Global Carbon Stores and Flows

Active learning works for Global Carbon Stores and Flows because students need to visualize scales from gigatons to processes that span seconds to millennia. Handling real data through sorting, modeling, and simulation builds quantitative reasoning and corrects oversimplified views of carbon’s movement.

• Year 13
• Geography
• 4 activities
• 20 min–45 min

Learning Objectives

1. Compare the relative sizes of the atmosphere, ocean, terrestrial biosphere, and geological carbon reservoirs using quantitative data.
2. Explain the chemical and biological processes that transfer carbon between the atmosphere and the oceans.
3. Analyze the role of photosynthesis and respiration in the fast carbon cycle, quantifying annual fluxes.
4. Evaluate the significance of volcanic activity and silicate weathering as drivers of the slow carbon cycle.
5. Synthesize information to differentiate between the fast and slow carbon cycles, identifying key reservoirs and fluxes for each.

Concept Mapping

⏱ 25 min·Pairs

Pairs: Flux Card Sort

Provide cards listing carbon processes and flux rates. Pairs sort them into fast or slow cycles, then calculate annual net changes using provided data. Pairs share one insight with the class.

Prepare & details

Differentiate between the fast and slow carbon cycles.

Facilitation Tip: During Flux Card Sort, give each pair a laminated card set with flux names, rates, and reservoir pairs to physically manipulate while referencing the provided data sheet.

Setup: Tables with large paper, or wall space

Materials: Concept cards or sticky notes, Large paper, Markers, Example concept map

• Understand
• Analyze
• Create
• Self-Awareness
• Self-Management

Concept Mapping

⏱ 45 min·Small Groups

Small Groups: Ocean Carbon Model

Groups layer saltwater tanks to represent ocean zones, adding CO2 indicators (like pH strips). Stir to simulate upwelling and observe gas exchange with air above. Record changes and link to sink/source roles.

Prepare & details

Explain the role of oceans as a carbon sink and source.

Facilitation Tip: For Ocean Carbon Model, assign roles (e.g., oceanographer, chemist, recorder) so each student contributes to measuring CO2 exchange in stratified tanks using pH indicators and timers.

Setup: Tables with large paper, or wall space

Materials: Concept cards or sticky notes, Large paper, Markers, Example concept map

• Understand
• Analyze
• Create
• Self-Awareness
• Self-Management

Concept Mapping

⏱ 35 min·Whole Class

Whole Class: Volcanic Input Simulation

Project a global carbon budget diagram. As a class, adjust sliders in an online simulator for volcanic CO2 emissions versus human sources. Discuss long-term versus short-term cycle implications.

Prepare & details

Analyze how volcanic activity contributes to the long-term carbon cycle.

Facilitation Tip: In Volcanic Input Simulation, use a clear plastic bottle with baking soda and vinegar to visibly connect chemical reactions to geological carbon release, asking students to record gas volume changes over time.

Setup: Tables with large paper, or wall space

Materials: Concept cards or sticky notes, Large paper, Markers, Example concept map

• Understand
• Analyze
• Create
• Self-Awareness
• Self-Management

Concept Mapping

⏱ 20 min·Individual

Individual: Store Comparison Graph

Students plot bar graphs of carbon store sizes from data tables, annotate dominant fluxes. Compare pre- and post-industrial totals to infer human perturbation.

Prepare & details

Differentiate between the fast and slow carbon cycles.

Setup: Tables with large paper, or wall space

Materials: Concept cards or sticky notes, Large paper, Markers, Example concept map

• Understand
• Analyze
• Create
• Self-Awareness
• Self-Management

Teaching This Topic

Teachers should emphasize timescales early and often, pairing numerical data with visual timelines to prevent students from conflating fast and slow processes. Avoid letting students focus solely on biological examples; use the model and simulation to foreground geological fluxes. Research shows that students grasp carbon stores better when they physically manipulate scaled representations of reservoirs rather than passively observe diagrams.

What to Expect

Successful learning looks like students confidently distinguishing fast and slow fluxes, accurately ranking reservoirs by size, and explaining how human actions alter natural balances. They should use evidence from activities to justify their claims about carbon exchanges.

Watch Out for These Misconceptions

Common Misconception

During Flux Card Sort, watch for students who categorize all biological processes under ‘photosynthesis and respiration’ without separating fast and slow cycles.

What to Teach Instead

Prompt pairs to sort processes by timescale first, using the provided data to place weathering and volcanism under slow cycles, then justify their placements in a class share-out.

Common Misconception

During Ocean Carbon Model, watch for students who assume the ocean always absorbs CO2 without considering upwelling or temperature effects.

What to Teach Instead

Have groups run two trials: one with cold water and one with warm, then ask them to explain why the model shows CO2 release in one but uptake in the other.

Common Misconception

During Volcanic Input Simulation, watch for students who dismiss volcanic emissions as insignificant compared to human activity.

What to Teach Instead

Ask students to compare their simulated gas volume to a classroom CO2 sensor reading, then discuss why small natural fluxes matter over geological time.

Assessment Ideas

Quick Check

After Store Comparison Graph, present students with a shuffled list of reservoirs and ask them to rank from largest to smallest store in pairs, then justify their top two choices using data from their graphs.

Discussion Prompt

During Ocean Carbon Model, circulate and ask each group, ‘How does your observation of CO2 release in warm water challenge the idea that oceans only absorb carbon?’ Facilitate a class debrief to synthesize explanations.

Exit Ticket

After Volcanic Input Simulation, have students sketch a two-panel diagram on an index card: one panel showing their simulated volcanic flux and one panel showing a human emission flux, labeling reservoirs and carbon movement in each.

Extensions & Scaffolding

• Challenge: Ask students to research a specific country’s carbon budget and compare its annual emissions against volcanic output from the simulation.
• Scaffolding: Provide pre-labeled reservoir cards with empty flux arrows for students to complete during the Flux Card Sort.
• Deeper: Have students program a simple spreadsheet model to predict ocean carbon uptake under different temperature scenarios using data from the Ocean Carbon Model.

Key Vocabulary

Carbon Sink	A natural reservoir that accumulates and stores carbon-containing chemical compounds for an indefinite period, removing carbon dioxide from the atmosphere.
Carbon Source	A reservoir that releases carbon-containing chemical compounds into the atmosphere, increasing atmospheric carbon dioxide levels.
Photosynthesis	The process used by plants and other organisms to convert light energy into chemical energy, absorbing carbon dioxide from the atmosphere and releasing oxygen.
Respiration	The process by which organisms release energy from organic molecules, often involving the consumption of oxygen and the release of carbon dioxide as a byproduct.
Silicate Weathering	The breakdown of silicate rocks through chemical reactions with atmospheric carbon dioxide and water, a slow process that removes CO2 from the atmosphere over geological timescales.