Climate change is melting permafrost soils that have been solid for thousands of years, and as the soils melt they have the potential to release ancient viruses and bacteria that may be capable of springing back to life.
The most recent discovery of an ancient virus came when French and Russian scientists investigated a 30,000-year-old piece of Siberian permafrost.
Pithovirus
In a paper published in 2014 in the Proceedings of the National Academy of Sciences, scientists had discovered a new “giant virus” that they named Pithovirus sibericum.
Giant viruses are so-called because they are much larger than traditional viruses.
Pithovirus is the biggest ever found and measures 1,500 nanometres (billionths of a metre) across. That’s more than 10 times larger than the HIV virus.
After thawing the Pithovirus from its frozen state was still infectious.
Fortunately, the virus’ targets are amoebae, and Pithovirus poses no danger to humans.
However, giant viruses can sometimes be harmful to people.
Revival of such an ancestral amoeba-infecting virus suggests that the thawing of permafrost either from global warming or industrial exploitation of circumpolar regions might not be exempt from future threats to human or animal health.
Warming viruses
While global warming has yet to expose any ancient viruses harmful to humans, it has begun re-exposing more familiar diseases that modern society thought it had eradicated.
In August 2016, a 12-year-old boy in northern Russia was killed after being infected by Anthrax. The Anthrax outbreak, which saw up to 20 people hospitalised, was blamed on unusually warm weather in the arctic circle.
Scientists have also discovered DNA fragments of smallpox in the Siberian permafrost.
Bigger threats
While the risk of infectious diseases being released by thawing permafrost is real, scientists are at pains to point out that the chances of any future pandemic are incredibly low.
The idea that melting ice would release harmful viruses, and that those viruses would circulate extensively enough to affect human health, stretches scientific rationality to the breaking point.
And rather than diseases being released by melting ice, some argue that as Earth warms northern countries will become more susceptible to outbreaks of "southern" diseases like malaria, cholera and dengue fever, as these pathogens thrive at warmer temperatures.
In warmer countries climate change is already having a devastating effect on people’s health. In central America incidences of chronic kidney disease are on the rise, and are being blamed on increased dehydration as hotter days become more frequent.
