The Great Gobi in the West in 1950s
In fact, Rome was not built in a day, and "Huanglong" has been raging for several years. Several examples provided by authoritative departments are amazing. For example, Alashan League in Inner Mongolia used to be a natural pasture with abundant water plants and enjoyed the reputation of "Juyan Granary". Since the 1960s, the amount of water entering the oasis has increased from 900 million due to the extensive utilization of the black river water resources in the upper reaches.
The cubic meter has been reduced to less than 200 million cubic meters now, which has caused the East and West Juyan Seas to dry up, hundreds of lakes to disappear and 930,000 hectares of natural forests to die. 85% of the land in Alxa League has been desertified, and Ejina Oasis is shrinking rapidly at the rate of10.3 million hectares per year.
Example 2: Due to the long-term land reclamation in the upper reaches of Tarim River Basin in Xinjiang, the 350km downstream has been cut off. The area of Populus euphratica forest decreased sharply, from 520,000 hectares in 1950s to 280,000 hectares in 1990s. The "green corridor" blocking Taklimakan Desert and Kumutage Desert gradually disappeared. 265,438+08 National Highway and Tarim Oilfield are facing serious threats, and Lop Nur and taitema lake have dried up and become deserts.
Case 3: The ecological environment in Bashang area of Hebei Province has been seriously damaged due to deforestation and overgrazing. According to the interpretation and analysis of land satellite images of Weichang County in Hebei Province and Duolun County in Inner Mongolia 1987 and 1996, during these nine years, the forest area decreased from 363,500 hectares to 222,400 hectares, and the quicksand area increased from 68,000 hectares to 129 and 100 hectares.
Case 4: In 1950s, the Hunshandake Sandy Land in Inner Mongolia was still an oasis, known as the "desert garden". Since 1960' s, the phenomenon of land degradation and desertification has gradually intensified. From 1950s to 1990s, the desertified land here expanded by 103 square kilometers every year on average. Before the 1990s, the desertified land was scattered, and after the 1990s, many of them were connected together, devouring the available land at the rate of 1.43 square kilometers per year.
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Sandstorms wreak havoc and form a new ecological crisis, which is manifested in the decrease of available land resources and the decline of land quality. Statistics show that since the founding of New China, there are 7.722 million hectares of cultivated land and 65.438+0.05 billion hectares of degraded grassland.
The destruction of living conditions has led to the emergence of "ecological refugees". More than 50,000 villages across the country are often harmed by sandstorms, which have flooded farmhouses and turned thousands of farmers and herdsmen into "ecological refugees". It aggravated the poverty in the west and widened the gap between the east and the west. A quarter of the rural poor in China live in desertification areas.
Seriously threaten the safety of large and medium-sized cities, transportation, reservoirs and rivers. In recent nine years, the area of quicksand in Bashang area in northern Beijing has increased by 89.9%, which directly threatens the ecological security of Beijing. China has more than 3,000 kilometers of railways, 30,000 kilometers of highways and 50,000 kilometers of channels that have been harmed by sandstorms all the year round.
Scientific research shows that the expansion of desertification land is mainly due to the destruction of vegetation on the sand surface by human activities. The specific reasons are as follows: First, blind reclamation. According to some data, from the 1950s to the end of 1970s, the northwest region successively destroyed grass and forests for land reclamation three times on a large scale. In recent years, especially in the ecotone between agriculture and animal husbandry, some farmers have set their goals on the reclamation of sandy wasteland in order to get rich, and the momentum of deforestation and weeding is very strong.
The second is overgrazing. Since 1950s, the number of livestock in China pastoral areas has increased from 29 million to more than 90 million, while the grassland area has been decreasing year by year due to reclamation, degradation and desertification.
The third is indiscriminate mining and logging. There are 247,000 hectares of firewood forests in sandy areas of China, which can provide 5.94 million tons of firewood every year, accounting for only 14.2% of the actual demand for firewood. This huge shortage has led to large-scale deforestation and vicious circle.
The fourth is to dig up desert plants such as wild Chinese herbal medicines. It is estimated that each kilogram of licorice will destroy 0.53 to 0.67 hectares of land.
Fifth, the utilization of water resources is unreasonable. Overirrigation not only wastes water resources, but also salinizes the land. Large-scale reclamation in the upper reaches of the river, excessive use of water in violation of the plan, construction of water conservancy projects to store fresh water, resulting in the reduction of water in the lower reaches, the river cut off and vegetation died. Over-exploitation of groundwater causes the groundwater level to drop below the absorbent layer of plant roots, leading to vegetation decline and even death.
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Combating desertification is a major concern of all countries. It has been listed by the international community as one of the major problems facing mankind in the 2 1 century, and its legislation has also attracted much attention. The global convention has been formulated, and national legislation can be divided into three situations: one is to formulate a separate law, the other is to formulate a legally binding action plan, and the third is to regulate it as an important part of environmental law.
1992, the United Nations General Assembly adopted resolution 47/ 188, and decided to establish an intergovernmental negotiating committee to combat desertification and draft the United Nations Convention to Combat Desertification in Those Countries Experiencing Serious Drought and/or Desertification, Particularly in Africa. The Convention was adopted in Paris on 1994 and is open to all countries for signature. At present, more than 40 countries have signed the Convention, and China signed it in 1994. When China joined the Convention, the word desertification was translated into desertification, and later the relevant authorities in China decided to translate it into desertification.
Some countries have independently enacted laws to combat desertification, such as Denmark, which was promulgated by the King in 1539 and revised in 1779 and 1792 respectively. Japan promulgated the sand prevention law in Meiji 30, and revised it in Showa 62. 17 19, the United States enacted a law to prevent the destruction of vegetation against the destruction of coastal sand dunes, 1976, which stipulated in the federal land management law that desert areas with historical and natural resources should be designated as desert reserves.
Land desertification began to appear in Australia in this century. The federal parliament promulgated the grassland management regulations in 1936 and the soil protection and land conservation bill in 1989. The former Soviet Union promulgated the Law on Nature Protection in 1960, which clearly stipulated that wind-eroded land should be included in the natural objects protected by law.
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According to the provisions of the United Nations Convention, many countries in the world have formulated action plans to combat desertification, and China is one of the first countries to formulate action plans. Under the framework of China 2 1 century agenda-21century China white paper on population, environment and development, the forestry development plan has been formulated, and sand control is an important content.
On the eve of the new century, the authoritative department submitted a motion to the National People's Congress Standing Committee (NPCSC) for deliberation on the Draft Law on Desertification Control. Just after the Spring Festival this year, the highest legislature deliberated the draft. This draft puts forward more targeted measures to prevent and control desertification in special areas in order to solve the particularly urgent problem of rapid expansion of desertification. The draft consists of seven chapters and 49 articles, which clearly stipulates the planning of desertification control, land desertification control, desertification land management and legal responsibility.
Authorities pointed out that compared with some existing provisions in the draft, it is necessary to put forward some stricter measures.
It is undoubtedly a very wise choice to try to bind "Huanglong" through various means including law. The reality is extremely urgent. In the spring in the capital of a big country, sand and stones often fly. How can we not be ashamed? For the sake of our lush land and no new "ecological refugees", let's "hold the long tassel in our hands" and tie the "Huanglong".
The Sahara region is vast and sparsely populated, with an average of less than 1 person per square kilometer. Mainly Arabs, followed by Berbers, etc. Residents and agricultural production are mainly distributed in the Nile valley and oasis, and some are mainly nomadic. Since 1950s, abundant minerals have been found in the desert, such as oil, natural gas, uranium, iron, manganese and phosphate. With the large-scale exploitation of mineral resources, the economic outlook of some countries in this region has changed. For example, Libya and Algeria have become the world's major oil producers, and Niger has become a famous uranium producer. Road networks, air lines and new settlements have also appeared in the desert.
The climate in the Sahara desert is hot and dry. However, it is puzzling that there was a prosperous ancient civilization in this extremely arid and water-deficient mining area with cracked land and few plants. Many exquisite large-scale murals in the desert are the crystallization of this ancient civilization. People are not only puzzled by the drawing date of these murals, but also ignorant of the strange shapes in them, which has become a mystery in the history of human civilization.
The Story of the Sahara, one of Sanmao's famous works, records the interesting stories of Sanmao's life in the Sahara desert, including her experience as a bride in the desert. The Sahara desert she described emotionally was covered with a mysterious, romantic and beautiful color. In addition, the crying camel has collected many fascinating desert stories.
The whole territory is controlled by the subtropical high pressure belt, and the dry and hot Hamadan wind prevails most of the year, with little precipitation, dryness and heat, forming a typical tropical desert climate. The average annual precipitation in most areas is below 50 mm, and some inland areas even have no rain for many years. The annual change rate of precipitation is very large. Evaporation is vigorous, and the annual potential evaporation is more than 2000 mm, and the highest is 4500 ~ 6000 mm, which further aggravates the climate drought. The annual average temperature is generally above 25℃. The average temperature in July is above 35 ~ 37℃, the absolute maximum temperature exceeds 50℃, and the high temperature lasts for a long time. The absolute maximum temperature in Azizi reached 58℃, and it is known as the "hot pole" in the world. The daily temperature difference is very large, generally 15 ~ 30℃, and the absolute daily temperature difference of 38.2℃ was observed in Luoceng, Corroto. Solar energy resources are extremely rich. The annual sunshine hours are generally above 3,600 hours, and the central part can reach 4,300 hours.
Except for the outflow of the Nile in the east, the rest are in the inflow area or no-flow area, and the water flow is unstable all year round, and there is short-term water in the dry valley when it rains. Some dry valleys were formed in the warm and humid period of Quaternary. At that time, a large amount of precipitation infiltrated and became the main source of groundwater in the Sahara desert. Many oases have been formed in the dry valleys and small basins in the foothills of Artes and the central highlands, which have become the main areas of economic activities in the desert, such as Siwa Oasis, Dakhla Oasis, Fezan Oasis Group, Couvrat Oasis Group and Ain Salah, Thugut, Gula and Valguela Oases in Algeria. Most oases use groundwater for irrigation, and irrigation methods include karez irrigation, well irrigation and spring irrigation.
Plants are scarce, mostly xerophytes and ephemeral plants. Besides oases, trees and shrubs are extremely rare. There are many plants in the southern edge of the desert, including shrubs and hard grass, with fenugreek as the most. A narrow strip along the Atlantic coast is rich in succulent Euphorbia plants. There are Mediterranean tree species in Ahagar and Tibesti Plateau, such as acacia, fig, olive and oleander. There are Tamarix plants in some arid valleys. There are more lush plants in the oasis, mainly date palms, with as many as 20 ~ 30 species. In addition, there are small plants of Leguminosae, Compositae and Cruciferae scattered in many places. The soil is mainly desert soil, followed by shallow rocky soil and sandy soil, and the saline soil appears in sheets. Oasis area has excellent farming soil. Adapting to the desert ecological environment, animals have the characteristics of thirst tolerance, hunger tolerance, developed vision and hearing, and fast running speed. Most of them live in dry valleys, oases and lakes with rich vegetation. There are mainly reptiles, ostriches, rodents, antelopes, bats, hedgehogs, foxes, camels and so on.
The Sahara region is vast and sparsely populated, with an average of less than 1 person per square kilometer. Mainly Arabs, followed by Berbers, etc. Residents and agricultural production are mainly distributed in the Nile valley and oasis, and some are mainly nomadic. Since 1950s, abundant minerals have been found in the desert, such as oil, natural gas, uranium, iron, manganese and phosphate. With the large-scale exploitation of mineral resources, the economic outlook of some countries in this region has changed. For example, Libya and Algeria have become the world's major oil producers, and Niger has become a famous uranium producer. Road networks, air lines and new settlements have also appeared in the desert.
65,438+0,000 years ago, the Sahara, now the largest desert in the world, was once full of weeds and bushes. But later, the temperature rose in summer and there was almost no rain. This climate change has destroyed many ancient creatures and forced those who survived to migrate to other areas.
Researchers say that another less serious climate change in the Sahara desert occurred between 6700 and 5000 years ago.
According to these scientists from the Potsdam Institute of Meteorology, desertification in the Sahara Desert is one of the most drastic climate changes since 1. 1.000 years ago. This meteorological model shows that human land use is not an important factor affecting the formation of the Sahara desert.