Climate change exacerbates almost two-thirds of pathogenic diseases affecting humans

Climate change is an unprecedented threat to human civilization as we know it. The large number of diseases that are sensitive to climate change and their numerous transmission pathways represent an insurmountable task for disease control in the absence of aggressive mitigation of greenhouse gas emissions. Arguably, the COVID-19 pandemic has revealed substantial disparities in disease outbreak preparedness globally, and further emphasizes that humanity is currently unable to prepare for the onslaught of multiple coinciding disease outbreaks that are worsened by climatic hazards. Thus, urgent action as a global community to reduce greenhouse gas emissions is necessary to diminish the effects of increased incidence, transmission, and geographical distribution of rarer and more serious diseases.

We present a conservative estimate for diseases aggravated by climatic hazards, as our findings are limited to what has been previously documented. For instance, rare diseases and outbreaks in rural or impoverished areas are historically not well documented. Furthermore, disease outbreaks among Indigenous populations are often undocumented, whereas these groups disproportionately face some of the strongest effects of climate change³. Yet, even with conservative estimates, the message is clear — greenhouse gas emissions must be reduced. The large body of evidence for numerous climate-change-aggravated diseases, case examples and transmission pathways demonstrates that the consequences of continuing under the ‘business as usual’ scenario will result in grave outcomes for human health.

Tristan McKenzie
¹and Isabella M. Gaw
²¹Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden.
²Department of Life Sciences, University of Hawaiʻi at Mānoa, Honolulu, HI, USA.