To reduce risk to water scarcity, adaptation measures, at both the supply and the demand side, have been suggested . Several measures are already in place showing high technical and institutional feasibility . The effectiveness of options varies regionally . For example, in SEU many water reservoirs are already in place. Irrigation is used to support agriculture where rain-fed supplies are not sufficient . Their future extension depends on available precipitation. Also, wastewater reuse can only be effective if sufficient wastewater is available. Improvements in water efficiency and behavioural changes are very effective in SEU  . Investments in large water infrastructures and advanced technologies , water transfer, water recycling and reuse, and desalination will allow to buy time and therefore to cope with additional warming . Beyond 2.5°℃ GWL, transformational adaptation is needed to lower risk levels, such as planned relocation of industry, abandonment of farmland or the development of alternative livelihoods . In WCE, the solution space to water scarcity is expanding with considerable potential for investments in large water infrastructure and advanced technologies , for reducing risks above 3ºC GWL . Under medium warming a larger portfolio of
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report