The paper titled, "An update on eukaryotic viruses revived from ancient permafrost" acknowledges that melting ice due to global warming could mean that these viruses could become a threat to public health very soon. It is currently located in a preprint server for biology research and is yet to be peer-reviewed. 
The oldest virus detected in the ice is the more than 48,500 year old Pandoravirus yedoma found in a lake around Yakutia, Russia and is a massive one visible under a simple light microscope. The team demonstrated the dangers of these viruses by using single celled-amoeba cultures. 

Noting that a quarter of the Northern Hemisphere has permafrost, the scientists reiterated that, "Due to climate warming, irreversibly thawing permafrost is releasing organic matter frozen for up to a million years, most of which decompose into carbon dioxide and methane, further enhancing the greenhouse effect". The study has found 12 other viruses, each with its own genome.