Education Team
Sep 17, 2026
Why healthcare workers have a role to play
Every year on 26 September, World Environmental Health Day reminds us of a simple but often overlooked truth - the health of people is inseparable from the health of the environments in which they live.
The theme for World Environmental Health Day 2026 is “Environmental Health: Standing with Science to Protect Communities”. Across the world, rising temperatures, extreme weather, air pollution, changing patterns of infectious disease, and threats to food and water security are increasingly shaping the patients who arrive at our clinics and hospitals.
For healthcare workers, climate change is therefore no longer an abstract environmental concern. It is a health issue, and it is already in our healthcare facilities.
The 2025 Lancet Countdown on Health and Climate Change, produced by 128 experts from 71 institutions and tracking 57 indicators, paints an increasingly concerning picture. Across 13 of its 20 indicators of climate-related health hazards, exposures and impacts, risks have reached record levels. Perhaps nowhere is this clearer than with extreme heat. The rate of heat-related mortality has increased by 23% since the 1990s, reaching an estimated 546,000 deaths each year. In 2024, the average person experienced 16 days of dangerous heat that would not have been expected without human-induced climate change. Infants and the elderly experienced particularly high levels of exposure.
Heat doesn’t just stop at heatstroke. It can worsen cardiovascular and respiratory disease, increase dehydration and kidney injury, disrupt sleep and reduce people's ability to work safely. Pregnancy, infancy, older age and many chronic illnesses can further increase vulnerability.
Climate change also threatens health through food insecurity. Heatwaves and drought were associated with an additional 124 million people experiencing moderate or severe food insecurity in 2023. For health systems already managing childhood malnutrition and household food insecurity, the relationship between climate and nutrition is increasingly difficult to ignore.
Extreme weather brings additional threats. In 2024, exposure to wildfire smoke was associated with an estimated 154,000 deaths from fine particulate air pollution globally. And the economic effects ultimately become health effects too. Heat exposure resulted in an estimated 640 billion potential labour hours lost in 2024, equivalent to approximately US$1.09 trillion in lost productivity.
Why this matters for Southern Africa
Africa sits at the centre of a profound climate injustice. Many countries on the continent have contributed relatively little to historical greenhouse gas emissions, yet communities across Africa are experiencing substantial consequences of a changing climate. For Southern Africa, climate change intersects with health systems already carrying significant burdens of infectious disease, malnutrition, maternal and child health challenges, and non-communicable diseases.
Children, older people, pregnant women, people living with chronic illnesses, outdoor workers, and communities experiencing poverty or inadequate housing are often among those most vulnerable. Climate change therefore acts not only as a health threat, but amplifies existing inequalities and vulnerabilities.
Recognising the need for locally generated evidence, the Lancet Countdown launched its Africa Regional Centre in 2025, headquartered at the University of Pretoria. Its aim is to strengthen African-led research examining the relationship between climate change and health and, crucially, to translate this evidence into action.
What Can We Do?
Avoid unnecessary investigations and treatments where clinically appropriate, reduce avoidable waste, support environmentally responsible procurement and encourage recycling systems that are safe and feasible. Small improvements multiplied across hospitals and health systems can become substantial.
Learn to recognise climate-related health risks. Ask how extreme heat, air pollution, flooding, drought and food insecurity may be affecting the communities you serve. Incorporate environmental exposures into clinical thinking when relevant. Talk about climate change as a health issue. Healthcare professionals are uniquely positioned to translate an enormous global problem into something tangible: asthma exacerbations, malnutrition, heat illness, infectious disease, cardiovascular disease and disrupted access to care.
And finally, contribute to the evidence. For junior healthcare professionals, climate and health represents a rapidly developing research field. We need locally relevant evidence on heat exposure, infectious diseases, nutrition, air pollution, climate-resilient healthcare systems and the populations most vulnerable to environmental change.
Globally, healthcare contributes approximately 4–5% of greenhouse-gas emissions. Importantly, much of this footprint sits within the healthcare supply chain - the medicines, equipment, consumables, food and other products that health systems purchase and use.
Quality improvement is already embedded in healthcare. We audit hand hygiene, antibiotic prescribing, waiting times and adherence to clinical guidelines. Environmental sustainability can be approached in much the same way.
A ward or department could, for example, conduct a simple waste audit measuring how much general and healthcare-risk waste the ward produces, whether waste is being correctly segregated, how often general waste is unnecessarily placed into infectious or hazardous-waste streams, which disposable items are frequently opened but never used, and where potentially avoidable waste is being generated.
Healthcare workers can look critically at routine practices that generate unnecessary consumables. Are procedure packs routinely opened before we know all their contents will be required? Are supplies expiring because wards routinely over-order stock?
Southern Africa should not simply be a setting in which climate-health research happens. We should be among those asking the questions, generating the evidence and determining what solutions work for our communities.
Further reading
Want to get involved? You don't have to start from scratch
There are already organisations building the climate-and-health community in Southern Africa.
Wits Planetary Health Research (Wits PHR), based in Johannesburg, conducts research specifically at the intersection of climate change and human health. Current projects include the HE²AT Center, which is developing heat-health early-warning and monitoring tools for vulnerable African populations; the Bio-HEAT study investigating heat exposure and adverse maternal and child health outcomes in South Africa; and the Global Heat Attribution Project examining the contribution of climate change to maternal and child health outcomes internationally.
At a broader level, the Global Climate and Health Alliance connects organisations representing millions of healthcare workers internationally and provides opportunities to engage with climate-and-health advocacy, events and networks