The below is part of some comments I made at Climate Etc to JCH and Jim D:
CO2 density is higher than before above the oceans. The ocean emits a photon that hits CO2 a higher percentage of the time. Half the time when the CO2 emits the same photon it ends up back on the surface of the ocean. If it misses the ocean it may later still end up back there after some more jumps. I suppose that assuming a random direction the photon migrate to places with less GHGs. Upwards I suppose. They can make longer jumps on average into less dense areas. So it seems that the additional CO2 can swat the photons more effectively back into the ocean. The more CO2, the more the oceans are slowed with their LW photon emissions. The oceans are a very important source of warmth. On the other hand since the surface is warmer it can emit more than before, perhaps canceling CO2s swat back enhancement. And on one more hand, I suppose the photons can travel downwards through the water. I am assuming photons on the ocean surface radiate in all directions.
I just checked out RealClimate on the question. It is now more difficult for photons to escape the ocean on average. The oceans are storing heat they receive as short and long wave. However shortwave has been pretty flat. So we are looking at primarily the change in longwave IR. Most of it attributed to GHGs. Assuming for long periods of time 90% of the warming is going into the oceans what is going to reverse that? We could assume in 1950 0% of the warming was going into the oceans, or if not, go back to 1850. This thing as explained at RealClimate, why would it stop? The CO2 will be around keeping more heat in the oceans. Yes it is possible and ocean circulations do change and that could change things. Jim D you said something about reaching a balance. So the oceans need to gain heat to restore the balance, and then we’ll be at equilibrium. In doing so they are going to have to save some heat for themselves. Which leaves me thinking they will do that. Taking the same watts as they did in 1950 and releasing less of them to the atmosphere.
Peter Minnett at RealClimate has an article that has a diagram that says more heat remains in the upper oceans. There is a new temperature gradient across the skin layer. So the balance needs to be restored by emitting less LW photons to the atmosphere. On average and all other things being equal, atmospheric CO2 insulates the atmosphere from ocean warmth. However, sea ice gains or losses are not considered.
Additional commet of mine added 2/09/17:
It occured to me that if we take the instant reemission of energy from the skin layer as a given which a do not, we have increased evaporation and increased salinity. A kind of instant evaporation suggested leaves behind salt which make the warmer water heavier which makes it sink more than before. Warmth moved further from the surface would make the oceans a bit warmer as there is less joules emitted to the atmosphere with that.