Viruses that have been trapped in permafrost start to be freed

To start us off with a quote from CNN - 

Warmer temperatures in the Arctic are thawing the region’s permafrost — a frozen layer of soil beneath the ground —This is important because inside the Perma frost is potentially stirring viruses that, after lying dormant for tens of thousands of years, could endanger animals and human health. 

Needless to say there is a lot going on with permafrost at the moment. It is important that we keep as much permafrost frozen as possible. It serves as a kind of time capsule, preserving — in addition to ancient viruses — the mummified remains of a number of extinct animals that scientists have been able to unearth and study in recent years, including two cave lion cubs and a woolly rhino. The reason permafrost is a good storage medium isn’t just because it’s cold; it’s an oxygen-free environment that light  doesn’t penetrate. 

But current day Arctic temperatures are warming up to four times faster than the rest of the planet, weakening the top layer of permafrost in the region. To better understand the risks posed by frozen viruses, Jean-Michel Claverie, an Emeritus professor of medicine and genomics at the Aix-Marseille University School of Medicine in Marseille, France, has tested earth samples taken from Siberian permafrost to see whether any viral particles contained therein are still infectious. He’s in search of what he describes as “zombie viruses” — and he has found some such as - 

Pithovirus sibericum 

Mollivirus silbericum 

Pithovirus mammoth 

Pandoravirus mammoth 

Pandoravirus yedoma

Pacmanvirus lupus 

Cedratvirus lena 

 So far, scientists have only studied permafrost viruses that infect single-celled organisms called amoebas, because these viruses are harmless and provide a good model for others that may be lurking under the ice."We will never risk isolating a virus eventually capable of infecting modern mammals," Claverie told Live Science in an email. "We do not have formal proof that viruses other than amoeba-specific viruses could survive as long, but there would be no reason why not because all viruses basically have the same property of being inert particles while outside their host cells. We do not wish to take the immense risk of starting a new pandemic with unknown 'zombie' viruses from the distant past just to demonstrate that we are right. So we know the virus are there. We don’t know for sure that they are still alive. But our reasoning is that if the amoeba viruses are still alive, there is no reason why the other viruses will not be still alive and capable of infecting their own hosts. Therefore to keep these viruses from being released into the world we must keep as much of the Perma frost frozen as possible to keep these viruses sealed.