Tackling climate change and improving access to safe sanitation are two of the defining challenges of the 21st century but are rarely considered together. Successful adaptation requires joined up action and better use of climate finance for sanitation.

Tackling climate change is the most urgent priority of the 21st century. We are already locked in to changes in the climate as global temperatures increase. The UN recently reported that there is no credible pathway to limiting global temperature increase to 1.5 degrees Celsius, which means the world needs to pay far more attention to how we adapt to the changing climate. Sanitation forms a bedrock of public health, but global estimates show that 3.6 billion people continue to lack access to safely managed sanitation, and nearly half a billion continue to practice open defecation. Addressing this deficit is one of the most pressing global public health and social issues.

The important relationships between these twin problems continue to be ignored despite the growing evidence that they are closely linked and that joined up actions are required. The relationships fall into three major areas where action is required. Two deal with adaptation and resilience, and one deals with sanitation as a source of greenhouse gas emissions that drive climate change.

Sanitation is key to resilience

Sanitation is critical to building the resilience of communities, societies, and economies. When communities are hit by extreme weather events, inadequate sanitation can lead to widespread distribution of faecal matter in the environment. This leads to the spread of infectious diseases, causing populations to be more vulnerable and less able to cope with the other consequences of extreme events. Such critical challenges to limited sanitation systems further increases the psychosocial stresses associated with such disasters. Women and girls in particular may be at increased risk of sexual violence and harassment as they seek places to relieve themselves and who have the added stress of managing their periods. Provision of good sanitation is therefore a cornerstone of community resilience.

Countries with good sanitation tend to have healthier and more productive workforces, which are better able to cope with climate threats and challenges. Countries without good sanitation suffer economically. They spend money on avoidable healthcare costs, lose productive days of work in the workforce, and attract less investment. Key sectors, such as in tourism and food exports, may also suffer as countries are affect by export restrictions because of concerns over food safety, and tourists avoid countries because of concerns over disease.

Climate change directly affects sanitation

If sanitation is to support communities to be more resilient, then sanitation systems themselves need to be resilient to climate. Sanitation can be highly vulnerable to climate events: floods cause latrines and septic tanks to overflow; and droughts can lead to blockages in water-based sanitation and cause problems with sewage management. Storm surges and freshwater floods can swamp wastewater treatment plants, leading to the release of poorly or untreated waste into the environment. And a warming climate will affect the biological processes in wastewater treatment, making them less effective.

The lack of resilience in most sanitation systems is obvious. It can be seen in the flooding of villages and slums that rely on latrines and tanks, or the increasing frequency of combined sewer overflows experienced in the UK. Building resilience in sanitation needs to consider the changing nature and extent of climate threats and what infrastructure and operational changes are required to make systems more robust. This will mean, for instance, shifting away from on-site sanitation where groundwater flooding is likely to increase, or using modified sewerage that uses less water where water scarcity increases.

A key element in building resilience is professionalisation in the management of sanitation systems. For far too many households, sanitation is something they must build themselves, with services to empty latrines and tanks offered by providers with little technical skill and inadequate equipment. Resilience will require much greater government engagement and oversight of service provision, with stronger control on what and how sanitation is provided. Resilience will also require more investment in treatment of waste and better planning of the location of such plants. Too many wastewater treatment plants continue to be built with no consideration of flood risks and so are vulnerable to inundation and damage.

Sanitation contributes to climate change

Sanitation systems emit greenhouse gases. As faecal waste decomposes, it produces methane and nitrous oxide, both more potent greenhouse gases than carbon dioxide. Action to reduce emissions from sanitation was given additional impetus with the commitments to reduce methane made at COP26 in Glasgow in 2021.

Assessments at a global level suggest that on-site sanitation may contribute one to two percent of global methane emissions, and research in cities of low- and middle-income countries indicates that onsite sanitation can contribute to over half of the greenhouse gases emitted. But we need a better understanding of emissions, and the ways to reduce these, from on-site sanitation. There are ongoing empirical studies to estimate emissions, which should help improve quantification. Analysis of options to reduce emissions points to better operation and maintenance and changes in design – essentially smaller containments that are emptied more frequently. But doing this will require much more investment by local and national authorities in utilities, as well as households, and occupational health concerns for sanitation workers will need to be addressed.

Reducing emissions will also require investment in wastewater treatment so that it can cope with increased septage volumes. At wastewater treatment plants, the capture of methane and its use in biogas may also play a role. The evidence points to this being effective when used in centralised plants. Community level biogas systems have a poor track record and are unlikely to offer a widely applicable solution.

The need for climate finance

Joined up action on sanitation and climate resilience will require investment from climate finance. To date, however, climate funds have made very limited investments in sanitation. Climate finance often demands a demonstration of “additionality” – that is that the funds do not fund development needs but are used as extra investment to specifically address climate change. This is largely because of the political debate on the role of official development assistance in tackling climate.

This demand for additionality is clearly not fit for purpose. Because sanitation is central to resilience, additionality should not be required because sanitation investments are foundational. Likewise, there needs to be investment from climate finance to reduce emissions from sanitation. Increasing investment by climate finance in improved sanitation will require the climate funds to use high quality indicators when assessing the quality of sanitation proposals. This is achievable, and examples already exist of measures and metrics that could be used.

We have an opportunity to support adaptation and improve public health by investing in sanitation – but we need joined action and it is needed now.

Professor Guy Howard is the Director of the Cabot Institute for the Environment and Global Research Chair in Environmental and Infrastructure Resilience at the University of Bristol: Professor Guy Howard – Our People (bristol.ac.uk). He spent 16 years working for DFID in a number of roles, including as policy lead for WASH.  

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