Greenhouse Effect and Greenhouse Gases

Overview

• Objective: Understand the greenhouse effect in terms of short and long wavelength radiation.
• Focus: Identify the main greenhouse gases.

Atmospheric Composition

• Main Gases:
  • Nitrogen: 78%
  • Oxygen: 21%
  • Other Gases: 1%
• Variable Component:
  • Water Vapor: Changes with temperature
• Greenhouse Gases:
  • Carbon Dioxide: ~0.04%
  • Methane: Tiny amounts

Greenhouse Gases

• Key Greenhouse Gases: Water vapor, carbon dioxide, methane
• Exam Tip: Be prepared to name these gases as greenhouse gases.

The Greenhouse Effect

• Radiation from the Sun:
  • Travels as short wavelength radiation (e.g., ultraviolet, visible light).
  • Some reflect back into space.
  • Most pass through the atmosphere as they do not interact strongly with gas molecules.
• Earth's Surface Interaction:
  • Absorbs energy and emits it as long wavelength radiation (e.g., infrared).
• Interaction with Greenhouse Gases:
  • Long wavelength radiation interacts with greenhouse gases.
  • Energy is absorbed, trapping heat in the atmosphere, thus increasing temperature.

Importance of the Greenhouse Effect

• Life Support:
  • Maintains Earth's temperature to support life.
  • Without it, Earth would be too cold for most organisms.

Future Topics

• Upcoming Focus: Changes in greenhouse gas levels and their effects on Earth.

Additional Resources

• Revision Workbook: Available through the provided link in the video.