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Human Energy Systems | Lesson 3 - Explaining Connections between Patterns

Lesson 3: Explaining Connections between Patterns

Students examine the relationship between atmospheric CO2 and atmospheric temperature rise.

Guiding Question

How do we know atmospheric CO2 is increasing, and what does that do to global temperatures?

Activities in this Lesson

  • Activity 3.1 Millions of Flasks of Air (25 minutes)
  • Activity 3.2 The Greenhouse Effect (20 min)
  • Activity 3.3 Correlations between Earth Systems (20 min)


  • Locate organic and inorganic carbon pools near the Earth’s surface (atmosphere, biomass, soil, fossil fuels, and ocean).
  • Describe pools as changing in size over time.
  • Explain changes in atmospheric CO2 in terms of fluxes associated with carbon-transforming processes: combustion, photosynthesis, cellular respiration.
  • Describe carbon cycling within Earth and Human systems.
  • Identify carbon fluxes associated with human economic activities.
  • Identify energy transformations involved in carbon fluxes.
  • Trace energy associated with human lifestyles to its sources, particularly combustion of fossil fuels.
  • Describe energy as flowing through Earth systems, from sunlight to chemical energy to heat that is radiated into space.
  • Explain the consequences of lifestyle and energy system choices for changes in atmospheric CO2 concentration.

NGSS Performance Expectations

Middle School

  • Waves and Electronic Radiation. MS-PS4-2. Develop and use a model to describe that waves are reflected, absorbed, or transmitted through various materials.
  • Earth's Systems. MS-ESS2-1. Develop a model to describe the cycling of the Earth’s materials and the flow of energy that drives this process.
  • Human Impacts. MS-ESS3-4. Construct an argument supported by evidence for how increases in human population and per-capital consumption of natural resources impact Earth's systems.
  • Earth and Human Activity. MS-ESS3-5. Ask questions to clarify evidence of the factors that have caused the rise in global temperatures over the past century.

High School

  • Ecosystems: Interactions, Energy, and Dynamics. HS-LS2-5. Develop a model to illustrate the role of photosynthesis and cellular respiration in the cycling of carbon among the biosphere, atmosphere, hydrosphere, and geosphere.
  • Earth’s Systems. HS-ESS2-2. Analyze geoscience data to make the claim that one change to Earth’s surface can create feedbacks that cause changes to other Earth systems.
  • Weather and Climate. HS-ESS2-4. Use a model to describe how variations in the flow of energy into and out of Earth’s systems result in changes in climate.
  • Earth and Human Activity. HS-ESS3-5. Analyze geoscience data and the results from global climate models to make an evidence-based forecast of the current rate of global or regional climate change and associated future impacts to Earth systems.
  • Earth and Human Activity. HS-ESS3-6. Use a computational representation to illustrate the relationships among Earth systems and how those relationships are being modified due to human activity.

Background Information

In this Lesson, students examine key foundational knowledge about how CO2 interacts with energy in the atmosphere. In order to understand the longer chain of events that leads to arctic sea ice decrease and sea level rise, students must first understand that (a) we have evidence that CO2 is increasing in the atmosphere, and that (b) greenhouse gases interact with long-wave radiation coming from the Earth’s surface in ways that increases temperatures.

Our goal for the unit as a whole is to help students explain relationships between multiple Earth Systems, but this will take several lessons. The goal of this lesson is to helps students identify the causal relationship between atmospheric CO2 concentrations and temperature (the greenhouse effect), and to establish the problem for a deeper study of the Keeling Curve.

In Activity 3.1 students learn about a scientist named Charles Keeling by reading a short story and listening to a radio broadcast. These stories explain how Keeling’s research alerted the global community to the fact that atmospheric CO2 is increasing, and what work lead to the discovery of this important information. Previously, students used the graphs but did not yet know how the data were collected.

In Activity 3.2, students examine the greenhouse effect. This gives them the first piece of evidence they need to eventually explain that increasing atmospheric CO2 is the driving factor among the multiple Earth systems they examined in the previous lesson. This causal chain of events includes the greenhouse effect, or the interaction between greenhouse gases and long-wave radiation coming from Earth that traps heat in the atmosphere.

In Activity 3.3, students use a concept map to document their ideas about the relationships between different Earth systems at this stage in the unit. With their new knowledge of the greenhouse effect, this should begin to resemble a scientific explanation for the relationship between increases in atmospheric CO2 and temperature rise, but they may not yet be able to explain how temperature rise causes sea level rise and arctic ice melt.