Well, we realy know little about how it works. We can only observe it over a long time and point out that this or that has changed. The fact that we have studied the weather accurately for only a very short time hinders any opinions we may form about it.
However, we know that global warming will melt the Antarctic causing fresh water to mix with salt water. This would aparently cause the stream of warm water to stop flowing and probably cause another ice age.
Your best source of information would be: The world wide web virtual library.