AQA · A-Level · Geography
Course version: 7037 · Version from Sept 2018
The carbon budget and the impact of the carbon cycle upon land, ocean and…
Full specification wording
The carbon cycle: The carbon budget and the impact of the carbon cycle upon land, ocean and atmosphere, including global climate.
The carbon budget is the balance between carbon emissions and removals across all global reservoirs.
Checked against the AQA 7037 specification (opens in a new tab) on .
- Point 4 of 4
- 3 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
The carbon budget is the balance between carbon emissions and removals across all global reservoirs. Understanding this budget is crucial for assessing the carbon cycle's impact on Earth's systems. On land, increased atmospheric carbon stimulates plant growth through carbon fertilisation, but alters soil dynamics and thaws permafrost. In the oceans, absorbing excess carbon dioxide causes ocean acidification, lowering pH and threatening marine calcifying organisms like corals. In the atmosphere, rising carbon dioxide and methane concentrations enhance the greenhouse effect. This directly drives changes in the global climate, resulting in rising temperatures, altered precipitation patterns, and more frequent extreme weather events.
What earns the marks
- Define the carbon budget as the difference between the inputs and outputs of carbon within a specific reservoir or the global system.
- Explain the impact of the carbon cycle on land, including carbon fertilisation effects on vegetation and the release of carbon from thawing permafrost.
- Describe the process of ocean acidification, where increased dissolved carbon dioxide lowers ocean pH, impacting marine ecosystems.
- Analyse the atmospheric impact of the carbon cycle, specifically the role of carbon dioxide and methane in the enhanced greenhouse effect.
- Evaluate how changes in the atmospheric carbon store drive global climate change, including temperature increases and shifting weather patterns.
Common mistakes and how to put them right
Defining the carbon budget solely as human emissions.
Put it right: Define the carbon budget as the net balance of all carbon fluxes (both natural and human) between the atmosphere, land, and oceans.
Stating that ocean acidification involves the ocean becoming a strong acid.
Put it right: Explain that the ocean remains slightly alkaline, but its pH is decreasing (becoming less alkaline) due to carbonic acid formation.
Confusing the natural greenhouse effect with the enhanced greenhouse effect.
Put it right: Specify that the enhanced greenhouse effect, driven by a surplus in the atmospheric carbon budget, is responsible for recent global climate change.
Exam tips
- Link the concept of the carbon budget to tipping points, such as the irreversible thawing of permafrost.
- Use the chemical process of carbon dioxide dissolving in seawater to form carbonic acid to demonstrate a deep understanding of ocean impacts.
- When evaluating impacts on global climate, discuss both temperature changes and secondary effects like sea-level rise and altered atmospheric circulation.
Try the lesson
The start of the The carbon cycle: The carbon budget and the impact of the carbon cycle upon land, ocean and atmosphere, including global climate. lesson, made from checked teaching notes for this specification point.
Have a go first
What is meant by the term 'global carbon budget' in the context of the carbon cycle?
Listen
The carbon budget is the balance between carbon emissions and removals across all global reservoirs. Understanding this budget is crucial for assessing the carbon cycle's impact on Earth's systems. On land, increased atmospheric carbon stimulates plant growth through carbon fertilisation, but alters soil dynamics and thaws permafrost. In the oceans, absorbing excess carbon dioxide causes ocean acidification, lowering pH and threatening marine calcifying organisms like corals. In the atmosphere, rising carbon dioxide and methane concentrations enhance the greenhouse effect. This directly drives changes in the global climate, resulting in rising temperatures, altered precipitation patterns, and more frequent extreme weather events. A strong answer earns marks for these points. Define the carbon budget as the difference between the inputs and outputs of carbon within a specific reservoir or the global system. Explain the impact of the carbon cycle on land, including carbon fertilisation effects on vegetation and the release of carbon from thawing permafrost. Describe the process of ocean acidification, where increased dissolved carbon dioxide lowers ocean pH, impacting marine ecosystems. Analyse the atmospheric impact of the carbon cycle, specifically the role of carbon dioxide and methane in the enhanced greenhouse effect. A common slip: Defining the carbon budget solely as human emissions. Instead, Define the carbon budget as the net balance of all carbon fluxes (both natural and human) between the atmosphere, land, and oceans. Exam tip: Link the concept of the carbon budget to tipping points, such as the irreversible thawing of permafrost.
Key words
Say what each word means before you turn the card.
Carbon budget
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Ocean acidification
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Enhanced greenhouse effect
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See every definition
- Carbon budget
- The balance between carbon emissions and removals across all global reservoirs, or the difference between the inputs and outputs of carbon within a specific reservoir or the global system.
- Ocean acidification
- A process where increased dissolved carbon dioxide lowers ocean pH, impacting marine ecosystems, with the ocean remaining slightly alkaline but becoming less alkaline due to carbonic acid formation.
- Enhanced greenhouse effect
- Driven by a surplus in the atmospheric carbon budget, this is responsible for recent global climate change, with carbon dioxide and methane playing a role.
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