Extreme heat is becoming Southern Africa’s defining climate and health threat, report warns

As temperatures in parts of the Western Cape and Namakwa District soared to record-breaking highs last month, a new scientific assessment is warning that extreme heat is no longer a future threat in Southern Africa: it is becoming one of the region’s most dangerous public health and climate risks.

After issuing a heatwave advisory on 8 March, the South African Weather Service confirmed that several stations across the Western Cape and Northern Cape had broken long-standing March records. Alexander Bay reached 44.8°C, Garies 43.5°C and parts of Cape Town climbed to nearly 40°C.

But the searing temperatures are not just an isolated weather event. According to a new consensus study by the Academy of Science of South Africa, funded by the department of science, technology and innovation, extreme heat is emerging as one of the most urgent and fast-escalating threats facing countries across the Southern African Development Community (SADC).

The report is the first integrated regional assessment of how rising temperatures are affecting health systems, labour conditions, food security, urban environments and ecosystems across Southern Africa.

“Extreme heat is no longer a distant projection; it is already reshaping the lived realities of millions of people across Southern Africa,” said Professor Jerome Amir Singh, who chaired the expert panel behind the study. 

“This report highlights the urgency of strengthening heat-health preparedness and provides clear, evidence-based pathways for governments and communities to respond.”

At the centre of the report is the idea of extreme heat as an “integrator hazard”, a climate threat that does not strike in isolation but amplifies a web of existing risks. 

Rising temperatures intensify drought, increase wildfire risks, worsen air pollution and place additional stress on water, energy and health systems, disproportionately affecting vulnerable populations. 

Global temperature trends underscore the urgency. Nineteen of the world’s 20 hottest years have occurred since 2000 and record-breaking monthly temperatures now occur five times more frequently than in the past. 

In SADC countries, the trends intersect with structural vulnerabilities including high levels of outdoor labour, rapid urbanisation and strained public-health systems.

Africa is warming faster than the global average and the report notes that many countries remain highly vulnerable because of poverty, inadequate infrastructure and poor housing. In many low-income communities, homes built with heat-absorbing materials such as tin sheeting can become dangerously hot during extreme heat.

The report noted that despite accounting for less than 1.3% of global emissions in 2010, SADC countries remain committed to both mitigation and adaptation, with a particular focus on practical strategies that can protect communities. 

Gaps in research and implementation mean urgent attention is needed to identify knowledge gaps and develop evidence-based responses.

The health consequences of rising temperatures are visible. Extreme heat increases the risk of heat exhaustion, heatstroke, kidney injury and cardiovascular disease, contributing to higher emergency department visits, hospital admissions and heat-related mortality. 

Certain groups are particularly at risk. Emerging research shows that pregnant women exposed to extreme heat are more likely to experience stillbirth, preterm birth, maternal complications and low birth weight. Infants and young children are highly vulnerable because of their limited thermoregulatory capacity, while older adults experience the highest rates of heat-related mortality.

“Emerging evidence shows extreme heat is directly threatening lives across the life course, from newborns to older adults,” Singh noted. 

Labour patterns in Southern Africa amplify the risk of exposure to extreme heat. Agriculture remains the largest employer in many SADC countries, alongside construction, mining, transport and informal trading, all sectors that rely heavily on outdoor or manual labour. 

In several member states, up to 80% to 90% of workers are employed informally, often without workplace protections, shade or cooling infrastructure. Millions of workers are therefore forced to endure extreme temperatures, exposing them not only to health risks but also to lost productivity and income.

“Labour markets in Southern Africa place millions of people in direct contact with extreme heat, often without adequate protections, amplifying both economic and health risks,” the study notes. 

Rapid urbanisation across the SADC region, with urban populations set to grow sharply by 2050, is expected to intensify heat exposure, particularly in informal settlements and densely built areas, the report says. 

Extreme heat also increases competition over scarce water and arable land, sometimes driving displacement and conflict. 

The report also points to mounting indirect impacts. Climate-related shocks are increasingly linked to stress, anxiety and depression, while hotter conditions worsen air pollution by increasing ozone and particulate matter, adding further strain to respiratory and cardiovascular health.

Heat further affects disease ecology: warming accelerates the breeding of vectors and the development of parasites for malaria, dengue and Rift Valley fever, though extreme temperatures can also reduce vector survival, producing complex, nonlinear impacts.

“Extreme heat is not only a physical hazard; it affects mental health, air quality and the spread of infectious diseases, compounding the burden on vulnerable communities,” the study notes.

Urban areas face further challenges. Rapid urbanisation and poorly planned cities create urban heat islands, which trap heat and intensify exposure for residents, particularly those living in informal settlements with limited access to water, electricity and cooling. 

The report warns that urban design and infrastructure can either protect or expose communities and calls for investment in cooling spaces, green cover and water access to reduce heat-related risks.