Screener: The Carbon Budget

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Task Title: Balancing the Global Carbon Budget

Grade: High School (9-12)

Date: 2026-04-18

Criterion A. Tasks are driven by high-quality scenarios that are grounded in phenomena or problems.

i. Making sense of a phenomenon or addressing a problem is necessary to accomplish the task.

  1. Is a phenomenon and/or problem present?

Yes. The rise of atmospheric CO2 (Keeling Curve) despite the existence of natural carbon sinks.

  1. Is information from the scenario (simulation) necessary to respond successfully to the task?

Yes. Evidence about the magnitudes of fluxes (photosynthesis/respiration) and the long-term trends of reforestation versus combustion must come from simulation data.

ii. The task scenario is engaging, relevant, and accessible to a wide range of students.

Features of scenarios Yes Somewhat No Rationale
Scenario presents real-world observations [x] [ ] [ ] Uses the Keeling Curve and the “1 Trillion Trees” policy debate.
Scenarios are based around at least one specific instance [x] [ ] [ ] Focuses on the global carbon budget balance.
Scenarios are presented as puzzling/intriguing [x] [ ] [ ] Poses why natural sinks can’t “keep up” with human inputs.
Scenarios create a “need to know” [x] [ ] [ ] Students need to quantify fluxes to evaluate climate solutions.
Scenarios effectively use at least 2 modalities [x] [ ] [ ] Uses graphs, data tables, and dynamic arrow diagrams.
The local, global, or universal relevance is made clear [x] [ ] [ ] Directly addresses the global climate crisis.
Evidence of quality for Criterion A: [ ] No [ ] Inadequate [ ] Adequate [x] Extensive

Criterion B. Tasks require sense-making using the three dimensions.

i. Completing the task requires students to use reasoning to sense-make about phenomena or problems.

Students must reason that adding CO2 at a faster rate than it can be absorbed leads to disequilibrium, even if absorption rates increase.

ii. The task requires students to demonstrate grade-appropriate dimensions:

Evidence of SEPs: Students use Developing and Using Models to illustrate the cycling of carbon among the four spheres.

Evidence of CCCs: Students analyze Systems and System Models to explain how human activities disrupt the natural feedback loops of the carbon cycle.

Evidence of DCIs: Students demonstrate understanding of Cycles of Matter and Energy Transfer in Ecosystems (LS2.B).

Evidence of quality for Criterion B: [ ] No [ ] Inadequate [ ] Adequate [x] Extensive

Criterion C. Tasks are fair and equitable.

i. The task provides ways for students to make connections of local, global, or universal relevance.

The task asks students to evaluate real-world climate policy (reforestation), connecting classroom science to global challenges.

iii. The task is accessible, appropriate, and cognitively demanding for all learners.

Features Yes Somewhat No Rationale
Task includes appropriate scaffolds [x] [ ] [ ] Guide steps lead from observation to complex argumentation.
Tasks are coherent from a student perspective [x] [ ] [ ] The focus on “budgeting” carbon is a clear and consistent framing.
Tasks use accessible language [x] [ ] [ ] Concepts like “fluxes” are visualized clearly in the tool.
Evidence of quality for Criterion C: [ ] No [ ] Inadequate [x] Adequate [ ] Extensive

Criterion D. Tasks support their intended targets and purpose.

Assessment Purpose:

Evidence of quality for Criterion D: [ ] No [ ] Inadequate [ ] Adequate [x] Extensive

Overall Summary

The task is highly effective at having students model a complex system. It avoids superficial climate change discussions by forcing students to look at the actual carbon fluxes and reservoir totals, leading to a mathematically grounded understanding of the carbon cycle.

Final recommendation: