Freshwater is water that contains less than 0.5 grams of salt per liter. Freshwater mainly refers to river water well water rainwater and other natural water can be used for people to drink, freshwater is weakly acidic freshwater molecular weight is 18u is an important resource for human survival relative to the heavy water, freshwater is a light water on land, there is an abundance of freshwater seawater desalination can be obtained freshwater, freshwater resources is what we usually call water resources refers to the freshwater resources on land.

Shortage of freshwater resources

Due to the increase in per capita water consumption due to population growth and economic development in the past three centuries, the amount of freshwater resources extracted by mankind has increased 35 times in 1970 to reach 3,500 square kilometers in the second half of the century, the amount of freshwater extracted by an annual increase of 4 percent to 8 percent, of which Irrigated agriculture and industry accounted for most of the increase, especially during the Green Revolution of the 1970s, when irrigation water use doubled.

According to the projections of relevant international organizations, by 2050, the population living in water-scarce countries is projected to increase to between 1.06 billion and 2.43 billion people, accounting for about 13 to 20 percent of the world's projected population, which consists of water from rivers and lakes, high mountains, snow, glaciers, and groundwater, etc. Without water there would be no life, and only three percent of the earth's water is freshwater, and all life on earth is ultimately dependent on freshwater. In the final analysis, all depend on fresh water, which determines the distribution of life on Earth.