Climate change is important because of the threat it poses to human health and well-being as well as all other life on the planet. The effects of climate change are all around us, with a third of Pakistan recently underwater and Europe recovering from the worst drought in 500 years.

In Africa, we are also seeing the impact of prolonged drought in the Horn of Africa destroying livelihoods, deepening poverty and food insecurity; as well as in South Africa with over 400 people losing their lives from a “rain bomb” in Durban. Unsurprisingly, The Lancet, one of the world’s leading medical journals, has pronounced climate change as the greatest threat to human health and well-being in the 21st century.

Despite this there has been relatively little attention given to understanding the health impact of climate change and health sciences, particularly in Africa, have not engaged with the issue of climate change. It is time for us to better prepare health professionals for the effects of climate change and to research not only the impact, but also how health systems can become more resilient.

Mitigation to reduce the carbon footprint of health systems is important globally, but the contribution of African health systems is trivial by comparison.

There are three important relationships in the nexus between climate change, human health and health systems. Firstly, how climate change impacts the burden of disease. Secondly, how the burden of disease and climate change impact health facilities and services, and thirdly, how health systems contribute to the problem of climate change.

It is important to keep in mind that climate change is not the only important ecological driver of environmental change with an impact on health and well-being. Other drivers include the loss of biodiversity and what the World Wildlife Fund has called the sixth mass extinction.

Humans have also caused profound changes in land use and coverage as well as substantial amounts of pollution in the air, ocean and land. All of these changes combined have created an environmental crisis that impacts human health.

The severity of this impact will however also depend on the resilience of society and our ability to adapt. Societies with many resources and wealth, effective leadership and governance, suitable technology and a strong social foundation may be able to reduce the impact.

On the other hand, low- and middle-income countries, many of which are in Africa, will have less ability to withstand the impact.

Ultimately, the effects on human health are predictable and we are already seeing many of them. Malnutrition will be a problem for many communities as climate change reduces food production. Crops are impacted by extreme weather events such as high temperatures, drought, storms and fires, as well as changes in pests and diseases. Many pastoralists and farmers will lose their livelihoods and be forced deeper into poverty as we are seeing in the Horn of Africa.

The prevalence of vector-borne infectious diseases will change and there will be outbreaks of water-borne diseases. For example, the geographical footprint of mosquitoes will be altered and with this the spread of malaria. Communities suffering from storms report that more stagnant water is also increasing the incidence of malaria.

Water in drought-stricken areas will have higher concentrations of pathogens, particularly where sanitation is poor, leading to outbreaks of gastroenteritis. Breakdown in water supplies and sanitation after extreme weather events, such as cyclones, can also lead to outbreaks of diseases such as cholera.

Extreme temperatures above 40°C will become more common and heat waves will create new health challenges. High temperatures can cause sleep problems, heat exhaustion, heat stroke, increased aggression and skin problems. Manual labourers, pregnant women, small children, the elderly and those with other conditions such as diabetes or heart disease will be particularly vulnerable.

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Injuries and trauma are also likely. Extreme weather events, such as the floods in Durban, cause many injuries alongside deaths. Displacement of people and migration can also lead to conflict over resources. Up to 17-40 million people may be climate migrants in Africa by 2050.

Gender-based violence in these unstable situations may increase. There are also concerns that women have to travel further in search of water in many communities and, as such, will be more at risk.

Longstanding symbiotic relationships may be altered by seasonal changes. For example, in Nigeria, herders are bringing their livestock into the farming areas before the harvest is collected, leading to violence and conflict.

Not surprisingly, as people try to cope with the impact of climate change, they may suffer from mental health disorders such as post-traumatic stress, depression and anxiety. Health services for mental health problems in Africa are already scanty and ineffective.

How then should our health services prepare to cope with climate change?

The World Health Organization says “a climate resilient health system is one that is capable to anticipate, respond to, cope with, recover from and adapt to climate-related shocks and stress, so as to bring sustained improvements in population health, despite an unstable climate.”

Such a health system must pay attention to its leadership and governance, health workforce, health information, infrastructure and technology, service delivery and financing. Climate change should be a stimulus to African governments to strengthen their health systems. Resilient health systems will improve the ability of society as a whole to adapt to climate change.

Governments must ensure that health policy includes plans for climate resilience and adequate funding of these plans. Global funding for adaptation to climate change should be channelled to health systems.

Although Africa has contributed the least to causing climate change, it will suffer the most from its impact. The Global North has a responsibility to pay for the loss and damage caused by climate change. We expect most of the world’s leading medical journals to make such a call in the lead-up to COP27 in Egypt later this year.

We must ensure that our health workforce is sufficient in numbers to respond to the challenges, capacitated to cope, and aware of the links to climate change. Many should raise their voices as healthcare workers to ensure that governments respond.

In primary healthcare, we must help communities reduce their vulnerability through community engagement and multisectoral action. Health information systems must track climate-sensitive diseases, give warnings of extreme weather events and help identify vulnerabilities at the community level.

Our buildings must be designed to withstand high temperatures and remain functional during extreme weather events with energy, water, waste and telecommunications. Thought must be given to maintaining supply chains and to issues such as temperature-sensitive medications.

All our facilities should have disaster management plans and emergency preparedness. Services should anticipate the challenges from a changing burden of disease as outlined above.

According to a recent report from Health Care Without Harm, “if the health sector were a country, it would be the fifth-largest emitter on the planet.” Of course, it is the health systems in the Global North that have contributed the most to this. Nevertheless, our health systems should develop responsible consumption and ensure they contribute to targets set in the Paris Agreement.

For example, in Cape Town, health services are planning to become carbon-neutral by 2050. The City of Cape Town is one of 40 cities worldwide that have committed to this goal.

The Global Green and Health Hospitals network helps health systems to be environmentally responsible. The Department of Health in the Western Cape has joined this network as has the Faculty of Medicine and Health Sciences at Stellenbosch University. The Faculty is preparing future health professionals to be environmental stewards and to lead healthcare without environmental harm.

In doing this we are following a 10-point agenda that focuses on leadership, energy, water, waste, food, transport, biodiversity, purchasing, chemicals and buildings. The faculty has set goals in all these areas for 2024 and recently appointed a lecturer in planetary health to lead education and research.

An environmental plan has recently been approved, which aims to become carbon neutral through the use of solar voltaic energy, technical efficiencies in the use of energy, behaviour change and carbon offsetting.

Water efficiencies were introduced after Cape Town’s drought a few years ago with stormwater storage for irrigation, grey water systems for the toilets, boreholes and plans for stormwater collection to replenish the aquifer. All new buildings are planned with at least a 4-star green rating and must be carbon neutral by 2030. Students and staff are involved in ecosystem restoration, reforestation and cleaning of the natural environment.

When The Lancet declared that climate change was the greatest threat to human health of the 21st century, they also said that it is the “greatest opportunity to redefine the social and environmental determinants of health”.

Let’s hope that we are up to the challenge. DM

This article is based, in part, on a recent Stellenbosch Forum lecture by Prof Mash.

Prof Bob Mash is a family physician and the executive head of family and emergency medicine at Stellenbosch University. He is the president of the South African Academy of Family Physicians, the professional body for family physicians.