Definitions of water scarcity have evolved to take account of a broader set of factors. For example, physical water scarcity indicates that an insufficient quantity of water is available to meet requirements. A commonly used measure of physical water scarcity is the Falkenmark index which measures the amount of renewable freshwater available per capita . However, the Falkenmark index is now regarded as an incomplete measure, as it does not account for water needed for non-human needs . Therefore, EFRs have begun to be incorporated in recent water scarcity assessments . Quality-induced water scarcity is an additional factor beginning to be considered  .
IPCC
Climate Change 2022: Impacts, Adaptation and Vulnerability
IPCC Report