Evolution has a fast mode and a slow mode. The fast mode is that if there is enough genetic diversity in the population that a subset have a combination of tra

Evolution has a fast mode and a slow mode. The fast mode is that if there is enough genetic diversity in the population that a subset have a combination of traits that suffices, natural selection quickly will reduce the genetic diversity and all of the survivors will have those traits. The advantage of sexual reproduction is that much of the genetic diversity is retained and gets to recombine in interesting ways allowing the next challenge to be addressed. The slow mode is that if overcoming a barrier requires random mutations to produce new traits, it takes many generations for that to happen. The current pH allows some to survive and others not to. But with projected future pH levels, none will be able to survive. Therefore natural selection will select out the entire population as there isn't enough time for a new set of traits to evolve.