The scary thing is that these reefs are so incredibly diverse & their creation took millions of years. Millions of years to create and they can be globally destroyed in just 200 or so years.
It's also scary is to consider what else may be balanced just as precariously.
Slight increases make it impossible for some creatures to create shells. Those creatures are key parts of the food chain, which means that fisheries (already under sever pressure from over-fishing) risk total collapse.
http://news.nationalgeographic.com/news/2014/05/140502-ocean...
http://www.pmel.noaa.gov/co2/story/What+is+Ocean+Acidificati...
But not all species are going to be vulnerable to this. Some grow thicker shells. http://www.whoi.edu/oceanus/feature/ocean-acidification--a-r...
> Under very high experimental CO2 conditions, the shells of clams, oysters, and some snails and urchins partially dissolved. But other species seemed as if they would not be harmed, and crustaceans, such as lobsters, crabs, and prawns, appeared to increase their shell-building (see interactive).
The entire discussion around coral reefs has been going on since I was young and can remember(at least 20-odd years). It was always emotional (think of the children level guilt-tripping, almost), and was always "assumed" and dictated. There was never any convincing, discussing; it was just the way it is and we as young children were to accept it.
And despite all of that, we as a society have spoken the other way around and gone ahead and potentially ruined the delicate environment required for these creatures. It's who a majority of us are. Perhaps not who we should be, or who we'd like to be, but this is largely of our doing and our inability to convince those in power and the rest of society to protect the things we value.