A deadly outbreak of anthrax hit Yamal Peninsula, an area of Siberia located above the Arctic Circle, in late July and officials have zeroed in on the cause. A heat wave caused permafrost to melt, thawing an infected reindeer that died of anthrax an estimated 75 years ago. The bacteria then spread to infect over 2,000 reindeer, and as it spread it sickened dozens of people and caused the death of a 12-year-old boy.
According to NPR:
Russian officials say they're working hard to get the outbreak under control. They're vaccinating reindeer and burning the carcasses of dead animals. There's likely to be more cases of anthrax resurfacing, says Birgitta Evengard, a microbiologist at Umea University in Sweden. That's because climate change is causing the temperature in the Arctic Circle to rise very quickly. "It's rising about three times faster in the Arctic than in the rest of the world," she says. "And that means the ice is melting and the permafrost is thawing."
Because of the frozen state of permafrost, those people and animals that have died of disease can't be buried all that deep. Periods of unusual heat thaw the upper levels of the ground. As the ground thaws, so too does everything held within it, including deadly bacteria and viruses found in cemeteries and animal burial grounds.
Luckily, the diseases that may be resurrected through warming temperatures are tackled with modern medicine and control systems, and outbreaks can hopefully be kept small and isolated.