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Melting permafrost poses multiple environmental dangers with unknown consequences

Scientists are warning of an increasing threat to our environment and potentially human health, due to the emergence of “time-traveling” pathogens released from melting permafrost. 

The research suggests that ancient viruses and bacteria, long trapped in ice, could break free to wreak havoc on our modern ecosystems. 

The study, led by Giovanni Strona of the European Commission Joint Research Centre, serves as yet another stark reminder of the potentially catastrophic consequences of a warming world.

Quantifying the risks of melting permafrost

The concept that these age-old pathogens could re-emerge due to thawing glaciers and permafrost isn’t new. However, the actual extent of the threat these microbes could pose to our health and the environment has remained largely speculative until now.

“Permafrost thawing and the potential ‘lab leak’ of ancient microorganisms generate risks of biological invasions for today’s ecological communities, including threats to human health via exposure to emergent pathogens,” wrote the researchers.

“Whether and how such ‘time-traveling’ invaders could establish in modern communities is unclear, and existing data are too scarce to test hypotheses.”

The team has attempted to quantify these potential risks, utilizing sophisticated digital simulations to emulate the interactions between ancient microbes and modern bacterial communities. 

Studying time-traveling pathogens

The researchers conducted a series of artificial evolution experiments in which digital constructs, representing virus-like pathogens from epochs past, invaded simulated communities of bacteria-like hosts.

The effects of these invading pathogens on the host bacteria’s diversity were then compared against control simulations where no such invasions took place. The findings were both intriguing and alarming.

What the researchers discovered 

It turns out that in these virtual experiments, many of the ancient pathogens managed to survive and evolve within the modern bacterial communities. Overall, approximately three percent of these invaders survived, evolved, and became dominant within their new environments. 

Although the majority of these dominant invaders had negligible effects on the overall composition of the wider community, about one percent of them generated unpredictable and significant outcomes.

Some of these outcomes included causing up to one-third of the host species to die out, while others unexpectedly increased diversity by up to 12 percent compared to the control simulations.

Further research is needed 

Despite the seemingly small percentage of these destructive invaders, the study warns that due to the vast number of ancient microbes being released regularly into modern communities, the potential risks could still be substantial. 

What was once confined to the realm of science fiction – the resurgence of time-traveling pathogens – could indeed pose significant threats to human health and act as potent catalysts of ecological change.

Further research is needed to fully comprehend the scale and consequences of this threat. The study is published in the journal PLOS Computational Biology.

More about the dangers of melting permafrost 

The melting of permafrost – permanently frozen ground that covers nearly a quarter of the Northern Hemisphere – presents one of the most significant yet underappreciated threats posed by climate change. 

This phenomenon not only stands to release dangerous ancient pathogens, as the study by Giovanni Strona and his team suggests, but also has the potential to instigate a series of ecological and environmental crises.

Release of greenhouse gases

Perhaps the most alarming threat from melting permafrost is the release of vast amounts of greenhouse gases, specifically carbon dioxide and methane. These gases have been locked in the frozen soil for thousands of years as part of plant and animal matter. 

As the permafrost thaws, it provides an environment for bacteria to break down this organic matter, releasing these potent greenhouse gases into the atmosphere. This could further accelerate global warming, creating a feedback loop that results in even more permafrost thaw.

Damage to infrastructure

Buildings, roads, pipelines, and other infrastructure built on permafrost are in danger of severe structural damage as the ground beneath them thaws and shifts. This presents significant logistical and financial challenges, especially in Arctic regions, where whole communities may have to relocate.

Impact on wildlife

The thawing permafrost significantly alters the habitats of many wildlife species, leading to disruptions in their feeding, mating, and migration patterns. This could have profound impacts on the biodiversity of these regions and trigger a cascade of changes throughout the ecosystem.

Sea level rise

Melting permafrost contributes to rising sea levels. This, in turn, can lead to coastal flooding, erosion, and the displacement of human and wildlife populations. It also has the potential to alter ocean currents and weather patterns, leading to far-reaching climatic effects.

Release of toxic mercury

A study published in 2018 found that permafrost soils are the largest reservoir of mercury, a potent neurotoxin, in the world. As permafrost melts, this mercury can be released into nearby rivers and oceans. From there, it impacts the aquatic ecosystems and enters the food chain, posing a significant risk to human health.

More about pathogens

Pathogens, infectious agents capable of causing disease or illness in their host organism, represent a broad group that includes various types of organisms such as viruses, bacteria, fungi, and parasites. They contribute significantly to human, animal, and plant disease across the globe.

Classification of Pathogens

Pathogens divide into four primary classes: viruses, bacteria, fungi, and parasites.


Viruses represent the smallest form of pathogens, measuring only a few nanometers in size. They cannot reproduce on their own; they require a host cell to replicate.

Viruses consist of genetic material (DNA or RNA) encased within a protein shell, or capsid. They cause a range of diseases, such as influenza, HIV/AIDS, and COVID-19.


Bacteria represent single-celled organisms with a simple cellular organization. They reproduce independently, often through binary fission, which involves splitting into two daughter cells.

Many bacteria perform crucial roles in various ecosystems, but some species cause diseases such as tuberculosis, pneumonia, and food poisoning.


Fungi, another class of pathogens, include yeasts, molds, and mushrooms. They have a more complex cellular organization than bacteria.

While most fungi are harmless or beneficial, some species can cause diseases, particularly in immunocompromised individuals. Examples of fungal diseases include ringworm, athlete’s foot, and candidiasis.


Parasites live off other organisms, called hosts, to survive. They can be microscopic, such as the Plasmodium species that cause malaria, or larger organisms like tapeworms. Parasitic diseases also include toxoplasmosis and schistosomiasis.

Modes of transmission

Pathogens spread through various means. Direct contact, such as touching or kissing, can transfer pathogens. Airborne transmission occurs when pathogens are released into the air. This typically occurs through sneezing or coughing, and inhaled by a new host.

Vector-borne transmission involves an intermediary organism, or vector. One example is a mosquito, which carries the pathogen from one host to another. Finally, pathogens can spread through contaminated water or food.

Pathogenicity and virulence

Pathogenicity refers to a pathogen’s ability to cause disease, while virulence describes the degree of damage it can inflict. Pathogens display a range of virulence, from mild to severe.

Factors affecting virulence include the pathogen’s ability to enter the host, evade the host’s immune system, and damage the host’s cells.

Pathogens and the immune system

The immune system is the primary defense mechanism against pathogens. The immune response starts with physical barriers, such as skin and mucus membranes, which prevent pathogen entry.

If a pathogen bypasses these defenses, the innate immune system responds with generalized defenses, including inflammation and fever. If these measures prove insufficient, the adaptive immune system provides a tailored response. This response creates specialized cells to fight the specific pathogen.

Treatment and prevention

Treatment of diseases caused by pathogens often involves antimicrobial drugs such as antibiotics, antivirals, antifungals, and anti-parasitics. However, the overuse or misuse of these drugs can lead to antimicrobial resistance, a growing global health concern.

Prevention strategies often focus on limiting the spread of pathogens. These measures can include hygiene practices, vaccination, and public health interventions like vector control and safe food handling procedures.

In summary, pathogens, despite their microscopic size, pose significant challenges to global health. Understanding their biology, transmission, and interactions with the immune system is crucial to developing effective treatments and preventative measures.

With the rise of antimicrobial resistance, the need for continued research and innovative solutions is more critical than ever.


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