|
Arabic
Bengali
Chinese
English
French
German
Hebrew
Hindi
Italian
Japanese
Korean
Malay
Polish
Portuguese
Spanish
Turkish
Ukrainian
Vietnamese|
BASICS OF SAFE LIFE
Desertification problem. Basics of safe life
Directory / Basics of safe life Desertification at the moment is one of the most significant global problems of mankind. During the plowing of fields, myriads of particles of fertile soil cover rise into the air, disperse, are carried away from the fields by streams of water, are deposited in new places, and are irrevocably carried away in huge quantities into the World Ocean. The natural process of water and wind destroying the top layer of soil, washing away and dispersing its particles is greatly enhanced and accelerated when people plow too much land and do not allow the soil to "rest". Under the influence of living organisms, water and air, the most important ecosystem, thin and fragile, is gradually formed on the surface layers of the lithosphere - the soil, which is called the "skin of the Earth". It is the keeper of fertility and life. A handful of good soil contains millions of microorganisms that support fertility. It takes a century to form a layer of soil with a thickness of 1 cm. This layer can be lost forever in one field season. According to geologists, before people began to engage in agricultural activities, graze livestock and plow land, rivers annually carried about 9 billion tons of soil into the oceans. Now this number is estimated at about 25 billion tons. Soil erosion - a purely local phenomenon - has now become universal. In the US, for example, about 44% of cultivated land is subject to erosion. In Russia, unique rich black soils with a humus content of 14-16%, which were called the citadel of Russian agriculture, disappeared. In Russia, the areas of the most fertile lands with a humus content of 10-13% have decreased by almost 5 times. Soil erosion is especially great in the largest and most populous countries. The Yellow River in China annually carries about 2 billion tons of soil into the oceans. Soil erosion not only reduces fertility and yields: as a result of this process, artificially constructed water reservoirs are silted up much faster than usually envisaged in projects, the possibilities of irrigation and the generation of electricity from hydroelectric power stations are reduced. A particularly difficult situation arises when not only the soil layer is demolished, but also the parent rock on which it develops. Then comes the threshold of irreversible destruction, there is an anthropogenic desert. A striking picture is the Shillong Plateau in the Cherrapunji region, located in the northeast of India. This is the wettest place in the world, where on average more than 12 m of precipitation falls per year. But in the dry season, when the monsoon rains stop (in October-May), the Cherrapunji area resembles a semi-desert. The soils on the slopes of the plateau are practically washed away, barren sandstones are exposed. One of the most global and fleeting processes of our time is the expansion of desertification, the fall and - in the most extreme cases - the complete destruction of the biological potential of the Earth, which leads to conditions similar to those of a natural desert. Natural deserts and semi-deserts occupy more than 1/3 of the earth's surface. About 15% of the world's population lives on these lands. Deserts are areas with an extremely dry continental climate, usually receiving an average of only 150-175 mm of precipitation per year. Evaporation from them is much higher than their moisture content. The most extensive arrays of deserts are located on both sides of the equator, between 15 and 45 ° N. sh., and in Central Asia and Kazakhstan deserts reach 50 ° N. lat. sh. Deserts are natural formations that play a certain role in the overall ecological balance of the planet's landscapes. However, as a result of human activity, by the last quarter of the 9th century. more than 2 million km43 of deserts appeared, and in total they already covered XNUMX% of the total land area. In the 90s. desertification began to threaten arid lands. There are 3,6 million hectares, which is 70% of potentially productive drylands or 1/4 of the total land area, and these data do not include the area of natural deserts. About 1/6 of the world's population suffers from the process of desertification. It occurs in different climatic conditions, but is especially violent in hot, arid regions. Africa contains almost a third of all the arid regions of the world; they are also widespread in Asia, Latin America and Australia. On average, 6 million hectares of cultivated land per year are subject to desertification (completely destroyed), in addition, over 20 million hectares of land are reducing their productivity. This is the rate of approach to the threshold of irreversible destruction. According to UN experts, the modern loss of productive land has led to the fact that by now the world has lost almost 1/3 of its arable land. Such a loss during a period of significant population growth and an increase in food demand can be truly disastrous for humanity. Desertification is a process of degradation of all natural life-support systems: in order to survive, the local population must either receive outside help or leave in search of lands suitable for life. More and more people around the world are becoming environmental refugees. The process of desertification is usually caused by the combined action of nature and man. This action is especially detrimental in arid regions with their inherent fragile, easily destroyed ecosystems. Destruction of sparse vegetation due to excessive grazing, cutting down of trees and shrubs, as well as plowing of lands unsuitable for agriculture, and other types of economic activity that violate the delicate balance in nature, greatly increase the effect of wind erosion, the drying up of the upper layers of the soil. The water balance is sharply disturbed, the level of groundwater decreases, wells dry up. The structure of soils is destroyed, their saturation with mineral salts increases. Due to excessive economic load, complexly organized basin-river systems turn into primitively organized desert landscapes. Desertification and devastation can occur in any climatic conditions as a result of the destruction of the natural system. But in arid areas, the "engine" of desertification is also drought. In the history of mankind there are examples of how desertification, developing as a result of inept and immoderate economic activity, destroyed entire civilizations. In schools all over the world, children are taught that history must be known in order to learn lessons for the future. Has mankind learned lessons from the history of the death of past civilizations covered with sand? The main difference between the experience of history and today is the pace and scope. Excessively active economic activity, the damage from which has been accumulating for centuries and even millennia, has now been compressed into decades. If earlier individual civilizations perished under a layer of sand, now the process of desertification, originating in different places and having different regional manifestations, has taken on a global scale. Accumulation of carbon dioxide in the atmosphere, increased dust and smoke in the atmosphere accelerate the aridization of land. This process covers not only arid areas. The expansion of the desert area contributes to the emergence of dry climatic conditions, which are likely to greatly increase the frequency of long-term droughts. Sahel (from Arabic - coast, outskirts): this is the name of the transition zone up to 400 km wide, which extends from the Sahara desert to the south, to the savannas of West Africa. At the end of the 60s. a long-term drought began in this zone, which reached its climax in 1973. As a result, about 250 people died in the African countries of the Sahel zone - Senegal, Gambia, Mauritania, Mali, etc. There was also a massive loss of livestock, and meanwhile, cattle breeding is the basis of economic activity and is the source of livelihood for the majority of the population of these areas. Many wells have dried up and even such large rivers as the Niger and Senegal. The area of Lake Chad has shrunk by 000/1. In the 3s. the disasters brought by drought and desertification have taken on continental proportions in Africa. The consequences of these processes are experienced by 80 African countries and 34 million people. In 150, about 1985 million of its inhabitants died in Africa and 1 million people became "environmental refugees." The rate of advancement of the borders of the desert in Africa is up to 10 km per year. The fate of forests and the history of mankind on all continents have been intertwined. Forests served as the main source of food for primitive communities that lived by hunting and gathering. They were a source of fuel and building materials for the construction of dwellings. Forests have served as a refuge for people and, to a large extent, the basis of their economic activity. The life of forests and the life of people, the connections between them are reflected in the culture, mythology, religion of most peoples of the world. About 10 years ago, before the dawn of agriculture, dense forests and other forested areas covered more than 6 billion hectares of land. By the end of the 1th century, their area was reduced by almost 3/4 and now they occupy only a little more than 80 billion hectares. In France, for example, where forests originally covered about 14% of the territory, by the end of the 400th century. their area decreased to 1920%; in the USA, where forests at the beginning of the 2th century. almost 3 million hectares were covered, by XNUMX the forest cover was destroyed by XNUMX/XNUMX. All considered aspects affect not only the general well-being, but, mainly, the health of mankind. Authors: Aizman R.I., Krivoshchekov S.G.
▪ Technological ways to solve the problem of cooling in power plants ▪ Rules for safe driving a bicycle and a moped ▪ Psychoactive substances and mechanisms of drug addiction formation
The world's tallest astronomical observatory opened
04.05.2024 Controlling objects using air currents
04.05.2024 Purebred dogs get sick no more often than purebred dogs
03.05.2024
▪ Good cholesterol protects against sepsis ▪ ASUS PA32Q Professional 4" 328K Monitor ▪ Dogs understand words and intonations just like humans ▪ Antiquarks and proton rotation
▪ section of the site Standard instructions for labor protection (TOI). Selection of articles ▪ article Barcode. History of invention and production ▪ electrical injury article. Health care ▪ article Putty for rubber products. Simple recipes and tips
Home page | Library | Articles | Website map | Site Reviews
www.diagram.com.ua |
We recommend interesting articles Section 
See other articles Section 
Latest news of science and technology, new electronics:
All languages of this page