As global temperatures rise, it is the water cycle that is changing most dramatically, most unpredictably, and with some of the greatest consequences for people everywhere. Climate change is disrupting water availability and quality, amplifying floods and storms, and increasing the frequency of droughts. For water-sector decision makers, all of these impacts add up to a fundamental disruption: decisions that were once based on historical data are now afloat in uncertainties about the climate of the future.
At the same time, the water sector is, itself, a place to take on the drivers of climate change. The sector currently contributes up to 5% of global greenhouse gas emissions, and with demand for water set to increase by 20-30%  in the next 30 years, its emissions will only rise – unless something is done.
Municipal systems, global commitments
Strong mitigation potential lies in urban water and wastewater systems, whose energy consumption, mostly driven by fossil fuels, makes up as much as 40% of municipal energy use in some cities. In developing and emerging countries, water and wastewater utilities often rely on inefficient pumps, leaky distribution lines and dated treatment technologies. They emit carbon dioxide from their energy use, and even more potent greenhouse gases – methane and nitrous oxide – from the breakdown of untreated or poorly treated sewage. Since 2014, the project Water and Wastewater Companies for Climate Mitigation (WaCCliM) has been working with selected countries and utilities to prove that in the urban water sector, climate mitigation action can be achieved alongside, and in harmony with, climate-resilient sustainable development.
WaCCliM’s experience has shown that the flow of water into, through and out of cities connects some of the largest commitments of developing and emerging countries. Among these, two stand largest: the Nationally Determined Contributions (NDCs) that governments have pledged in order to reach the climate targets of the Paris Agreement; and the Sustainable Development Goals (SDGs) that they are striving to achieve by 2030.
Clean water and sanitation command their own SDG, Goal 6, but in truth water runs through nearly all of the goals, and unites them with success or failure in climate action. Even in a stable climate, countries would be facing an enormous challenge just to reach Goal 6 – availability and sustainable management of water and sanitation for all. Billions of people still live without safe water, sanitation or both, and the effects undermine other goals like health, equality and the vision of sustainable cities. Now the uncertainties of the climate require thinking even harder about water insecurity, including in cities; about which people have as much water as they need without having more than they can manage, about how clean that water will be under all possible conditions, and about how to generate the energy that will get it there.
A climate-smart roadmap
The NDCs that countries have submitted reveal an awareness of just how central water is to climate adaptation. According to a Global Water Partnership analysis of 80 NDCs, investing in water infrastructure, institutions or governance is a key priority in 89% of the surveyed countries, and practically all countries indicate that some kind of water action is necessary for adaptation. Far fewer NDCs, however, mention the substantial opportunities to reduce greenhouse gas emissions found in the urban water and wastewater sector. It’s here that WaCCliM is guiding countries to mitigation opportunities, starting at the utility level.
The Project has introduced a roadmap of systematic steps and measures towards low-carbon water and wastewater utilities that can also plan for climate risks and improve their services to better support sustainable development. Helping utilities on this path is the project’s Energy Performance and Carbon Emissions Assessment and Monitoring Tool (ECAM), which any utility can use to assess its emissions and pinpoint opportunities to use less energy – or even generate its own energy.
From the utility up
WaCCliM has piloted mitigation solutions, ranging from energy-efficient pumps to technologies for generating power with wastewater biodigesters, with utilities in Jordan, Mexico, Peru and Thailand. The measures prioritised in these pilots have achieved total mitigation equivalent to 10,000 tons of carbon dioxide – or planting 50,000 trees – per year. WaCCliM is also introducing adaptation thinking by helping the pilot utilities develop climate risk plans, advising utility personnel on ways to build water system resilience to the risks identified, reducing water losses and recycling treated wastewater. The toolbox of both mitigation and adaptation planning measures will be available to utilities everywhere on the knowledge platform Climate Smart Water.
Through these tools WaCCliM´s approach can substantially help meet NDCs across developing and emerging countries, and by building climate-smart urban water systems, it can help achieve the SDGs, too. This is a big vision, and it has to be achieved on a local, national and global scale. So while WaCCliM works with national and international partners to enable local action, it does this with a larger transformation in mind. The water and wastewater utilities using WaCCliM tools to pioneer greenhouse gas benchmarking and climate-smart planning are becoming national sector leaders, and they are providing evidence for an increased consideration of water as a sector for combined mitigation and adaptation action in the next round of NDCs. As that happens, they will also be poised to make a significant contribution to the sustainable development agenda.
 UN Water (2019): World Water Development Report 2019