There are diseases that have been hidden in ice for thousands of years. Climate change might wake them up. If that happens, they might be exposed to deadly bacteria and viruses that they have never seen before.

Throughout history, humans have existed side by side with bacteria and viruses. From the bubonic plague to smallpox, they have evolved to resist them, and in response, they have developed new ways of infection humans.

They have had antibiotics for most off a century, always since discovered Penicillin by Alexander Fleming. In reaction, bacteria have answered by developing resistance to antibiotics. The battle is unlimited because we spend so much time with pathogens, they occasionally develop a natural stalemate kindly.