Is Climate Change Causing Disease Rise in the Pacific and Africa?

The Earth has been warming rapidly over the past century. While natural processes have influenced the planet’s climate throughout history, the speed and intensity of warming over the last 100 years cannot be attributed solely to natural causes. The UN’s Intergovernmental Panel on Climate Change (IPCC) attributes this acceleration to human activities, notably the burning of fossil fuels.

According to the European Copernicus Climate Service, global temperatures have averaged approximately 1.28 °C above pre-industrial levels since the late 19th century. In fact, 2024 was the warmest year on record, with climate change identified as the primary driver of this phenomenon. Rising temperatures are already altering weather patterns worldwide.

How warming fuels the spread of vector-borne diseases

The effects of climate change go beyond extreme weather. Shifts in rainfall, flooding, and drought are altering the spread of vector-borne diseases, including dengue and malaria. Warmer conditions directly influence the behaviour of mosquitoes, ticks, and flies, the diseases they carry, and their interaction with human hosts.

The Pacific Islands are already experiencing one of the worst dengue outbreaks in a decade. According to The Guardian, Samoa, Fiji, and Tonga are among the hardest hit, with more than 16,000 confirmed cases and 17 deaths since early 2025. Samoa alone has reported over 5,600 infections and six deaths, Fiji has confirmed nearly 11,000 cases and eight deaths, and Tonga has recorded over 800 cases and three deaths since February.

A 2025 case study on dengue virus transmission on Aedes aegypti mosquitoes, which transmit dengue, found a strong correlation between rising temperatures, altered rainfall patterns, and increased mosquito density. The study projects a 25% increase in global mosquito populations and a 35% rise in dengue incidence by 2050, with Southeast Asia, South America, and Sub-Saharan Africa at the highest risk.

Malaria resurgence in Southern Africa

The warming climate is also fueling a surge in malaria in Southern Africa. According to The Economist, countries such as Botswana, Eswatini, Namibia, and Zimbabwe are experiencing severe outbreaks. Zimbabwe has been hit hardest, reporting nearly four times as many cases and six times more deaths compared to the same period in 2024.

The Malaria Atlas Project (MAP) warns that climate change could undermine eradication efforts, predicting an additional 550,000 malaria deaths between 2030 and 2049 if no stronger measures are taken.

According to the article, warmer weather can extend the malaria season and speed up the mosquito life cycle.  Heavier rains could create stagnant pools that are perfect breeding grounds for these malaria-carrying mosquitoes. 

Another reason for the surge in cases in Zimbabwe is that people are reluctant to use insecticide-treated bed nets. These bed nets are set up at nighttime to protect people from mosquito bites; however, in warm temperatures, they could be uncomfortable or too hot to sleep in, and people, especially pregnant women, refrain from using them.

How governments are responding

The Economist notes that countries in Southern Africa are struggling to cope with the increasing number of vector-borne diseases, including malaria. While South Africa has a significantly lower rate of malaria cases compared to other African nations, such as Mozambique, which reports millions of cases, many individuals from Mozambique migrate to South Africa in search of job opportunities.

In response, it has expanded free screenings and malaria treatments.

Other strategies include:

• Sterilising male mosquitoes to limit breeding.
• Vaccinations: Pilot programs in Ghana, Kenya, and Malawi have cut child mortality by 13%, and over 20 countries now administer malaria vaccines.
• Preparedness measures, such as stockpiling essential supplies like drugs and nets, and utilising climate data to anticipate outbreaks.

These initiatives underscore the pressing need for climate adaptation in public health, as rising global temperatures complicate and intensify the control of diseases.