Baku, January 8, AZERTAC

In the unusually hot summer of 2016, a bacterium that causes anthrax killed more than 2,500 reindeer in Siberia’s remote Yamal Peninsula, according to UN Environment Programme.

Normally locked deep in a layer of permanently frozen land, or permafrost, the once-dormant pathogen eventually spread to humans, claiming the life of a 12-year-old boy and causing dozens of others to fall ill.

Some researchers believe the outbreak is a sign of things to come. As climate change rapidly warms the Artic, scientists say it could unleash a wave of potentially deadly microbes that for centuries have been trapped in ice.

That threat is being highlighted in Navigating New Horizons, a report from the United Nations Environment Programme (UNEP) and the International Science Council that explores emerging challenges to planetary health and human wellbeing.   

“The fact that these microbes are present in the permafrost means it’s hard to say how widespread, or dangerous, this problem could be,” says Andrea Hinwood, UNEP’s Chief Scientist. “But there are reasons to be concerned.”

The Arctic, which spans 14 million square kilometres across eight countries, is covered by a layer of thick permafrost, a frozen mixture of soil, rocks, ice and organic material. However, the Arctic is warming four times faster than the rest of the globe, with thawing permafrost potentially setting free ancient bacteria and viruses, experts say. According to a study in the journal Environmental Sustainability, an estimated four sextillion microbes – that’s a four with 21 zeros – are released annually due to thawing permafrost.

Some researchers are especially worried about the thawing of long-dead Arctic animals, whose bodies may house dormant microbes. The Siberian outbreak was traced to a reindeer burial ground; many of those animals died more than 70 years ago from anthrax.

Hinwood says what is playing out in the Artic has taken place in warmer climates for centuries, with pathogens hopping between people and animals, often with deadly results.

“This is not a new phenomenon but it’s happening in a new place.”

As warming opens the Artic to shipping, mining and other industries, Hinwood says that could put more people in close proximity to thawed permafrost and its resident microbes.

“We could be witnessing a complete change of land use in the Arctic and that could be dangerous,” she said.

The spread of disease isn’t the only problem with the thawing of the Arctic.

The world’s permafrost contains an estimated 1,500 gigatonnes of carbon, about twice as much as the atmosphere. As permafrost thaws, its carbon is broken down and released into the atmosphere as carbon dioxide or methane. Those greenhouse gases warm the planet further, melting more permafrost in a potentially catastrophic cycle.

To avert runaway climate change and disease outbreak, Hinwood says the world must rein in the greenhouse gases driving climate change. Countries also need to continue to monitor receding permafrost and invest in charting the types of microbes that reside there.

“At the moment, we are very much in an ‘if-and-maybe scenario’,” she says. “There is a lot of uncertainty and the best we can do is use the tools and science we have to inform ourselves.”