Funny, I always thought hot fluids rise. Guess I need go back to chemistry class.
Not to validate their malarkey, but if you heat the surface of a liquid, conduction can transfer the heat to greater depths.
Skip chemistry and try physics ;-)
Amazing isn't it.
Hot salty water will sink under cooler water of lower salinity. The study I saw said that salinity is at record high levels, which means the process has not yet peaked and can likely accommodate much more heat input before it is overwhelmed. The ocean is what we scientists like to call “very big.”
This is a process that self regulates, and is yet more evidence that the Earth has several overlapping systems that keep temperatures relatively stable.