Potential One Health risk of downwind exposure to airborne pathogens from thawing Siberian permafrost

Abstract Permafrost degradation in Arctic and Subarctic regions, accelerating due to rapid climate change, exposes vast extents of ice- and organic matter-rich soils directly to the atmosphere. This ancient permafrost is known to harbor metabolically active microbes, including potentially harmful pathogens that have survived for thousands of years under extreme environmental conditions. The release and subsequent long-range dispersal of these organisms via atmospheric transport presents a significant, yet often neglected, pathway for novel disease emergence. Here, we develop a quantitative risk framework to geographically identify downwind areas in the Palearctic region potentially reached by air-transported pathogens emerging from Siberian retrogressive thaw slumps. We simulate air-mass trajectories to derive a hazard metric that accounts for the accelerating rate of slumps thawing. This hazard is coupled with the distribution of humans, major crops, or livestock representing the exposure term. We evaluate the associated health risk by introducing a novel hierarchical Pareto ranking approach, which prioritizes locations based on the joint effect of hazard and exposure without applying subjective weights. The results indicate that high risks are not only concentrated near source areas, but also extend to distant, densely populated urban centers in Russia, China, and Japan, and impact key agricultural regions. Given the increasing rates of permafrost thawing and the consequent risk of exposure of distant host populations, we call for a better characterization of the pathosphere in Arctic frozen grounds and for the development of credible models to identify and monitor specific One Health risk hotspots for plant, animal, and human populations.