Alaska and Northern Canada face substantial risks. These regions host vast tracts of discontinuous permafrost that are warming rapidly. If Yersinia pestis remains preserved in the frozen carcasses of ancient rodents, a thaw can expose the bacteria to modern fleas and marmots.
The Tibetan Plateau is another high-risk zone. High-altitude permafrost here is degrading, potentially releasing pathogens into a region where plague still circulates in wild populations. This overlap increases the chance of a spillover event.
Greenland and Northern Scandinavia also have thawing ground, though their lower rodent densities might limit the transmission cycle. Pneumonic plague specifically requires a human-to-human respiratory bridge or direct inhalation of contaminated aerosols. While the odds of a massive outbreak remain low, the warming Arctic makes these pockets dangerous. Local wildlife shifts often precede human infection.
