>>16696474 (OP)Straight up fear mongering! Just ponder how many percent of new species replaced them.
As individuals are getting smaller since the dinosaurs, possibly allowing for more diversity, there's no thing as extinction but rather regeneration.
Looking at an ecosystem simulation (like 'foxes and rabbits') it's easy to conclude there's no reason to worry about a final extinction from human activity. Even after a nuclear war, radiation-hardy lifeforms would just make the new foundation for further evolution.