Ecology: Climate change can aggravate over half of known human pathogens

Climate hazards have aggravated 58% of human infectious diseases, according to a study published in Nature Climate Change. The findings highlight further risks to human health under continued climate change.

The impact that climate change can have on human vulnerability to a range of diseases is well accepted. Studies have primarily focused on specific groups of pathogens (for example, bacteria or viruses), the response to certain hazards (such as heatwaves or increased flooding), or transmission types (for instance, food- or water-borne). However, the full threat to humanity in the context of climate change and disease is unknown.

Camilo Mora and colleagues systematically screened the literature, revealing 3,213 empirical cases linking 286 unique, human pathogenic diseases to 10 climate hazards, such as warming, floods or drought. Of these, 277 were found to be aggravated by at least one climate hazard, with only nine exclusively diminished by climatic hazards. Overall, 58% of an authoritative list of infectious diseases documented to have impacted humanity have already been shown to be aggravated by climatic hazards. Examples of hazards include those that bring humans closer to pathogens, for instance storms and floods causing displacements associated with cases of Lassa fever or Legionnaires’ disease, and those that bring pathogens closer to humans, for instance warming increasing the area over which organisms that transmit diseases, such as Lyme disease, dengue and malaria, are active.

The authors conclude that these findings reveal unique pathways in which climatic hazards can lead to disease, underlining the limited capacity for societal adaptation, and emphasising the need to reduce greenhouse gas emissions.