1. Human Energy Systems Unit Activity 3.2
Tell students that this activity helps us understand why scientists and other people care about the Keeling Curve.
The Greenhouse Effect

2. The Greenhouse Effect CO2 CO2 CO2 CO2 CO2
The Greenhouse Effect is a naturally occurring phenomenon that helps keep our planet warm. The greenhouse effect is important! It helps us survive.
CO2
CO2

3. The Greenhouse Effect CO2 CO2
Light energy enters the atmosphere. Light energy from the sun can pass through the atmosphere and go all the way to the earth’s surface.
Teacher Note: “Light energy” from the sun refers to the the sun’s electromagnetic radiation, which includes ultra violet radiation (among others). Ultraviolet radiation is shortwave and can pass through the atmospheric particles without getting trapped.

4. The Greenhouse Effect CO2
Light energy from the sun interacts with the earth’s surface, and is returned to the atmosphere in the form of infrared radiation. Some of this energy is trapped by greenhouse gases, which keeps the earth warm. Some goes back to space. The earth’s atmosphere contains many types of greenhouse gases, including carbon dioxide. When these greenhouse gases trap infrared radiation, the planet stays warm.
Teacher Note: There are many greenhouse gases. In this unit, we focus mainly on carbon dioxide because this is the product of fossil fuel combustion. Other greenhouse gases include methane, nitrous oxides, fluorinated gases, and others.

5. What do you think will happen to the temperature of the earth if we add more greenhouse gases to the atmosphere?
CO2
CO2
CO2
CO2
Question: What do you think will happen to the temperature of the earth if we add more greenhouse gases to the atmosphere?
CO2

6. Additional greenhouse gases trap more infrared radiation from Earth’s surface.
CO2
Additional greenhouse gases trap more infrared radiation from the earth’s surface.

7. So where do additional greenhouse gases come from?
This causes the planet to heat to unnatural temperatures (global warming), which causes our climate to change.
So where do additional greenhouse gases come from?
The addition of more greenhouse gases causes the planet to heat to unnatural temperatures (global warming), which causes our climate to change.

8. Burning fossil fuels releases CO2
Coal
Gasoline / petroleum
Have students come up with examples of fossil fuels before sharing the examples on the slide.
Natural gas

9. Fossil Fuel Use over Time
Have students make predictions and interpret the graph before explaining the patterns in the data.
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10. CO2 and Temperature
Use this graph to point out that increases in CO2 in the past 120 years correlate with global temperatures.
This graph is taken from the 2013 Draft National Climate Assessment, which can be found here:
That might not sound like a lot, but this is almost ten times faster than any other naturally occurring warming periods (that come after ice ages) in Earth’s history.