Water for the win-win-win
The role of water in climate action and the energy revolution, a blog from the UN-Water Expert Group on Water and Climate Change
As the international community strives for net zero, we tend to concentrate on how to overcome inertia, how to innovate, or how to foster political will.
What we don’t focus on enough is the role of water.
Indeed, in the 25 pages of the historic Paris Agreement from the UN Climate Change Conference in 2015 (COP 21), “water” is not mentioned at all.
Of course, water flows through all the issues in the document, but as an implicit and indirect factor rather than as a key part of efforts to adapt to and limit global warming.
It wasn’t until the COP 27 agreement in 2022 that water was explicitly mentioned and given dedicated consideration for the first time.
Two years on, there is growing consensus on the interdependency between climate action and water action.
However, while it is widely recognized that the climate crisis is inextricably linked to the water crisis – usually in terms of surviving and adapting to changes in the water cycle – what is less commonly understood is the relationship water plays in mitigating climate change.
Energy production is – and will remain – highly water intensive
Water serves as a crucial component in the production of renewable fuels like hydrogen and biofuels (as well as represents a source of clean energy through hydropower), is essential for cooling nuclear power plants and is used in mining rare earths used in battery production.
At COP 28 in 2023, the UN-Water Expert Group on Water and Climate Change presented the preliminary findings of a study, being carried out in collaboration with the International Universities Climate Alliance, showing that at the global scale, by 2030, the water required for the clean energy mitigation measures required by the Paris Agreement (such as biofuels, hydrogen fuels and battery components) could be as high as 900 cubic kilometres of water per year, which equates to approximately a third of the water withdrawn by irrigation worldwide.
Despite uncertainties – arising from the assumptions and approximations made, which are illustrated in the report – the research points at a crucial fact: the volume of water required for the energy transition is significant.
In principle, future water consumption by the energy sector could even increase, far exceeding current demands. This possibility calls for urgent action in policy, and further research.
Water is critical to climate mitigation measures
Early estimates from the research show how the ‘water efficiency’ of various climate change mitigation measures varies wildly.
For example, green hydrogen production saves approximately 68 tonnes of carbon emissions for every million litres of water used; whereas for the same amount of water, liquid biofuels could achieve 5 tonnes of carbon emissions reduction, and electrification of light duty vehicles could save 1.7 tonnes.
The selection of these measures will depend on context, but chief among the considerations must be the water impact, especially in water-scarce regions.
Another crucial factor is that the human-managed water cycle is itself a source of carbon emissions.
Poorly managed wastewater, and water in wetlands, and artificial reservoirs and irrigation systems are a major source of direct emissions of greenhouse gases, especially methane and nitrous oxide.
Water for climate mitigation must be secured and sustainable
Clearly, the success of the climate mitigation objectives outlined in the Paris Agreement depends critically on the integrated, sustainable management of water resources.
Sustainable, affordable and scalable water solutions include:
Improving carbon storage by protecting peatlands, restoring and expanding mangroves.
Harvesting rainwater to ensure supplies for dry periods and reducing flood risk.
Adopting climate-smart agriculture such as drip irrigation.
Safely reusing wastewater for irrigation and industrial and municipal purposes, and as a source of energy, nutrients and other recoverable materials.
Exploring, protecting and sustainably using groundwater to adapt to changing precipitation patterns and meet the needs of a growing population.
The transition to a fairer, more sustainable, more stable world will only happen with integrated, equitable and sustainable management of water.
In doing so, we can create a ‘win-win-win’ for the water-energy-climate nexus that will ripple out far and wide.
The UN-Water Expert Group on Water and Climate Change supports cooperation and coordination of efforts and messages of UN-Water members and partners on water and climate. Contributes to raising the awareness on the importance of water in climate change adaptation and mitigation and vice versa as well as knowledge on good adaptation practices.
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The UN-Water Expert Group on Water and Climate Change is undertaking a study on the water requirements of climate mitigation measures, in collaboration with the International Universities Climate Alliance (IUCA).
