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In August 2016, an outbreak of anthrax in Siberia sickened 72 people and took the life of a 12-year-old boy. Health officials pinpointed the outbreak to an unusual source.
Abnormally high temperatures had thawed the corpses of long-dead reindeer and other animals. Some of these bodies may have been infected with anthrax, and as Wired explained, the soil in Siberia is normally much too cold to dig deep graves. “The disease from thawing human and animal remains can get into groundwater that people then drink,” Wired reported.
Scientists are worried that as more permafrost thaws, especially in Siberia, there may be more outbreaks of long-dormant anthrax as burial grounds thaw.
That’s because the deep freeze of the permafrost doesn’t just keep carbon from escaping — it keeps microbes intact as well.
Permafrost is the place to preserve bacteria and viruses for hundreds of thousands — if not a million — years, explains Jean-Michel Claverie, a genomics researcher who studies ancient viruses and bacteria. “It is dark, it is cold, and it is also without oxygen. … There is no [ultraviolet] light.” All the bacteria need is a thaw to wake back up. “If you take a yogurt and put it in permafrost [that remains frozen], I’m sure in 10,000 years from now it still will be good to eat,” he said in a 2017 interview.
Claverie is part of a scientific team that determined it’s possible to revive 30,000-year-old viruses trapped in the permafrost. His work is centered on viruses that infect amoebas, not humans. But there’s no reason why a flu virus, smallpox, or some long-lost human infection couldn’t be revived the same way. These microbes are like time travelers — and they could thrive waking up in an age when humans have lost an immune defense against them.
I asked Claverie if there’s an upper limit to how long viruses and (certain types of) bacteria could survive in the permafrost.
“The limit is the limit given by the permafrost,” he explained, meaning he sees no limit. Permafrost is 1,000 meters deep in places, “which make it about a million, 1.5 million year old,” he said.
The danger here, he emphasized, is not from the slow thawing of the permafrost itself. That is, if the permafrost melts, and we leave the land alone, we’re unlikely to come into contact with ancient deadly diseases. The fear is that the thawing will encourage greater excavation in the Arctic. Mining and other excavation projects will become more appealing as the region grows warmer. And these projects can put workers into contact with some very, very old bugs.
The threat is tiny. But it exists. The big lesson is that even viruses thought to be eradicated from Earth — like smallpox — may still lurk frozen, somewhere.
“We could actually catch a disease from a Neanderthal’s remains,” Claverie says. “Which is amazing.”
4) Roadways are warping, foundations are shifting
When the permafrost melts, it literally changes the landscape.
“Oftentimes, permafrost has a great deal of ice in it, so you can get half the volume of that permafrost [that] may be frozen water,” Holmes says. “And so when that thaws, the water just runs off, you know? The water may head downhill or the water has a lower volume than is ice, so the ground just slumps and kind of falls apart.”
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