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Human Energy Systems | Activity 3.3

Activity 3.3: Why We Care About the Keeling Curve (20 min)

Students share their ideas about climate change through an anonymous assessment and discuss the connection between the greenhouse effect and global warming.

Resources Provided


Prepare a computer with a projector to display the PPT. Print one copy of 3.3 Explaining Relationships Between Earth Systems Worksheet per student.


1. Have students recall ideas about the relationship between CO2 and temperature.

Remind students that in the previous activity they examined the mechanism called the “greenhouse effect.” Ask volunteers to explain in their own words what the greenhouse effect is.

  • Use student ideas to construct a group explanation for the greenhouse effect.
  • Listen for and highlight key ideas: short-wave radiation entering Earth’s atmosphere passes through GHGs; long-wave radiation is emitted into the atmosphere after it interacts with the Earth’s surface; long-wave radiation interacts with GHGs which causes an increase in temperature.


Use the 3.3 Grading the Explaining Relationships Between Earth Systems Worksheet as a guide during the small and large group discussions in this activity. Because the goal of the conversation is consensus, try to encourage the class to discuss any ideas that diverge from the scientific explanation. By the time they have finished constructing their written explanations, they should be able to point to increasing CO2 levels as the driver of all Earth systems on the worksheet, which causes increased global temperatures, which in turn causes sea level rise and arctic ice melt.


Have students sit in small groups of 3-4 during the introduction to the worksheet so that they have an opportunity to discuss possible relationships between the graphs before sharing out with the class. From the first group, you can have one person from the group report out their thoughts. The next (and remainder of the) groups can either agree or share other ideas they have about relationships between the graphs. If conflicting ideas arise, have students talk to each other to evaluate the differences – ideally they should be able to reach consensus.

Extending the Learning

From the worksheet, students can research and list other evidence that supports the relationships they identified between the four graphs.