Climate: A Delicate Balance
Lesson 4 Questions
Test your knowledge of Earth's radiation balance by working through the following questions. Refer back to the lesson pages and learning tools as needed.
What is a Radiation Balance?
- What are the factors that cause Mars, Earth, and Venus to have such different climates?
- Why is it important for a planet to have a radiation balance?
- What is a blackbody radiator?
- Compare the frequencies, wavelengths, and energies of infrared, visible, and ultraviolet radiation.
- Challenge: Considering the relative energies of IR, visible and UV radiation, which do you think is the most dangerous for humans to be exposed to? Why?
Incoming Solar Radiation
- The primary source of all of Earth’s energy is the sun. We rarely think of the energy we use on a daily basis to light our lamps or heat our houses as coming from the sun. Is it correct to say that ALL of our energy comes from the sun?
- Recall the “Build a Planet” simulator. How does increasing the distance from the sun affect overall incoming radiation?
- What type of electromagnetic radiation is used by plants in photosynthesis?
- Describe three possible fates of visible light photons entering Earth's atmosphere from the sun.
Reflection of Solar Radiation
- What does the term albedo mean?
- If 50% of Earth's ice cover melted, what would the effect be on Earth's albedo? How would this affect Earth's temperature?
- Is albedo different in various regions of the world, or is it constant for the whole planet?
- Challenge: Can you describe three human processes that might reduce the albedo of certain regions?
Emission of Infrared Radiation
- What type of radiation is primarily emitted by the earth? Why doesn’t the Earth emit visible light and glow like the sun?
- Challenge: Do light bulbs emit energy of a higher or lower frequency than Earth?
- What is a mirage?
- Challenge: Many stories that take place in desert regions describe characters in the desert as going mad and seeing mirages. Why might mirages appear more in deserts than in the tundra or in a forest?
- Consider the radiometer images of Earth above. When comparing the left image (reflected radiation) with the right image (emitted infrared radiation), what do you notice about the areas of reflection and emission? Are they similar or different?
The Greenhouse Effect
- How would Earth's radiation balance (the balance between incoming and outgoing energy) change if there were no greenhouse gases in Earth's atmosphere? How would Earth's temperature be affected?
- Describe the characteristics of greenhouse gases.
- Challenge: Determine which of the following atmospheric gases have the ability to act as greenhouse gases: carbon dioxide, oxygen, water, nitrogen, methane, ozone, sulfur dioxide, and nitrous oxide. What makes these gases greenhouse gases?
- Explain the difference between the natural and the enhanced greenhouse effect.
- Challenge: Describe three types of greenhouse gases that are produced by human activities.