AQA · GCSE · Chemistry
Course version: 8462 · Version from Sept 2018
However, it is difficult to model such complex systems as global climate…
Full specification wording
Human activities which contribute to an increase in greenhouse gases in the: However, it is difficult to model such complex systems as global climate change.
Global climate is a complex system with many interacting parts, including the atmosphere, oceans, ice, land and living things.
Checked against the AQA 8462 specification (opens in a new tab) on .
- Point 4 of 6
- 4 key terms
Study notes
From the checked teaching notes for this specification point.
The idea
Global climate is a complex system with many interacting parts, including the atmosphere, oceans, ice, land and living things. These parts affect one another through feedback loops, such as melting ice reducing reflectivity and causing more warming. Because of this complexity, computer models that predict climate change have limitations. They may simplify processes, rely on incomplete data, or struggle to represent clouds and ocean currents accurately. This makes long-term predictions uncertain. For example, different models may give a range of possible temperature rises. Scientists improve models by comparing them with observations and updating them as new peer-reviewed evidence emerges.
What earns the marks
- Global climate involves many interacting components, such as atmosphere, oceans, ice and land.
- Feedback mechanisms, such as ice melting and reduced reflectivity, make the system complex.
- Computer models simplify or omit some processes, leading to uncertainty in predictions.
- Incomplete data and limited understanding of some processes make modelling difficult.
- Models are improved by testing against observations and revising with new peer-reviewed evidence.
Common mistakes and how to put them right
Thinking models are useless because they are uncertain.
Put it right by explaining they provide useful projections with ranges of uncertainty.
Believing climate change is not happening because models are imperfect.
Put it right by distinguishing between uncertainty in details and the overall trend.
Ignoring feedback loops; correct this by giving an example such as melting ice reducing reflection of sunlight.
Exam tips
- Use the word complex when explaining why modelling is difficult.
- Give a specific reason, such as incomplete data or simplified processes, rather than saying it is just hard.
- Mention that models are tested against real observations to improve reliability.
Try the lesson
The start of the Human activities which contribute to an increase in greenhouse gases in the: However, it is difficult to model such complex systems as global climate change. lesson, made from checked teaching notes for this specification point.
Have a go first
How is the Earth's climate described when scientists attempt to model global climate change?
Listen
Global climate is a complex system with many interacting parts, including the atmosphere, oceans, ice, land and living things. These parts affect one another through feedback loops, such as melting ice reducing reflectivity and causing more warming. Because of this complexity, computer models that predict climate change have limitations. They may simplify processes, rely on incomplete data, or struggle to represent clouds and ocean currents accurately. This makes long-term predictions uncertain. For example, different models may give a range of possible temperature rises. Scientists improve models by comparing them with observations and updating them as new peer-reviewed evidence emerges. A strong answer earns marks for these points. Global climate involves many interacting components, such as atmosphere, oceans, ice and land. Feedback mechanisms, such as ice melting and reduced reflectivity, make the system complex. Computer models simplify or omit some processes, leading to uncertainty in predictions. Incomplete data and limited understanding of some processes make modelling difficult. A common slip: Thinking models are useless because they are uncertain. Instead, explaining they provide useful projections with ranges of uncertainty. Exam tip: Use the word complex when explaining why modelling is difficult.
Key words
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Complex systems
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Feedback mechanisms
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Climate modelling
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Uncertainty
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See every definition
- Complex systems
- Global climate is one of these, with many interacting parts including the atmosphere, oceans, ice, land and living things.
- Feedback mechanisms
- These are loops through which the parts of the climate system affect one another, such as melting ice reducing reflectivity and causing more warming.
- Climate modelling
- Computer models that predict climate change have limitations because they may simplify processes, rely on incomplete data, or struggle to represent clouds and ocean currents accurately.
- Uncertainty
- Long-term predictions are made uncertain by the complexity of the climate system, so different models may give a range of possible temperature rises.
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