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| Changes in temperature, rainfall and humidity can influence mosquito ecology and malaria transmission, but the effects are not the same everywhere. |
Malaria has always been closely connected to the environment.
The mosquitoes that transmit malaria need suitable temperatures, water and humidity to survive and reproduce. The malaria parasites developing inside those mosquitoes are also affected by environmental conditions.
As Africa's climate changes, scientists are increasingly asking an important question:
Could malaria begin appearing at different times of the year or become more suitable for transmission in places where the risk was previously lower?
Research suggests that climate change could alter malaria transmission across parts of Africa. But the story is more complicated than simply saying that warmer weather will create more malaria everywhere.
Some areas may become more suitable for transmission. Others could become less suitable. Floods and other extreme weather events can also increase malaria risk indirectly by disrupting healthcare, displacing communities and interfering with prevention programmes.
Understanding these differences will be increasingly important for Nigeria and other African countries trying to control and eventually eliminate malaria.
What Is Malaria?
Malaria is a potentially serious disease caused by Plasmodium parasites.
People usually become infected when they are bitten by an infected female Anopheles mosquito.
Several species of Plasmodium can infect humans, but Plasmodium falciparum is responsible for most malaria deaths in Africa.
Common symptoms can include fever, chills, headache and weakness. Without prompt diagnosis and appropriate treatment, some infections can progress to severe malaria.
The burden remains heavily concentrated in Africa.
According to the World Health Organization, there were an estimated 282 million malaria cases and 610,000 deaths globally in 2024. The WHO African Region accounted for approximately 95% of both cases and deaths.
Children younger than five years remain particularly vulnerable.
Why Does Climate Affect Malaria?
Malaria transmission depends on a chain of events.
There must be mosquitoes capable of transmitting the parasite. Those mosquitoes must survive long enough for the parasite to develop inside them. Humans carrying malaria parasites must be present, and environmental conditions must allow transmission to continue.
Climate influences several parts of this process.
Three factors are particularly important:
Temperature
Rainfall
Humidity
Changes in any of these can influence mosquito breeding, mosquito survival and the development of malaria parasites.
But they do not operate independently.
Human behaviour, housing, mosquito-control programmes, immunity, access to healthcare, urbanisation, land use and socioeconomic conditions also affect malaria transmission.
That is why climate is an important malaria driver without being the only one.
How Temperature Can Affect Malaria Transmission
Mosquitoes are sensitive to temperature.
Temperature influences how quickly mosquitoes develop, how often they feed, how long they survive and how quickly malaria parasites develop inside them.
In places that have historically been too cool for sustained malaria transmission, warming temperatures could potentially make conditions more suitable.
This is particularly important in some higher-altitude regions of Africa.
WHO has previously noted evidence from African highlands where increasing temperatures have contributed to malaria becoming established in areas that had previously been unsuitable for sustained transmission.
However, there is another side to the relationship.
Hotter does not always mean better conditions for malaria.
Mosquitoes and malaria parasites have temperature ranges within which they function effectively. Extremely high temperatures can reduce mosquito survival or otherwise make conditions less suitable.
Climate change can therefore shift malaria suitability rather than simply expanding it uniformly.
Rainfall Creates Opportunities, But the Relationship Is Complicated
Mosquitoes require water for their aquatic life stages.
Rainfall can create pools, puddles and other collections of water where mosquitoes may breed.
This means increased rainfall can sometimes increase the number of potential breeding sites.
But once again, more rainfall does not automatically mean more mosquitoes.
Very heavy rainfall can wash away some breeding sites. Drought can reduce some natural mosquito habitats while simultaneously encouraging people to store water around homes, potentially creating other mosquito habitats depending on the mosquito species and local environment.
What matters is the interaction between rainfall, drainage, land use, water storage and mosquito ecology.
Humidity Also Matters
Humidity affects mosquito survival.
Mosquitoes generally survive better under suitable humid conditions than in extremely dry environments.
Longer periods of favourable humidity could therefore extend the amount of time during which malaria transmission is possible in some locations.
Changes in humidity can also interact with temperature and rainfall.
This is why scientists increasingly analyse several environmental variables together rather than looking at temperature alone.
Climate Change Could Alter Malaria Seasons
In many parts of Africa, malaria transmission has a seasonal pattern.
Cases may rise during or following rainy periods when mosquito populations increase.
Climate change could alter those familiar patterns.
If rainy seasons begin earlier, end later or become less predictable, the timing of malaria transmission may also change.
Warmer temperatures could potentially extend suitable transmission periods in some locations.
In other places, increasing heat or changing rainfall could reduce environmental suitability.
This creates an important challenge for public-health programmes.
Malaria interventions are often planned around expected seasonal patterns. If those patterns shift, surveillance and prevention programmes may need to adapt.
Could New Malaria Hotspots Appear?
Potentially.
Areas sitting close to the environmental limits for malaria transmission may be particularly sensitive to climate change.
A relatively small change in temperature, rainfall or humidity could make an area more suitable for mosquito survival or parasite development.
Higher-altitude areas are one example because historically cooler temperatures have limited transmission in some locations.
Changing conditions could therefore alter the geographical boundaries of malaria risk.
Recent African research using environmental and geospatial data has continued to show that variables including temperature, rainfall, vegetation, water availability and altitude can help explain differences in mosquito breeding and malaria transmission.
But identifying a climate that is suitable for malaria is not the same as predicting that an outbreak will definitely occur.
Climate Change Does Not Mean Everywhere Will Become a Malaria Hotspot
This is one of the most important points.
A warmer Africa does not automatically mean malaria transmission will increase everywhere.
Some places may become more suitable.
Some may experience longer transmission seasons.
Some could become less suitable because temperatures become too high or rainfall patterns change unfavourably for local mosquito populations.
And some places may remain environmentally suitable while malaria falls because effective prevention, diagnosis and treatment interrupt transmission.
Climate determines part of the opportunity for malaria transmission.
Public-health systems help determine whether that opportunity becomes disease.
Extreme Weather Can Increase Malaria Risk in Another Way
Climate change does not affect malaria only through mosquitoes.
Floods, cyclones, droughts and other extreme events can disrupt entire communities.
A major flood, for example, can damage health facilities, interrupt medicine supplies, displace families and reduce access to mosquito-control interventions.
People may temporarily move into crowded or poorly protected accommodation.
Health workers who normally provide malaria testing and treatment may be responding to multiple emergencies simultaneously.
These indirect effects can sometimes be as important as changes in mosquito biology.
WHO has highlighted extreme weather as an important concern for malaria control because climate shocks can affect both transmission and the health systems responsible for controlling it.
Why This Matters for Nigeria
Nigeria already carries one of the world's largest malaria burdens.
Climate change therefore does not introduce malaria into a country where the disease was previously absent. Instead, it could change an already complicated transmission environment.
Nigeria contains very different ecological zones.
Conditions in coastal southern Nigeria are different from those in the Sahelian north. Rainfall, vegetation, temperature, altitude, population density and water availability also vary substantially across the country.
Climate change may therefore affect malaria differently from one state or ecological zone to another.
This means a single national assumption about when and where malaria occurs may become increasingly inadequate.
Local surveillance becomes essential.
Surveillance May Need to Become Climate-Informed
Traditional disease surveillance tells public-health authorities where malaria cases are being reported.
Climate-informed surveillance can add another layer.
Health authorities can combine information on malaria cases with environmental information such as rainfall, temperature, flooding and other indicators.
The goal is not to allow a computer model to declare exactly where the next outbreak will happen.
The goal is to improve preparedness.
If environmental conditions indicate that malaria risk could increase in a particular location, programmes may be able to strengthen surveillance, prepare health facilities, ensure diagnostic tests and medicines are available and intensify appropriate prevention activities.
WHO is increasingly encouraging countries to develop climate-informed health surveillance and early-warning systems for climate-sensitive diseases.
Digital tools could become increasingly useful here. As discussed in our article on Artificial Intelligence in African Healthcare, AI and other analytical technologies can potentially help health systems identify patterns in large datasets. Their usefulness, however, still depends on reliable underlying data and appropriate human interpretation.
Better Data Will Matter
Climate-informed malaria control depends on data from several sources.
Health facilities need to report malaria cases accurately and promptly.
Laboratories need reliable diagnostic systems.
Meteorological information needs to be available.
Mosquito surveillance can provide information about vector populations and insecticide resistance.
Geographical information can identify communities experiencing changing environmental conditions.
Digital health systems can potentially bring some of these information streams together.
But digitisation alone does not guarantee good surveillance.
Poor-quality information entered into a sophisticated computer system remains poor-quality information.
The principles discussed in our guide to Electronic Health Records also apply here: digital systems are most useful when the information is accurate, accessible to authorised users, secure and integrated into real clinical or public-health decision-making.
Climate Change Is Not the Only Challenge Facing Malaria Control
Focusing exclusively on climate could create another problem: ignoring the other reasons malaria remains difficult to control.
WHO identifies multiple continuing challenges, including gaps in access to prevention and treatment, humanitarian emergencies, limited resources, insecticide resistance and antimalarial drug resistance.
Housing quality matters.
Access to healthcare matters.
Poverty matters.
Availability and correct use of insecticide-treated nets matter.
Rapid diagnosis and effective treatment matter.
Vaccination is becoming another important component of malaria prevention for eligible children in countries introducing WHO-recommended malaria vaccines.
Climate change should therefore be understood as a risk multiplier, not a complete explanation for Africa's malaria burden.
What Can Communities Do?
The changing climate does not make malaria prevention useless. In fact, effective prevention becomes even more important when transmission patterns are changing.
People living in malaria-endemic areas should continue following locally recommended malaria-prevention measures.
These can include using insecticide-treated mosquito nets, reducing appropriate mosquito breeding sites around homes, using other locally recommended vector-control measures and seeking timely testing when malaria is suspected.
Pregnant women and young children require particular attention because of their increased vulnerability to severe malaria.
A fever should also not automatically be assumed to be malaria.
Several illnesses can cause fever, and appropriate testing helps guide treatment.
Malaria Vaccines Are Adding Another Layer of Protection
Africa's malaria-control toolkit is also changing.
WHO has recommended malaria vaccines for children living in areas where P. falciparum malaria poses a significant public-health risk.
Recent evidence from the malaria vaccine implementation programme in Ghana, Kenya and Malawi has strengthened evidence that vaccination can contribute meaningfully to reducing childhood deaths when incorporated into broader malaria-control programmes.
Vaccines do not replace mosquito nets, diagnosis, treatment or other malaria interventions.
They add another layer of protection.
This becomes particularly valuable when countries are dealing simultaneously with climate change, insecticide resistance, health-system constraints and persistent malaria transmission.
What Should African Health Systems Prepare For?
The most important change may be moving away from the assumption that tomorrow's malaria patterns will always resemble yesterday's.
Countries need surveillance systems capable of detecting changes in where malaria occurs, when transmission peaks and which populations are becoming vulnerable.
That means connecting epidemiological surveillance with meteorological and environmental information.
Health facilities also need resilience against floods, heat and other extreme events so that malaria testing and treatment do not disappear precisely when communities need them most.
Research will remain important because there is still considerable uncertainty about exactly how long-term climate change will affect malaria in individual African locations.
The Bottom Line
Climate change could reshape malaria transmission across Africa, but it will not do so uniformly.
Temperature can influence mosquito survival and parasite development. Rainfall can create or remove breeding opportunities. Humidity can affect mosquito survival. Extreme weather can disrupt health services and displace communities.
Together, these changes may alter where malaria transmission is possible, when malaria seasons occur and which communities face greater risk.
But climate is only one part of the malaria equation.
Strong surveillance, mosquito control, malaria vaccination where recommended, timely testing, effective treatment and resilient health systems can still substantially change what happens.
The question for Africa is therefore not simply:
Will climate change increase malaria?
A more useful question is:
Where is malaria risk changing, when is it changing, and can health systems identify those changes early enough to respond?
That is where climate-informed malaria surveillance could become increasingly important.
Frequently Asked Questions
Does climate change cause malaria?
Climate change does not directly cause malaria. Malaria is caused by Plasmodium parasites transmitted mainly through infected female Anopheles mosquitoes. Climate conditions can influence whether mosquito populations and malaria transmission are able to thrive in a particular place.
Will climate change increase malaria everywhere in Africa?
No. Climate change could increase suitability in some areas, reduce it in others and alter transmission seasons elsewhere. Local environmental conditions and the strength of malaria-control programmes also matter.
Does more rain always mean more malaria?
No. Rainfall can create mosquito breeding sites, but extremely heavy rainfall can also disrupt some breeding habitats. The relationship depends on local mosquito species, drainage, water availability, temperature and other environmental conditions.
Could malaria spread into cooler areas?
Potentially. Locations that were previously too cool for efficient malaria transmission may become more suitable as temperatures rise. Higher-altitude regions are therefore an important area for surveillance.
Is malaria preventable?
Yes. Malaria is preventable and curable. Prevention can include insecticide-treated nets, vector-control interventions, preventive medicines for eligible populations and malaria vaccination for eligible children in areas where it is recommended. Prompt testing and effective treatment are also essential.
References and Further Reading
World Health Organization. Malaria. WHO Fact Sheet, updated December 2025.
World Health Organization. World Malaria Report.
World Health Organization. Climate Change and Health.
World Health Organization. Integrated Surveillance and Climate-Informed Health Early Warning Systems.
Symons, T. L., et al. (2026). Projected impacts of climate change on malaria in Africa. Nature.
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