This chapter draws on previous IPCC reports and new methodologies  and assesses the impacts of climate change on natural and human dimensions of the water cycle with a particular focus on water-related vulnerabilities and adaptation responses . Section 4.2 assesses observed changes in the hydrological cycle, and Section 4.3 focuses on their societal impacts and detects which parts of these changes are directly attributable to climate change. Section 4.4 assesses projected risks of changes in the hydrological cycle on various components of the hydrological cycle, and Section 4.5 assesses the same for sectoral risks. Projections and risks assessments for future impacts are framed in terms of GWLs and time horizons, as these are useful for informing mitigation policy under the Paris Agreement and informing adaptation planning. Sections 4.6 and 4.7 assesses current and future water-related adaptation responses in reducing climate and associated impacts and risks and looks at limits to adaptations, especially in a future warmer world. Finally, Section 4.8 outlines the enabling principles for meeting water security, SDGs and climate resilient development.
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report