I enjoyed reading this because of your perspective and focus as a marine specialist. I typically write from a more "climate systems" perspective in which oceans are just one of multiple systems.
At root, the problem is that the oceans are rapidly heating up.
Starting around 1985, the oceans have been accumulating the equivalent of five Hiroshima class atomic bombs worth of heat energy PER SECOND.
There are 31,536,000 seconds in a year, which means about 157,680,000 Hiro’s worth of energy was getting pumped into the oceans each year.
But even that can be hard to grasp other than intellectually. One hundred and fifty-eight million is just too big a number to relate to in visceral terms.
So, here’s an even easier way to visualize it.
The surface area of the world’s oceans is roughly 139 million square miles. Which means that between 1985 and 2015.
The world’s oceans absorbed the equivalent of 1.15 Hiro’s per square mile, every year. Or a total of 33 atomic weapons worth of energy FOR EVERY SQUARE MILE OF OCEAN ON EARTH.
Since 2015 the rate of warming has doubled to 0.36C per decade.
The Oceans are now absorbing 1O Hiros per second of energy.
The ONLY way to save the oceans is to stop additional CO2 emissions. It should be the ONLY issue that any of us care about at this point.