Essentially we are landlubbers. For us the oceans are a strange place. Sure we can navigate them, but we do not understand how they function, or the life that’s in it (we are still at the "hunter/gatherer" stage, as far as the oceans are concerned (we do some farming along the coasts). A large amount of biomass is in the oceans http://bit.ly/RB6HTn
Belatedly, we are getting around to exploring the links between climate change and changes in the oceans.
One first area is its chemistry: we only began to focus on ocean acidification ten years ago or so. Small shifts may be devastating for life in the oceans, in particular unicellular structures like algae and microbes and in general phyto/zooplankton.
Another area is changes in the behavior of sea currents. We’ve heard the “scare story” about the Gulfstream stopping and bring an ice age to Europe. The dance between El Niño, la Niña and the monsoons is reaching our awareness.
The third major are is the evaporation of the oceans. For that’s where rain comes from, mostly. Here is a short article on the complexity of studying such phenomena http://bit.ly/RB6HTn It’s a good introduction to the subject, but barely: pollution, in particular the films of hydrocarbons on the water surface left by boats as they travel, can wreak havoc with the models.
We won’t know for quite a while the full extent of these processes – and expect the unexpected along the way.