Ocean as climate hero

Lesson overview

This lesson focuses on carbon sequestration and its role in mitigating climate change. Students will explore three major carbon stores: forests, blue carbon ecosystems, and the continental shelf. The lesson introduces key concepts such as carbon stores and carbon burial, using relatable comparisons to help students grasp the scale of carbon sequestration in nature.

The main activity is a decision-making exercise where students analyse different climate action strategies. They will evaluate options ranging from protecting existing habitats to changing global food systems, considering factors such as carbon storage potential, feasibility, and economic impact. The lesson concludes with a class discussion where students present and defend their chosen strategies, encouraging critical thinking about complex environmental issues.

Learning outcomes
  • Explore how we know about the ocean through science
  • Understand how ocean and coastal habitats help store carbon
  • Find out how humans can disrupt the capture and storage of blue carbon
  • Judge the importance of protecting blue carbon habitats

This lesson requires students to have access to an atlas, detailed world map, or online map.

Lesson steps

1. Recap and the Convex Seascape Survey (10 minutes)

Introduce the lesson and learning objectives using slide 2. Connect to the previous lesson’s learning on the continental shelf using the prompt questions on slide 4. The aim is to get students to mention carbon sequestration and some of the human activities that may disturb this carbon store.

Use slides 5 to 8 to remind students of the main points around carbon sequestration and nature-based solutions to climate change. Slide 7 emphasises the importance of long-term carbon storage in the sediment and soil.

Introduce the work of the Convex Seascape Survey, working to find out more about the sediment carbon of the continental shelf using slides 9 to 12. Should you wish to give students more information about how carbon ends up on the seabed use slide 13 to show the main sources. Of these options, the most important are rivers and glaciers bringing carbon from land and biological processes in the ocean, where phytoplankton absorbs carbon dioxide and is eaten by zooplankton and larger animals. Faeces and dead bodies and structures sink to the bottom of the ocean, contributing to the sediment, in a process known as marine snow.

2. Carbon store quiz (5 minutes)

The decision-making exercise later in the lesson compares solutions that variously look at carbon storage and burial in three main habitats: land forests, blue carbon (mangroves, saltmarshes, and seagrasses), and the continental shelf.

Slides 15 to 20 contain whole class quiz questions to bring these habitats to the fore of students’ minds and compare their size and the total carbon stored.

3. Carbon definitions (5 minutes)

Depending on the ability of your class and their prior learning, use slides 22 to 26 to brief the class on units and terms used in the decision-making exercise. These definitions are also mentioned on the Student Sheet Climate debate activity.

4. Climate debate: analysing options (20 minutes)

For the main decision-making exercise, divide the class into seven groups, so that there is one group per option on Student Sheet Climate debate cards. Hand out the Student Sheets and any other materials.

Either allow students to choose their own option, or run this activity closer to a balloon debate and assign a different option to each group.

Use slides 28 and 29 and the information on Student Sheet Climate debate activity to brief students, and clarify any misunderstanding.

5. Climate debate: presentations (15 minutes)

Student groups present their chosen option to the class. There may be time for students to ask further questions. After students have finished presenting, if you are using a balloon debate format, ask students to vote on the best presentation / preferred option. Remind students that they cannot vote for themselves!

6. Conclusion and Reflection (5 minutes)

End the lesson using the reflection questions on slide 31:

  • If you had a magic wand which climate action, would you choose to happen immediately and why?
  • If you had a magic wand which climate action, would you choose to happen immediately and why?
  • If you met the Prime Minister, what would you ask them to do based on today’s lesson?
Home learning

Ask students to research a real-world example of a carbon sequestration project or policy. They should prepare a short report explaining the project, its impacts, and how it relates to the strategies discussed in class.

Notes on data

The data for this lesson is from several sources. Data for carbon stores and carbon burial rates is based on estimates published in research. For blue carbon habitats, and especially for the continental shelf, there are few samples and high spatial variability. Mid-range figures have been used where possible, and more research is needed for greater accuracy. Having stated this caveat, students will be able to gauge that:

  • Forests represent large carbon stores in vegetation and soil and play an important role in continuing to capture and store carbon.
  • Blue carbon habitats (mangroves, saltmarshes, and seagrasses) represent a much smaller area than terrestrial forests, but have a far greater capacity for carbon burial on an annual basis.
  • The continental shelf, being the busiest area of seabed for human activity, is the ocean sediment ocean store at greatest risk for human disturbances. However, research is much needed for greater accuracy in quantifying this carbon store, analysing its spatial variability, and understanding the flows and levels of carbon into the continental shelf sediment.

The papers and articles used for estimates in this lesson are: