“We are opening a Pandora’s Box of disease,” said Camilo Mora, a geographer at the University of Hawaii. “Because of climate change, we have all these triggers all over the world, over 1,000 of them. There are diseases out there just waiting to be unleashed. It’s like we are poking a stick at a lion – at some point the lion will come and bite us in the ass.”
More than half of the human diseases caused by pathogens have been worsened at some point by the sort of impacts associated with the climate crisis, a new and exhaustive study of the link between disease and climatic hazards has found. The researchers combed through more than 70,000 scientific papers that analysed the links between different climatic hazards and infectious disease.
Diseases such as Zika, malaria, dengue, chikungunya and even Covid-19 have been aggravated by climate impacts such as heatwaves, wildfires, extreme rainfall and floods, the paper found. Global heating and changed rainfall patterns are expanding the range of disease vectors such as mosquitoes, ticks and fleas, resulting in the spread of malaria, Lyme disease, West Nile virus and other conditions. Storms and flooding have displaced people, bringing them closer to pathogens that cause outbreaks of gastroenteritis and cholera, while climate impacts have weakened humans’ ability to cope with certain pathogens – drought, for example, can lead to poor sanitation, resulting in dysentery, typhoid fever and other diseases.
The World Health Organization has warned that the climate crisis “threatens to undo the last 50 years of progress in development, global health, and poverty reduction” and has estimated that an additional 250,000 people will die each year from 2030 to 2050 due to proliferating diseases such as malaria and diarrhoea, as well as malnutrition and heat stress.