Shoutbox

I think you need to ask your teacher again to explain it properly then, because CO2 or whatever gas (might not be CO2 itself but accompanying gasses) sure contributes a big part of it, although indirectly. Or he is actually talking about something else, like how the earth regulates its own "termostat" so to speak to keep temperature somewhat balanced (as that is very roughly speaking what the oceans do). But that the oceans are responsible to the global warming is a bit wrong I think.

Global warming is not something which is been going on since the start of time (in fact, it would be more like global cooling if anything). Global warming is what we understand about the rapid (most likely unnatural) warming up of the earth as the result of the green house effect.