With a steadily increasing demand, freshwater scarcity is increasingly perceived as a threat to sustainable development of human society. Nowadays, around four billion people, i.e., two-thirds of the global population, live under conditions of severe water scarcity at least 1 month of each year; nearly half of those people live in India and China, a research team from the University of Twente in Netherlands reported.
In a recent report, the World Economic Forum lists water crises as the largest global risk in terms of its potential consequences. At the global level, freshwater is enough to meet human needs on an annual basis, but variations of water demand and availability are large during different seasons across the world, leading to spatial and temporal water scarcity in some areas.
The main driving forces underlying the rising global demand for water include increasing world population, improving living standards, changing consumption patterns, and expansion of irrigated agriculture. Therefore, high water scarcity levels appear to prevail in the areas with either high population density or much irrigated agriculture, or both.
According to the report of the University of Twente, moderate to severe water scarcity usually occurs in Mexico and India. In the Western America, Southern Europe, Turkey, Central Asia, and North China, there are many areas experiencing moderate to severe water scarcity in the spring-summer period. Other areas with moderate to severe water scarcity during more than half of a year include parts of Argentina, northern Chile, Africa, the Middle East, Pakistan, and Australia.
The report indicates that the number of people facing severe water scarcity for at least 4 to 6 months per year is 1.8 to 2.9 billion worldwide. Half a billion people face severe water scarcity all year round. Of those half-billion people, 180 million live in India, 73 million in Pakistan, 27 million in Egypt, 20 million in Mexico, 20 million in Saudi Arabia, and 18 million in Yemen. Overall, about 4.0 billion people lives under severe water scarcity at least 1 month of a year. Of these 4.0 billion people, 1.0 billion live in India and another 0.9 billion live in China. Other populations facing temporal water scarcity live in Bangladesh (130 million), the United States (130 million), Pakistan (120 million), Nigeria (110 million), and Mexico (90 million).