What impact does human activity have? The impact of human activities on nature
From century to century, people have used the surrounding nature as a source of resource consumption. But until a certain time, this activity did not have a detrimental effect on surrounding a person world. For example, plants have always served as a source of food for man, building material for huts, plants have been used to feed livestock.
Developing, mankind increasingly consumed plant materials, and with the advent of various devices, mechanisms, production, vegetable world began to suffer serious losses. For example, if a couple of decades ago, about 5 thousand items of products were produced from wood, now there are already about 15 thousand of them.
A person strives to make his life better, more comfortable, therefore he takes more and more resources from nature. As a result, this human influence on plants results in the return of toxic production waste to him, which is difficult to dispose of. In turn, this becomes a threat to both humans and the environment.
Only at the end of the last century, scientists paid attention to the results of the harmful effects of economic activity man to the plant world. In this regard, scientific programs began to be created, grants were issued to develop ways to improve the environmental situation.
Economic activity of man and flora
Industrial emissions and have a detrimental effect on plants. For example, phytotoxicants emitted into the air have a detrimental effect on coniferous forests - forests dry out from these substances. AT recent times tropical forests, which are the main suppliers of oxygen to the surrounding atmosphere, began to suffer from industrial facilities. Restoring tropical forests is a very difficult and extremely time-consuming task.
For the production of electricity, hydroelectric stations and water storage facilities are built on the rivers. As a result, vast areas of the soil are flooded. Incorrect human activity in cultivating floodplains of rivers and lakes provoked their siltation, which means the disappearance of many aquatic plants.
Increase in population, urbanization
It should be noted that the degree of detrimental human influence on the plant world also depends on the population. Indeed, in connection with this, more and more food, energy resources are needed, housing problems need to be solved, etc. The population is constantly growing, new generations require more and more resources. But, unfortunately, the possibilities and resources of the planet are not unlimited. Therefore, the problem of insufficient resources must be seriously and quickly addressed now.
In addition, the rapid growth of the world's population causes urbanization, which means that there are more and more cities and they occupy all large areas. But at the site of their construction and expansion, natural areas are being destroyed. Therefore, often at the place where new cities appear, even the climate becomes different.
Flora - as an object of protection
Under the influence of human activity (direct or indirect), many plant species are on the verge of destruction. They have become rare, disappearing or have disappeared altogether. Currently, about 30 thousand plant species are known to be under complete threat of extinction.
As an object of protection, all plants are divided into aquatic, soil, underground and terrestrial:
Aquatic vegetation growing in reservoirs is extremely important for the ecosystem of the reservoirs themselves and the organisms living in them. Man weakly uses this group of plants.
Soil vegetation is fungi, bacteria, some algae. All of them have an impact on the soil, making it more fertile. A person also does not actively use them.
Terrestrial plants growing on the surface of the earth are most actively used by man. It was from this group that most of the plants disappeared.
As a result of their activities, vast areas of wild plants have been replaced by agricultural crops, as man is constantly transforming the surrounding nature in his own interests. In addition, plants are disappearing due to unsystematic grazing of farm animals. They eat the plants, and those that remain are damaged by their hooves. As a result of this, degeneration of pastures occurs, water and wind soil erosion occurs.
If the presence and constantly growing number of industrial enterprises and power plants can be justified by industrial necessity, then spontaneous dumps, massive littering of hayfields and pastures cannot be justified in any way. Spontaneous garbage dumps, the removal of industrial waste to places not intended for this, have the most negative impact on a fragile ecosystem. Also, unorganized collection has a very detrimental effect on the plant world. medicinal plants, flowers and activities of tourists leaving behind mountains of rubbish.
Man increasingly began to face the impoverishment of the recently green corners of nature, pastures, meadows and forests. Thus, he has to study deeper and deeper the laws of nature of the surrounding world. Humanity has begun to realize the serious danger of further detrimental effects of its activities on plants, which means that humanity will find ways to reduce it.
In accordance with population density, the degree of human impact on environment. However, with the current level of development of productive forces, the activity of human society affects the biosphere as a whole. Mankind, with its social laws of development and powerful technology, is quite capable of influencing the secular course of biospheric processes.
Air pollution. In the course of his activities, man pollutes air environment. Above cities and industrial areas, the concentration of gases in the atmosphere increases, which in rural areas are contained in very small quantities or are completely absent. Polluted air is harmful to health. In addition, harmful gases, combining with atmospheric moisture and falling out in the form of acid rain, degrade soil quality and reduce crop yields.
The main causes of air pollution are the combustion of fossil fuels and metallurgical production. If in the 19th century the combustion products of coal and liquid fuel entering the environment were almost completely assimilated by the vegetation of the Earth, at present the content of harmful combustion products is steadily increasing. From furnaces, furnaces, exhaust pipes of cars, a number of pollutants enter the air. Sulfur dioxide, a poisonous gas that is easily soluble in water, stands out among them.
The concentration of sulfur dioxide in the atmosphere is especially high in the vicinity of copper smelters. It causes the destruction of chlorophyll, the underdevelopment of pollen grains, the drying and falling of the leaves of the needles. Part of SO 2 is oxidized to sulfuric anhydride. Solutions of sulphurous and sulfuric acids, falling with rain on the surface of the Earth, harm living organisms, destroy buildings. The soil becomes acidic, humus (humus) is washed out of it - organic matter containing the components necessary for the development of plants. In addition, it reduces the amount of salts of calcium, magnesium, potassium. In acidic soils, the number of animal species living in it also decreases, and the rate of decay of litter is slowed down. All this creates unfavorable conditions for plant growth.
Billions of tons of CO 2 are released into the atmosphere every year as a result of fuel combustion. Half of the carbon dioxide produced by burning fossil fuels is absorbed by the ocean and green plants, and half remains in the air. The content of CO 2 in the atmosphere is gradually increasing and has increased by more than 10% over the past 100 years. CO 2 prevents thermal radiation into space, creating the so-called "greenhouse effect". Changes in the content of CO 2 in the atmosphere significantly affect the Earth's climate.
Industrial enterprises and cars cause many toxic compounds to enter the atmosphere - nitrogen oxide, carbon monoxide, lead compounds (each car emits 1 kg of lead per year), various hydrocarbons - acetylene, ethylene, methane, propane, etc. Together with water droplets they form a poisonous fog - smog, which has a harmful effect on the human body, on the vegetation of cities. Liquid and solid particles (dust) suspended in the air reduce the amount of solar radiation reaching the Earth's surface. Yes, in big cities solar radiation is reduced by 15%, ultraviolet radiation by 30% (and in the winter months it can completely disappear).
Fresh water pollution. Scale of use water resources are rapidly increasing. This is due to the growth of the population and the improvement of the sanitary and hygienic conditions of human life, the development of industry and irrigated agriculture. Daily water consumption for household needs in rural areas is 50 liters per person, in cities - 150 liters.
A huge amount of water is used in industry. For the smelting of 1 ton of steel, 200 m 3 of water is needed, and for the manufacture of 1 ton of synthetic fiber - from 2500 to 5000 m 3. Industry absorbs 85% of all water used in cities.
More water is needed for irrigation. During the year, 12-14 m 3 of water is consumed per 1 ha of irrigated land. In our country, more than 150 km 3 is annually spent on irrigation.
The constant increase in water consumption on the planet leads to the danger of "water hunger", which necessitates the development of measures for the rational use of water resources. Except high level The shortage of water is caused by its growing pollution due to the discharge of industrial and especially chemical waste into the rivers. Bacterial contamination and toxic chemicals (such as phenol) lead to the death of water bodies. Mole rafting of timber along the rivers, which is often accompanied by traffic jams, also has harmful consequences. When wood stays in water for a long time, it loses business qualities, and the substances washed out of it have a detrimental effect on fish.
Rivers and lakes also receive mineral fertilizers washed out from the soil by rains - nitrates and phosphates, which in high concentrations can dramatically change the species composition of water bodies, as well as various pesticides - pesticides used in agriculture for pest control. For aerobic organisms living in fresh waters, unfavorable factor the discharge of warm water by enterprises also serves. In warm water, oxygen is poorly soluble and its deficiency can lead many organisms to death.
Pollution of the oceans. The waters of the seas and oceans are exposed to significant pollution. With river runoff, as well as from maritime transport, pathogenic wastes, oil products, salts enter the seas. heavy metals, poisonous organic compounds, including pesticides. Pollution of the seas and oceans reaches such proportions that in some cases caught fish and shellfish are unfit for human consumption.
Anthropogenic changes in the soil. The fertile soil layer is formed for a very long time. At the same time, tens of millions of tons of nitrogen, potassium, and phosphorus, the main components of plant nutrition, are removed from the soil along with the harvest every year. Humus, the main factor of soil fertility, is contained in chernozems in an amount of less than 5% of the mass of the arable layer. On poor soils, humus is even less. In the absence of soil replenishment with nitrogen compounds, its reserve can be used up in 50-100 years. This does not happen, since cultural agriculture involves the application of organic and inorganic (mineral) fertilizers to the soil.
The nitrogen fertilizers introduced into the soil are used by plants by 40-50%. The rest is restored by microorganisms to gaseous substances, volatilizes into the atmosphere or is washed out of the soil. Thus, mineral nitrogen fertilizers are quickly consumed, so they have to be applied annually. With insufficient use of organic and inorganic fertilizers, the soil is depleted and crops fall. Unfavorable changes in the soil also occur as a result of incorrect crop rotations, i.e., the annual sowing of the same crops, such as potatoes.
Erosion (corrosion) is one of the anthropogenic changes in the soil. Erosion is the destruction and demolition of the soil cover by water flows or wind. Water erosion is widespread and most destructive. It occurs on the slopes and develops with improper cultivation of the land. Together with melt and rainwater, millions of tons of soil are annually carried away from the fields into rivers and seas. If nothing prevents erosion, small gullies turn into deeper ones and, finally, into ravines.
Wind erosion occurs in areas with dry bare soil, with sparse vegetation. Excessive grazing in the steppes and semi-deserts contributes to wind erosion and the rapid destruction of grass cover. It takes 250-300 years to restore a layer of soil 1 cm thick under natural conditions. Consequently, dust storms bring irreparable losses of the fertile soil layer.
Significant areas with formed soils are withdrawn from agricultural circulation due to the open-pit mining of minerals occurring at shallow depths. Open-pit mining is cheap, as it eliminates the construction of expensive mines and a complex system of communications, and is also safer. Dug deep quarries and dumps of soil destroy not only the lands to be developed, but also the surrounding territories, while the hydrological regime of the area is disturbed, water, soil and atmosphere are polluted, and crop yields are reduced.
Human influence on flora and fauna. Human impact on wildlife consists of direct influence and indirect changes in the natural environment. One of the forms of direct impact on plants and animals is deforestation. Selective and sanitary cuttings, which regulate the composition and quality of the forest and are necessary for the removal of damaged and diseased trees, do not significantly affect the species composition of forest biocenoses. Another thing is the clear-cutting of a tree stand. Once suddenly in an open habitat, the plants of the lower tiers of the forest are adversely affected by direct solar radiation. In shade-loving plants of the herbaceous and shrub layers, chlorophyll is destroyed, growth is inhibited, and some species disappear. Light-loving plants that are resistant to high temperatures and lack of moisture settle on the site of clearings. is changing and animal world: species associated with the forest stand disappear or migrate to other places.
A tangible impact on the condition of the vegetation cover is exerted by the massive visitation of forests by vacationers and tourists. In these cases, the harmful effect consists in trampling, soil compaction and its pollution. The direct influence of man on the animal world is the extermination of species that are food or other material benefits for him. It is believed that since 1600 more than 160 species and subspecies of birds and at least 100 species of mammals have been exterminated by man. The long list of extinct species includes the tour - a wild bull that lived throughout Europe. In the XVIII century. was exterminated described by the Russian naturalist G.V. Steller's sea cow (Steller's cow) is an aquatic mammal belonging to the siren order. A little over a hundred years ago, the wild horse tarpan, which lived in southern Russia, disappeared. Many species of animals are on the verge of extinction or have survived only in nature reserves. Such is the fate of the bison, who inhabited the prairies of North America by tens of millions, and of the bison, formerly widespread in the forests of Europe. On the Far East the sika deer is almost completely exterminated. Intensified cetacean fishing has brought to the brink of extinction several species of whales: gray, bowhead, blue.
The number of animals is also influenced by human economic activities not related to fishing. The number of the Ussuri tiger has sharply decreased. This happened as a result of the development of territories within its range and the reduction of the food supply. AT pacific ocean several tens of thousands of dolphins die every year: during the fishing period, they get into the nets and cannot get out of them. Until recently, before the adoption of special measures by fishermen, the number of dolphins dying in nets reached hundreds of thousands. Marine mammals are very adversely affected by water pollution. In such cases, the ban on trapping of animals is ineffective. For example, after the ban on catching dolphins in the Black Sea, their numbers are not restored. The reason is that in the Black Sea with river water and through the straits from mediterranean sea a lot of toxic substances come in. These substances are especially harmful to baby dolphins, whose high mortality prevents the growth of the number of these cetaceans.
The disappearance of a relatively small number of animal and plant species may not seem very significant. Each species occupies a certain place in the biocenosis, in the chain and no one can replace it. The disappearance of a particular species leads to a decrease in the stability of biocenoses. More importantly, each species has unique, unique properties. The loss of the genes that determine these properties and are selected in the course of long evolution deprives a person of the opportunity to use them in the future for his practical purposes (for example, for selection).
Radioactive contamination of the biosphere. The problem of radioactive contamination arose in 1945 after the explosion atomic bombs dropped on the Japanese cities of Hiroshima and Nagasaki. Tests nuclear weapons produced before 1963 in the atmosphere caused global radioactive contamination. During the explosion of atomic bombs, very strong ionizing radiation occurs, radioactive particles are scattered over long distances, infecting the soil, water bodies, and living organisms. Many radioactive isotopes have long half-lives, remaining hazardous throughout their lifetime. All these isotopes are included in the circulation of substances, enter living organisms and have a detrimental effect on cells.
Nuclear weapons testing (and even more so when these weapons are used for military purposes) has another negative side. At nuclear explosion a huge amount of fine dust is formed, which is kept in the atmosphere and absorbs a significant part of solar radiation. Calculations by scientists from around the world show that even with a limited, local use of nuclear weapons, the resulting dust will delay most solar radiation. There will be a long cold snap (“nuclear winter”), which will inevitably lead to the death of all life on Earth.
At present, almost any territory of the planet from the Arctic to Antarctica is subject to diverse anthropogenic influences. The consequences of the destruction of natural biocenoses and environmental pollution have become very serious. The entire biosphere is under ever-increasing pressure from human activity, so environmental protection measures are becoming an urgent task.
Acid atmospheric impacts on land. One of the most acute global problems of today and the foreseeable future is the problem of increasing acidity of precipitation and soil cover. Areas of acidic soils do not know droughts, but their natural fertility is lowered and unstable; they are rapidly depleted and yields are low. Acid rain causes not only acidification of surface waters and upper soil horizons. Acidity with downward water flows extends to the entire soil profile and causes significant acidification of groundwater. Acid rain occurs as a result of human activities, accompanied by the emission of colossal amounts of oxides of sulfur, nitrogen, carbon. These oxides, entering the atmosphere, are transported over long distances, interact with water and turn into solutions of a mixture of sulfurous, sulfuric, nitrous, nitric and carbonic acids, which fall in the form of "acid rain" on land, interacting with plants, soils, waters. The main sources in the atmosphere are the burning of shale, oil, coal, gas in industry, agriculture, and at home. Human economic activity has almost doubled the release of sulfur oxides, nitrogen oxides, hydrogen sulfide and carbon monoxide into the atmosphere. Naturally, this affected the increase in the acidity of atmospheric precipitation, ground and ground waters. To solve this problem, it is necessary to increase the volume of systematic representative measurements of atmospheric pollutant compounds over large areas.
Economic activity affects not only directly, but also indirectly on the atmosphere and the processes occurring in it. Especially strong impact human economic activity has an impact on the climate of entire regions - deforestation, plowing of land, large-scale land reclamation, mining, fossil fuel combustion, military operations, etc.
Human economic activity does not violate the geochemical cycle, and also has a significant impact on the energy balance in nature. During human economic activity, various chemical compounds, which are tens of times greater than the appearance of substances during weathering rocks and volcanoes. In some regions with large populations and industrial production the volumes of generated energy have become comparable with the energy of the radiation balance and have a great influence on the change in the microclimate.
The modern composition of the atmosphere is the result of a long historical development of the globe. The composition of the atmosphere is oxygen, nitrogen, argon, carbon dioxide and inert gases. Above cities and industrial areas, the concentration of gases increases in the atmosphere, which are usually found in very small quantities or not at all in rural areas. Polluted air is harmful to health. In addition, harmful gases, combining with atmospheric moisture and falling out in the form of acid rain, degrade soil quality and reduce crop yields.
According to the results of studies of checking the amount of oxygen in the atmosphere, it was determined that the decrease occurs by more than 10 million tons per year. Therefore, the content carbon dioxide in the atmosphere can reach a critical situation. According to the calculations of some scientists, it is known that a 2-fold increase in the amount of CO2 in the atmosphere will increase the average temperature of the Earth by 1.5-2 degrees due to the "greenhouse effect". and also, a rise in the level of the World Ocean by 5 m is possible.
According to scientists, every year in the world as a result of human activity, 25.5 billion tons of carbon oxides, 190 million tons of sulfur oxides, 65 million tons of nitrogen oxides, 1.4 million tons of freons, organic lead compounds, hydrocarbons, including carcinogenic, a large number of solid particles (dust, soot, soot).
global pollution atmospheric air affects the state of natural ecosystems, especially the green cover of our planet. Acid rains, caused mainly by sulfur dioxide and nitrogen oxides, cause great harm to forest biocenoses. Forests, especially conifers, suffer from them.
The main cause of air pollution is the combustion of fossil fuels and metallurgical production. If in the 19th and early 20th centuries, the products of combustion of coal and liquid fuel entering the environment were almost completely assimilated by the vegetation of the Earth, then at present the content of combustion products is steadily increasing. From furnaces, furnaces, exhaust pipes of cars, a number of pollutants enter the air. Among them, sulfur dioxide stands out - a poisonous gas that is easily soluble in water. The concentration of sulfur dioxide in the atmosphere is especially high in the vicinity of copper smelters. It causes the destruction of chlorophyll, underdevelopment of pollen grains, drying and falling of leaves, needles.
Soil - the top layer of land, formed under the influence of plants, animals, microorganisms and climate from the parent rocks on which it is located. This is an important and complex component of the biosphere, closely related to its other parts. Under normal natural conditions, all processes occurring in the soil are in balance.
As a result of the development of human activities, pollution, changes in the composition of the soil and even its destruction occur. Pollution of the soil cover with mercury (with pesticides and waste from industrial enterprises), lead (from lead smelting and from vehicles), iron, copper, zinc, manganese, nickel, aluminum and other metals (near major centers ferrous and non-ferrous metallurgy), radioactive elements (as a result of precipitation from atomic explosions or when removing liquid and solid waste from industrial enterprises, nuclear power plants or research institutes related to the study and use of atomic energy), persistent organic compounds used as pesticides. They accumulate in soil and water and, most importantly, are included in ecological food chains: they pass from soil and water to plants, animals, and eventually enter the human body with food. The inept and uncontrolled use of any fertilizers and pesticides leads to disruption of the circulation of substances in the biosphere.
Erosion is one of the anthropogenic changes in soils. The destruction of forests and natural grass cover, repeated plowing of the land without observing the rules of agricultural technology lead to soil erosion - the destruction and washing away of the fertile layer by water and wind. The most destructive water erosion is also widespread. It occurs on the slopes and develops with improper cultivation of the land. Together with melt and rainwater, millions of tons of soil are annually carried away from the fields into rivers and seas. Significant areas with formed soils are withdrawn from agricultural circulation due to the open-pit mining of minerals occurring at shallow depths.
At present, the area of land developed by man has reached 60% of the land. Built-up land now occupies about 300 million hectares. Man today is subject to the regulation of hydrological regimes in large areas. It can significantly, although still locally, change the climate, landscapes and green cover of the planet. The wealth that nature has been collecting for centuries in the bowels of the planet, people extract and spread over its entire surface. For almost 50 years since the beginning of the scientific and technological revolution, there are no signs of slowing down technical progress. The power of modern civilization is growing rapidly, and science and technology are opening up new horizons for its development. Never before has civilization provided humanity with so many benefits as it is happening now.
The impact of man on wildlife consists of direct influence and indirect changes in the natural environment. One form of direct impact on plants and animals is deforestation. Once suddenly in an open habitat, the plants of the lower tiers of the forest are adversely affected by direct solar radiation. In heat-loving plants of herbaceous and shrub layers, chlorophyll is destroyed, growth is inhibited, and some species disappear. Light-loving plants that are resistant to high temperatures and lack of moisture settle on the felling sites. The animal world is also changing: the species associated with the forest stand disappear or migrate to other places.
Due to intensive economic activity, there is a gradual depletion and destruction of the natural environment, i.e., the loss of those natural irreplaceable resources that serve as a source of economic activity for a person. At the current rate of consumption, the proven reserves of coal, oil, natural gas and other minerals, according to scientists, will be enough for industrial use for 50-500 years. Moreover, a smaller indicator applies to liquid hydrocarbons, i.e. oil.
True, society has the prospect of using other types of energy, in particular nuclear, wind, solar, sea tides, geothermal waters, hydrogen energy, the reserves of which are still considered inexhaustible. However, the use of atomic energy in large-scale production is hampered by the unresolved problem of nuclear industry waste disposal. The development of hydrogen as an energy source is still possible only theoretically, since technologically this problem has not yet been solved.
One of the sharp contemporary problems- Lack of clean fresh water. In developing countries, up to 9 million people die every year from water pollution. According to scientists, already in 2000 more than 1 billion people lacked drinking water. In general, there is a lot of water on Earth. The hydrosphere contains approximately 1.6 billion km3 of free water; 1.37 billion km 3 of it falls on the World Ocean. On the continents - 90 million km 3, of which 60 million km 3 of water is underground - almost all of this water is salty, 27 million km 3 of water is stored in the glaciers of Antarctica, the Arctic, and high mountains.
Ecological ignorance and ecological nihilism have become the result of insufficient public attention to the problems of environmental protection. What they have in common is a disregard for knowledge and the use of environmental patterns in communication between man and the environment. Ecological ignorance - unwillingness to study the laws of the relationship between man and the environment; ecological nihilism - unwillingness to be guided by these laws. Unfortunately, ignorance and ecological nihilism, combined with consumer psychology, become dangerous for the existence of all life on Earth.
In accordance with the population density, the degree of human impact on the environment also changes. However, with the current level of development of productive forces, the activity of human society affects the biosphere as a whole. Mankind, with its social laws of development and powerful technology, is quite capable of influencing the secular course of biospheric processes.
Air pollution.
In the course of their activities, a person pollutes the air environment. Above cities and industrial areas, the concentration of gases in the atmosphere increases, which in rural areas are contained in very small quantities or are completely absent. Polluted air is harmful to health. In addition, harmful gases, combining with atmospheric moisture and falling out in the form of acid rain, degrade soil quality and reduce crop yields.
The main causes of air pollution are the burning of fossil fuels and metallurgical production. If in the 19th century the combustion products of coal and liquid fuel entering the environment were almost completely assimilated by the vegetation of the Earth, at present the content of harmful combustion products is steadily increasing. From furnaces, furnaces, exhaust pipes of cars, a number of pollutants enter the air. Sulfur dioxide, a poisonous gas that is easily soluble in water, stands out among them.
The concentration of sulfur dioxide in the atmosphere is especially high in the vicinity of copper smelters. It causes the destruction of chlorophyll, the underdevelopment of pollen grains, the drying and falling of the leaves of the needles. Part of SO 2 is oxidized to sulfuric anhydride. Solutions of sulphurous and sulfuric acids, falling with rain on the surface of the Earth, harm living organisms, destroy buildings. The soil acquires an acidic reaction, humus (humus) is washed out of it - an organic substance containing components necessary for the development of plants. In addition, it reduces the amount of salts of calcium, magnesium, potassium. In acidic soils, the number of animal species living in it also decreases, and the rate of decay of litter is slowed down. All this creates unfavorable conditions for plant growth.
Billions of tons of CO 2 are released into the atmosphere every year as a result of fuel combustion. Half of the carbon dioxide produced by burning fossil fuels is absorbed by the ocean and green plants, and half remains in the air. The content of CO 2 in the atmosphere is gradually increasing and has increased by more than 10% over the past 100 years. CO 2 prevents thermal radiation into space, creating the so-called "greenhouse effect". Changes in the content of CO 2 in the atmosphere significantly affect the Earth's climate.
Industrial enterprises and cars cause many toxic compounds to enter the atmosphere - nitrogen oxide, carbon monoxide, lead compounds (each car emits 1 kg of lead per year), various hydrocarbons - acetylene, ethylene, methane, propane, etc. Together with water droplets they form a poisonous fog - smog, which has a harmful effect on the human body, on the vegetation of cities. Liquid and solid particles (dust) suspended in the air reduce the amount of solar radiation reaching the Earth's surface. So, in large cities, solar radiation decreases by 15%, ultraviolet radiation - by 30% (and in the winter months it can completely disappear).
Fresh water pollution.
The use of water resources is rapidly increasing. This is due to the growth of the population and the improvement of the sanitary and hygienic conditions of human life, the development of industry and irrigated agriculture. Daily water consumption for household needs in rural areas is 50 liters per person, in cities - 150 liters.
A huge amount of water is used in industry. For the smelting of 1 ton of steel, 200 m 3 of water is needed, and for the manufacture of 1 ton of synthetic fiber - from 2500 to 5000 m 3. Industry absorbs 85% of all water used in cities.
More water is needed for irrigation. During the year, 12-14 m 3 of water is consumed per 1 ha of irrigated land. In our country, more than 150 km 3 is annually spent on irrigation.
The constant increase in water consumption on the planet leads to the danger of "water hunger", which necessitates the development of measures for the rational use of water resources. In addition to the high level of water consumption, the shortage of water is caused by its growing pollution due to the discharge of industrial and especially chemical waste into the rivers. Bacterial contamination and poisonous chemical substances(for example, phenol) lead to the necrosis of water bodies. Mole rafting of timber along the rivers, which is often accompanied by traffic jams, also has harmful consequences. When wood stays in water for a long time, it loses its business qualities, and the substances washed out of it have a detrimental effect on fish.
Mineral fertilizers, nitrates and phosphates, washed out from the soil by rains, which in high concentrations can dramatically change the species composition of water bodies, as well as various pesticides used in agriculture to control insect pests, also enter rivers and lakes. For aerobic organisms living in fresh waters, the discharge of warm water by enterprises is also an unfavorable factor. In warm water, oxygen is poorly soluble and its deficiency can lead many organisms to death.
Pollution of the oceans. The waters of the seas and oceans are exposed to significant pollution. With river runoff, as well as from maritime transport, pathogenic wastes, oil products, salts of heavy metals, toxic organic compounds, including pesticides, enter the seas. Pollution of the seas and oceans reaches such proportions that in some cases caught fish and shellfish are unfit for human consumption.
Anthropogenic changes in the soil.
The fertile soil layer is formed for a very long time. At the same time, tens of millions of tons of nitrogen, potassium, and phosphorus, the main components of plant nutrition, are withdrawn from the soil along with the harvest every year. Humus, the main factor of soil fertility, is contained in chernozems in an amount of less than 5% of the mass of the arable layer. On poor soils, humus is even less. In the absence of soil replenishment with nitrogen compounds, its reserve can be used up in 50-100 years. This does not happen, since cultural agriculture involves the application of organic and inorganic (mineral) fertilizers to the soil.
The nitrogen fertilizers introduced into the soil are used by plants by 40-50%. The rest is reduced by microorganisms to gaseous substances, volatilizes into the atmosphere or is washed out of the soil. Thus, mineral nitrogen fertilizers are quickly consumed, so they have to be applied annually. With insufficient use of organic and inorganic fertilizers, the soil is depleted and crops fall. Unfavorable changes in the soil also occur as a result of incorrect crop rotations, i.e., the annual sowing of the same crops, such as potatoes.
Erosion (corrosion) is one of the anthropogenic changes in the soil. Erosion is the destruction and demolition of the soil cover by water flows or wind. Water erosion is widespread and most destructive. It occurs on the slopes and develops with improper cultivation of the land. Together with melt and rainwater, millions of tons of soil are annually carried away from the fields into rivers and seas. If nothing prevents erosion, small gullies turn into deeper ones and, finally, into ravines.
Wind erosion occurs in areas with dry bare soil, with sparse vegetation. Excessive grazing in the steppes and semi-deserts contributes to wind erosion and the rapid destruction of grass cover. It takes 250-300 years to restore a layer of soil 1 cm thick under natural conditions. Consequently, dust storms bring irreparable losses of the fertile soil layer.
Significant areas with formed soils are withdrawn from agricultural circulation due to the open-pit mining of minerals occurring at shallow depths. Open-pit mining is cheap, as it eliminates the construction of expensive mines and a complex system of communications, and is also safer. Dug deep quarries and dumps of soil destroy not only the lands to be developed, but also the surrounding territories, while the hydrological regime of the area is disturbed, water, soil and atmosphere are polluted, and crop yields are reduced.
Human influence on flora and fauna.
Human impact on wildlife consists of direct influence and indirect changes in the natural environment. One form of direct impact on plants and animals is deforestation. Selective and sanitary cuttings, which regulate the composition and quality of the forest and are necessary for the removal of damaged and diseased trees, do not significantly affect the species composition of forest biocenoses.
Another thing - a continuous felling of trees. Once suddenly in an open habitat, the plants of the lower tiers of the forest are adversely affected by direct solar radiation. In shade-loving plants of the herbaceous and shrub layers, chlorophyll is destroyed, growth is inhibited, and some species disappear. Light-loving plants that are resistant to high temperatures and lack of moisture settle on the site of clearings. The animal world is also changing: the species associated with the forest stand disappear or migrate to other places.
A tangible impact on the condition of the vegetation cover is exerted by the massive visitation of forests by vacationers and tourists. In these cases, the harmful effect consists in trampling, soil compaction and its pollution. The direct influence of man on the animal world is the extermination of species that are food or other material benefits for him. It is believed that since 1600 more than 160 species and subspecies of birds and at least 100 species of mammals have been exterminated by man. The long list of extinct species includes the tour - a wild bull that lived throughout Europe.
In the XVIII century. was exterminated described by the Russian naturalist G.V. Steller's sea cow (Steller's cow) is an aquatic mammal belonging to the siren order. A little over a hundred years ago, the wild horse tarpan, which lived in southern Russia, disappeared. Many species of animals are on the verge of extinction or have survived only in nature reserves. Such is the fate of the bison, who inhabited the prairies by tens of millions. North America, and bison, formerly widespread in the forests of Europe. In the Far East, the sika deer is almost completely exterminated. Intensified cetacean fishing has brought to the brink of extinction several species of whales: gray, bowhead, blue.
The number of animals is also influenced by human economic activities not related to fishing. The number of the Ussuri tiger has sharply decreased. This happened as a result of the development of territories within its range and the reduction of the food supply. In the Pacific Ocean, several tens of thousands of dolphins die every year: during the fishing period, they get into the nets and cannot get out of them. Until recently, before the adoption of special measures by fishermen, the number of dolphins dying in nets reached hundreds of thousands.
Marine mammals are very adversely affected by water pollution. In such cases, the ban on trapping of animals is ineffective. For example, after the ban on catching dolphins in the Black Sea, their numbers are not restored. The reason is that many toxic substances enter the Black Sea with river water and through the straits from the Mediterranean Sea. These substances are especially harmful to baby dolphins, whose high mortality prevents the growth of the number of these cetaceans.
The disappearance of a relatively small number of animal and plant species may not seem very significant. Each species occupies a certain place in the biocenosis, in the chain and no one can replace it. The disappearance of a particular species leads to a decrease in the stability of biocenoses. More importantly, each species has unique, unique properties. The loss of the genes that determine these properties and are selected in the course of long evolution deprives a person of the opportunity to use them in the future for his practical purposes (for example, for selection).
Radioactive contamination of the biosphere.
The problem of radioactive contamination arose in 1945 after the explosion of atomic bombs dropped on the Japanese cities of Hiroshima and Nagasaki. Nuclear weapons tests carried out before 1963 in the atmosphere caused global radioactive contamination. When an atomic bomb explodes, a very strong ionizing radiation, radioactive particles are dispersed over long distances, contaminating the soil, water bodies, living organisms. Many radioactive isotopes have long half-lives, remaining hazardous throughout their lifetime. All these isotopes are included in the circulation of substances, enter living organisms and have a detrimental effect on cells.
Nuclear weapons testing (and even more so when these weapons are used for military purposes) has another negative side. In a nuclear explosion, a huge amount of fine dust is formed, which is kept in the atmosphere and absorbs a significant part of solar radiation. Calculations by scientists around the world show that even with a limited, local use of nuclear weapons, the resulting dust will retain most of the solar radiation. There will be a long cold snap (“nuclear winter”), which will inevitably lead to the death of all life on Earth.
At present, almost any territory of the planet from the Arctic to Antarctica is subject to diverse anthropogenic influences. The consequences of the destruction of natural biocenoses and environmental pollution have become very serious. The entire biosphere is under ever-increasing pressure from human activity, so environmental protection measures are becoming an urgent task.
Acid atmospheric impacts on land.
One of the most acute global problems of today and the foreseeable future is the problem of increasing acidity of precipitation and soil cover. Areas of acidic soils do not know droughts, but their natural fertility is lowered and unstable; they are rapidly depleted and yields are low. Acid rain causes not only acidification of surface waters and upper soil horizons. Acidity with downward water flows extends to the entire soil profile and causes significant acidification of groundwater.
Acid rain occurs as a result of human activities, accompanied by the emission of colossal amounts of oxides of sulfur, nitrogen, carbon. These oxides, entering the atmosphere, are transported over long distances, interact with water and turn into solutions of a mixture of sulfurous, sulfuric, nitrous, nitric and carbonic acids, which fall in the form of "acid rain" on land, interacting with plants, soils, waters. The main sources in the atmosphere are the burning of shale, oil, coal, gas in industry, agriculture, and at home.
Human economic activity has almost doubled the release of sulfur oxides, nitrogen oxides, hydrogen sulfide and carbon monoxide into the atmosphere. Naturally, this affected the increase in the acidity of atmospheric precipitation, ground and ground waters. To solve this problem, it is necessary to increase the volume of systematic representative measurements of atmospheric pollutant compounds over large areas.