Yet another potential impact of a warmer planet has been discovered: ancient viruses being brought back to life as a result of melting ice.

This possible risk was discovered in Siberia, where scientists found a 30,000-year-old virus that became exposed in the melting permafrost.

“This is the first time we’ve seen a virus that’s still infectious after this length of time,” Professor Jean-Michel Claverie of the National Center for Scientific Research at the University of Aix-Marseille in France told the BBC News. Claverie is one of the authors of a study that details the scientific discovery.

Known as Pithovirus sibericum, the contagion is a “giant” virus (1.5 micrometers)—the largest ever found in fact, and can be seen under a microscope (unlike most viruses).

But Pithovirus sibericum cannot infect humans, experts say, just amoebas.

The discovery, though, serves as a warning about buried viruses that may become exposed to the atmosphere when global warming causes frozen tundra to thaw.

The French and Russian researchers say Pithovirus sibericum may be just the first of other long-gone viruses to return to life, including those that can impact human health.

One example cited by Claverie is smallpox, which hasn’t been around (outside of laboratories) for decades.

“If it is true that these viruses survive in the same way those amoeba viruses survive, then smallpox is not eradicated from the planet - only the surface,” he said.

The region in Siberia where the ancient virus was discovered will continue to lose its permafrost, the researchers predict. As the land has become more accessible, industry has targeted it for its natural resources. With an unknown number of viral threats lying in wait, such digging portends potential dangers.

“It is a recipe for disaster,” Claverie told the BBC. “If you start having industrial explorations, people will start to move around the deep permafrost layers. Through mining and drilling, those old layers will be penetrated and this is where the danger is coming from.”

-Noel Brinkerhoff, Danny Biederman

To Learn More:

30,000-Year-Old Giant Virus 'Comes Back to Life' (by Rebecca Morelle, BBC )

Scientists Revive 30,000 Year Old 'Giant Virus' from Siberian Permafrost - and Warn More Could be Exposed Due to Global Warming (by Mark Prigg, Daily Mail)

Thirty-Thousand-Year-Old Distant Relative of Giant Icosahedral DNA Viruses with a Pandoravirus Morphology (by Matthieu Legendre, Julia Bartoli, Lyubov Shmakova, Sandra Jeudy, Karine Labadie, Annie Adrait, Magali Lescot, Olivier Poirot, Lionel Bertaux, Christophe Bruley, Yohann Couté, Elizaveta Rivkina, Chantal Abergel, and Jean-Michel Claverie; Proceedings of the National Academy of Sciences)

California Documents the Damage Already Done by Global Warming (by Ken Broder, AllGov California)

Global Warming Isn’t All Bad…If You’re an Archaeologist (by Noel Brinkerhoff, AllGov)