4.12 - Greenhouse Effect

- a) UV light from the sun - sort wave length or high energy 
- b) 50% of this light is reflected back into space (plants reflect)
- c) absorption on the surface - UV --> infrared 
- d) infrared light - long waves 
- e) lost to space as heat 
- f) greenhouse gases (water vapour, CO2, methane) 
- g) infrared light hits the GHG and absorb the energy then reemits it in all directions, including downwards 
     - The ones that go down towards the surface are what cause the temperature to rise. 


Enhanced greenhouse effect 
if you raise the levels of GHG they will absorb more of the escaping infrared radiation and emit it backwards towards the earth. - High temperatures so climate change. 


CFCs - ozone layer 
           - Carbon, Florine, Chlorine
Cl3F ---sunlight---> CCl2F- +Cl-      = this breaks down O3 into O2. 
- O3 is much better at absorbing UV light


 - depletion of the ozone layer