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Defrost: No longer just a microwave setting

Using a freezer is a staple of modern life for most people. Whether it’s keeping your ice cream safe from melting or holding those leftovers that you keep promising to thaw and eat again, but will be thrown out in six months, you’re probably familiar with the concept of using a freezer to keep something from going bad for a very long time. 

Here’s a cool thing about freezing temperatures, though: They can also keep things alive in a dormant state. I’m not talking about urban legends of Walt Disney’s head or stories from comic books like Captain America. I’m not even talking about animals that can freeze and then seemingly come back to life, like the wood frog.  I’m talking about viruses. The ability to freeze a virus, rendering it dormant but remaining intact, sounds amazing when viewed through the lens of scientific research. And the ability to safely research something that could potentially be deadly has the potential to save countless lives. 

But what happens when you come home from vacation to find that in your haste to have ice cream before you left, you didn’t take proper care in closing the freezer door and now everything is thawing out? Well, that’s annoying and a pain to clean up. But imagine that it is not ice cream, but now a live replicating virus. Now it is more than a hassle; it has the potential to be a health hazard. And imagine that it isn’t a freezer, but it’s miles and miles of land which was previously frozen and now it’s starting to thaw for the first time in thousands of years, and we have no idea what kind of viruses are there or what impact they could have on global health. 

According to the National Snow and Ice Data Center (Yes, this is a real place. No, I didn’t know it existed either), “Permafrost exists where the ground stays at or below 0° Celsius (32° Fahrenheit) for at least two years in a row.” Permafrost covers up to 9 million square miles of land. Most of that land is in in places like Siberia, Alaska, Canada, and the Tibetan Plateau. As Earth’s climate continues to warm, the amount of land which is permafrost is shrinking. And as the permafrost thaws, the micro-organisms and viruses in the permafrost also thaw. Then what? 

In 2015, a 12-year-old boy in Siberia died from the Anthrax virus. Twenty other people were diagnosed and there were over 100 suspected cases. Over 2,000 reindeer also died from Anthrax in the same region.  The source of the anthrax? Thawing permafrost. Not only did the lives lost have a devastating impact on the families of close-knit communities, but losing that many head of reindeer in their herd of livestock had a drastic impact on their economic well-being.   

The area of Siberia where this occurred hadn’t had a case of anthrax in 75 years, but in 2014 and 2015, Jean-Michel Claverie (Professor of Microbiology at Aix-Marseille University in France) found two infectious viruses from a chunk of 30,000-year-old Siberian permafrost that were still active. Luckily those viruses only affect single-celled organisms, but the discovery is an indication that some viruses with potential to infect humans or drastically impact plant and animal life could be preserved in the permafrost.   

You may be thinking, “Zach, I live in the South. I’ve never even seen permafrost. What am I supposed to do to keep it from thawing?” And that’s a great question. Many times, we think that the idea of “saving the environment” or “stopping climate change” is too big for one person to do, so we just do nothing. But considering a OneHealth perspective helps us recognize that not only are we connected to people who live on the other side of the world, but we are also connected to the plant and animal life there, too. The world is huge and each of us lives in our own small part of it, but small things like using cloth napkins, running the dishwasher instead of hand washing dishes, turning off water while you brush your teeth, and other minor lifestyle adjustments can make a big difference in the long run. You don’t have to go buy a Tesla or put solar panels on the roof of your home to help. Just reuse things and decrease your single-use plastics consumption. These small things do add up.  

If we’re lucky and diligent, we will not face the threats waiting frozen in the permafrost. But if the permafrost continues to thaw, it may reveal viruses that we know about and have an idea how to treat. But with only a few hundred years of experience in studying virology, there is also a chance that the thawing permafrost could unleash a virus that we have never heard of or have any idea how to treat. Hopefully that will not happen, but if it does it could be 2020 all over again … or worse. 


Goudarzi, S. (2016, November 1). As Earth warms, the diseases that may lie within permafrost become a bigger worry. Scientific American. Retrieved November 19, 2021, from

National Snow and Ice Data Center. (n.d.). National Snow and Ice Data Center. Where is Frozen Ground? | National Snow and Ice Data Center. Retrieved November 19, 2021, from


Zach Stich 
Public Programs Coordinator 

Connect With Your Wild Side #onlyzooatl