It is the fate of most living things eventually to go extinct. The species diversity now is almost certainly greater than it ever has been in the past, but paleontologists tell us that more than 99% of the species that have ever lived are now extinct.
Some take comfort that we seem to have recovered from the great extinctions of the past
We're still here, these people would argue, and the world doesn't look so bad. Until a few years ago, I argued that the fossil record showed that recovery from these extinctions took a long time.2 But reanalysis of the record of Phanerozoic diversity for marine invertebrates [8,9] suggests that the apparent delay in recovery could be an artifact of the incompleteness of the fossil record. The recovery of biodiversity may, in fact, be geologically instantaneous, i.e., on the order of 5 million years or less.
So the optimist in me says that we are very unlikely to destroy life on this planet and that the diversity of life will recover fairly quickly once we are gone. The pessimist in me points out that I don't want to live in a world that has substantially less diversity than the one I live in now, and that even if life's diversity recovers instantaneously from the perspective of deep geological time, it's not likely to happen on a time scale of any interest to human beings.3 To me, that means we want to do what we can to reduce the rate of extinction, ideally to a rate 10-100 times lower than it is now.4