Climate Change 3.1-3.2

• The atmosphere is a thin layer of gas that surrounds the Earth
• It protects us from harmful radiation
• Layers of the atmosphere:

  • Troposphere
  • Stratosphere
  • Mesosphere
  • Thermosphere
• Composition of the atmosphere:

  • Nitrogen: 78%
  • Oxygen: 21%
• Greenhouse gases include:

  • most abundant greenhouse gass Water vapor (H2O)
  • Carbon dioxide (CO2)
  • Methane (CH4)
• Troposphere (up to 12 km):

  • Almost all weather and clouds occur here
  • 15% of the air is in this layer
  • Air pressure drops and temperature decreases with altitude
• Stratosphere (12 km - 50 km):

  • Ozone layer is found here
  • Warmer than the troposphere due to UV energy
• Mesosphere (50 km - 85 km):

  • Meteors burn up in this layer
  • Very thin air
• Thermosphere (500 km - 1,000 km):

  • Thickness varies with solar activity
  • Extremely thin air
  • Low Earth orbit satellites orbit in this layer
• Exosphere:

  • Where the atmosphere merges into the vacuum of space
• Greenhouse effect is a process that keeps the Earth's surface warm
• Most energy reaching Earth from the sun is visible light energy
• Energy from the sun reaches Earth in the form of visible light, and the atmosphere is largely transparent to visible light
• Light energy is absorbed by the Earth's surface, heating it up, and then radiates back out to space in lower frequency infrared radiation
• Advantages of the greenhouse effect:
• Maintains temperature for living things
• Serves as a filter for unwanted solar energy
• Helps in growing or sustaining plants throughout seasons
• Solar-powered operations benefit from the greenhouse effect
• Earth's energy budget is the balance between the amount of energy incoming to Earth from the sun and the energy outgoing from Earth back to space
• Incoming solar energy is measured in Watts per square meter (W/m2)
• Solar energy is reflected away by white clouds, ice, or absorbed by the atmosphere
• Solar energy that reaches the ground warms the Earth's surface
• Warm ground and oceans release this heat back into the atmosphere in the form of infrared or thermal radiation
• The amount of infrared radiation emitted depends on temperature
• Clouds and gases absorb infrared energy and emit it as radiation both into space and back onto the Earth's surface