It is a global scandal that 2.3 billion people do not have access to basic sanitation facilities and services.¹ This means, based on a back-of-the-envelope calculation, that several thousand tonnes of faeces are unsafely dumped into the environment each day – enough to fill Wembley Stadium! This is leading to enormous health burdens and economic costs disproportionately borne by the world’s poorest and most vulnerable people, particularly women and girls. And now climate change threatens to make this crisis much worse.

Climate change is now widely recognized as a major global health risk multiplier. Even on the optimistic end of emissions scenarios, the World Health Organization (WHO) estimates a quarter million additional deaths due to climate change per year between 2030 and 2050. Many of these deaths are directly linked to preventable diseases associated with inadequate sanitation and hygiene.

For example: diarrhoeal diseases, already a leading cause of child mortality and morbidity (especially malnutrition) are the highest preventable disease burden from environmental risks. Diarrhoeal diseases are also estimated by WHO and other health research (here and here, for example) to dramatically increase in direct proportion to rising temperatures in low income countries. An upsurge of other global scourges linked to poor sanitation and hygiene, such as cholera, typhoid, and a battery of neglected tropical diseases are also expected due to climate change.

This is because a potent combination of rising temperatures, unpredictable rain patterns, flooding and increased frequency and intensity of extreme weather events are expected to proliferate faecal-environmental-oral contamination routes. Overflowing sanitation facilities, disrupted hygiene habits, and accelerated pathogen development due to warmer temperatures will all add increasing stress on fragile health systems. Moreover, as a driver of inequality, climate change will be a growing factor that prevents increasingly vulnerable people to fulfil their human right to safe sanitation.

The growing health risks are clear. The bad news is that existing investment is not enough. According to the 2015 GLAAS Report, and a recent World Bank Study that tracks global water, sanitation and hygiene investment trends,²> current levels of financing are not sufficient to reach the Sustainable Development Goal targets and pre-empt anticipated climate change-linked health burdens.

The good news is that there is a growing recognition that public health is a bona fide climate change issue; the Ministerial Declaration on Health, Environment, and Climate Change, signed at COP 22 in Marrakesh in 2016, is another confirmation that the Paris Agreement is an international treaty for addressing the global disease burden. This offers an opportunity to recognize sanitation (and hygiene) at COP 23 and beyond as part of a broader climate adaptation package.

And there’s more good news: there are many cost-effective and scalable sanitation and hygiene interventions that directly target preventable diseases amplified by climate change. New insights, innovations and forward-thinking partnerships are continuously developing in the sector.

Sustainable behaviour change

Behaviours, habits and norms are foundations for improving sanitation and hygiene. After all, the most resilient sanitation service chains can only safeguard public health if they are actually used, and according to the most recent available figures, nearly 900 million people practice open defecation. In an era of unpredictable weather patterns, engrained and sustainable habits are an important aspect of resilience when rising numbers of floods, cyclones, and other disasters disrupt everyday sanitation and hygiene routines – just when communities are most susceptible to disease outbreaks.

Collective behaviour change approaches, such as Community-led Total Sanitation (CLTS), are a cost-effective and scalable solution. By focusing on empowering communities to end open defecation on their own terms, leveraging local knowledge, technologies and investments, rather than external hardware subsidies, approaches such as CLTS have the potential for locally responsive, community-led climate adaptation. Moreover, the Water, Sanitation and Hygiene (WASH) sector has greatly refined its understanding of what works and what doesn’t, with CLTS and similar approaches applied at increasing scale with the support of governments, non-governmental organizations, and global financing mechanisms such as WSSCC’s Global Sanitation Fund.

Affordable infrastructure and services

Overflowing and damaged sanitation facilities (e.g. pit latrines) from heavy rains and flooding are a significant potential source of water contamination from faecal waste, putting entire populations at risk. As a WHO/DFID report on WASH resilience notes, household-managed sanitation technologies are the likely future of the world’s population in both rural and urban environments, and have the adaptive potential to be highly resilient to climate change – especially non water-based systems. Improving the robustness of household facilities is only part of the resilience equation. As the Sustainable Sanitation Alliance’s ‘shit flow’ diagram tool illustrates, in the absence of safe emptying, transportation, treatment and disposal/reuse of waste, the vast majority of human waste flows straight back into the environment. With the ‘circular economy’ concept gaining traction in both the WASH and environmental sectors, as articulated by organizations such as UN Environment and the Toilet Board Coalition, viewing human waste as a resource incentivizes sorely needed sector investment across the sanitation value chain.

Sanitation as climate mitigation

To this end, sanitation can provide solutions to climate change mitigation. For example, substituting nitrogen-based chemical fertilizers for organic compost from safely treated human waste would result in significant emissions reductions due to lower energy inputs. There are also exciting new initiatives to transform waste into biogas – like in Nepal – which reduce emissions from carbon fuels, prevent deforestation, and improve indoor air quality. As a nascent industry, however, catalyzing investment across the sanitation service chain will likely require strong public-sector support to correct market failures, incentivize service delivery for the poorest, ensure robust public health protections, and enforce strong regulations to protect the rights and safety of sanitation workers.

While there is a lot of room for the sector to improve how it integrates climate change risks and opportunities into programmes and policies, sanitation and hygiene are undoubtedly essential components of a comprehensive climate adaptation and mitigation package. Many potential and proven solutions are already on the table. Nearly all National Adaptation Plans published by the UN Framework Convention for Climate Change identify improving sanitation and hygiene as a priority. The challenge remains for climate finance to turn these Plans into action for the 2.3 billion people who lack access to basic sanitation facilities and services.

¹Progress on Drinking Water, Sanitation and Hygiene: 2017 Update and SDG Baselines. World Health Organization & UNICEF, 2017. http://who.int/mediacentre/news/releases/2017/launch-version-report-jmp-water-sanitation-hygiene.pdf

² The Costs of Meeting the 2030 Sustainable Development Goal Targets on Drinking Water, Sanitation, and Hygiene. World Bank, 2016. http://www.worldbank.org/en/topic/water/publication/the-costs-of-meeting-the-2030-sustainable-development-goal-targets-on-drinking-water-sanitation-and-hygiene