Thawing the World’s Freezer

Fear of frozen corpses lying beneath the tundra may even be the reason that the United States and Russia maintain stockpiles, according to Donald Henderson. Henderson, an epidemiologist currently at Johns Hopkins University, directed the World Health Organization’s smallpox eradication campaign. After hammering out an agreement between the two countries to reduce smallpox stockpiles, he was “just about ready to take this to the World Heath Assembly when a guy from Britain shows up.” This man was the head of the United Kingdom’s chemical and biological weapons program.

Henderson recalls their conversation.

How could you do that?

How could I do what?

Let me say this: Suppose you have bodies in the tundra? What would we do to protect people — we’ve destroyed the virus.

Henderson explained to the chemist that the possibility of virus frozen in the north has little to do with maintenance of laboratory stockpiles. But the chemist took his concerns to the U.S. Department of Defense, and, according to Henderson, the fear of naturally frozen virus is what led the military to withdraw from the resolution. “I can’t make it up,” he laughs.

Some life does exist in frozen soil and ice. Imre Friedmann, who had been in the research station with the body, points out that “in permafrost we find living bacteria in 3 million-year-old permafrost. So if bacteria survive, I don’t see why viruses don’t survive.” Friedmann is referring to a team from the Russian Academy of Sciences that found bacteria in ancient permafrost. Viruses have also been discovered in old ice cores: Scott Rogers of Bowling Green State University in Ohio found a 140,000-year-old RNA plant pathogen in Greenland.

Taken together — the possibility that viruses survive, the hardiness of smallpox and the expanse of frozen tundra — it seems possible that viable variola could be preserved in permafrost. “If it were going to be anywhere,” Henderson says, “if you were going to find something, [the tundra] would be the likely place.”

Global warming is thawing permafrost. In Siberia, botanists at Tomsk State University estimate that an area twice the size of California has changed from featureless tundra to a lake-dotted, slumped landscape. The decomposition of formerly frozen soil is in turn accelerating global warming because of the release of previously trapped methane gas. The northern Arctic is warming more quickly than other parts of the world, and, according to projections by the National Center for Atmospheric Research in Colorado, the uppermost 10 feet of the Northern Hemisphere’s permafrost may be gone by 2100.

“Obviously the delicate relationship between climate and permafrost is going to have to find new equilibrium,” says Wayne Pollard, a permafrost specialist at McGill University in Montréal.

But what does an accelerated thaw mean for smallpox? Some experts think that climate change reduces the chance of a smallpox reintroduction because the virus cannot survive multiple days unfrozen. To Tucker of the Center for Nonproliferation Studies, “the gradual thawing of the permafrost brought about by global warming [further diminishes] the likelihood of recovering infectious smallpox virus particles from the corpses of victims buried in the Arctic region.”

There is a caveat to this assumption, though. According to Pollard, there are different kinds of permafrost. The ice-rich permafrost is rapidly changing the northern landscape, but dry permafrost, on the other hand, could better preserve a body and the viruses harbored.

“It’s important to say ‘never say never’ with some of these things because it’s like saying life couldn’t have arrived on earth from an asteroid,” concludes Russell Regnery of the Poxvirus Program at the Centers for Disease Control and Prevention. He thinks that the disease impact from global warming will come from the ooze of tropical diseases such as malaria and leishmaniasis into newly available habitats rather than from the release of pathogens because of permafrost melt.

 . . .

The morning after finding the frozen corpse along the Kolyma River, several researchers carried it out of the Cherskii Research Station past a few scraggily evergreens. It was buried that day in 1990, just before the Soviet Union opened. Under normal circumstances, scientists might have examined an old body: one researcher thought the traditional reindeer skin clothing was about 300 years old. But the fear of the unknown — of smallpox — evaporated their intellectual interest.

But fear needs perspective. “These things don’t cough anymore,” says the CDC’s Regnery. Short of people wiping a newly exposed cadaver across their eye, it is hard for him to see how the virus could transfer. Epidemiologist Henderson adds that an outbreak of smallpox would kill people, but it could be contained. Sick people go to bed, and the disease transfers from person to person only when the pustules are obvious. Says Henderson: “There is a lot of docudrama stuff out there that is absolute poppycock.”

Note: Imre Friedmann died in June at the age of 85, after this article had been written.

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For a full rundown of the impacts of global warming, check out Scienceline’s Climate Change Series.