It suggests to me that sea-surface temps have little to do with air temps and what's going on in the atmosphere but plenty to do with underwater temps and circulations.
Critical atmospheric conditions are mostly visible (clouds) and measurable (air temps at various heights), so as surface dwellers we focus on these. But measurements of temperature, salinity and density at various levels and sites in the sea aren't perhaps as comprehensive. And while sea-surface currents may be measurable, knowledge of underwater circulations appears to me to be at best imprecise and at worst a mystery. I mean, I understand the principle of sampling compounds in the water and calculating when they were last exposed to air, but there's a hell of a lot of water out there to be sampled, even in the Channel.
And as a huge body of liquid (the sea) retains heat for longer than a huge body of gas (the atmosphere), we could be talking about changes which took place decades or even centuries ago which are only now reaching the surface of the sea.
So to answer the question in the opening post: I don't know.
Originally Posted by: some faraway beach