Here I corrected what I think was a bit off... You do not need to use "the" with Earth, Sun, Moon and other planets because they are one of a kind, but it's optional.
The Greenhouse effect is a term which describes the global warming ON Earth. It is A naturAL phenomenon triggered BY the sunbeams as they enter our atmosphere, so THE RESULT is relatively constant temperature on the Earth. But humans can influence this naturAL phenomenon by increasing the presence of gases in the atmosphere. Because gases are important factors they let the sun beams pass through to the SURFACE, which then reflects the sunlight back. So when the amount of gases is rising, the sunlight will stay in our atmosphere. The RESULT is an increase in temperature. This process is similar to the one that is used to grow vegetables in areas WITH COLD CLIMATE.
You can also add that it's called a "greenhouse effect" ;)
Hope I helped