4.12 Greenhouse Effect

recall that water vapour, carbon dioxide, nitrous oxide, methane and CFCs are greenhouse gases

(letters below represent the letters on the diagram)

a) UV light from the sun- short wave lengths or high energy.

b) 50% of light is reflected back into space- main cause is the clouds.

c) absorption on the earths surface- UV light converted and emitted as infrared.

d) infrared light (longer waves) emitted back outwards.

e) some of light is lost into space as heat.

f) some of the greenhouse gases- water vapour, carbon dioxide (CO2), methane (CH4)

-infrared light will hit the greenhouse gas and it will absorb the energy and it will re-emit it but in all directions including downwards to surface- which raises the surface temperature higher.

enhanced greenhouse effect.

-if we raised the levels of polluting gases (eg. CO2, CH4) then they will absorb more escaping radiation and emit it backwards towards earth- raising the temp- which leads to climate change.

-CFCs (chlorofluorocarbons)- well known for effect on ozone layer.

-Carbon Fluorine Chlorine.

-CCl3F -----sunlight----> CCl2F-+Cl-       =this breaks down O3 into O2.

-O3 is much better at absorbing UV light than O2.