First of all, we should understand the meaning of water resources. Water resources can be divided into broad sense and narrow sense.
Generalized water resources: refers to the general name of all water bodies on the earth.
Water resources in a narrow sense: refers to the fresh water resources on the earth.
1. Limited freshwater resources available
Water on earth is stored in the oceans, land and atmosphere. Ocean water accounts for 97% and is the main body of water on the earth. Atmospheric water mainly exists in gaseous state and has the lowest specific gravity. Land water is divided into fresh water and salt water according to different salinity. Salt water is mostly distributed in Inner Flow lakes and underground salt water. Fresh water accounts for 2.5% of the global water reserves, including river water, fresh lake water, underground fresh water and glaciers. Glaciers and deep groundwater account for 98% of the total fresh water, which is difficult to use under the existing technical conditions. At present, the freshwater resources used by human beings are mainly rivers, lakes and shallow groundwater, accounting for only 0.3% of the global freshwater resources.
2. Pollution of water resources with the population growth, the improvement of people's living standards and socio-economic development, the consumption of water resources has increased sharply, resulting in the reduction of available water resources. This limited water resource has also been polluted to varying degrees. What is the reason for water pollution? Mainly industrial wastewater, pesticides and fertilizers in agricultural production and urban sewage. The lack of freshwater resources is not a problem unique to individual countries, but a problem faced in global development. The world bank's 1995 survey report pointed out that 80 countries, accounting for 40% of the world's population, are facing a water crisis. About 1 billion people in developing countries do not have access to clean water, 1.7 billion people do not have good sanitation facilities, and about 25 million people die from drinking dirty water every year.
3. China's per capita share of water resources is very small
China is rich in total water resources, ranking sixth in the world; However, China's per capita share of water resources is small, only 1 / 4 of the world average; China is short of water resources. Saving and protecting water resources is the core way to solve the problem of water resources in China. Building water conservancy and inter basin water transfer can effectively alleviate the shortage of water resources in some areas and in some time, but this can only solve the symptoms, not the root cause. Water resources are renewable resources. From the perspective of the earth's water environment and the total amount of water resources, they should be recyclable and sustainable. However, on the one hand, water resources do not refer to all of the world's water bodies, but only to the fresh water resources that can be used by human beings, and the proportion of this part of fresh water resources that can be directly used by human beings is very small; On the other hand, in a certain space and time range, due to natural reasons (such as climate and river distribution) or man-made reasons (such as unreasonable use, pollution and waste), water resources are not only limited, but also may be exhausted. Therefore, we should understand the "recycling" of water resources and the "recycling" of our life. We should protect water resources, save every drop of water and avoid the last drop seen by our future generations. Although some scientists suggest melting the glaciers on the ground of the north and south poles for many years, if the glaciers at the poles are melted, the sea level will rise sharply and many coastal countries will be submerged. The consequences are unimaginable.
If we are still stubborn and do not save water, we are likely to repeat the tragedy of "loulanting" in the future: children become ruins due to serious water shortage!
Saving water is urgent. We should start now, start with small things and save water: when washing vegetables, don't flush water; The waste water from washing vegetables and hands is used to mop the floor and clean the windows; When the faucet is not turned off tightly, turn it off in time