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Human Energy Systems | Activity 6.3

Activity 6.3: How Our Decisions Affect Earth’s Future (30 min)

Students use graphs of projections from computer models to consider the impacts of increasing atmospheric CO2 on Earth’s systems and on living things.

Resources Provided


Prepare a computer with a projector to display the presentation. Print one copy of Big Idea Probe: What Would Happen if We Cut Fossil Fuel Use in Half? per student if you are using it.


1. Review how carbon emissions are impacting global climate systems.

Tell students in this unit we have been examining how and why carbon emissions are increasing in our atmosphere. But what is that doing to Earth’s systems?

  • Open the 6.3 How Our Decisions Affect the Earth’s Future PPT and display slide 2. Remind students of the systems they studied in Lesson 2 of this Unit.
  • Use slide 3 to review how rising atmospheric CO2 intensifies the greenhouse effect and increases global temperatures, which in turn lead to sea level rise and decreases in Arctic Sea ice.
  • Use slide 4 to explain that if we could lower CO2 emissions then we could also have an impact on global temperature rise, sea ice melt, and sea level rise.
  • Use slide 5 to review what students learned from using the Simple Climate Model in Activity 6.2. (1) If CO2 emissions stay constant at current levels (about 10 GtC/year) atmospheric CO2 (and thus temperature) would continue to increase, and (2) we would have to significantly decrease CO2 emissions in order to stop the upward trend of atmospheric CO2.
  • Use slide 6 to review the imbalance in carbon pools and introduce the driving question: What will happen to Earth’s systems if we don’t reduce carbon emissions?


Listen for the students’ ideas about uncertainty in the predictions for sea level rise, global temperature, and arctic sea ice. How do they explain uncertainty in climate models?


The Human Energy Systems Unit provides a foundation for understanding how human activities are increasing atmospheric CO2 and how that leads to increased temperatures and other effects (sea level rise and declining Arctic Sea ice).  This unit has barely scratched the surface of many important questions that you may want to explore further. Below are some ideas:

  • Climate change mitigation:What can we do to decrease CO2 emissions and the amount of CO2 already in the atmosphere?

Resource: Mitigation of climate Change video (about 12 minutes):

  • Effects of climate change:How will the effects of climate change affect humans and other living things?

Students can research the effect of climate change on something that is personally interesting to them. Some examples include: extreme weather such as storms and droughts, agriculture and food production, changes in animal habitats and breeding seasons, spread of mosquito-borne illnesses (malaria, Dengue Fever, West Nile virus, and Zika Virus), ocean acidification, effects of sea level rise on coastal habitats or flooding of human cities.

  • Climate models:How were the RCP scenarios developed and how do scientists use them?

Resource: The Beginner’ Guide to Representative Concentration Pathways:

  • Climate feedbacks:How will changes to one Earth system affect others?

Students could research how the following phenomena are related to positive and negative climate feedbacks: ice and land reflectivity (albedo), clouds, plant growth, and precipitation.

  • Media literacy:Are the arguments about climate change presented in news stories based on reliable data?

Students can use what they learned in this unit to evaluate and critique the claims, evidence, and reasoning about climate change that are presented in the news, magazines, or websites.