In the long term
I said that as far as I understood, reefs had on quite a few occasions in recent geological history been quite resilient over tens of thousands of years. Looking ahead, human activity (direct impacts and pollution, global warming, ocean acidification) might not wipe out reefs altogether or at least not the capacity of some corals and other organisms to build new reefs. But recovery and renewal - if it came - might be quite a long time in the future, perhaps several thousand more years. In the meantime the consequences could be grave.
"Ah yes", said Morton (who has written a book about Mars and keeps this blog), "I tend to think on much longer geological timescales".