what's the difference between global warming and the greenhouse effect?

Global warming is a general term for exactly what it says: the increase in average temperatures across the world.

The Greenhouse Effect is one particular phenomenon which may be contributing TOWARDS global warming.

Global Warming is the greenhouse effect, gone wild.

Global Warming starts with the greenhouse effect.  In a greenhouse the light passes through the glass and the heat carried by it is trapped inside the greenhouse making it more of a pleasant environment for the plants.  The carbon dioxide does the same thing in our atmosphere; and it is the 4th most common gas in our atmosphere.  So only a slight change in it makes a big difference.

Global Warming continues when the ice sheets melt.  All that white reflective snow will be replaced with darker land that will absorb more heat so if you pass a certain tipping point you will have a run away effect.  Also with global warming the frozen ice now melts and ends up in the sea covering ports and most of Florida.

Salt water is heavier than fresh water so all that fresh water being dumped into the oceans could affect the water currents and that can increase effects like El Nina or El Nino, which are warm areas of the Pacific off of South America.

Finally, global warming will cause most of the North Pole to disappear, leaving the Polar Bear homeless.  The species could either go extinct or move south becoming a problem in Canada and Siberia.

It does have one advantage in that new lands will be uncovered which can be developed and maybe even new resources can be found there; but that benefit will be offset by the loss of some of the most expensive real estate in the world (like Manhattan Island or Tokyo).

The Greenhouse Effect is the trapping of Heat from the sun's rays in the earth. Like in a greenhouse, its walls and ceilings trap the sun's heat inside, proving energy for plants, which is good. But in earth's case, it's bad, very very bad. it causes Global Warming. Global warming is the state where earth's temperature is higher than normal, causing polar ice to melt, making tides rise. All in all, the difference (besides spelling, pronunciation, and syllabication) between Global Warming and Greenhouse Effect is that Global Warming is CAUSED by Greenhouse Effect. so there, satisfied? be happy to be of any help ^_^