Water, one of the most critical elements for survival, although abundantly available in oceans, is available in a mere fraction as a freshwater resource. As described by Samuel Taylor Coleridge in his writings for the sailors, "Water, water everywhere, nor any drop to drink" is now becoming a reality for the majority. About two-thirds of the world face severe scarcity for at least one month each year (UNICEF), which will be further affected due to the increase in the global population and climate change. Quantifying water availability for the future is essential for managing physical water. Identifying the population and places facing scarcity in the future is vital to achieving the sustainable development goal 6 of "clean water and sanitation for all."
The increase in water trading to improve the socioeconomic situation in different parts of the world has often enhanced the water allocation and distribution. Even though water transportation in its original form has limitations considering the distance, the trading has continued in the form of commodities to a broader extent. While physical water trade is compared with the country's economy, virtual water trading is also equally associated with the social and economic condition of the location. Research on water scarcity primarily considers the physical water scarcity, whereas the socioeconomic conditions and distributions are often neglected to identify the future water-scarce hot spots.
To understand the past and future scenarios of physical and economic water scarcity in different regions, we considered the freshwater availability and economy per capita. Future water scarcity analysis considering multiple scenarios representing global sustainability (SSP1–RCP2.6), regional rivalry (SSP3–RCP7.0), and economic optimism (SSP5–RCP8.5) taken by the world, justifies the importance of change in socioeconomic conditions over climate. Our findings reflected a significant difference in identifying water scare regions in future for urban concentrated and dispersed population assumptions for each scenario. The variation in the results for water-scarce prediction based on different population distribution for the same scenario reflected similar variations observed for several future pathways. This result identifies a notable finding which implies the importance of consideration of socioeconomic distribution in water scarcity prediction.
The findings indicate the importance of socioeconomic scenarios and their distribution for analysing future water scarcity, which will improve research on water availability and allocation. The results will also benefit the scientific community, policymakers and other communities working towards the development of adaptation and mitigation measures.