1. Heat in the Atmosphere

2. Methods of Heat Transfer
Heat in the atmosphere can be moved around in 3 main ways:
Conduction = transfer of heat through matter by molecular activity
This happens when things are directly in contact with each other

3. Methods of Heat Transfer
Convection = transfer of heat by movement of a mass from one place to another
This happens when hot air rises and cool air falls
Radiation = transfer of heat in all directions from a heat source
We get energy from the sun this way

4. Solar Radiation
All energy that heats our atmosphere ultimately comes from solar radiation
This radiation is emitted along the whole electromagnetic spectrum
The most important types of radiation for our atmosphere are visible light, infrared (IR), and ultraviolet (UV)

5. Solar Radiation
When solar radiation enters the atmosphere, only 20% of the IR radiation is absorbed by clouds and the atmosphere
50% is absorbed by land and water
The remaining 30% is lost back into space either by reflection (like a mirror) or scattering (like a white wall)

6. Reflection of Radiation
Reflected radiation does not help heat Earth’s atmosphere
The amount of radiation reflected from a surface (land, water, clouds) is called its albedo
Dark surfaces like asphalt do not reflect much radiation and light surfaces like clouds reflect more radiation

7. Absorption of Radiation
Heat from radiation is absorbed by specific gases in the atmosphere
Oxygen and ozone absorb UV radiation
Water vapour, CO2, methane, are called greenhouse gases (GHGs) because they absorb IR radiation and heat most of the atmosphere

8. Absorption of Radiation
They radiate this energy back towards Earth and increase the temperature of the atmosphere
This is called the greenhouse effect because it is similar to what happens to trap heat within a greenhouse

9. Climate Change
Climate change occurs because the atmosphere is warming much faster than would naturally occur = enhanced greenhouse effect
The changes in atmospheric temperature have resulted in shifts in weather patterns and changes in regional climates
All of the effects of climate change are not known, but we have already seen some in the increase in extreme weather events and droughts worldwide