Chemicals involved:
-Carbon Dioxide (CO2)
-Methane (CH4)
-Water Vapour (H2O)

The Greenhouse effect is when the layer of gases; carbon dioxide, methane, water vapour trap the sun’s radiation in earth, and let some out; This keeps the earth warm. The enhanced greenhouse effect is when there is an excess (extra, or too much) of the greenhouse gases in the atmosphere, so less of the sun’s radiation escaping, resulting in a temperature rise on earth.
For example, the carbon dioxide from our cars goes into the atmosphere, adding to the greenhouse gases, and enhancing the already enhanced greenhouse effect.