（Purely personal perceptions, not necessarily correct ！）
The total volume of water on the earth is about 1.386 billion cubic kilometers, 96.5% of which is in the oceans. There is only 35 million cubic kilometers of fresh water, which accounts for 2.5% or so. 70% of the rare fresh water resources is frozen in the Antarctic and Arctic ice sheets. What is worse, there are inaccessible mountain glaciers and permafrost snow. Therefore, only 0.26% of the earth’s total water supply can be used by humans. In this way, fresh water resources in the world are not only in short supply but also extremely unbalanced in regional distribution.
About 1.5 billion people in more than 80 countries are currently facing a shortage of fresh water. 300 million people in 26 countries are entirely under water shortage stress. By 2025, 3 billion people in more than 40 countries and regions are expected to suffer from water shortages.
With so serious problem of water sources, human beings are polluting water on a large scale, leading to the deterioration of water quality. Water pollution is mainly caused by waste water, waste gas and waste residue produced by human beings. 426 billion tons of sewage is discharged each year and it leads to the pollution of 5.5 billion cubic meters of water, which accounts for more than 14% of the global runoff.
Both fresh water pollution and sea water pollution have led to shocking results. Plastic debris has even been found in the Mariana Trench, the deepest place in the world. Some deep sea plastic garbage has become a breeding ground for some marine animals.
Data showed that since plastics were developed in the 1850s, humans have produced at least 8.3 billion tons of plastics as of 2017, 6.3 billion tons of which are completely waste products. However, only 9 % of this waste was recycled; another 12 % was incinerated while the remaining 79 % was buried in the soil or dumped into the sea. In 1997, people paid attention to the “eighth continent”. According to rough estimate of scientists, the “eighth continent” is made up of 4 million tons of plastic waste, covering an area of 1.4 million square kilometers, which is about four times the size of Japan. What is more, the area is growing every year. The plastic waste is damaging the ecosystem of the ocean. What is even worse is that plastic waste can also be degraded to microplastics, with small pieces of plastic ranging in size from a few microns to a few millimeters. These microplastics also make their way up the food chains and into human bodies. In March 2022, scientists detected microplastic contamination in human blood for the first time and the tiny particles were found in nearly80% of test subjects’ samples.
Because of countless humans’ material desire, a highly developed industrial society has been formed, but this also leads to a series of serious consequences.