10 m of seawater over the globe contains about the mass of the entire atmosphere. A nice big sink, that's for good.
However, the ocean temp cannot explain the glacial melting that occures. Glacial melting basically goes with the air temp, while both affect the sea ice. But melting sea ice does not raise SL.
So, glacial melting is also a very good indicator on temperature development in our hemosphere. Either way, the result is the same, - warming.
Now this is happening at a time when the sun has a cold. So higher up in the atmosphere, we do have a cooling. AFAIK.
You may say, "well, it's colder than last year or before", that may be true, since many a record was broken in 2007. New records were not to be made, so the graph goes down, but it's still in it's place, don't let the perspective confuse you.