Climate data is complex and subject to media speculation, peer review helps confirm that the evidence linking CO 2 to rising temperatures is robust. About 97% of climate scientists agree human activity is causing climate change.

Define climate change .

Climate change is the long-term alteration of global temperatures and weather patterns, driven primarily by the enhanced greenhouse effect as greenhouse gas concentrations in the atmosphere increase.

Give four specific effects of climate change.

Effects of climate change include: Rising sea levels due to melting ice caps and glaciers More frequent and severe droughts causing crop failure More intense storms and extreme weather events Loss of habitats and species

True or False? Saying "the Earth gets hotter" is an acceptable answer when asked to describe an effect of climate change.

False. "The Earth gets hotter" is too vague and gains no marks. Specific effects must be stated, such as rising sea levels, melting polar ice, droughts, crop failure, more intense storms, or loss of habitats.

Rising sea levels caused by climate change result from the ________ of polar ________ and glaciers.

Rising sea levels caused by climate change result from the melting of polar ice caps and glaciers.

How does climate change threaten food production?

Climate change increases the frequency of droughts, leading to crop failure. Flooding and extreme heat events further damage agricultural land, reducing yields and threatening food security in many regions.

Why must you be specific when describing the consequences of climate change?

Vague statements such as "the weather changes" or "the environment is damaged" do not show understanding. Specific consequences include rising sea levels, melting glaciers, droughts, flooding, extreme storms, forest fires, and loss of habitats.

Define carbon footprint .

A carbon footprint is the total amount of greenhouse gases released over the full life cycle of a product or activity, expressed as an equivalent mass of CO 2 .

What are the four stages of a life cycle assessment (LCA)?

The four stages are: Extraction of raw materials Manufacture Use and distribution Disposal. All four stages contribute to the overall carbon footprint.

True or False? The disposal stage does not need to be included in a life cycle assessment because it happens after the product is used.

False. Disposal is one of the four essential stages of an LCA. Examiners often comment about students missing it out. It must be included alongside extraction of raw materials, manufacture, and use and distribution.

The four stages of a life cycle assessment are: Extraction of raw ________ ________ Use and ________ ________

The four stages of a life cycle assessment are: Extraction of raw materials Manufacture Use and distribution Disposal

Give three ways an individual or company can reduce their carbon footprint.

Ways an individual or company can reduce their carbon footprint include: Switching to renewable energy sources Using public transport or electric vehicles Eating less meat Reducing food miles Carbon offsetting Increasing recycling Carbon capture and storage

Why is it difficult to reduce carbon footprints on a global scale?

Challenges include the high cost of renewable energy infrastructure, the need for widespread changes in personal behaviour and lifestyle, the requirement for international cooperation, and uncertainty around the effectiveness of methods such as carbon offsetting.

GCSEScienceAQACombined Science: TrilogyChemistryFlashcardsChemistry of the AtmosphereCO2 & CH4 as Greenhouse Gases

CO2 & CH4 as Greenhouse Gases (AQA GCSE Combined Science: Trilogy: Chemistry): Flashcards

Exam code: 8464

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FrontGreenhouse Gases
Name the three main greenhouse gases.
BackGreenhouse Gases
The three main greenhouse gases are:
Carbon dioxide (CO₂)
Methane (CH₄)
Water vapour
These gases trap heat energy in the atmosphere and maintain temperatures needed to support life.
BackGreenhouse Gases
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Cards in this collection (24)

Name the three main greenhouse gases.
The three main greenhouse gases are:
- Carbon dioxide (CO₂)
- Methane (CH₄)
- Water vapour
These gases trap heat energy in the atmosphere and maintain temperatures needed to support life.
Describe the greenhouse effect in terms of radiation wavelength.
Short wavelength (UV) radiation from the Sun enters the atmosphere. It is absorbed by the Earth's surface, then re-emitted as longer wavelength (IR) radiation. Greenhouse gases absorb this IR radiation, trapping heat energy and warming the atmosphere.
True or False?
Greenhouse gases work by reflecting radiation back towards the Earth's surface.
False.
Greenhouse gases absorb the longer wavelength (IR) radiation re-emitted by the Earth.
The words "reflected" or "bounced off" are explicitly not accepted by mark schemes.
________ wavelength radiation enters the atmosphere. It is absorbed by the Earth and re-emitted as ________ wavelength radiation. This is ________ by greenhouse gases, which ________ the temperature.
Short wavelength radiation enters the atmosphere. It is absorbed by the Earth and re-emitted as longer wavelength radiation. This is absorbed by greenhouse gases, which increase the temperature.
Which gas is not a greenhouse gas?
- Carbon dioxide
- Methane
- Nitrogen
- Water vapour
Nitrogen is not a greenhouse gas.
Carbon dioxide, methane, and water vapour are all greenhouse gases.
Nitrogen is the most common wrong answer when students are asked to name a greenhouse gas.
Why does increasing the concentration of greenhouse gases cause global temperatures to rise?
More greenhouse gas molecules means more IR radiation is absorbed by the atmosphere rather than escaping into space. This traps extra heat energy, causing the average temperature of the Earth's atmosphere to increase.
Give two human activities that are increasing methane levels in the atmosphere.
Methane levels are increasing due to:
- More waste being sent to landfill sites (as the human population grows)
- Increased levels of farming (livestock and rice paddies produce methane).
How does deforestation contribute to rising CO₂ levels?
Trees absorb CO₂ during photosynthesis. Fewer trees means less CO₂ is removed from the atmosphere, causing levels to rise.
Additionally, if trees are burned, the stored carbon is released directly as CO₂.
True or False?
Burning fossil fuels is the only human activity causing atmospheric CO₂ to rise.
False.
Deforestation is also a major cause: fewer trees means less CO₂ is absorbed by photosynthesis.
Both burning fossil fuels and deforestation are required for a complete answer.
What methods do scientists use to estimate historical climate conditions before accurate measurements existed?
Scientists analyse:
- Gas bubbles trapped in ancient ice cores
- Tree rings (ring width reflects climate conditions)
- The fossil record.
These methods are less precise and less globally representative than modern instruments.
Methane levels are rising due to more ________ sites and increased ________.
CO₂ levels are rising due to burning ________ fuels and ________.
Methane levels are rising due to more landfill sites and increased farming.
CO₂ levels are rising due to burning fossil fuels and deforestation.
Why is peer review important for climate change evidence?
Peer review means other scientists check the results and conclusions for validity.
Climate data is complex and subject to media speculation, peer review helps confirm that the evidence linking CO₂ to rising temperatures is robust. About 97% of climate scientists agree human activity is causing climate change.
Define climate change.
Climate change is the long-term alteration of global temperatures and weather patterns, driven primarily by the enhanced greenhouse effect as greenhouse gas concentrations in the atmosphere increase.
Give four specific effects of climate change.
Effects of climate change include:
- Rising sea levels due to melting ice caps and glaciers
- More frequent and severe droughts causing crop failure
- More intense storms and extreme weather events
- Loss of habitats and species
True or False?
Saying "the Earth gets hotter" is an acceptable answer when asked to describe an effect of climate change.
False.
"The Earth gets hotter" is too vague and gains no marks.
Specific effects must be stated, such as rising sea levels, melting polar ice, droughts, crop failure, more intense storms, or loss of habitats.
Rising sea levels caused by climate change result from the ________ of polar ________ and glaciers.
Rising sea levels caused by climate change result from the melting of polar ice caps and glaciers.
How does climate change threaten food production?
Climate change increases the frequency of droughts, leading to crop failure.
Flooding and extreme heat events further damage agricultural land, reducing yields and threatening food security in many regions.
Why must you be specific when describing the consequences of climate change?
Vague statements such as "the weather changes" or "the environment is damaged" do not show understanding.
Specific consequences include rising sea levels, melting glaciers, droughts, flooding, extreme storms, forest fires, and loss of habitats.
Define carbon footprint.
A carbon footprint is the total amount of greenhouse gases released over the full life cycle of a product or activity, expressed as an equivalent mass of CO₂.
What are the four stages of a life cycle assessment (LCA)?
The four stages are:
1. Extraction of raw materials
2. Manufacture
3. Use and distribution
4. Disposal.
All four stages contribute to the overall carbon footprint.
True or False?
The disposal stage does not need to be included in a life cycle assessment because it happens after the product is used.
False.
Disposal is one of the four essential stages of an LCA.
Examiners often comment about students missing it out. It must be included alongside extraction of raw materials, manufacture, and use and distribution.
The four stages of a life cycle assessment are:
- Extraction of raw ________
- ________
- Use and ________
- ________
The four stages of a life cycle assessment are:
- Extraction of raw materials
- Manufacture
- Use and distribution
- Disposal
Give three ways an individual or company can reduce their carbon footprint.
Ways an individual or company can reduce their carbon footprint include:
- Switching to renewable energy sources
- Using public transport or electric vehicles
- Eating less meat
- Reducing food miles
- Carbon offsetting
- Increasing recycling
- Carbon capture and storage
Why is it difficult to reduce carbon footprints on a global scale?
Challenges include the high cost of renewable energy infrastructure, the need for widespread changes in personal behaviour and lifestyle, the requirement for international cooperation, and uncertainty around the effectiveness of methods such as carbon offsetting.

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