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Time-traveling pathogens from melting permafrost pose great risk to the Earth

Climate change isn’t just raising sea levels and increasing the frequency of extreme weather events. It’s also threatening to unleash potentially devastating pathogens from melting permafrost and ice that have been trapped for thousands of years.

With the permafrost melting at an alarming rate, these ancient, ‘time-traveling’ pathogens could pose a significant risk to the global environment and even humanity.

Melting permafrost and glaciers could bring back many forms of dormant pathogens. The specific extent of harm they could inflict on contemporary ecosystems remains largely unknown.

How to study time traveling pathogens

However, new research from Dr. Giovanni Strona of the European Commission Joint Research Centre and Professor Corey Bradshaw, the Matthew Flinders Professor of Global Ecology at Flinders University in Australia, provides a sobering glimpse into what the future could hold.

Their research, published today in the open-access journal PLOS Computational Biology, is the first of its kind to calculate the ecological risks posed by the release of these ancient microbes. They utilized a digital platform to simulate how pathogens from the past might interact with modern bacterial communities.

In this eye-opening study, Strona and Bradshaw carried out simulated experiments in which they released digital replicas of ancient pathogens into host communities akin to bacterial colonies. They then compared the effect of these invasions on the bacterial diversity to the results in similar communities that did not allow invasions.

What the research team found

What they found was a testament to the resilience and adaptability of these ancient pathogens. In many of the simulations, the ancient pathogens not only survived in the modern environment but also evolved. Remarkably, about 3% of these pathogens became dominant in their new environment.

The findings became more startling when around 1% of the invading pathogens caused unpredictable outcomes. Some of these pathogens wiped out up to a third of the host species. Other pathogens increased diversity by up to 12% compared to the control simulations that did not allow pathogenic invasions.

While the risk posed by this 1% may seem insignificant at first glance, considering the vast number of ancient microbes being continuously released into modern ecosystems, these events represent a tangible threat.

Great concern about time-traveling pathogens

Strona remarked, “The scientific debate on the topic has been dominated by speculation, due to the challenges in collecting data or designing experiments to elaborate and test hypotheses. For the first time, we provide an extensive analysis of the risk posed to modern ecological communities by these ‘time-travelling’ pathogens through advanced computer simulations.”

“Our findings suggest that threats so far confined to science fiction could in reality pose serious risk as powerful drivers of ecological damage,” he added, expressing concern over the unpredictable nature of these ancient pathogens.

Professor Bradshaw also emphasized the importance of their findings, stating, “Our results are worrisome, because they point to an actual risk deriving from the rare events where pathogens currently trapped in the melting permafrost and ice produce severe ecological impacts.”

He also warned about the potential for irreversible damage caused by the invasion of these ‘black swan’ pathogens. “In the worst, but still entirely plausible case, the invasion of a single ancient pathogen reduced the size of its host community by 30% when compared to our non-invasive controls.”

Humanity must act now to halt melting permafrost

He urged society to recognize the potential risk associated with the release of these ancient microbes.

“As a society, we need to understand the potential risk posed by these ancient microbes so we can prepare for any unintended consequences of their release into the modern world. The results tell us that the risk is no longer simply a fantasy that we shouldn’t be prepared to defend against.”

The tool used for these simulations was Avida, an artificial-life software platform developed by Michigan State University. This allowed the researchers to build and test the simulated release of digital pathogens into biological communities.

While this study calls for more research, it underscores the potentially dire consequences of climate change that extend beyond rising temperatures and extreme weather.

As we continue to grapple with the complexities of our changing climate, understanding the hidden threats lurking in the ancient ice is becoming increasingly urgent.

More about permafrost

Permafrost, a crucial component of the Earth’s cryosphere, refers to the permanently frozen ground found primarily in the polar regions.


Permafrost is soil, rock, or sediment that remains at or below the freezing point of water (0°C or 32°F) for two or more consecutive years. It consists of an active layer on top that undergoes seasonal thawing and a permanently frozen layer underneath.

Formation and structure

Permafrost forms when the temperature of the ground drops below the freezing point of water for long enough to solidify the soil or rock. Its thickness can vary from less than a meter to more than 1,500 meters. As the planet warms, the permafrost melts.

The structure of permafrost consists of two primary layers. The top layer, known as the “active layer,” thaws during the warmer summer months and freezes again in the colder winter months. Beneath this active layer lies the “permafrost layer,” which remains frozen year-round.


Permafrost is predominantly found in the high latitudes of the Northern Hemisphere, including large sections of Siberia, Alaska, Canada, and Scandinavia. It also occurs in the Southern Hemisphere, notably in parts of Antarctica. It can be found in high-altitude areas like the Tibetan Plateau and the Andes as well.

Ecological role

Permafrost plays a vital role in the global carbon cycle. It contains a significant amount of organic material, including dead plants and animals, trapped and preserved within the ice.

Because of its frozen state, the organic material in permafrost does not decompose and thus stores vast amounts of carbon. Scientists estimate that permafrost contains twice as much carbon as is currently present in the atmosphere.

Thawing permafrost and climate change

Rising global temperatures due to climate change are causing permafrost to melt at an increasing rate. This thawing poses serious ecological and environmental concerns.

When permafrost thaws, the organic material it contains begins to decompose. This releases greenhouse gases such as carbon dioxide and methane into the atmosphere. This release exacerbates global warming in a positive feedback loop known as the “permafrost carbon feedback.”

Thawing permafrost also impacts local ecosystems and human infrastructure. As the ground melts and becomes less stable, buildings, roads, and pipelines can collapse, posing significant challenges in Arctic communities.

In summary, permafrost is an essential element of the Earth’s cryosphere. It plays a critical role in maintaining global climate and serving as a significant carbon sink.

However, the ongoing threat of climate change and the resultant thawing of permafrost present substantial ecological, environmental, and societal challenges. Scientists continue to study permafrost to better understand its dynamics and the potential impacts of its thawing.

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