What do you say when they tell you it's hopeless?

My first draft of what I wanted to say about the quotation below was so desparing that it had to be struck out.  I will let the quotation to stand as it is, for you to draw your own moral lessons from it as you prefer.    
The statement comes from one of the world's authorities on coral reefs, Roger Bradbury, an ecologist specializing in resource management at Australian National University:   

"the global coral reef ecosystem — with its storehouse of biodiversity and fisheries supporting millions of the world’s poor — will cease to be.  Overfishing, ocean acidification and pollution are pushing coral reefs into oblivion. Each of those forces alone is fully capable of causing the global collapse of coral reefs; together, they assure it.  The scientific evidence for this is compelling and unequivocal, but there seems to be a collective reluctance to accept the logical conclusion — that there is no hope of saving the global coral reef ecosystem.

You can't say it more clearly:  The global coral reef system is dying.
What do we say to that?  And are other conditions in our environment approaching such a state?  What is there to do about such trajectories?