Study reveals pathogenic diseases exacerbated by climate change

Researchers have discovered that more than 58% of human diseases caused by pathogens, such as pneumonia and malaria, have been aggravated by climate change at one point.

Scientists from the University of Hawai’i at Manoa assessed scientific literature and searched for examples of impacts on pathogenic disease by 10 climatic hazards sensitive to emissions.

Hazards include warming, drought, heatwaves, wildfires, extreme precipitation, floods, storms, sea level rise, ocean biogeochemical change and land cover change.

The team found that climatic hazards were all found to influence diseases triggered by viruses, bacteria, animals, fungi, protozoans, plants and chromists.

58%, or 218 out of 375, of human pathogenic diseases have been affected at some point in time by at least one climatic hazard.

‘Given the extensive and pervasive consequences of the COVID 19 pandemic, it was truly scary to discover the massive health vulnerability resulting as a consequence of greenhouse gas emissions,’ said Camilo Mora, geography professor in the College of Social Sciences (CSS) and lead author of the study. ‘There are just too many diseases, and pathways of transmission, for us to think that we can truly adapt to climate change. It highlights the urgent need to reduce greenhouse gas emissions globally.’

They have revealed how climatic hazards are currently bringing pathogens closer to people, as warming and precipitation changes have been associated with the expansion of vectors such as mosquitoes, ticks, fleas, birds, and several mammals involved with disease outbreaks.

Climatic hazards have also caused the forced migration and displacement of people, leading to increased contact with pathogens, according to the study.

Additionally, the climate crisis has diminished human capacity to cope with pathogens, by altering body conditions, adding stress from exposure to hazards, forcing people into unsafe conditions and damaging infrastructure.

However, the team found that in some instances warming has reduced the spread of 63 viral diseases, but most diseases diminished by one hazard were aggravated by another.

‘We knew that climate change can affect human pathogenic diseases,’ said co-author Kira Webster, CSS geography PhD student. ‘Yet, as our database grew, we became both fascinated and distressed by the overwhelming number of available case studies that already show how vulnerable we are becoming to our ongoing growing emissions of greenhouse gases.’

The researchers have developed an interactive web page allowing users to see connections between each climatic hazard and a disease.

Photo by SJ Objio