As the Arctic's permafrost melts, long-dormant microbes are awakening, posing serious threats to both humans and animals, a UN report explores emerging challenges to planetary health and human wellbeing.    

In 2016 summer, a bacterium that causes anthrax killed more than 2,500 reindeer in Siberia’s remote Yamal Peninsula, according to a study. 

Trapped deep within permanently frozen permafrost, the reawakened pathogen eventually infected humans, resulting in the tragic death of a 12-year-old boy and leaving dozens more sick.

Some researchers assume that the outbreak as a warning of what lies ahead. With climate change accelerating Arctic warming, scientists warn it could release a surge of potentially deadly microbes that have been locked in ice for centuries.

A report from the United Nations Environment Programme (UNEP) and the International Science Council highlighted the threat in Navigating New Horizons

“The presence of these microbes in permafrost makes it difficult to determine the extent or severity of the potential risk,” says Andrea Hinwood, UNEP’s Chief Scientist. “However, there are clear reasons for concern.”

Covering 14 million square kilometers across eight countries, the Arctic is blanketed by thick permafrost—a frozen mix of soil, rocks, ice, and organic material. However, the region is warming four times faster than the global average, and experts warn that thawing permafrost could release ancient bacteria and viruses. A study published in Environmental Sustainability estimates that thawing permafrost releases approximately four sextillion microbes—a four followed by 21 zeros—every year.

Some researchers are particularly concerned about the thawing of long-dead Arctic animals, which may harbor dormant microbes. The Siberian outbreak was linked to a reindeer burial site, where many of the animals had died over 70 years ago from anthrax.

Hinwood noted that the dynamics unfolding in the Arctic have been occurring in warmer climates for centuries, where pathogens frequently jump between humans and animals, often with lethal consequences.

"This isn’t a new phenomenon, but it’s happening in new a place," she said. 

As warming makes the Arctic more accessible to shipping, mining, and other industries, Hinwood warns this could bring more people into close contact with thawing permafrost and its ancient microbes.

“We may be seeing a complete transformation in Arctic land use, and that carries significant risks,” she said.

The dangers of a warming Arctic, however, extend far beyond the potential spread of disease.

The world’s permafrost holds an estimated 1,500 gigatonnes of carbon—about twice the amount in the atmosphere. As permafrost thaws, this carbon breaks down and is released as carbon dioxide or methane, two potent greenhouse gases that accelerate global warming and trigger more permafrost melt in a potentially disastrous cycle.

To prevent runaway climate change and further disease outbreaks, Hinwood emphasizes the need for the world to curb the greenhouse gases driving climate change. Nations must also continue monitoring the retreat of permafrost and invest in mapping the microbes that lie within it.

“We’re currently facing an ‘if-and-maybe’ scenario,” she says. “There’s a lot of uncertainty, and the best we can do is use the tools and science available to inform ourselves.”

[Disclaimer: This story is a part of ‘Punascha Pruthibi – One Earth. Unite for It’, an awareness campaign by Sambad Digital.]