Climate, health and WASH: how water, sanitation and hygiene can secure people’s health in our changing climate

The links between climate change and health are being recognised in global climate discussions – and water, sanitation and hygiene (WASH) need to be part of the conversation. We explain how these three issues are related and how WASH is a crucial and affordable solution to the climate and health crises.

For the first time at a UN climate summit, the critical intersections between climate change and health will be explored as part of a thematic day at COP28. Health Day (3 December), led by the World Health Organization (WHO), will seek to mainstream health into the global climate change agenda. It will also include the first ever Climate-Health Ministerial, where ministers from health, environment, finance, and other sectors will identify key areas for action and explore the socio-economic opportunities for health and wellbeing, delivered by climate action.

At WaterAid, we have been campaigning for investment in WASH for health since 2015, and for climate adaptation since 2020. But how are climate, health and WASH linked, and how can WASH help tackle both the climate and health crises simultaneously?

What is the climate, health and WASH nexus?

Every year, environmental factors including inadequate access to WASH cause 13.7 million deaths worldwide – almost a quarter of global deaths. We know that the climate crisis is a water crisis, and so increased water insecurity and limited access to WASH due to climate impacts will also contribute to a health crisis, and an increase in these deaths.

The precise impacts of a changing climate are difficult to predict; they will vary by location, and by season within the same area. Yet it is already clear that these impacts will negatively affect health in many ways, such as by increasing the burden of water-related diseases, to which women and girls are especially vulnerable. In fact, by 2030, it’s expected that ill-health linked to climate change will cost US$2-4 billion a year globally.

Coupled with economic and social factors, such as poverty and gender, the impact of the climate change, health and WASH nexus is a clear cause for concern – and an impetus for urgent investment.

A perfect storm: the resurgence of cholera as a climate, WASH and health crisis

Cholera is a deadly waterborne disease, mainly spread through contaminated water and food. While the disease has been eliminated in many high-income countries and regions, it continues to act as a measure of inequality, posing a dangerous threat to the poorest and most vulnerable communities.

Over the past two years, there has been an unprecedented spread of the disease globally. In 2022, cholera was reported in 44 countries – up by a quarter on the previous year – and WHO estimates that one billion people are now at risk due to the ongoing surge in infections. This unprecedented spread has been exacerbated by the impacts of climate change – through both too much and too little water.

Severe weather events have played a major role in aggravating seasonal patterns of cholera outbreaks. Flooding caused by storms and cyclones damages already weak WASH systems, causing water sources to be contaminated with faecal matter, and continuing the cycle of disease. And while cholera tends to spread more during the rainy season, we are seeing a worrying pattern of cases persisting into the dry season in Malawi and Mozambique, two countries among the worst affected by cholera in Africa in 2023.

In other countries, such as Kenya, drought and water scarcity have direct correlations with an increase in cholera cases. When water becomes scarce, it can rarely be spared for essential hygiene measures such as handwashing, and where the bacterium that causes cholera is present, the absence of effective hygiene measures creates the perfect conditions for the disease to spread.

Changes to weather patterns also make the management of waterborne diseases more difficult, and the impacts are experienced most by people who are already vulnerable or experience marginalisation, such as those living in informal settlements and underserved rural areas, and women and girls who face greater exposure to infectious diseases through a combination of social and economic factors, both at home and in the health workforce.

But the increase in cases of infectious diseases like cholera are by no means the only way in which climate change is already, and will continue to, impact people’s health. In Europe, the effects of extreme heat contributed to the deaths of more than 60,000 people in 2022 alone, and the climate crisis will continue to place further burdens on already overstretched health systems, especially in the world’s least developed countries.

WASH as an affordable climate and health solution

The provision of safe WASH services is key to bringing the cycle of infections to an end, not just of cholera but of a host of other infectious diseases. Safe and sustainable WASH services are also absolutely crucial for effective climate adaptation and to ensure communities can become resilient to the effects of climate change.

And yet, in the world’s least developed countries, nearly half of all healthcare facilities don’t have basic water services and more than 2 in 3 do not have basic hand hygiene facilities. Inadequate WASH makes effective infection prevention and control impossible. But this is an avoidable tragedy, and a solvable problem.

The estimated cost of achieving universal access to WASH in existing healthcare facilities in these settings is around $9.6 billion – an average of just $0.60 per person per year in the world’s least developed countries,. These investments would not only yield benefits of up to 16 times their value, but also start paying for themselves within a year and produce savings of around $1.50 for every dollar invested thereafter.

Despite this stark evidence, there is nowhere near enough funding allocated to these low-regret, high-impact investments. On average, only 3% of all climate finance is water-related, and only 6% is targeted to any kind of adaptation measures (PDF). Unlocking climate finance to support WASH as a critical adaptation measure for health will be fundamental to building the long-term resilience of health systems, protecting the people in the communities they serve and ensuring they can cope with the effects of the climate crisis.

It remains to be seen how COP28 and the Climate-Health Ministerial will move forward the conversation on climate and health, or how the international community will respond to these interlinked challenges. But as the climate crisis deepens, WASH must not be overlooked as a crucial and affordable solution to securing people’s health and resilience in a changing climate.

Arielle Nylander is WaterAid’s Senior Policy Analyst – Health

Read more about our engagement at COP28

Top image: Mtima Grey, 38, washes her hands with soap at a handwashing station at the main gate of Ntchisi District Hospital. June 2023.