EarthLabs > Climate and the Carbon Cycle: Unit Overview > Lab 2: The Carbon Cycle > 2B: Carbon - Going Global!

The Carbon Cycle: What Goes Around, Comes Around

Part B: Carbon - Going Global!

In Part A, you examined how carbon moves through a forest carbon cycle. In this activity, you will explore the larger more complex global carbon cycle using the interactive below.

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Examine the carbon cycle interactive diagram with a partner. Here are some hints to help you use the interactive:

Checking In

  • Identify the four largest reservoirs of carbon. (Hint: Largest in this case refers to the number of gigatons or carbon. Remember that one gigaton(Gt) of carbon equals one billion metric tons. You will need to click on the reservoir tabs to find this information.
    The four largest reservoirs of carbon are: sedimentary rock, deep ocean, coal, oil,and gas, and soil and organic carbon.
Now that you are familiar enough with using the carbon cycle interactive, you are ready to start the global carbon cycle activity.

Materials you will need are:

In this group activity, you will follow carbon's journey through two of the many carbon pathways within the global carbon cycle. One carbon journey should be on a shorter time scale - days to hundreds of years. The other carbon journey should be on a much longer time scale - thousands to millions of years.

Follow the five steps below and be prepared to present your fast and slow carbon journey to the class or another group.

With your partner or group do the following:
  1. Choose one of the many reservoirs to start your carbon journeys. Hint: Besides the arrows on the diagram, there are clues in the information pop-ups that may tell you where the carbon goes next.
  2. Determine a journey your carbon atoms will take, starting from your entry point. There are multiple carbon cycle pathways for you to choose from. For example, a carbon atom released from a tree may go through any one of the terrestrial pathways or one of the ocean pathways or both.
  3. Your carbon journey must begin and end at the same reservoir. For example- if your carbon journey started in the atmosphere, it must end in the atmosphere.
  4. Create a flow chart of your carbon's journey
    • Identify the processes and reservoirs on your chart.
    • Indicate the number of gigatons of carbon stored in the reservoirs on your flow chart, if available.
    • Identify which Earth-system component the reservoirs are in.
  5. As you draw your arrows between the reservoirs, think about about how long it takes for these carbon atoms to move from one reservoir to another. For example, a carbon atom can stay in sedimentary rocks for millions of years before moving to a different carbon reservoir. This would be an example of a "very long, slow time scale." If the information is available, indicate a time scale for movement of carbon in your carbon journey.
    • Fast carbon cycle ( These carbon journeys take between days to hundreds of years)
    • Slow carbon cycle ( These carbon journeys take between thousands of years to millions of years)
  6. Prepare for your 5 minute presentation to the rest of the class. In your presentation, you will need to do the following:
    • Describe the journey through the reservoirs and processes. What processes move the carbon out of one reservoir into another.
    • Does the carbon change from one type of carbon compound to another when it moves between reservoirs. For example, it may start off as a gas and change to a solid, or carbon may be present in one reservoir as carbon dioxide but in another reservoir may be a complex organic carbon compound such as carbohydrate sugar, calcium carbonate or a hydrocarbon.
    • What organisms are involved (if any) and what is their role in moving and storing the carbon in the two pathways you have chosen.
    • How long does the carbon stay in the reservoirs? What are the time scales for carbon moving from one reservoir to another?


In a class discussion, talk about the following:
  1. Does carbon move fastest through the biosphere or the geosphere? What evidence from the pathways supports your answer?
  2. Carbon dioxide in the atmosphere is a greenhouse gas and is responsible for making our atmosphere and global climate as warm as it is today. Which processe(s ) have the greatest potential to warm our climate further? Why?
  3. Many countries are cutting down forests to make way for agriculture and roads. How might this practice disrupt the carbon cycle?
  4. The world's population has passed the 7 billion mark. As the population increases, the need for energy will increase. More coal, gas and oil will be burned to provide that energy. How might this disrupt the global carbon cycle? Why?

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