I don't understand this type of skepticism, in the absence of indications to the contrary I would expect the claim for the article to be true: environmental cha

I don't understand this type of skepticism, in the absence of indications to the contrary I would expect the claim for the article to be true: environmental change means changes in niche for both micro and macro organisms. So natural selection pressure will optimize towards a new nearby optimum. Compared to macro organisms, micro organisms have shorter life cycles (so more generations per unit of time) and higher body counts (the number of elephants must necessarily be dwarfed by the number of bacteria, since a single elephant will have numerous bacteria on its skin alone...) So micro organisms are buying natural selection lottery tickets both in bigger bulk as well as at higher frequency compared to macro organisms. Normally thats not a problem, since both micro and macro organisms were effectively equilibrated to a long-term relatively stable niche, so it didn't matter that micro-organisms and macro-organisms converged to their respective optima at different rates, since they were already near optimum. That difference in convergence rate will become clear as the optimum shifts location.