New research indicates that climate change is currently driving a global increase in dengue infections, with projections suggesting that cases could rise by 60% by 2050. Nearly 20% of dengue cases, a mosquito-borne viral disease, are linked to climate change. If global warming continues unchecked, this figure could reach 60% by the middle of the century.
These estimates are based on an analysis of roughly 1.5 million dengue infections from 21 countries in Asia and the Americas between 1993 and 2019. The research focused on regions where the disease is endemic—areas where it consistently circulates. The study considered factors such as temperature increases, changes in rainfall, and shifts in population density. Researchers determined that rising temperatures were a significant driver of dengue infections, responsible for 19% of all cases. This marks the first time a direct link between climate change and the spread of dengue has been established.
For years, scientists have speculated about how climate change could influence mosquito-borne diseases. Mosquitoes, being cold-blooded, have body temperatures that fluctuate with their surroundings. Warmer temperatures accelerate mosquito development, boosting their population and increasing the risk of bites and disease transmission. However, until now, no study had provided concrete evidence linking rising temperatures directly to the spread of such diseases.
The study focused on dengue fever because it thrives in warmer temperatures, making it especially susceptible to the effects of global warming. Researchers noted that the disease’s spread would likely intensify in both regions where it is already prevalent and in areas that have yet to see significant outbreaks.
The research highlighted an optimal temperature range for dengue transmission. Below 59°F (15°C), the virus multiplies too slowly within mosquitoes to be easily spread. As temperatures climb, the virus replicates faster, with transmission rates peaking around 84.2°F (29°C). In areas like Peru, Mexico, Bolivia, and Brazil—where dengue is already common—projections indicate infections could increase by over 150% in the coming decades as temperatures reach this peak range.
Above 86°F (30°C), however, dengue transmission rates may begin to decline. While the virus develops rapidly in warmer weather, extremely high temperatures can shorten mosquito lifespans, reducing the number of infected mosquitoes. In particularly hot regions, such as southern Vietnam, this phenomenon could slightly curb infection rates despite rising overall temperatures.
Reducing carbon emissions, and by extension global warming, could help prevent a significant spike in global dengue infections. The study suggests that achieving net-zero carbon emissions by 2050 could lead to a 7% decrease in the predicted rise of dengue cases, with some countries potentially seeing a 30% reduction.
Most individuals infected with dengue exhibit mild or no symptoms, but severe cases can lead to life-threatening complications like organ failure and internal bleeding. About 1% of treated patients die, and the mortality rate can soar to 20% if left untreated. These figures underscore the importance of mitigating carbon emissions to control the spread of this disease.
The findings were recently presented at the American Society of Tropical Medicine and Hygiene’s annual meeting in New Orleans, and preliminary results were shared in January on the medRxiv preprint server. The study is awaiting peer review.
Although the US was not included in this analysis due to insufficient long-term data, there are signs that climate change is increasing dengue risks within the country. Dengue is currently endemic to certain US territories, but not to any mainland states. However, locally acquired cases have been documented in states like California, Texas, Florida, Hawaii, and Arizona, indicating that the disease is becoming more common domestically. In June 2024, the Centers for Disease Control and Prevention (CDC) cautioned that Americans might face an elevated risk of dengue due to the rising number of cases globally.
The situation is evolving as temperatures in the US become more favorable for local dengue transmission. Moreover, increased cases overseas mean a higher risk of travelers bringing the virus into the country. With warmer conditions spreading across the southern United States, the potential for localized dengue outbreaks grows. Experts stress the need for proactive public health measures to combat the rise in mosquito populations and reduce the number of infections.
“Dengue is coming, and dengue is going to get worse in places currently on the edge of the temperature range for transmission,” warned one researcher. This trend includes tropical high-altitude areas, parts of southern Brazil, and regions in North America and Europe that have historically seen minimal dengue activity. These areas may need to ramp up mosquito control and public health efforts to limit the spread of the virus.
This research underscores the broader implications of climate change on global health. As temperatures continue to rise, so does the potential for mosquito-borne diseases to reach new areas, creating challenges for regions unaccustomed to dealing with these illnesses. Addressing this threat will require international cooperation and a concerted effort to reduce carbon emissions and curb global warming, which could be crucial in slowing the spread of diseases like dengue.
The findings also suggest that climate adaptation strategies, such as urban planning and changes in infrastructure, could play a role in mitigating the impact. By focusing on sustainable urban development and increasing green spaces, cities can potentially manage rising temperatures more effectively, reducing mosquito breeding grounds and lowering infection rates.
In the meantime, public health campaigns targeting at-risk populations, encouraging the use of mosquito nets, insect repellents, and proper sanitation, will be essential. Raising awareness about the risks associated with warmer temperatures and providing tools to reduce mosquito exposure can help vulnerable regions prepare for a potential rise in dengue cases.
The economic impact of increased dengue infections could also be substantial. Countries already burdened by healthcare costs and public health challenges may face additional strain as cases rise. This could lead to a greater focus on preventive measures and research into vaccine development.
Overall, the research indicates that climate change is not just an environmental issue but a public health concern with far-reaching consequences. Addressing the root causes of global warming may be one of the most effective strategies to combat the future spread of dengue and other mosquito-borne diseases, which increasingly threaten both tropical regions and temperate zones alike.