Environment, group of elements abióticos (solar energy, floor, dilutes and air) and bióticos (alive organisms) that integrate the thin layer of the Earth called biosphere, sustenance and the alive beings' home.
CONSTITUENT OF THE environment
The atmosphere that protects to the Earth of the excess of ultraviolet radiation and it allows the existence of life it is a gassy mixture of nitrogen, oxygen, hydrogen, dioxide of carbon, vapor of water, other elements and compound, and powder particles. Heated by the Sun and the radiant energy of the Earth, the atmosphere circulates around the planet and it modifies the thermal differences. Regarding the water, 97% is in the oceans, 2% is ice and 1 remaining% it is the sweet water of the rivers, the lakes, the underground waters and the atmospheric humidity and of the floor. The floor is the thin matter mantel that sustains the terrestrial life. It is product of the interaction of the climate and of the rocky sustrato or rock mother, as the morrenas glaciers and the sedimentary rocks, and of the vegetation. Of all them the alive organisms depend, including the human beings. The plants are served as the water, of the dioxide of carbon and of the solar light to transform matters cousins into carbohydrates by means of the photosynthesis; the animal life, in turn, depends on the plants in a well-known sequence of interconnected bonds as net trófica.
During their long history, the Earth has changed slowly. The continental drift (result of the tectonic one of badges) it separated the continental masses, the oceans invaded mainland and they retired of her, and they ran off with and erosionaron mountains, depositing silts along the costs (to see Geology). The climates became warm and they cooled, and they appeared and forms of life disappeared when changing the environment. The most recent in the important environmental events in the history of the Earth took place in the quaternary one, during the pleistoceno (between 1,64 millions and 10.000 years behind), call also glacial period. The subtropical climate disappeared and it changed the face of the north hemisphere. Big layers of ice advanced and they retired four times in America of the North and three in Europe, making oscillate the climate of cold to temperate, influencing in the vegetable life and animal and, ultimately, giving place to the climate that today knows. Our it was she/he receives, indistinctly, the names of recent, postglacial and holoceno. During this time the environment of the planet has remained more or less stable.
The species Homo sapiens, that is to say, the human being, appeared belatedly in the history of the Earth, but it has been able to modify the environment with his activities. Although, apparently, the humans made their appearance in África, they didn't take in being dispersed all over the world. Thanks to their peculiar mental and physical capacities, they were able to escape to the environmental constrictions that limited to other species and to alter the environment to adapt it to their necessities.
Although the first humans without a doubt lived more or less in harmony with the environment, as the other animals, their estrangement of the wild life began in the prehistory, with the first agricultural revolution. The capacity to control and to use the fire allowed them to modify or to eliminate the natural vegetation, and the domesticación and shepherding of herbivore animals took to the sobrepastoreo and the erosion of the floor. The cultivation of plants also originated the destruction of the natural vegetation to make hollow to the crops and the firewood demand led to the denudación of mountains and the exhaustion of whole forests. The wild animals were hunted by their meat and they were destroyed in the event of being considered plagues or depredadores.
While the human populations continued being small and their modest technology, its impact on the environment was solely local. Nevertheless, when going growing the population and improving and increasing the technology, more significant and more widespread problems appeared. The express advances technological taken place after the half age it culminated in the Industrial Revolution that she/he brought I get the discovery, use and exploitation of the fossil fuels, as well as the intensive exploitation of the mineral resources of the Earth. It was with the Industrial Revolution when the human beings really began to change the face of the planet, the nature of their atmosphere and the quality of their water. Today, the unprecedented demand to which the human population's quick growth and the technological development subject to the environment is producing a more and more quick decline in the quality of this and in its capacity to sustain the life.
Dioxide of carbon
One of the impacts that the use of fossil fuels has taken place on the terrestrial environment has been the increase of the concentration of dioxide of carbon (CO2) in the atmosphere. The atmospheric quantity of CO2 had remained stable, seemingly during centuries, but from 1750 it has been increased approximately in 30%. The significant of this change is that it can cause an increase of the temperature of the Earth through the well-known process as effect hothouse. The dioxide of atmospheric carbon spreads to impede that the radiation of wave long escape to the external space; since more heat takes place and it can escape less, the global temperature of the Earth increases.
A significant global heating of the atmosphere would have serious effects on the environment. It would accelerate the coalition of the polar caps, she/he would make go up the level of the seas, it would change the regional climate and globally, it would alter the natural vegetation and it would affect to the crops. These changes, in turn, would have an enormous impact on the human civilization. In the XX century the half temperature of the planet 0,6 ºC and the scientific prevén that the half temperature of the Earth will ascend between 1,4 and 5,8 ºC between 1990 and 2100 increased.
Also associated to the use of fossil fuels, the acidification is due to the emission of dioxide of sulfur and nitrogen oxides for the thermal power stations and for the escapes of the vehicles to motor. These products interactúan with the light of the Sun, the humidity and the oxidizers sulfuric and nitric acid that you/they are transported by the atmospheric circulation taking place and they fall to earth, crawled by the rain and the snow in the call sour rain, or in form of dry deposits, particles and atmospheric gases.
The sour rain is an important global problem. The acidity of some precipitations in the north of United States and Europe is equivalent to that of the vinegar. The sour rain eats away the metals, it wears away the buildings and stone monuments, it damages and it kills the vegetation and it acidifies lakes, currents of water and floors, mainly in certain areas of the northeast of United States and the north of Europe. In these regions, the lacustrine acidification has made populations of fish die. Today is also a problem in the southeast of United States and in the central area of the África north. The sour rain can also slow the growth of the forests; she/he associates to the decline from these to big altitudes as much in United States as in Europe.
Destruction of the ozone
In the decades of 1970 and 1980, the scientists began to discover that the human activity was having a negative impact on the layer of ozone, a region of the atmosphere that protects to the planet of the ultraviolet harmful rays. If that gassy layer, the life didn't exist it would be impossible on our planet. The studies showed that the layer of ozone was being affected by the growing use of chlorfluorocarbons (CFC, made up of fluorine) that are used in refrigeration, conditioned air, solvent of cleaning, materials of having packed and aerosols. The chlorine, a secondary chemical product of the CFC attacks to the ozone that is formed by three oxygen atoms, snatching him one of them to form monoxide of chlorine. This reacts next with oxygen atoms to form oxygen molecules, liberating molecules of chlorine that decompose more molecules of ozone.
At the beginning it was believed that the layer of ozone was decreasing in a homogeneous way in the whole planet. Nevertheless, later investigations revealed, in 1985, the existence of a great hole centered on the Antártida; 50% or more than the ozone located on this area it disappeared seasonally. In the year 2001 the hole reached a surface of 26 million square kilometers, a similar size to the one detected in the last three years. The weigh loss of the layer of ozone exposes to the terrestrial life to an excess of ultraviolet radiation that can produce skin cancer and waterfalls, to reduce the answer of the system inmunitario, to interfere in the process of photosynthesis of the plants and to affect to the growth of the oceanic fitoplancton. Due to the growing threat that they represent these dangerous effects on the environment, many countries try to join efforts to reduce the emissions of gases of effect hothouse. Nevertheless, the CFC can remain in the atmosphere during more than 100 years, for what the destruction of the ozone will continue during decades.
The extensive use of derived synthetic pesticidas of the hydrocarbons clorados in the control of plagues has had disastrous colateral effects for the environment. These pesticidas organoclorados is very persistent and resistant to the biological degradation. Very not very soluble in water, they adhere to the fabrics of the plants and they accumulate in the floors, the sustrato of the bottom of the currents of water and the ponds, and the atmosphere. Once volatilizados, the pesticidas is distributed all over the world, contaminating wild areas at great distance of the agricultural regions, and even in the arctic and antarctic areas.
Although these synthetic chemical products don't exist in the nature, they penetrate in the alimentary chain. The pesticidas is ingested by the herbivores or they penetrate directly through the skin of aquatic organisms as the fish and diverse spineless. The pesticida concentrates even more when passing from the herbivores to the carnivores. It reaches high concentrations in the fabrics of the animals that occupy the highest links in the alimentary chain, as the hawk pilgrim, the eagle and the osprey. The hydrocarbons clorados interferes in the metabolism of the calcium of the birds, producing a weigh loss of the shells of the eggs and the rising reproductive failure. As a result of it, some big birds depredadoras and piscívoras they are on the edge of the extinction. Due to the danger that the pesticidas represents for the wild fauna and for the human beings, and also to that the insects have developed resistance to them, the use of hydrocarbons halogenados like the DDT it is diminishing quickly in the entire world western, although they continue being used in big quantities in the developing countries. At the beginning of the decade of 1980, the EDB or dibromoetano, a pesticida halogenado, also woke up great alarm for its nature in carcinogen power, and it was finally forbidden.
Another group exists of compound intimately linked the DDT: the bifenilos policlorados (PCB). they have been used during years in the industrial production, and they have finished penetrating in the environment. Their impact on the human beings and the wild life has been similar to that of the pesticidas. Due to their carried to an extreme toxicity, the use of PCB has been restricted to the insulating of the transformers and electric condensers.
The TCDD is the most toxic in another group related of compound highly toxic, the dioxinas or dibenzo-for-dioxinas. The toxicity degree for the human beings of these carcinogen compounds has not been even proven. The TCDD can be in impurity form in conservantes for the wood and the paper and in herbicides. The agent orange, a very used defoliante, it contains dioxina appearances.
Other toxic substances
The toxic substances are chemical products whose production, processed, distribution, use and elimination represent a risk inasumible for the human health and the environment. Most of these toxic substances are synthetic chemical products that penetrate in the environment and they persist in him during long periods of time. In the drains of chemical products significant concentrations of toxic substances take place. If these filter to the floor or the water, they can contaminate the supply of water, the air, the crops and the domestic animals, and they have been associated to human congenital defects, abortions and organic illnesses. In spite of the well-known risks, the problem doesn't take on the way to being solved. Recently, they have been manufactured more than 4 million new synthetic chemical products in a fifteen year-old period, and they are believed from 500 to 1.000 new more products a year.
Although the atmospheric nuclear tests have been prohibited by most of the countries, what has supposed the elimination of an important source of radioactive rain, the nuclear radiation continues being an environmental problem. The power stations always liberate small quantities of nuclear residuals in the water and the atmosphere, but the main danger is the possibility that nuclear accidents take place that they liberate enormous quantities from radiation to the environment, like it happened in Chernóbil, Ukraine, in 1986. A more serious problem to which faces the nuclear industry is the storage of the nuclear residuals that you/they conserve its toxic character from 700 to 1 million years. The security of a storage during geologic periods of time is, at least, problematic; among so much, the radioactive residuals accumulate, threatening the integrity of the environment.
Loss of virgin lands
A number every time bigger than human beings it begins to even fence the virgin lands that are, in areas considered more or less safe of the exploitation. The insatiable energy demand has imposed the necessity to exploit the gas and the petroleum of the arctic regions, putting in danger the delicate ecological balance of the tundra ecosystems and its wild life. The pluvisilva and the tropical forests, mainly in the Asian Southeast and in the Amazonia, they are being destroyed to an alarming rhythm to obtain wood, to clear floor for grasses and cultivations, for plantations of pines and it stops human establishments. In the decade of 1980 you ended up estimating that the forest masses were being destroyed to a rhythm of 20 there is per minute. Another estimate gave a destruction rate of more than 200.000 km2 a year. In 1993, the data obtained via satellite allowed to determine a destruction rhythm of almost 15.000 km2 a year, only in the amazon basin. This tropical deforestation could take to the extinction of up to 750.000 species, what would represent the loss of an entire multiplicity of products: foods, fibers, fármacos, tints, rubbers and resins. Also, the expansion of the cultivation lands and of shepherding for domestic livestock in África, as well as the illegal trade of threatened species and animal products could represent the end of the big African mammals.
Erosion of the floor
The erosion of the floor is accelerating in all the continents and it is degrading about 2.000 million hectares of cultivation earth and of shepherding, what represents a serious threat for the global supply of provision. Every year the erosion of the floors and other forms of degradation of the lands cause a loss of between 5 and 7 million hectares of arable lands. In the Third World, the growing necessity of foods and firewood they have had the deforestation and cultivation of hillsides as a result with a lot of slope, what has produced a severe erosion of the same ones. To complicate even more the problem, is to keep in mind the loss of lands of cultivation of first quality due to the industry, the swamps, the expansion of the cities and the highways. The erosion of the floor and the loss of the cultivation lands and the forests also reduce the capacity of conservation of the humidity of the floors and she/he adds silts to the currents of water, the lakes and the reservoirs. See you also Degradation of the floor.
It demands of water and air
The erosion problems described above are increasing the growing world problem of the supply of water. Most of the problems in this field are given in the semi-arid and coastal regions of the world. The human populations in expansion require irrigation systems and it dilutes for the industry; this is draining the underground aquifers that it begins to penetrate in them salted water along the coastal areas in United States, to such an extent Israel, Syrian, the Arab states of the gulf Peach and some areas of the countries that skirt the sea Mediterranean (Spain, Italy and Greece mainly). Some of the biggest cities in the world are draining their supplies of water and in metropolises like New Delhi or México D.F. is pumping water of more and more far away places. In areas inland, the porous rocks and the silts you compactan when losing the water, causing problems for the progressive sinking of the surface; this phenomenon is already a serious problem in Texas, Florida and California.
The world also experiences a progressive descent in the quality and readiness of the water. In the year 2000, 508 million people lived in 31 countries affected by shortage of water and, according to estimates of the World Organization of the Health (OMS), approximately 1.100 million people lacked access to non polluted water. In many regions, the reservations of water are polluted with toxic chemical products and nitrates. The illnesses transmitted by the water affect to the humanity's third and they kill to 10 million people a year.
During the decade of 1980 and at the beginning of that of 1990, some industrialized countries improved the quality of their air reducing the quantity of particles in suspension as well as that of toxic chemical products as the lead, but the emissions of dioxide of sulfur and of nitrous oxides, precursors of the sour deposition, are still important.
The Summit of the Earth
In June of 1992, the Conference has more than enough environment and Development of the United Nations, also well-known as the Summit of the Earth, she/he met during 12 days in the proximities of River of Janeiro, Brazil. This summit developed and it legitimated a calendar of measures related with the environmental, economic and political change. The purpose of the conference was to determine what you reform medioabientales it was necessary to undertake long term, and to begin processes for its installation and international supervision. They took place conventions to discuss and to approve documents it has more than enough environment. The main topics approached in these conventions included the climatic change, the biodiversity, the forest protection, the Calendar 21 (a project of environmental development of 900 pages) and the Declaration of River (a document of six pages that demanded the environment integration and economic development). The Summit of the Earth was a historical event of great meaning. She/he didn't only make of the environment a priority to world scale, but rather to her delegates of 178 countries attended, what transformed it into the biggest conference taken place until that moment.
Between August 26 and September of 2002, 4 ten years after that she/he took place the first Summit of the Earth, she/he took place in the city of Johannesburgo the Summit of the United Nations on the Sustainable Development, also known as Río+10. Representatives of 191 countries attended and she/he remembered a Plan of Action that included the commitment of reducing the number of people that you/they don't have access to the drinkable water and the nets of reparation of residual waters, the defense of the biodiversity or the recovery of the shrunk fishing reservations.
The future perspectives, in what refers to the environment are not very clear. In spite of the economic and political changes, the interest and the concern for the environment is still important. The quality of the air has improved, but they are pending of solution and they require a coordinated action the problems of the sour rain, the chlorfluorocarbons, the loss of ozone and the enormous atmospheric contamination of the east of Europe. While it doesn't diminish the sour rain, the loss of life it will continue in the lakes and currents of the north, and she/he can it turns affected the growth of the forests. The contamination of the water will continue being a problem while the demographic growth continues increasing the pressure on the environment. The infiltration of toxic residuals in the underground aquifers and the intrusion of water salted in the coastal aquifers of sweet water has not been interrupted.
The exhaustion of the aquifers in many parts of the world and the growing demand of water will produce conflicts among the agricultural, industrial and domestic use of this. The shortage will impose restrictions in the use of the water and the cost of its consumption will increase. The water could become the energy crisis of beginnings of the XXI century. The contamination of the sweet and coastal waters, together with the sobreexplotación, the resources of the caladeros piscícolas that it would be necessary to suspend the fishing during one period from five to ten years has shrunk to such an extent so that the species recovered. If efforts are not developed coordinated to save hábitats and to reduce the furtivismo and the traffic international illegal of wild species, many of them will extinguish. In spite of our knowledge on how to reduce the erosion of the floor, this continues being a problem of world reach. This is owed, in great measure to that many agronomists and urbanistas show a scarce interest to control it. Lastly, the destruction of virgin lands, so much in the temperate regions as in the tropical ones, it can produce a massive extinction in vegetable ways of life and animals.
To reduce the environmental degradation, the societies should recognize that the environment is finite. The specialists believe that, when going growing the populations and their demands, the idea of the continuous growth should open step to a more rational use of the environment, but that this can only be achieved with a spectacular change of attitude on the part of the human species. The impact of the human species on the environment has been compared with the big catastrophes of the geologic past of the Earth; independently of the attitude of the society regarding the continuous growth, the humanity should recognize that to attack the environment puts in danger the survival of her own species.
Inside the efforts to control the environmental deterioration, in March of 2002, she/he put on in orbit the European environmental satellite Envisat, with the purpose of obtaining precise information on the environment. The Envisat has 10 scientific instruments that will pick up data on the level of the oceans, the emissions of gases of effect hothouse, the floods, the size of the layer of ozone, or the deforestation, among others. The data sent by the satellite will serve, she/he doesn't only stop to know the state of the ecosystems, but also to make political decisions and to control the execution, on the part of the different countries, of the Protocol of Kioto and of other environmental treaties.