How climate change is driving dangerous disease outbreaks

Extreme weather and accelerating climate-driven migration heighten exposure to diseases, increasing risks for vulnerable communities as pathogens spread into new regions. By Tulio de Oliveira and Cheryl Baxter

- By Tulio de Oliveira and Cheryl Baxter

Public health officials spray the streets in Abidjan, Ivory Coast, in 2023 to eliminate mosquitoes that cause dengue fever.

(Photo: Sia Kambou/AFP/Getty Images)

Rising temperatures, changing rainfall patterns and extreme weather events create ideal conditions for pathogens and their vectors — such as mosquitoes, midges and ticks — to thrive.

This is confirmed by a recent report for the global climate change conference, COP30. The report was produced by a team of Global South scientists from the Climate Amplified Diseases and Epidemics consortium, which studies and figures out ways of responding to infectious diseases that climate change is making worse. It sets out how deadly diseases like the West Nile virus, dengue and chikungunya are now spreading to new regions in Africa and Europe because of the changing climate.

Some of the authors of the report, Tulio de Oliveira, Cheryl Baxter and PhD candidate Maambele Khosa, explain what needs to be done to keep people at risk of infection safe and prevent infectious disease from multiplying.

There are several compounding factors. First, pathogens (such as a virus or bacterium that can cause disease) can adapt to new vectors and climates. This was recently seen with chikungunya virus mutations that made it easier for Aedes albopictus — a mosquito species now widespread in Asia, Europe and North America to spread the virus.

Second, extreme weather events like droughts and floods disrupt ecosystems and human settlements. The disruptions allow waterborne pathogens such as Vibrio cholerae, which causes cholera, to thrive. Flooding can also enhance breeding sites for vectors and delay public health responses.