> The time scale for new species adapted to a completely new climate is many millions of years, not a few thousands. What we destroy today won’t be replaced whi

> The time scale for new species adapted to a completely new climate is many millions of years, not a few thousands. What we destroy today won’t be replaced while humans as a species as we know it today even exists. When it comes to changing climate (and some degree of pollution) instead of newly evolved adaptations you get migrations or selection for particular alleles. Adjust up and back down and you can end up with diversity constraints on both ends.