Could Ice Melt in the Arctic Lead to Future Pandemics?
Molly Herring
As global warming accelerates, the poles are heating up two to four-times faster than the rest of the earth. This is causing an important layer of soil called the permafrost to melt for the first time, which is thawing everything that has been trapped in this icy prison for hundreds of thousands of years. Could permafrost melt unleash ancient bacteria that could reignite past pandemics?
Light blue chunks of ice floating. Photo: Bethany Legg (Unsplash).
Can bacteria stuck in permafrost survive?
You wiggle your fingers first, and then your toes. You stretch out your arms and legs, feeling the warmth flood back into your fingertips. You brush the frost away from your eyes and blink them open. The world is as white as it was when you fell asleep, but it’s different now. There are roots burrowing into the ground, and bits of green poking up through the frost. The air feels warmer, the sun brighter. Hundreds of thousands of years after your sleep began, you are awake again, and it feels like summer.
Bacteria growing in a petri dish. Photo: Unsplash.
In the Arctic, buried deep in a layer of soil called the permafrost, lie frozen secrets of the past - ancient fossils, tools, and organic material. All across the earth, temperatures are increasing and ice is melting. As the permafrost thaws, history is waking up. Tiny organisms called microbes such as ancient bacteria are beginning to wiggle their toes. Some of these caused pandemics in the past that have long since died out, but should we be worried about them becoming contagious once again?
Why isn’t the bacteria dead after all these years? If fresh food is left in the refrigerator past its expiration date, it starts to smell. If that food is instead stored in the freezer, it stays fresh for much longer and can be thawed, cooked, and eaten months later. This is because sub-zero temperatures keep bacteria from decomposing food, which prevents rot. Extremely cold temperatures also prevent the decay of microscopic organisms, or microorganisms, frozen inside the soil. Without decay, these organisms have the potential to “wake up” as good as new once thawed, sometimes referred to as “zombie bacteria.”
How do microbes become active after thawing?
The earth is warming because of certain gasses called “greenhouse gases” that trap heat in the atmosphere. Carbon dioxide is one of those gases. An estimated 1400 gigatons of not yet decomposed organic material, made of carbon, are stored in the permafrost. This is four times more than what has been emitted by humans since the industrial revolution, and twice as much as the carbon currently held in the atmosphere. If the ice continues to melt, the organic material housed in the ice will be released as carbon dioxide and continue warming our atmosphere.
Frozen ice in Baikal, Russia. Photo: Unsplash.
As the atmosphere warms, the ice in the ground turns to water. If you are deep in sleep in the middle of the night and someone throws a bucket of cold water on you, chances are, you will jump out of bed. These tiny, ancient organisms have been stuck in the permafrost in a deep sleep. As the soil begins to melt due to global warming, they also seem to “wake up” in the presence of liquid (rather than frozen) water, which reactivates their biological processes.
“[Having] liquid water available makes it possible for bacteria to do what they do - eat organic carbon. As soon as [the ice] melts the bacteria are like, ‘time to party!”
With water around, many are able to thrive once again. Scientists have discovered that some organisms can survive being frozen for more than 30,000 years. One study sampled permafrost deposits from northeastern Siberia and documented nematodes that, once warmed up, began to move and eat after 42,000 years of being frozen.
Will permafrost melting lead to future pandemics?
Not all microbes that survive the melt are dangerous. There is ongoing research on what exactly lies within the permafrost, with some saying the permafrost layer contains tens of thousands of human bodies that have not yet rotted, some victims of past pandemics like smallpox and the 1918 flu. Some of these microbes are indeed pathogenic, which means they cause disease, but once unfrozen, these must quickly find a host to survive.
Protective masks, normally used for surgery, are now in use to fight Coronavirus. Photo: Unsplash.
There are currently about 4 million people living in the Arctic, approximately 0.0005% of the global population. However, as temperature increase, many animals are migrating North to cooler temperatures. Humans tend to follow their food, so we may find ourselves headed towards the poles as well.
As the permafrost melts, animals and humans may be stumbling upon the habitats of these ancient bacteria looking for hosts. This already occurred in 2016, when more than 2,000 reindeer died in the Siberian tundra due to an anthrax outbreak that is largely attributed to the thawing of a 75-year-old reindeer carcass that died of an anthrax bacterial infection. The infected reindeer caused outbreaks in nearby villages, leading to the death of one person.
In addition to animal and human migration, exploitation of the Arctic like drilling and mining could disturb this previously deserted region and accelerate permafrost melt. This could potentially release microbes into groundwater stores and freshwater rivers, where they are more likely to encounter and infect hosts.
Melting glacier in iceland. Photo: Unsplash.
Why is this important and what can we do?
As the earth warms, the delicate ecosystem at the poles is particularly at risk. Scientists are not sure yet whether viruses like the one that causes COVID-19 can survive to “wake up” after being frozen, let alone become infectious again. More research can inform about all the sources of possible future pandemics so that we can be prepared if faced with another disaster.
As tiny organisms become mobile again after hundreds of thousands of years asleep, they will have to adapt to a warmer, greener world to continue to survive. For bacteria that cause disease, this means finding a host to infect and beginning to spread. If climate change continues to accelerate, the melting permafrost will wake up microbes we don’t even know exist that will be looking for a way to survive.
It is important to research and take local and policy level action to help combat climate change and slow the warming of the earth. We can collectively act to preserve delicate habitats like the Arctic, not only for the animals and indigenous peoples that live there, but also to keep the tiny, infectious microbes in a comfortable slumber.