On the Water Resources of the Earth

On the earth, water that can be directly or indirectly used by human beings is an important part of natural resources. Natural water resources include river runoff, groundwater, snow and glaciers, lake water, swamp water and seawater. According to water quality, it is divided into fresh water and salt water. With the development of science and technology, people use more and more water, such as seawater desalination, artificial catalytic precipitation, and the utilization of Antarctic continental ice. Due to the change of climatic conditions, various water resources are unevenly distributed in time and space, and the natural water resources are not equal to the available water. Reservoirs and underground reservoirs are often used to regulate water storage sources or recycle industrial and domestic sewage to expand the utilization of water resources. Different from other natural resources, water resources are renewable and can be reused. As well as the quantitative changes within and across the year, have certain cycles and laws; The storage form and movement process are influenced by natural geographical factors and human activities.

global water reserves

The total amount of water stored in the earth is about1386×1000000000000 cubic meters, of which ocean water1338×1000000000000 cubic meters accounts for 96.5% of the global total water. In the remaining water, surface water accounts for 1.78%, and groundwater accounts for 1.69%. The fresh water mainly used by human beings is about 3.5× 1 100 million cubic meters, accounting for only 2.53% of the total water storage in the world. A few of them are distributed in lakes, rivers, soil and shallow groundwater below the surface, and most of them are stored in the form of glaciers, permanent snow and permafrost. Among them, the storage capacity of glaciers is about 2.4× 1 100 million cubic meters, accounting for 69% of the global fresh water, and most of them are stored in Antarctica and Greenland.