PROBLEMATIC PATHOGENS

Ancient pathogens escaping from melting permafrost have real potential to damage microbial communities. In computer simulations, the ancient invading pathogens could often survive and evolve in the modern community, and about 3 percent became dominant. While most had little effect on the composition of the larger community, about 1 percent yielded unpredictable results. Some caused up to a third of the host species to die out. The risks posed by the 1 percent of released pathogens may seem small, but given the sheer number of ancient microbes regularly released into modern communities, outbreak events could still be powerful drivers of ecological change and threats to human health. This doesn’t take into account the deaths in 2016 from anthrax released from Siberian permafrost. AN IMPENDING CALAMITY is a novel about that. 

https://phys.org/news/2023-07-time-traveling-pathogens-permafrost-pose-environment.html
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8463397/