Why ocean warming can not be caused by global warming

Recent ocean warming over the past century and a half can not be caused by alleged CO2-induced global warming for three main reasons:

1) Most of the warming occurred before the time of significant atmospheric CO2.

2) The warming occurs 100s of metres deep down – too deep for that warmth to have come from the surface – and is so disparate from ocean to ocean as to suggest local or natural causes, not a global one like AGW.

3) The magnitude of the ocean warming is some 45 times that of the air in energy terms. If you believe that a change in air temperature can produce a 45 times larger change in ocean heat content then you believe CO2 is a magic molecule, which climate scientists do. (Officially climate scientists say about 1/5 of that 45x is due to humans but it's a sheer guess).

What the above suggests is that the oceans are very influential in 20th century warming rather than AGW.