The whole reason to do anything about the acidification is that it's "not natural". Nature adapting to changing circumstances is the very definition of what nature is. You can't have it both ways.

Plus it won't be catastrophic at all. Some very low-level species, like algae, will adapt by changing their internal chemistry. And because we eat them (through intermediaries) we will have effectively adapted too.

And don't you believe in evolution ? If this doesn't happen, then we die, and in that case we should die. The whole point of creation is that it adapts to these sort of things. Adapt or die. Works on a large scale as well as a small one.

That is not the reason to worry about acidification. The reason is that we like coral reefs, and don't want them to die out. Not only are they beautiful, they are great sources of biodiversity (good for research), and they protect many sea-level human installations like shipping harbors and city waterfronts.