Science · Grade 9 · Earth Systems and Climate Change · Term 3

Carbon Sequestration Technologies

Evaluating technological solutions for removing carbon dioxide from the atmosphere.

• Ontario Curriculum Expectations
• HS-ESS3-4
• HS-ETS1-3

About This Topic

Carbon sequestration technologies capture atmospheric carbon dioxide to mitigate climate change by storing it long-term in geological formations, soils, or products. Students examine direct air capture machines that chemically bind CO2 from ambient air, point-source carbon capture and storage at industrial sites, and enhanced weathering that accelerates mineral reactions to lock away carbon. These methods address the key question of slowing global warming rates through engineered carbon removal.

This topic aligns with Ontario Grade 9 science expectations for understanding Earth systems and climate impacts, while building engineering design skills to evaluate solutions. Students compare technologies on criteria like energy requirements, costs, scalability, and permanence of storage, which sharpens their ability to analyze trade-offs in real-world applications.

Active learning benefits this topic greatly because technologies operate at vast scales beyond direct observation. Student-led debates, jigsaw expert groups, and simple prototype models using household items make complex processes concrete, encourage evidence-based arguments, and connect abstract data to decision-making skills teachers aim to foster.

Key Questions

1. Explain what role carbon sequestration plays in slowing the rate of global warming.
2. Compare different carbon capture and storage technologies.
3. Analyze the feasibility and scalability of various carbon sequestration methods.

Learning Objectives

• Analyze the chemical reactions involved in enhanced weathering for carbon sequestration.
• Compare the energy efficiency and cost-effectiveness of direct air capture versus point-source carbon capture.
• Evaluate the long-term storage permanence of CO2 in geological formations versus biomass.
• Explain the role of carbon sequestration technologies in mitigating atmospheric CO2 concentrations.
• Critique the scalability challenges associated with implementing global carbon capture projects.

Before You Start

Greenhouse Gases and the Greenhouse Effect

Why: Students need to understand the role of CO2 as a greenhouse gas to grasp why its removal from the atmosphere is important.

Chemical Reactions and Conservation of Mass

Why: Understanding basic chemical principles is necessary to comprehend how CO2 is captured and transformed in sequestration processes.

Key Vocabulary

Carbon Sequestration	The process of capturing and storing atmospheric carbon dioxide to reduce its presence in the atmosphere and mitigate climate change.
Direct Air Capture (DAC)	A technology that removes CO2 directly from the ambient air using chemical or physical processes, rather than from a single source like a power plant.
Point-Source Capture	The process of capturing CO2 emissions at the source, such as from industrial facilities or power plants, before they are released into the atmosphere.
Enhanced Weathering	A process that accelerates the natural weathering of silicate rocks, which consumes atmospheric CO2 and stores it as stable carbonate minerals.
Geological Sequestration	The long-term storage of CO2 in deep underground geological formations, such as depleted oil and gas reservoirs or saline aquifers.

Watch Out for These Misconceptions

Common Misconception

Carbon sequestration alone solves climate change.

What to Teach Instead

These technologies complement emission reductions but cannot remove historical CO2 fast enough. Role-playing scenarios where students balance tech with policy changes reveals the need for integrated strategies, correcting over-reliance through peer deliberation.

Common Misconception

All sequestration methods work equally well everywhere.

What to Teach Instead

Effectiveness varies by location, geology, and infrastructure; DAC suits any site but is energy-intensive, while CCS needs suitable reservoirs. Comparison matrices in groups highlight context-specific trade-offs, helping students refine broad assumptions with data.

Common Misconception

Captured carbon escapes storage easily.

What to Teach Instead

Geological sites trap CO2 for millennia under impermeable rock layers, monitored rigorously. Building timeline models of leakage risks versus benefits builds accurate mental models, as students quantify probabilities through collaborative calculations.

Active Learning Ideas

Jigsaw: Sequestration Tech Experts

Assign small groups one technology (DAC, CCS, BECCS, enhanced weathering). Groups research key features, pros, cons, and scalability using provided articles. Regroup into mixed expert panels to teach peers and complete a shared comparison matrix.

50 min·Small Groups

Stakeholder Debate: Tech Feasibility

Pairs represent stakeholders (scientist, policymaker, industry leader, community member) and prepare 2-minute arguments on scaling a chosen technology. Hold whole-class debate with voting on most feasible option, followed by reflection on evidence used.

45 min·Pairs

Prototype Station: Carbon Capture Models

Set up stations with materials for models: vinegar-baking soda CO2 generation captured by limewater (CCS sim), plant pots with biochar (soil seq.), and fan-blown 'air' through soda straw filters (DAC). Groups rotate, test, and record efficiency data.

40 min·Small Groups

Feasibility Matrix Challenge

Individuals score four technologies on a matrix for cost, energy use, scale, and risks using rubric and data sheets. Small groups discuss and revise scores, then present top recommendation to class with justifications.

35 min·Individual

Real-World Connections

• Engineers at Climeworks are developing and operating direct air capture facilities in Iceland, which capture CO2 and store it underground through mineralization.
• Researchers at Carbon Engineering are exploring large-scale direct air capture plants that use a chemical process to capture CO2, which can then be used to create synthetic fuels.
• The oil and gas industry utilizes enhanced oil recovery (EOR) techniques where CO2 is injected into mature oil fields, providing a method for both carbon storage and increased oil production.

Assessment Ideas

Discussion Prompt

Pose the following question to small groups: 'Imagine you are advising a government on which carbon sequestration technology to invest in. Which technology would you recommend and why? Consider factors like cost, efficiency, and environmental impact in your justification.'

Quick Check

Provide students with a short case study describing a hypothetical industrial facility. Ask them to identify whether point-source capture or direct air capture would be more appropriate for this facility and to briefly explain their reasoning.

Exit Ticket

On an index card, have students define one carbon sequestration technology in their own words and list one potential benefit and one potential challenge associated with its implementation.

Frequently Asked Questions

What role does carbon sequestration play in slowing global warming?

Carbon sequestration removes CO2 already in the atmosphere or from emissions, reducing radiative forcing and buying time for ecosystem adaptation. It addresses the imbalance where emissions exceed natural sinks. Students evaluate its potential to limit warming to 1.5°C when scaled with renewables, but emphasize it works best alongside cuts in fossil fuel use for net-zero goals.

How do CCS and direct air capture differ?

CCS captures CO2 at concentrated sources like power plants before release, cheaper per tonne but site-limited. Direct air capture pulls dilute CO2 from ambient air anywhere, using chemical sorbents regenerated by heat, but requires massive energy. Comparisons reveal CCS scales faster short-term, while DAC offers flexibility for residual emissions post-decarbonization.

What are the main challenges to scaling carbon sequestration?

High costs (DAC over $600/tonne), energy demands rivaling small countries, limited storage sites, and public concerns over leaks slow deployment. Feasibility hinges on policy incentives like carbon pricing and infrastructure. Student analyses of case studies, such as Iceland's Orca plant, reveal pathways forward through innovation and investment.

What active learning strategies work best for carbon sequestration technologies?

Jigsaws and debates engage students in expert roles, promoting deep comparison of tech trade-offs. Hands-on prototypes with CO2 indicators make invisible processes visible, while stakeholder role-plays build empathy for real debates. These methods boost retention by 30-50% over lectures, as collaborative evidence evaluation mirrors scientific practice and sparks interest in green careers.