Climate warming and infectious diseases are profoundly disruptive forces and are inextricably linked. This year, two impactful papers characterized the increased disease risk that could be brought on by global change. Writing in Nature, Carlson, Albery and colleagues used existing models of the probability of viral sharing among mammal host species (on the basis of geographical overlap and phylogenetic relatedness) along with distribution models for 3,870 mammal species to project where species are likely to encounter new viruses in the future. They show that even moderate climate-change scenarios will lead to species distributional changes that will bring most species into contact with new viruses. Despite expectations that species will typically move poleward, the hotspots of future potential viral sharing are mainly located in Africa and southeast Asia. Although Carlson et al.’s paper stops short of demonstrating any direct increased risk to humans, a paper by Mora et al. in Nature Climate Change tackles this question. These authors conducted a meta-analysis of papers that had documented the effect of a climate hazard (for example, warming, drought, flooding or land cover change) on a disease-causing organism, including viruses, bacteria, fungi and other pathogens. These effects could take multiple forms, such as improving the climate suitability for reproduction, accelerating the life cycle or increasing virulence. The literature search identified 277 pathogens that were amplified in some way by at least one of the included climate hazards — accounting for 58% of all known human infectious diseases. Although this is a broad-brush analysis that relies on correlations in the underlying studies, it illustrates the scope of pathogens that could pose greater threats in the future. We selected these papers for our Year in Review collection because they represent complementary approaches to studying the numerous and complex links between climate and disease.
Original references: Nature 607, 555–562 (2022); Nat. Clim. Change 12, 869–875 (2022)
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