"working with what we know, some of the very bases for the idea that the planet is warming in the first place, we can tell that the sea surface has warmed through consistent satellite "
ah, sea surface has warmed, in other words the currents that distribute and normalize ocean temp and salinity differentials are in a state of flux.
Well now you know what causes El Nino.
Carry on.
that's what el nino is not what causes it.
proceed.
That is very likely what causes El Nino, not what it is.
The oceans are systems that are constantly out of balance with large differentials between water temp and salinity from region to region. Inputs into the system are completely irregular, yet the system itself is bound to normalize these continual imbalances. The solution is simple, redistribute sea water toward equilibrium, it happens naturally based on the density of water.
But unlike river that have to follow valleys to exchange water to it's natural level the oceans are a 3 dimensional matrix of awesome scope. Water currents can travel in any direction across a 3 dimensional spherical plane and being driven by varying inputs they can't possibly maintain tight regularity. Chaos will be the natural result.
So when an El nino occurs, or a La Nina,
surface water temps may increase or decrease, but by no means does that mean that the ocean itself is warmer or colder. Only that the water on the surface is warmer or colder.
Which merely points toward a change in the way ocean waters are circulating. Pretty much a non event in an ocean that should be expected to continually adjust the pathways of circulation within it's vast body.
But even such a non event can have profound effects on the climate of the planet.
Not that I suggest this kind of nuance effects macro climate changes like ace age cycles and interglacial periods, but certainly it could be potent enough to effect short term cycles like mini ice ages in particular regions of the globe or mere decades long periods of apparent climate change.