The area has exceeded. Due to soil erosion, China loses more than 50 million tons of soil every year, which seriously damages land resources. In China, more than 5,000 people are directly affected by desertification. About 2 million mu of farmland in northwest, north China and northeast China is attacked by sandstorms every year, and the grain output is low and unstable. There is also 15000000 mu of grass that is seriously degraded and desertified; Thousands of farmland water conservancy facilities have been weakened by sandstorms.
The development of desertification is closely related to social economy. Whether the unreasonable economic activities of human beings are desertification is not only the main reason, but also the direct victim of human beings. Socio-economic factors and desertification include overpopulation, over-cultivation, over-grazing, deforestation and low irrigation level. Overexploitation and overgrazing are related to population growth and have direct causal relationship. Population growth will inevitably increase the demand for agricultural products and livestock, leading to over-cultivation and over-grazing. Conditions for excessive tillage to promote desertification: soil fertility and crop yield decline, soil surface hardening, soil erosion and soil erosion. Deforestation is also an important cause of desertification. The Loess Plateau in the middle reaches of the Yellow River is a dense forest, which has been destroyed by human development activities. The lack of forest protection can't stop the soil erosion of Siberian loess, forming a dry and desolate loess plateau, which seriously threatens desertification. V.G.T Dell Carter and the famous "Earth Civilization" wrote: "The progress of mankind has set foot on the earth and stayed in the wilderness in this place." The Nile Valley, the Tigris River and the Euphrates River Valley, as well as the ancient Indian civilization in the estuary, such as the birthplace of the Yellow River, have now become deserts. In Iraq, Syria, Lebanon, Palestine, Tunisia, Crete, Greece, Italy, Sicily, Mexico, Peru ... it will also cause visual desert soil erosion everywhere. This brings the tragedy of desertification, which is the social cost of desertification. Maintain the earth
Forests, fresh air, water conservation, soil and water conservation, wind and sand fixation, climate regulation, vacuum sterilization, beautification of ecological balance and noise elimination play an important and irreplaceable role. Today, the only remaining forest on the earth is about 280 billion hectares, and the sparse forest is 654.38+200 billion hectares, accounting for one-fifth of the earth's land area; The annual deforestation rate is11300,000 hectares. By the 20th century, the forest area on the earth will be reduced to one sixth of the land area of the earth.
The low forest is enough for people to wake up, understand people's ideological resources and develop and build a better home with their own hands, but it often actually damages their living environment and destroys the happiness of future generations. In fact, this has become an increasingly serious consequence.
The reduction of forests is mainly due to the pressure of population. 1995, the world population has reached 570 billion, of which more than 75% are concentrated in underdeveloped third world countries. Its main problems are still food and energy. In order to have food, clothing, shelter and hope, they have to get forests, cut down forests and pay for logging, which leads to the amazing disappearance of forests.
The second reason for the decrease of forests is cutting down trees. It has been 20 to 30 years since humans began to use tropical wood in large quantities. After nearly 20 years of development, tropical timber imports have increased by 16 times, accounting for 10% of the global timber and pulp supply. So as to protect developing countries from exploiting their domestic timber resources. European countries come from Africa, the United States imports wood from Central and South America, and Japan imports wood from Southeast Asia. Patent holder of disposable chopsticks in Japan. In order to produce such chopsticks, Japan went to Southeast Asia, and our hands extended to aggression. The Japanese government allowed the use of their own forest resources to produce disposable chopsticks, but dozens of forest chopsticks factories were jointly built in the northeast of China and the north of China, which were produced with great fanfare and then sold back to Japan. Only 1996, China exported 2 billion pairs of disposable chopsticks to Japan! The Japanese government will uniformly recycle used disposable chopsticks, export refined wood pulp paper, recover costs and earn foreign exchange. How ingenious this is! We should know that the forest coverage rate in Japan is 65%, while that in nearly 200 countries and regions in the world is only 13. With 65,438+0,265,438+0, China ranks only among developing countries, which account for three quarters of the world's population. Although there are more than 50% wood resources, the consumption of wood products only accounts for 14%. In Japan, the paper consumption per person per year is only equivalent to the wood consumption per household in developing countries.
Cutting firewood is the third reason for the sharp decline. According to the statistics of the United Nations Environment Programme, people cut down 22,000 square kilometers of burning forest every year for cooking and heating. The waste of most wood energy.
In addition, frequent fires are also a reason why forest pests and diseases are discarded.
Life is a kind of green, and human beings can't live without forests. Facing the reality that resources and environment have been seriously damaged, should the relationship between man and nature be adjusted?