In the summer of 2016, Siberia experienced an unusually hot season. This heat led to a deadly outbreak of anthrax. The outbreak killed over 2,500 reindeer on the Yamal Peninsula. The outbreak was linked to a bacterium locked earlier in permafrost. It claimed the life of a 12-year-old boy. Numerous others also fell ill. The incident has raised alarms among researchers, who fear that climate change could unlock other deadly microbes from the Arctic’s melting permafrost.
This issue is discussed in the United Nations Environment Programme (UNEP) report. The International Science Council’s Navigating New Horizons explores emerging challenges to planetary health. According to experts, as the Arctic warms, ancient pathogens trapped in the ice may pose new health risks. Scientists are closely monitoring this development.
LINK BETWEEN THAWING PERMAFROST AND DANGEROUS MICROBES
The Arctic spans 14 million square kilometers across eight countries. It is blanketed by thick permafrost. This permafrost is a frozen mixture of soil, rocks, ice, and organic matter. The Arctic warms at a rate four times faster than the rest of the globe. As it warms, thawing permafrost could release ancient bacteria and viruses. According to research published in Environmental Sustainability, an estimated four sextillion microbes are released annually. Four sextillion is four followed by 21 zeros. These microbes are released as the permafrost thaws.
Some researchers are particularly concerned about the thawing remains of long-dead Arctic animals. The 2016 Siberian outbreak was traced back to a reindeer burial ground. There, animals that died from anthrax more than 70 years ago were buried in the frozen earth. These bodies, preserved by the permafrost, contained dormant microbes that were reactivated by the thaw.
Andrea Hinwood, UNEP’s Chief Scientist, emphasizes the unknown risks of this phenomenon. “These microbes are present in the permafrost. This presence means it’s hard to say how widespread this problem could be. It is also challenging to determine how dangerous it might be,” she says. “But there are reasons to be concerned.”
GROWING RISK: HUMAN EXPOSURE TO THAWED PERMAFROST
The threat is not limited to microbes. As warming opens the Arctic to industries like shipping and mining, Hinwood warns that human exposure to thawed permafrost could increase. This will bring more people into close contact with dangerous microbes.
“We could be witnessing a complete change of land use in the Arctic, and that could be dangerous,” she notes. This shift in land use could expose workers and communities to microbes that were once safely contained beneath layers of frozen ground.
CLIMATE FEEDBACK LOOP: THAWING PERMAFROST AND GREENHOUSE GASES
In addition to releasing harmful pathogens, thawing permafrost has another significant environmental consequence. Permafrost contains an estimated 1,500 gigatonnes of carbon—roughly twice as much as the atmosphere. As permafrost thaws, this carbon is broken down and released into the atmosphere in the form of carbon dioxide or methane. These both are potent greenhouse gases that contribute to further global warming. This creates a potentially catastrophic feedback loop. The release of these gases accelerates climate change. This process causes more permafrost to melt.
PATH FORWARD: MITIGATING THE RISKS
Hinwood stresses the need for global action to reduce greenhouse gas emissions. This will prevent further climate change and the spread of disease. “We must rein in the greenhouse gases driving climate change,” she urges. Apart from addressing climate change, countries must keep monitoring the receding permafrost. They must also invest in researching the microbes contained within it.
“At the moment, we are very much in an ‘if-and-maybe scenario,’” Hinwood says. “There is a lot of uncertainty. The best we can do is use the tools and science we have to inform ourselves.”
