The Terrestrial Carbon Cycle:
A Role-Play
Overview
This activity is an adaptation of Please Pass the Carbon (Activity 4 from the Climate Change Back Pack,
http://www.sciencecentercollaborative.org/backpack.php) and is designed to enable students to visualize the terrestrial
carbon cycle and the human activities that lead to increased carbon dioxide in the atmosphere. To conclude this activity,
students are presented with the Keeling curve that shows atmospheric carbon dioxide increasing and seasonal fluctuations
in atmospheric carbon dioxide due to the onset of photosynthesis in the northern hemisphere in the spring. For simplicity,
the terrestrial carbon cycle is depicted in isolation from the aquatic carbon cycle; ideas for having students investigate the
aquatic carbon cycle as a culminating activity are presented.
Courses
Biology; Earth and Environmental Science
North Carolina Standard Course of Study for Biology
• 5.02 Analyze the flow of energy and the cycling of matter in the ecosystem.
• 5.03 Assess human population and its impact on local ecosystems and global environments.
North Carolina Standard Course of Study for Earth and Environmental Science
• Objective 2.07: Analyze the sources and impacts of society's use of energy.
• Objective 5.03: Analyze global atmospheric changes including changes in CO2, CH4, and stratospheric O3, and the
consequences of these changes.
Essential Questions
• What path does a carbon molecule take through the terrestrial ecosystem?
• What is the role of cellular respiration and photosynthesis in the carbon cycle?
• What human activities influence the amount of carbon dioxide in the atmosphere?
• Is the global atmospheric carbon dioxide concentration increasing or decreasing?
Materials
• Carbon Cycle Visual from textbook or Internet
• Signs for participants to wear (atmosphere, producers, soil, rock, fossil fuel deposit, deforestation, fossil fuel
consumer)
• 27 hand held items that are easy to see, hold, and pass (pencils, cups, pom-poms, etc.)
• Reforestation Headpiece, optional
• The Keeling Curve, Student Worksheet and Teacher Key
Student Preparation for Activity
Optional: Instruct students to create a visual of the carbon cycle individually or in small groups prior to this activity.
Duration
15-20 minutes
Procedure
1. Project a visual of the carbon cycle at the front of the room. Inform the class that you are going to lead a role-play to
help them visualize the terrestrial carbon cycle and to demonstrate how human activities are impacting the carbon
dioxide concentration in the atmosphere.
Adapted by UNC-Chapel Hill’s Environmental Resource Program
http://www.ie.unc.edu/erp/index.cfm
1
2.
Ask for five student volunteers to come to the front of the room and provide each person with a sign. Each participant
will assume the role of that carbon reservoir/sink: atmosphere, producers, soil, rock, fossil fuel deposit.
3.
Using the table below as a guide, give each participant the amount of pom-poms representative of their carbon
reservoir (the participant serving as rock will hold a sign stating 105,000 tons of carbon). Each pom-pom represents
one ton of carbon.
Reservoir
Atmosphere
Number of Pom-Poms
3
Producers
Soil
3
6
Rock
105,000
Fossil Fuels
15
4.
Prompt the volunteers to begin the role-play by asking the following questions:
• “How do organisms in terrestrial ecosystems acquire carbon?”
Plants are the producers in terrestrial ecosystems and obtain CO2for photosynthesis from the atmosphere and
incorporate it into sugars and other organic molecules.
• “Who needs to give a pom-pom away to represent this process?”
The person playing the role of the atmosphere will pass one pom-pom to the person playing the role of
producers.
• “This is the person you will pass to during this role play.”
• “How do consumers obtain carbon then?”
Consumers acquire carbon containing molecules by eating plants or other animals that have eaten plants.
Both plants and animals utilize these molecules for energy and then release CO2 back to the atmosphere
through the process of cellular respiration.
•
“Where does the carbon go when a plant or animal dies?”
Dead organic matter is stored in the soil as humus.
• “Who needs to give a pom-pom away to represent this process?”
The person playing the role of Producers will pass one pom-pom to the soil.
• “This is the person you will pass to during this role play.”
• “How do terrestrial ecosystems release most of their carbon?”
Microbes in the soil are involved in decomposition of dead organic matter into CO2 through cellular
respiration. Also, all living organisms release CO2 to the atmosphere through the process of cellular
respiration.
• “Who needs to give a pom-pom away to represent this process?”
The person playing the role of soil will pass one pom-pom to the atmosphere.
• “This is the person you will pass to during this role play.”
5.
Ask the volunteers to begin passing one pom-pom at a time in this order to represent the global terrestrial carbon cycle:
atmosphereÆ producers Æ soil Æ atmosphere. All three individuals pass and receive one pom-pom at a time. After
a few cycles, ask the group to stop passing- each person should still have the same number of pom-poms that they
started with. This represents a stable carbon cycle.
6.
Next, ask the class “Why did rocks and fossil fuels not directly participate in this cycling activity?
Rocks and fossil fuels play a role in the long term cycling of carbon.
•
•
Fossil fuels are derived from dead plants that have been buried underground for long periods of time – they would
remain there for millions of years if it weren’t for extraction by humans for energy.
Underground rocks provide a large reservoir of carbon – holding on to carbon for millions of years only to be
released to the atmosphere during a volcanic eruption.
7. Ask for two additional volunteers to come to the front of the room. One participant will represent deforestation, and the
second will represent a fossil fuel consumer; give each student their respective sign.
Adapted by UNC-Chapel Hill’s Environmental Resource Program
http://www.ie.unc.edu/erp/index.cfm
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•
•
•
•
•
•
•
8.
Next, direct the class to the fossil fuel consumer by asking, “Provide an example of something that consumes
fossil fuels.” A bus or car, a power plant.
“What is the connection between fossil fuels and CO2?”
When fossil fuels are burned CO2 is released to the atmosphere.
Ask the fossil fuel consumer to take three pom-poms from the fossil fuel deposit and give it to the atmosphere
person.
“This is the person you will pass to during this role play.”
“Next, give me an example of an activity that leads to deforestation.”
Burning trees for fuel or to clear land for housing or agriculture; removing trees for paper, lumber, and
furniture industries does not release carbon dioxide at an increased rate but it does interrupt the carbon
cycle by decreasing photosynthesis.
Ask the deforestation person to remove one pom-pom from the Producers person and give it to the atmosphere
person.
“This is the person you will pass to during this role play.”
Now ask the volunteers to continue passing the pom-poms (in the same order as before) to represent the terrestrial
carbon cycle in the presence of human activities (fossil fuel consumption and deforestation). After a few cycles, ask the
group to stop passing- the atmosphere person should have the most pom-poms. This represents a post-industrial
carbon cycle; more CO2 is present in the atmosphere than before as a result of human activities and more CO2
continues to be released to the atmosphere since these activities are on-going.
Concluding Questions
• How did these human activities impact the atmosphere?
More CO2 is present in the atmosphere and the atmosphere will warm as a result.
• What happened to the amount of carbon in the fossil fuel deposits during this role-play?
Fossil fuel deposits were depleted and not replaced and thus are non-renewable sources of energy.
• What happened to the amount of carbon stored in the Producers during this role-play?
Less carbon was stored by producers due to deforestation.
Extension: Reforestation
To show the effects of reforestation on atmospheric carbon dioxide levels, you can choose to continue this role-play:
• Present the person playing the role of Producers with a reforestation headpiece (provided, or it could also be a
green hat, or grapevine wreath, etc.) that will enable him/her to now take two carbons (pom-poms) from the
atmosphere at a time during the role-play.
• Ask the deforestation person to remove himself/herself from the role-play.
• Continue the role-play by proceeding through two to three rounds of the cycle.
• At the end of the role-play, the person playing the role of Producers will have more carbon than he/she started with
and the atmosphere person will have reduced their carbon level to some extent but not to the original pre-industrial
level (3 pom-poms). This scenario can be used to illustrate that reforestation helps to reduce carbon dioxide levels
in the atmosphere. However, reforestation efforts alone will not bring atmospheric carbon dioxide levels back to
pre-industrial levels, therefore, additional carbon dioxide emissions reduction strategies will have to be
implemented.
Culminating Activities
• Once students have a better understanding of the carbon cycle, present them with a graph (attached) of the Keeling
Curve that shows the recorded concentration of atmospheric CO2 at Mauna Loa Observatory from 1958- 2000. To
conclude this carbon cycle activity, prompt students to answer the provided questions and then open the floor for
further discussion if students have additional questions.
• Direct students to investigate the movement of carbon in a marine ecosystem and to develop their own poster or
role-play scenario. Ask students to include these terms in their presentation: atmosphere, ocean, aquatic
producers, calcium carbonate, sedimentary rock deposits, photosynthesis, cellular respiration, decomposition.
Adapted by UNC-Chapel Hill’s Environmental Resource Program
http://www.ie.unc.edu/erp/index.cfm
3
Differentiation
Students with Special Needs
• Give students additional time to complete this role-play.
• Students could be directed to view the carbon cycle animation at EPA’s Climate Change Kid’s site:
http://epa.gov/climatechange/kids/version2.html
AIG
•
Direct students to investigate the movement of carbon in a marine ecosystem and to develop their own poster or
role-play scenario. Ask students to include these terms in their presentation: atmosphere, ocean, aquatic
producers, calcium carbonate, sedimentary rock deposits, photosynthesis, cellular respiration, decomposition.
Resources
Earth Observatory: The Carbon Cycle
http://earthobservatory.nasa.gov/Library/CarbonCycle/
EPA’s Carbon Cycle
http://epa.gov/climatechange/kids/version2.html
Adapted by UNC-Chapel Hill’s Environmental Resource Program
http://www.ie.unc.edu/erp/index.cfm
4
Answer Key: Keeling’s Curve
Observe the Graph below and answer the questions that follow:
Questions:
1.
Based on the role-play you just completed, what is responsible for the rise in atmospheric CO2 concentration from
1958-2000? Release of CO2 through human (anthropogenic) activities: primarily through deforestation and the
burning of fossil fuels.
2.
Based on the role-play you just completed, what is responsible for the rise and fall of atmospheric CO2 during a
given year? Global CO2 concentration decreases in the spring when northern hemisphere plants absorb CO2 for
photosynthesis to power plant growth and development and decreases in the fall when photosynthesis ceases and
leaf decomposition occurs.
Adapted by UNC-Chapel Hill’s Environmental Resource Program
http://www.ie.unc.edu/erp/index.cfm
5
Student Worksheet: Keeling’s Curve
Name:
Observe the Graph below and answer the questions that follow:
Questions:
1.
Based on the role-play you just completed, what is responsible for the rise in atmospheric CO2 concentration from
1958-2000?
2.
Based on the role-play you just completed, what is responsible for the rise and fall of atmospheric CO2 during a
given year?
Created by UNC-Chapel Hill’s Environmental Resource Program
http://www.ie.unc.edu/erp/index.cfm
Atmosphere
Atmosphere
3 pom-poms
Producers
Producers
3 pom-poms
Soil
Soil
6 pom-poms
Rock
Rock
105,000
pom-poms
Fossil Fuel
Deposit
Fossil Fuel
Deposit
15 pom-poms
Deforestation
Fossil Fuel
Consumer
Reforestation Headpiece
cut along dashed line
staple
staple
staple
staple