A Simple Greenhouse Climate Model

The greenhouse effect is the warming of the planet that results from the radiative properties of the atmosphere. Use the interactive simple climate model on this page to answer the following questions. If you do not understand the terms used in the question, you might need to go to the alcove entrance and review previous material. Some definitions are also available for quick review.

Instructions on what you can vary in the model are given below.

QUESTIONS

• Why does the surface temperature change with a change in solar output?
• Explain why changing the planet's albedo modifies the planet's surface temperature.
• Can the surface temperature be less than the planet's emission temperature?
• If you increase the solar output, how can you decrease the surface temperature?
• Why does surface temperature increase with increasing atmospheric infrared emission?
• How might clouds impact the surface temperature?

Instructions:

You control three variables of this simple model: the atmospheric infrared emissivity, the planetary albedo, and the energy output of the Sun. The atmospheric emissivity is the ratio of the radiant energy emitted per unit time per unit area by the atmosphere to the energy emitted by an ideal blackbody at the same temperature. As you vary these parameters the emission temperature of the planet and the temperatures of the surface and atmosphere change. All temperatures are plotted on a graph as a function of altitude.