What is happening?

Dengue fever is spreading faster than ever before worldwide. Countries across Asia, the Pacific, and even parts of southern Europe are reporting record-breaking case numbers. Scientists now warn that climate change is one of the most important drivers behind this

rapid spread. Hotter average temperatures and more unpredictable weather patterns are creating ideal environments for mosquitoes. As a result, dengue is no longer limited to “tropical” countries like Thailand or Indonesia. It is now appearing in places where it had

never appeared before, including parts of France, Italy, and the United States. In many regions, dengue season starts earlier and ends later each year. Hospitals and health systems in developing countries are struggling to keep up with the rising number of patients. Health

officials say this trend is likely to continue unless climate change is addressed seriously. Communities that never worried about mosquito-borne diseases are now being told to prepare for outbreaks. Because dengue is spread by mosquitoes, any environmental change that

affects mosquito behavior will affect human health. This is why experts consider dengue one of the clearest examples of climate-related disease expansion.

Global temperatures are rising

The Aedes aegypti mosquito thrives in warm and humid environments. As global temperatures rise, mosquitoes can live in regions that used to be too cold for them to survive. Warmer weather also increases mosquito activity, meaning they bite more frequently. More

biting means a higher chance of dengue transmission between people. In some countries, the average temperature has risen by more than 1°C in just a few decades. This may sound small, but even a 1°C rise can dramatically change mosquito behavior. For example, mosquitoes

grow faster, reproduce more, and survive longer in warm conditions. Climate scientists have found that heat waves allow mosquitoes to expand into higher altitude regions, such as mountain villages. This puts new communities at risk — especially those with weak health

systems. Cities with urban heat island effects become hotspots for mosquito breeding. As the planet continues to warm, these high-risk zones will expand even further. This shows how rising temperatures directly reshape the geography of disease.

Heavy rainfall helps mosquitos breed

Climate change is causing more extreme rainfall, including stronger monsoons and unexpected downpours. After floods, water naturally collects in containers, plastic waste, rooftops, and small puddles. These small water collections become perfect breeding sites for

dengue-carrying mosquitoes. Urban areas with poor drainage systems are especially vulnerable. Even a bottle cap filled with water can produce dozens of mosquitoes in just a few days. Researchers say rainfall patterns are becoming harder to predict, making prevention

more challenging. Mosquito eggs can survive in dry conditions for months and hatch as soon as water appears. This means that even short periods of rain can trigger a sudden boom in mosquito populations. Communities in low-income areas face higher risks because they often

live near stagnant water. Climate disasters like typhoons and monsoon floods worsen this situation every year. As rainfall becomes more extreme, health workers must act faster toprevent outbreaks. Floods are no longer just an infrastructure problem — they are a major

disease risk.

Mosquito seasons are getting longer

Warmer temperatures mean that mosquito seasons now last longer than before. In the past, dengue transmission happened mainly in late summer. Today, cases are reported earlier in spring and later into autumn. Some tropical countries now experience dengue risk almost the

entire year. Longer mosquito seasons give the virus more time to spread from person to person. This also puts continuous pressure on hospitals, clinics, and public health workers. In places like Southeast Asia, medical systems must stay alert for dengue cases year-round.

Long seasons also mean that public awareness campaigns must run longer, requiring more money and resources. When mosquito activity overlaps with school semesters, children become more exposed. Travel during long mosquito seasons increases the risk of

cross-border spread. Climate models show that these long transmission periods will expand further in the next decade. This trend shows how strongly climate and disease seasons are now linked.

Who is most affected?

Dengue cases are rising fastest in Southeast Asia, the Pacific Islands, India, Bangladesh, and southern China. These regions experience warm climates, rapid urban growth, and frequent extreme weather events. Crowded cities provide many breeding sites and many people for

mosquitoes to bite. In Korea, the southern regions including Jeju are experiencing rising dengue-related mosquito activity. Children are especially vulnerable because they often spend time outdoors. Elderly people face higher risk of severe dengue symptoms. Communities

living in poor housing conditions face greater exposure to mosquitoes. People who live near standing water or inadequate drainage systems are more at risk. Health workers and caregivers also face danger because they contact infected patients. Tourists visiting newly

affected regions may not know how to protect themselves. Countries with weaker public health systems struggle to control outbreaks quickly. This shows that dengue is not only a health issue but also a social and economic one.

Why this matters?

Dengue can cause extremely high fever, intense pain, and sometimes life-threatening complications. The disease has no specific cure, and treatment focuses on managing symptoms. As outbreaks become more frequent, hospitals face increasing pressure. Some

countries experience shortages of hospital beds during peak seasons. Families often must stay home from work or school to care for sick members. Severe dengue can lead to bleeding, shock, and death if not treated quickly. The rising number of cases places a heavy financial

burden on healthcare systems. Communities with limited medical access face higher fatality rates. Dengue outbreaks also impact tourism and local economies. Climate scientists warn that the situation will worsen without serious climate action. Dengue is no longer just atropical disease — it is becoming a global threat. Protecting the environment is now directly connected to protecting public health.

What we can do?

Individuals can reduce risk by using mosquito repellent when outdoors. Wearing long sleeves and pants during mosquito season helps reduce bites. Homes should be checked regularly for standing water in pots or containers. Window screens and mosquito nets offer simple but effective protection. Community clean-up programs can help remove breeding sites. People should stay informed about local dengue alerts and weather warnings. Participating in vaccination programs, where available, adds another layer of protection. Families can teach

children how to avoid mosquito bites safely. Sharing information with neighbors helps build stronger community awareness. Following public health guidelines during outbreaks reduces spread. Every small action contributes to a larger public health effort. Personal responsibility

and community cooperation are both essential.

What governments should do

Governments should invest in mosquito-control programs and climate-monitoring systems. Climate and health data should be combined to predict outbreaks early. Urban planning must include better drainage and waste-management systems. Public health campaigns should be

conducted before peak mosquito seasons. Schools and community centers can serve as hubs for dengue education. Stronger environmental policies can reduce long-term climate risks. Governments should support research on vaccines and vector control technologies. Cross-border cooperation is important because mosquitoes travel across regions. Emergency response teams must be trained for climate-related disease outbreaks. Communities need access to accurate and timely health information. International organizations can provide funding and expertise to support poor regions. Only coordinated action can reduce the global threat of dengue.

Final message

Dengue fever is spreading because our planet is changing. Rising temperatures and extreme weather give mosquitoes more opportunities to thrive. This disease is no longer limited to distant tropical areas — it is appearing everywhere. Protecting the environment means

protecting ourselves and our families. Climate change is not only a weather problem; it is a health problem. Every country must take action to reduce climate risks. Communities must learn how to prevent mosquito breeding and protect vulnerable people. Individuals can make

small but meaningful changes in daily life. By working together, we can reduce the spread of dengue and save lives. The future of public health depends on how we treat the planet today. The climate crisis is also a health crisis — the two cannot be separated. A safer, healthier

world begins with action now.

References

1. World Health Organization. (2024, September 26). Vector-borne diseases. https://www.who.int/news-room/fact-sheets/detail/vector-borne-diseases World Health Organization

2. World Health Organization. (2023, October 12). Climate change and health. https://www.who.int/news-room/fact-sheets/detail/climate-change-and-health World Health Organization

3. De Souza, W. M., & Weaver, S. C. (2024, March 14). Effects of climate change and human activities on vector-borne diseases. Nature Reviews Microbiology, 22, 476-491. https://doi.org/10.1038/s41579-024-01026-0 Nature

4. Milman, O. (2025, August 12). Rise in dengue fever outbreaks across the Pacific driven by the climate crisis, experts say. The Guardian.

https://www.theguardian.com/world/2025/aug/12/dengue-fever-outbreaks-samoa-fiji-t onga-climate-crisis