(Henan Institute of Land and Resources Science, Zhengzhou 450053)
Bulletin of Geological Survey and Research in Henan Province, article number: 7-80097-870-2-0507-03.
In today's world, the focus of human social security has shifted to ecological environment security. The increasingly serious problem of land desertification has threatened the living environment of hundreds of millions of people in China and restricted the sustainable development of social economy. This paper discusses the distribution, harm and causes of land desertification in China, and analyzes and evaluates its prevention and control measures.
Land desertification, ecological environment, safety and sustainable development
In today's world, the focus of human social security has shifted to the issue of ecological environment security. For the country, a single military threat has actually been replaced by a diversified threat. Among them, environmental threats that are not restricted by national boundaries are the basic threats that endanger the survival and development of all countries and nations. Therefore, the security and progress of human society in 2 1 century will depend on whether human society takes the road of sustainable development; The security and development of a country will depend on its sustainable development ability. The root of these two problems lies in the degree to which the ecological environment safety problem has been paid attention to and solved.
Ecological environment is a "complex" composed of water, soil, forest, animals and plants, air and so on. Every progress and development of mankind is inseparable from the "comprehensive support" of various elements of the ecological environment, which is the basis for maintaining social and economic development. Ecological environment security is a "stable environment" to maintain the sustained and coordinated development of social economy in a region or a country. Once this "stable environment" is destroyed, national security will be threatened.
Sustainable development is a new strategic thought for the future development of mankind, the result of long-term reflection on human behavior, and the scientific strategy and the only choice for mankind to get out of the predicament, get rid of the crisis and seek survival and development. This concept of development will have a far-reaching impact on the future of all countries in the world and the world economic structure in the 2 1 century. From the perspective of environment and natural resources, it puts forward the long-term development strategy and model of human beings, and points out the importance of natural resources and environmental carrying capacity to the development process and their interaction and influence, aiming at realizing the sustainable utilization of resources, the all-round progress of society and the development of human beings from generation to generation. Sustainable development is not a concept that can be summarized from a single angle, but a comprehensive concept of economy, society and ecology. Economy, society and environment restrict and interact with each other, which constitutes the whole system of sustainable development.
The sandstorm weather in northern China since the beginning of spring this year is the highest in recent years-Gansu has suffered the longest and strongest sandstorm weather in recent years; There have been eight sandstorms in Beijing, which are rare in the past four years. Sandstorm weather with visibility less than 1 000m has occurred many times in northern Ningxia, central and western Inner Mongolia and Northeast China, Hebei, Tianjin, Henan and other places, which is the most frequent and serious weather over the years. Experts believe that land desertification is the main cause of sandstorms. The increasingly serious problem of land desertification has threatened the living environment of hundreds of millions of people in China and restricted the sustainable development of social economy.
The rapidly increasing world population and decreasing grain reserves have prompted human beings to expand and strengthen the unreasonable development and utilization of limited environmental resources intentionally or unintentionally, which has seriously damaged the ecological balance, thus causing a serious environmental problem-land desertification in arid, semi-arid and semi-humid areas of the world. Land desertification is a global environmental disaster. Since the 1960s, the population of arid, semi-arid and dry sub-humid areas in the world has increased rapidly, and the land development in this area has been expanding day by day, which has led to an unexpected global land desertification problem, involving more than 0/00 countries in all continents, and the global population of16 has been endangered. Up to now, the global desertification land area is 36 million km2, which is almost equivalent to the total land area of Russia, Canada, the United States and China, and it is expanding at the rate of 50,000-70,000 km2 every year, which is equivalent to swallowing one Belgium plus Denmark every year. Judging from the population distribution affected by desertification, Asia has the most concentrated population distribution in the world.
The results of the third national desertification and desertification monitoring show that the total area of desertification land in China is 2,636,200 km2, accounting for 27.46% of the total land area. Among them, the area of desertification land by wind erosion is 6.5438+839400 km2, accounting for 69.77% of the total area of desertification land; The land area of water erosion and desertification is 259,300 km2, accounting for 9.84%; Salinized land area is173,800 km2, accounting for 6.59%; The area of frozen-thawed desertification land is 363,700 km2, accounting for 13.80%. Desertification in China is distributed in 498 counties (cities, banners) of 65,438 provinces (autonomous regions and municipalities directly under the Central Government) such as Hebei, Shanxi, Inner Mongolia, Liaoning, Jilin, Shandong, Henan, Hainan, Sichuan, Yunnan, Tibet, Shaanxi, Gansu, Qinghai, Ningxia, Xinjiang, Beijing and Tianjin, with poor regional natural economic conditions and ecological environment. Desertification land is mainly distributed in Xinjiang, Inner Mongolia, Tibet, Gansu, Qinghai, Shaanxi, Ningxia and Hebei provinces (autonomous regions), accounting for 98.45% of the total desertification area in China, and other provinces (autonomous regions and municipalities directly under the Central Government) account for 1.55%. There are 65,438+0,755,438+000 km2 of desertified land in northern China alone, which is equivalent to the total land area of Xinjiang Uygur Autonomous Region and Liaoning Province.
Compared with 1999, the area of desertified land in China decreased by 37 924km2 in 2004, with an average annual decrease of 7 585km2. Among them, wind erosion desertification land decreased by 33 673km2, water erosion desertification land decreased by 5 525km2, and salinized land increased by 930km2. To the extent of desertification, the area of lightly desertified land increased by 90,700 km2, moderately desertified land increased by 1 17300 km2, severely desertified land decreased by 13 17000 km2, and extremely severely desertified land decreased by 1 14200 km2.
Before the end of 1990s, the expansion speed of land desertification was faster than the control speed, and the area of land desertification continued to increase. Only in terms of desertification area, it expanded by 1. 5 million km2 in 1950s and by 2 1. 0 million km2 in 1980s. In 1990s, the annual land desertification area was as high as 2 460km2, and a large number of grain fields, grasslands and woodlands were occupied by desert, which was equivalent to reducing the land area of a medium-sized county (city) every year. Since 1990s, there have been 23 sandstorms, obviously more than 8 in 1960s, 13 in 1970s and 14 in 1980s. In the past half century, more than 7.72 million hectares of cultivated land in China have been degraded by desertification, and 670,000 hectares of grain fields and 2.35 million hectares of grassland have turned into quicksand or desert, resulting in more than 3 billion kilograms of food losses every year. The direct economic loss caused by desertification in China reaches 54 billion yuan every year, with an average daily loss of nearly 65.438+0.5 billion yuan, and the indirect economic loss is 2 ~ 654.38+00 times of the direct economic loss. In recent years, land desertification has been curbed and the ecological environment has been improved through governance, but the overall situation is still grim.
Desertification and land desertification caused by it are called "global canker disease", which harms many aspects and has become a major environmental problem that seriously restricts the sustainable development of China's economy and society. The occurrence and development of desertification are closely related to human social economy. Unreasonable economic activities of human beings are the main cause of desertification, and in turn, human beings are the direct victims of desertification. Overfarming and overgrazing have a direct causal relationship with population growth. Population growth will inevitably increase the demand for agricultural products and livestock products, leading to over-cultivation and over-grazing. Excessive tillage promotes the formation conditions of desertification: the decline of land fertility and crop yield, soil surface hardening, soil erosion, soil erosion and so on. Socio-economic factors related to desertification include overpopulation, over-cultivation, over-grazing, deforestation and low irrigation level. Natural factors causing land desertification mainly refer to abnormal climatic conditions, especially severe drought conditions, which cause vegetation degradation and accelerate wind erosion and desertification. Land desertification is the result of comprehensive action of natural factors and human activities. In 1984, the United Nations Environment Programme (UNEP) concluded that desertification is mainly related to the following factors: the ecosystems in arid areas and adjacent humid areas are relatively fragile; Population pressure often leads to over-utilization of resources; Due to economic considerations, a reasonable land use model has not been formulated; Political turmoil has hindered the implementation of long-term actions in the action plan.
Land is an almost non-renewable natural resource. Without any disturbance, it takes 300 years to regenerate 25 mm soil surface. This rate of regeneration hardly compensates for the rapidly eroded land. So, how should we deal with the severe challenges of nature? Artificial technical measures to combat desertification are usually divided into three categories, namely, biological measures, mechanical measures and chemical measures, of which biological measures are the most widely used. Biological measures refer to the protection and restoration of natural vegetation through the establishment of artificial vegetation, and finally achieve the purpose of preventing and controlling desertification, managing and developing and utilizing desertified land. Its main advantages are: the increase of vegetation coverage can increase the surface roughness, reduce the wind speed near the surface, and reduce the erosion of the surface by sand flow; Planting vegetation can improve the above-ground and underground ecological environment conditions in vegetation-covered areas, which is conducive to the activities and reproduction of various organisms, thus promoting the formation of soil, increasing the content of organic matter, increasing the cementation of surface materials and enhancing the wind erosion resistance of the surface; Vegetation has the ability of self-reproduction and regeneration, and through succession, it can form a stable ecosystem that adapts to the local environment and has the ability of self-adjustment, so it can fix quicksand for a long time, prevent the harm of sandstorm, and greatly reduce the maintenance and management cost; Artificial or semi-artificial vegetation formed by artificial measures can generally graze moderately and provide a certain amount of firewood and building materials, which can reduce deforestation to a certain extent. Research practice at home and abroad shows that biological measures are the fundamental measures to prevent and control desertification, and mechanical measures and chemical measures are usually used as auxiliary measures for biological measures.
Land desertification control is a systematic project that focuses on restoring and improving the ecological environment and combines resource development with industrial construction. The control of land desertification needs systematic innovation in investment mechanism, management mechanism and incentive mechanism, so as to effectively curb desertification and realize the goal of sustainable utilization of land resources. In the process of desertification control, we must first deal with six major relationships: effectively deal with the relationship between ecological protection and economic development and implement sustainable development; Effectively handle the relationship between sand prevention and control, give priority to prevention and actively prevent and control; Effectively deal with the relationship between biological measures and engineering measures, focusing on biology and comprehensive management; Effectively handle the relationship between animal husbandry development and grassland protection in order to protect and promote development; Effectively handle the relationship between production water and ecological water, and pay attention to water conservation; Effectively handle the relationship between key governance and comprehensive governance, unify planning, and highlight key points.
Recently, the State Council issued the Decision on Strengthening Desertification Control, which emphasized the importance of desertification control, defined the guiding ideology, basic principles and objectives of desertification control, and demanded that the layout and planning of desertification control should be done carefully. With the support of laws and policies, by strengthening the environmental geological survey of desertification and implementing scientific countermeasures and measures to prevent and control desertification, land desertification in China will be controlled in a certain period of time, the ecological environment will be continuously improved, and the national economy will be stable, harmonious and sustainable.
refer to
Chen Guangting. 2004. Sand damage control technology. Beijing: Chemical Industry Press. 136 ~ 138.
Fan Zhiping, Zeng Dehui, Yu. 2006. Theoretical basis and construction technology of ecological engineering. Beijing: Chemical Industry Press. 172 ~ 174.
Fu Baorong, Hui Xiujuan. 2005. Ecological environment safety and management. Beijing: Chemical Industry Press. 2.
Li Hongyuan, home. 2005. Principles and practice of ecological restoration. Beijing Chemical Industry Press.
Liang Congjie, Yang Dongping. 2005. Environmental Crisis and Breakthrough in China. Beijing: Social Science Literature Publishing House. 99 ~ 10 1.
Wang Shuying, Gao Chundi. 2004. Environmental introduction. Beijing: China Building Industry Press. 277.
Discussion on ecological security and sustainable development caused by land desertification
Xing Zhang Yongqiang Guo Hongwei Zhang Wenxiu Yu
(Henan Institute of Land and Resources Science, Zhengzhou 450053)
Abstract: The security focus of today's human society has shifted to the ecological environment. The increasingly serious land desertification has threatened the living environment of hundreds of millions of people in China and restricted the sustainable development of social economy. This paper discusses the distribution, harm and causes of land desertification in China, and analyzes and evaluates the control countermeasures.
Keywords: land desertification; Ecological environment safety; sustainable development