The carbon cycle and climate

Lesson overview

In this introductory lesson, we look at the scientific processes and concepts of the carbon cycle. This will enable students to grow prior knowledge of food webs, respiration, and photosynthesis, as well as the combustion of fossil fuels into a more complete model. The lesson starts with an exercise to illustrate the range of different forms of carbon and carbon compounds and where they are found. This is followed by a gamified exploration of the carbon cycle. Key vocabulary and an understanding of the carbon cycle and its link to climate change is developed through a dominos task and short answer questions.

Learning outcomes
  • Identify where carbon can be found
  • Describe ten basic processes of the carbon cycle
  • Demonstrate their understanding of carbon stores and movement between them
  • Link increasing carbon in the atmosphere to climate change
Lesson steps
  1. What do we know about carbon? (5 mins)
    Take five minutes at the start of the lesson to allow students to share their current knowledge about carbon using the slideshow prompt questions as a starting point.
  2. Where is carbon? (10 mins)
    Use the Student Sheet Where is carbon to guide students through the different forms of carbon and carbon compounds. Students should then work individually or in pairs to consider where these different forms of carbon can be found. A plenary review, using the slides, can be used to correct students’ work.
  3. How does carbon move around the planet? (15 mins)
    Students need not be fully familiar with all the processes involved in the carbon cycle to play the Carbon dice activity. Students should work in groups of four and record their movements individually. It is important to take time to review this activity, emphasising that there is no set movement for carbon, as well as stressing that the formation of fossil fuels and rocks (creation of locked up carbon) is a long-term process that takes millions of years. It is also important to stress that combustion of fossil fuels is the only human process included in this simplified carbon cycle, and as such has caused an imbalance in the natural processes (see note below for further details). This links to students proper appreciation of the link between the carbon cycle and climate change. The interactive carbon cycle diagram can be used to support this lesson stage.
  4. Carbon dominos (10 mins)
    The carbon dominos activity is designed to consolidate an understanding of the processes involved in the carbon cycle. Definitions and further information are included in the Knowledge Organiser for this lesson.
  5. Why does this matter? (10 mins)
    Students are prompted to think about how the carbon cycle has changed and how this has affected the planet. In short, an increase in the combustion of fossil fuels has increased atmospheric concentrations of carbon dioxide. Approximately 30% of anthropogenic carbon emissions have been absorbed into the ocean. This has caused ocean acidification, with a decrease in ocean pH by 0.1pH since the Industrial Revolution, a 30% increase in acidity. Students should know about the associated increase in global temperatures, and be reminded that 90% of the heat increase has been absorbed by the ocean. Students can consolidate their learning answering the questions in class or as home learning.
  6. Learning review (10 mins)

    Students can review their learning using the review pyramid, and share learning as a whole class plenary.

Notes on human impacts

The only human process included in this simplified carbon cycle is the combustion of fossil fuels. There are other human impacts that have caused imbalance in the carbon cycle from land-use change and agriculture, fisheries extraction, to construction and cement production. These have not been included in this lesson aimed at a key stage 3 (ages 11-14) audience.

It should also be noted that when teaching the carbon cycle, combustion can be used as a short-hand for fossil fuel combustion. Where possible use the full term fossil fuel combustion or explain that combustion refers specifically to the burning of fossil fuels. This is to differentiate this process from the combustion of vegetation in wild fires, although it can be argued that this process has also been supercharged by human-induced climate change.


To extend students’ knowledge about ocean acidification see lessons from the Frozen Oceans | Science | Ages 11-14 unit.