The climate crisis is taking a devastating toll on global health, with a surge in yellow fever and dengue cases in South America. This alarming trend highlights the urgent need to address the impact of climate change on human well-being.
Experts warn that these infectious diseases, spread by mosquitoes, are not only affecting tropical regions but are now encroaching into temperate areas like Europe. The current wave of yellow fever, a disease causing fever and organ failure, follows Brazil's worst dengue year on record, with nearly 6.5 million cases and 5,000 deaths in 2024. Even Europe experienced a startling increase in dengue cases last year, surpassing the combined total of the previous 15 years.
Both yellow fever and dengue are transmitted by the Aedes mosquito, which thrives in warm, stagnant water conditions. The climate crisis, with its rising temperatures and intense rainfall, is exacerbating approximately half of all known human pathogenic diseases, according to scientific research. As the world heats up, disease-carrying mosquitoes are expanding their range, posing a growing threat to global health.
The sharp increase in transmitted diseases in the Amazon region coincides with UN climate talks in Belém, a Brazilian city near the Amazon river. Health, once overlooked in these annual summits, is now a priority, with the UN declaring "Health Day" at COP30 and promoting the Belém Health Action Plan. This plan, led by Brazil's government and the WHO, aims to support countries in dealing with climate-related health issues through surveillance, best practices, and capacity building.
"The climate crisis is a public health crisis," said Simon Stiell, the UN's climate chief. "Rising temperatures and extreme weather events are claiming lives, fueling diseases, and placing immense strain on healthcare systems."
However, climate advocates and health experts emphasize that more action is needed to address the consequences of extreme temperatures and worsening disasters. Al Gore, the former US vice-president, highlighted recent evidence showing that rising heat is killing one person every minute worldwide, indicating a severe failure of governments to mitigate the direct harm of the climate crisis.
"How long will we continue to turn up the heat, making these events even more catastrophic?" Gore asked.
Health experts attribute the expansion of infectious diseases to various factors, including deforestation for agriculture and housing, which brings humans closer to animals that can transmit zoonotic diseases. Maria Guevara, international medical secretary of Médecins Sans Frontières, emphasizes the role of globalization and the adaptability of mosquitoes and bacteria.
"Mosquitoes and bacteria are smarter than humans in this case because they're more adapted and will do whatever it takes to survive. We know what needs to be done about climate change, but we're not acting fast enough," Guevara said.
The extreme weather exacerbated by climate change is contributing to outbreaks of diseases like dengue and yellow fever, even outside the Amazon region. Rachel Vicente, an expert at Brazil's Federal University of Espírito Santo, explains that increased rainfall and high temperatures create ideal conditions for mosquito breeding and virus reproduction.
"It's a perfect storm. We all need to collaborate and build resilience because all countries will face these challenges, not just some."
The climate crisis is a global health emergency, and urgent action is needed to protect communities from the devastating impacts of climate-related diseases.
