1. Acid rain pollution. In 1950s, with the development of industrial production and the surge of population, the use of fossil fuels increased. Its main harm is the death of a large area of forest. There are three major acid rain areas in the world: Europe, North America and China, south of the Yangtze River.
2. Greenhouse effect (or global warming). The main reason for global warming is that human beings emit more and more carbon dioxide into the atmosphere, in which the United States is the largest country and China is the second largest country. The main hazards are the melting of the Antarctic and Antarctic ice sheets and rising sea levels. According to scientists' calculations, by the end of this century, the global temperature will rise by 2~5 degrees Celsius and the sea level will rise by 30~.
00 centimeters. This will have disastrous consequences.
3. Ozone layer destruction. The ozone layer above the earth can absorb 99% ultraviolet rays and protect human beings from harm. However, in 1985, the British Antarctic expedition first discovered the hole in the ozone layer over Antarctica. Scientists have found that this is a "masterpiece" of chlorofluorocarbons made by human beings.
4. Land desertification. The desert on the earth is eroding the land at the rate of 6 million hectares per year, that is, every minute 10 hectares. The reason is that the grassland vegetation has been destroyed. Every day, 500 hectares of land in our country are swallowed up by the desert. The recent frequent sandstorms are a serious warning.
5. The forest area has decreased. At present,120,000 hectares of forests disappear every year in the world, and most of them are concentrated in developing countries. One of the reasons is poverty. Have to exchange precious forest resources for foreign exchange; The second reason is that in some developing countries in Asia, Africa and Latin America, about 2 billion rural people use wood as their fuel; The third reason is deforestation. Due to the large population and small land, China's deforestation is very serious, and the forest coverage rate is only 13%, ranking 120 in the world.
6. Species extinction. At present, the earth is managing the sixth mass extinction. More and more species on the earth have suffered or are suffering from extinction because of the crazy hunting of wild animals and the pollution and destruction of the ecological environment.
7. Water crisis. Only 1% of global water resources can be used by human beings. With the economic development and population explosion, the growth rate of world water consumption exceeds the growth rate of population, and the water resource problem will soon become a profound social crisis. And there is no substance that can replace water at present. There are more than 600 cities in China, of which more than 300 are short of water and more than 40 are seriously short of water. In addition, the Yellow River is cut off and the Huaihe River is polluted, which seriously threatens the industrial and agricultural production and people's life in China.
8. Water loss. Due to the large-scale destruction of forests by human beings, many barren hills and mountains will cause flash floods as soon as it rains, and water resources and soil resources will be lost in vain. Soil will be brought into rivers and lakes, and it will also cause siltation in reservoirs and lakes, thus raising the riverbed, reducing the capacity of reservoirs and lakes and aggravating flood disasters.
9. Garbage is a disaster. At present, the increasing amount of garbage, including industrial garbage and domestic garbage, has become a thorny problem facing all countries in the world. Because the garbage in our country has not been treated, it not only accumulates more and more, but also occupies cultivated land and pollutes the air and groundwater. At present, two-thirds of cities in China are surrounded by garbage.
10. Urban air pollution. Urban air pollution in China is very serious. There are more than 600 cities in China, among which less than 1% of the air quality meets the national first-class standards. There are two main reasons for pollution. First of all, coal, which emits a lot of pollutants, is the main energy source in China. Secondly, the exhaust gas emitted by more and more cars in our city has seriously polluted the air.