A team of researchers from Australia and Finland has published in the journal PLOS a modeling study of the consequences of releasing ancient pathogens from melting glaciers and permafrost. Professor Corey Bradshaw from Flinders University and Giovanni Strona from the University of Helsinki ran thousands of computer simulations to assess what would happen if glacial archives of microorganisms were to enter modern ecosystems. The results show that even a minimal percentage of viable and aggressive pathogens could inflict serious damage on biodiversity and trigger the mass die-off of modern organisms.
Historical precedents: from 750,000-year-old bacteria to the anthrax outbreak
The ability of microorganisms to remain viable in glacial confinement has already been confirmed by a number of field studies. In 2003, on the Qinghai-Tibet Plateau, scientists revived bacteria from an ice core that was more than 750,000 years old. In 2014, the giant virus Pithovirus sibericum was extracted from Siberian permafrost, having spent roughly 30,000 years in a frozen state. The most dramatic real-world incident was the anthrax outbreak in Western Siberia in 2016: an abnormal thaw released Bacillus anthracis spores from the carcasses of dead reindeer, leading to the death of thousands of animals and the infection of dozens of people.
Methodology: thousands of simulations in the Avida environment
To quantify the risks, the study's authors used specialized software called Avida, designed for modeling evolutionary processes. In the experiment, they simulated the invasion of a single type of ancient virus into modern communities of host bacteria, varying the pathogen's adaptability, competitiveness, and replication rate. Each simulation reproduced population dynamics under conditions as close as possible to real ecological niches, allowing the researchers to track how a foreign agent interacts with already established communities.
Key figures: 3% adaptation and 30% population loss
After thousands of runs, the researchers found that in roughly three percent of cases the ancient pathogen successfully adapted to the new environment, evolved, and took a dominant position in the ecosystem. In the worst realistic scenarios, the appearance of a foreign virus led to a 30 percent reduction in the population of modern hosts compared with a control group that was not subjected to invasion. The authors emphasize that, although the share of catastrophic outcomes looks small in absolute terms, it is precisely this figure that becomes critical against the backdrop of the enormous volume of microorganisms being released.
Why a "small percentage" becomes a global risk
Estimates suggest that around four sextillion (10²¹) microorganisms are released into the environment each year from melting ice. Even if only one percent of them turns out to be viable and potentially aggressive, the absolute number of such particles remains astronomical. This creates a high probability of local and, upon accumulation, global ecological crises. The researchers conclude that ancient pathogenic microorganisms could become a new powerful driver of species extinction, one that has not yet been accounted for in traditional climate models and biodiversity change scenarios.
Direct risks to humans: what is known and what is missing
It is important to note that this study did not assess direct risks to human health. However, the authors point to a worrying pattern: most of the known dangerous viruses — SARS-CoV-2, the Ebola virus, HIV — entered the human population precisely through contact with animal carriers. In summary, the researchers warn that a thawed virus is capable of crossing the species barrier without losing its destructive properties, meaning that the ecosystem consequences of melting glaciers could, in the long run, transform into epidemiological threats to humans.
