Imagine that the coral reefs were going extinct. How long would it reasonably take to go from full health to gone? 1 year, 10, 100? Geologically speaking, having an entire biome wiped out in 100 years is insanely fast.

The point is that it may well be under grave threat your entire life and still exist when you die. That doesn't mean it isn't under grave threat. There have been northern white rhinos in existence my entire life. There still are presently: 2 -- both female. Last chance to see...