How climate change fuels epidemics

Report links rising temperatures, extreme weather, evolving pathogens, and climate migration to shifting disease patterns

- Sheree Bega

Knock-on effects: Climate affects mosquitoes and the diseases that they carry. Europe’s unusually warm and humid summer in 2025 contributed to 718 human cases of West Nile virus and 49 deaths in Italy alone. Photo: CDC

(CDC)

From mosquitoes carrying dengue and chikungunya in Indian Ocean islands to West Nile virus now endemic in parts of Europe, climate change is redrawing the global map of infectious diseases.

It is fuelling new epidemics globally, warns a new COP30 synthesis report by the Climate Amplified Diseases & Epidemics (Climade) Consortium, a coalition of leading scientific and public health organisations.

The report said rising temperatures, extreme weather, evolving pathogens and climate-driven migration are already intensifying outbreaks worldwide.

"We know from very accurate data that climate change has the potential to aggravate over 50% of pathogens," Tulio de Oliveira, the co-lead of Climade and director of the Centre for Epidemic Response and Innovation (Ceri) at Stellenbosch University, said at the launch of the report.

"What we're talking about is over half of diseases being amplified by climate change, getting the perfect storm between climate extreme events and then infectious disease."

The Global South contributes less than 10% of global emissions, but will bear the most significant health effects due to its proximity to biodiversity hotspots, high baseline disease burdens, and limited healthcare access.

"Addressing the intersection of climate change and infectious diseases is therefore urgent. Climate action must go hand in hand with efforts to strengthen health systems, particularly in underserved and climate-vulnerable regions," the report urged.

Climate brings together leading scientific and public health groups, capable of responding to climate-amplified epidemics.