4.12 Greenhouse Effect

Key points:
1. A represents UV light from the sun, short wavelength or high energy. B represents that about 50% of the light is reflected back out into outer space. C represents absorption on the earth's surface, where the UV light is converted into infra-red. D is when the infra-red light (long wave) being emitted back outwards.
2. F represents some of the greenhouse gases such as water vapour and CO2, and the infra-red hits the greenhouse gas and it will absorb this energy and it re-emits it in all directions, including downwards. So it remits infra-red but it redistributes with some of those waves hitting the surface raising the temperature a bit higher.
3. Enhanced greenhouse effect is where if the levels of greenhouse gases are increased, they will absorb more infra-red and deflect it back to the earth causing higher temperature and climate change.
4. CFCs, chlorofluorocarbons are well known for their effect of the ozone layer, some layers of gases O3

CCL3F ---> with sunlight ---> CCL2F- + CL-

The CL- catalyses the breakdown of O3 gases to O2, and this affects it because O3 is much better at absorbing UV Light than O2, and were effectively removing the protection of the ozone layer.