What we DO know, is the main cause of the mass ocean death. The increase in atmospheric CO2 (global warming) causes a rise in sea levels, and increases the acidity of the oceans, 2 key factors (in the overall gangbang) that was the Permian extinction. This increase in acidity was devastating, particularly in the 96% fatality rate of sea creatures, a great majority of which were calcium fixing shellfishlike creatures. With the higher acidity, these animals couldn’t form shells and died out over several millenia.
I think that the key take-away here is how long and drawn out an extinction event is, typically. I doubt any echinoderm knew what was happening during its short life, but I think we can draw better conclusions than an ocean proto-starfish, and maybe theorize that we are seeing some similar things that happened in past extinction events. The fact remains that ocean acidification was a key part in what killed off the ocean creatures back then, and we are seeing the ocean becoming more and more acidic. These are all theories, yes, but we can only theorize to the events that happened then, and the best fossil evidence greatly suggests the change in Ocean pH being a major factor.
The Permian extinction was a hollywood blockbuster of changing ocean pH, rising sea levels and temperatures, massive volcanic activities, possibly a meteroic event (still a very early theory), and huge releases of trapped methane under the ocean. It was basically all of your doomsday scenarios happening over a short few million years. While this was catastrophic for many land vertebrates and large bugs, the therapsids (proto-mammals) weathered the climate change much better.
God I wish we could still have giant bugs.
One interesting thing is that right before most extinction events there is a tremendous boom in biodiversity, and if this “sixth extinction” is happening right now, I don’t think we had the Permian “burst” that happened before it. This is probably due to the earth, over millions of years, recovering exponentially from the previous mass extinction with massive amounts of biodiversity. If you look at the extinction timeline, we have basically flattened off as a planet as of now, I don’t know what that is the case.
I think it would be foolish and naive to not draw at least some parallels to what extremely quick climate change is occurring now to catastrophic past events, but obviously things are not equivalent today to what they were back then. And while I personally think we are on the slippery slope of a mass extinction event, we can all know that it will probably take at least tens of thousands of years to happen, and if we aren’t in space by then, by golly, we deserve to die.