AQA · GCSE · Combined Science
Course version: 8464 · Version from Sept 2018
The carbon footprint and its reduction: The carbon footprint is the total amount of carbon dioxide and other greenhouse gases emitted over the full life cycle of a product, service or event.
A carbon footprint measures the total greenhouse gases released across every stage of a product, service or event.
- 3 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
A carbon footprint measures the total greenhouse gases released across every stage of a product, service or event. It is not just carbon dioxide: methane and other greenhouse gases count too, and each is often converted to a carbon dioxide equivalent so they can be added together. The phrase full life cycle means you must include raw material extraction, processing, manufacture, transport, use and disposal or recycling. For example, a cotton T-shirt includes growing and irrigating the crop, making and dyeing the fabric, shipping it, washing it many times and finally disposing of it. Because the footprint is a total, it is measured in kilograms or tonnes of carbon dioxide equivalent, written kg CO₂e or t CO₂e.
What earns the marks
- States that a carbon footprint is a total, not a single emission, so all relevant stages must be summed.
- Identifies carbon dioxide and at least one other greenhouse gas, such as methane, as contributors.
- Explains that the full life cycle covers extraction, processing, manufacture, transport, use and disposal or recycling.
- Applies the idea to a named product, service or event and identifies stages that add to the total.
- Recognises that greenhouse gases have different warming effects, so emissions are often expressed as carbon dioxide equivalent.
Common mistakes and how to put them right
Counting only carbon dioxide and ignoring methane or other greenhouse gases.
Put it right by naming at least one other greenhouse gas and explaining that it is included.
Stopping at manufacture and ignoring transport, use or disposal.
Put it right by listing every life-cycle stage from raw material to final disposal.
Treating the footprint as a rate or a concentration rather than a total.
Put it right by describing it as a summed mass over the whole life cycle.
Exam tips
- Use the phrase full life cycle and then list stages in order to show the examiner you understand the scope.
- When asked to compare two products, compare the same stages for each so the totals are fair.
- Include units such as kg CO₂e or t CO₂e when you quote a footprint value.
Try the lesson
The start of the The carbon footprint and its reduction: The carbon footprint is the total amount of carbon dioxide and other greenhouse gases emitted over the full life cycle of a product, service or event. lesson, made from checked teaching notes for this specification point.
Have a go first
Which statement describes the carbon footprint of a product?
Listen
A carbon footprint measures the total greenhouse gases released across every stage of a product, service or event. It is not just carbon dioxide: methane and other greenhouse gases count too, and each is often converted to a carbon dioxide equivalent so they can be added together. The phrase full life cycle means you must include raw material extraction, processing, manufacture, transport, use and disposal or recycling. For example, a cotton T-shirt includes growing and irrigating the crop, making and dyeing the fabric, shipping it, washing it many times and finally disposing of it. Because the footprint is a total, it is measured in kilograms or tonnes of carbon dioxide equivalent, written kg CO₂e or t CO₂e. A strong answer earns marks for these points. States that a carbon footprint is a total, not a single emission, so all relevant stages must be summed. Identifies carbon dioxide and at least one other greenhouse gas, such as methane, as contributors. Explains that the full life cycle covers extraction, processing, manufacture, transport, use and disposal or recycling. Applies the idea to a named product, service or event and identifies stages that add to the total. A common slip: Counting only carbon dioxide and ignoring methane or other greenhouse gases. Instead, naming at least one other greenhouse gas and explaining that it is included. Exam tip: Use the phrase full life cycle and then list stages in order to show the examiner you understand the scope.
Key words
Say what each word means before you turn the card.
Carbon footprint
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Full life cycle
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Carbon dioxide equivalent
Try answering aloud or in your head before turning the card.
See every definition
- Carbon footprint
- The total amount of carbon dioxide and other greenhouse gases emitted over the full life cycle of a product, service or event.
- Full life cycle
- Every stage from raw material extraction, processing, manufacture, transport, use and disposal or recycling.
- Carbon dioxide equivalent
- A way of expressing emissions so that greenhouse gases with different warming effects can be added together, written kg CO₂e or t CO₂e.
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