Are you asking for evidence of environmental utility provided by reef systems? There are plenty and my sister post already mentioned some of them.
But the metric of "does putting in all this money and effort to fix the problem we created give us something back in return?" is absolutely poisonous. It's that selfish "is preserving this environmental habitat that has been around for millions of years worth my time or money?" that allowed us to dig this grave in the first place.
I'm speaking of environmental impact. Sure, things may be looking good if you look at base crime statistics, hunger statistics, and war statistics. But certainly not if you look at the bigger picture. Way too many unknowns at this point in terms of consequences for unchecked industrialism for us to simply say, "Yep, things are good here."
But I'll bite. What metric are you using to say things are better than ever?
We are healthier than ever, living longer than ever. More of our babies are surviving for longer, even in the poorest places on Earth.
We are using more renewable energy, less coal. Every year we add more solar/wind capacity than the past decade (just a guess). Soon, driverless electric cars will transport people autonomously, without creating any pollution, and road accidents will dwindle down to ~0.
More people have access to clean water, modern medicine, and we have treatments/preventions for the deadliest of diseases.
You're focusing on positive aspects of the modern areas of the modern world. Not all of the world is so peachy keen.
Yes, we live with countless blessings. But this is in spite of continued industrial negligence and increasing international economic pressure.
In spite of the fact that our wages increasingly do not match our economic contributions, while the costs of living continues to rise just about everywhere in modern countries. In spite of increasingly militarized police states engaging in targeted socioeconomic suppression across the globe.
In spite of many, many things.
I want to have optimism for the future, too. But I'm not going to ignore the multitudes of problems we face today, and will face tomorrow.
Coral reefs are like the rainforests of the sea: they hold an immense amount of biodiversity and life. They are also a carbon sink:
>Coral reefs play a critical role in the carbon cycle of our planet, by taking calcium ions and dissolved carbon dioxide from the water and turning it into calcium carbonate forming their hard skeleton. http://www.reefrecovery.org/coral-reefs/
