The International Universities Climate Alliance (IUCA) and the UN-Water Expert Group on Water and Climate Change have published a study estimating water requirements of climate change mitigation measures. The report identifies trends related to the water intensity of mitigation and adaptation options considered by the Intergovernmental Panel on Climate Change (IPCC), and recommends countries take these into account in their climate policies.

Titled, ‘Water for Climate Mitigation: Estimating the Global Freshwater Requirements of Climate Mitigation Measures,’ the report underscores that meeting the goals of the Paris Agreement on climate change depends on the sustainable management of water resources. It urges policymakers to assess the water requirements of clean energy and carbon sequestration measures as they prepare the next round of their nationally determined contributions (NDCs).

The report “ranks” mitigation measures based on their estimated water requirements and efficiency. It notes that the applicability of each measure is contextual and depends on the spatial and seasonal availability of water and water quality requirements. At the same time, the measures “are not all directly interchangeable” as they respond to different policy objectives that may not be applicable in all countries.

The report emphasizes the relative value of natural solutions, such as maintaining and restoring the water tables of peatlands and afforestation. However, it notes that these measures are location specific and involve other ecological risks, for example those associated with the release of methane from peatlands and wetlands if these systems are not managed properly and the potential for afforestation to alter rainfall patterns.

The study also finds that “[n]atural solutions offer the best return on carbon sequestered per unit volume of water.”

A blog post the UN-Water Expert Group on Water and Climate Change published before the report’s launch underlines that the climate and water crises are inextricably linked, and their relationship needs to be better understood. It highlights that:

• Energy production is – and will remain – highly water intensive;
• Water is critical to climate change mitigation measures whose ‘water efficiency’ varies widely, with some requiring more freshwater than is now committed; and
• There is a need for sustainable, affordable, and scalable water solutions for climate change mitigation.

The report was launched on the opening day of the Bonn Climate Change Conference on 3 June 2024. [Publication: Water for Climate Mitigation: Estimating the Global Freshwater Requirements of Climate Mitigation Measures]