domingo, 30 de novembro de 2008

Acid rain

At present human activities (industries, from automobile exhaust, burning of fossil fuels), throw into the air many tons of toxic compounds such as oxides of sulfur, nitrogen and carbon and smoke going into the atmosphere
They are the most developed countries in the North the main culprits, since launch sulfur dioxide and nitrogen dioxide to the atmosphere in the form of water vapor. Then, return to Earth in the form of acid rain or snow.

Consequences:
-Acid rain is a problem to be taken into account, since they can be transported to places where there is no burning of fuels. And also one of the consequences of air pollution and can cause many problems in life, including humans, animals, plants, soil, water and even in buildings.
-When it reach the surface there is a change in the chemical properties of soil and water. This will cause disturbances at the level of food chains, plants and forests, buildings and monuments.
-The high concentrations of nitrogen oxides in the atmosphere causing irritation of the respiratory tract affecting higher animals and man. Moreover, in the presence of ultraviolet radiation, the gas reacts with unburned hydrocarbons (released, for example, exhaust pipes.

It is important to note that there are natural sources of toxic compounds - volcanic eruptions that occur in specific in time and space while human activities tend to occur in an ongoing global and at double the quantities.
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The Ozone Layer

Solar radiation that reaches the Earth's surface, 45% is the visible spectrum (visible light), 45% to 10% infrared radiation and the ultraviolet radiation.
The ozone (O3) is found especially in the upper layers of the atmosphere (stratosphere) to 15 km from the surface and form a shield. This thin layer is the only protection of the earth to filter the ultraviolet rays of the sun, thus allowing the existence of life on Earth.

The constant destruction of the ozone layer leads to an increase in ultraviolet rays (UV), high energy. These rays to reach the Earth will promote the destruction of proteins and DNA, leading to skin cancer, cataracts, changes in the immune system, damage to crops, in fish and plankton that feed.

In several areas, the shield of ozone is getting thinner, allowing the intensification of anything healthy ultraviolet rays and new holes may arise from any populated regions on latitude. The higher the fraction of ultraviolet rays to reach Earth the effects are more serious and smaller populations of fish and crops.
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Some advantages and disadvantages of Energy's

Ecological energy:


One of the advantages of renewable energy resources that produce no emissions of greenhouse gases and other emissions, contrary to what happens with fuel, whether fossil or renewable. Some sources do not emit additional carbon dioxide, except those needed for the construction and operation, and does not present any additional risks, such as the nuclear threat.


Renewables Pollutants:


Biomass, as the weight of carbon dioxide by releasing the oxygen to him. This energy is not really an inexhaustible energy, but as we know it is considered a renewable energy. Biomass is used even if only in limited.There is already some doubts regarding the ability of agriculture to provide the necessary quantities of plant mass, seesta source popularize it, which is showing the price increase of grain due to its use for the production of biofuels.But biofuels produced, providing a large amount of carbon dioxide per unit of power so this will be equivalent fossil energy.


There are sources of geothermal energy as pollutants, because the extraction of groundwater in high temperatures are caused by dragging to asuperficie of toxic.
Sources:
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sábado, 29 de novembro de 2008

5. Endangered Species

Man has been causing extition of species, because of his personal interests. Those interests are economical, social, cultural and of civilization. The animals are disappeared in very fast way. Some animals are endangered because of natural disasters, but others are endangered because of the Man.
Men build on empty lands, usually considerate as animal habitats. Sometimes animals are put away die. Sometimes they are hunt by Man just for the pleasure, of hunting. Man is making the world a dirtier place, so many animals can not live in it.
That’s why, there are so many endangered species:

Hyacinth Macaw – There only about 3.000 in Brazil, the destruction of its habitat and capture because they are very expensive pets let two its extinction.

Blue-Whale- It is threatened by fishermen.

African- Elephant- They live in African and they are threatened because of their teeth.

Mountain gorillas- they live in forests in Africa and they are endangered because of the hunters the destruction of their habitat.

Panda- they live in forests in China and they are endangered because of the hunters the destruction of their habitat.

Rhinoceros- They are critically endangered are only a few species they are threatened because of their horns. The horns of rhinoceros are made of keratin, the same type of protein that makes up hair and fingernails.
Bengal Tiger- habitat losses as the extremely edge scale incidents of poaching are serious threats to species survival. Other factors contributing to their loss are urbanization and a great civilization.

Sea turtle- are found in all the world’s oceans except the Arctic Ocean. They are an endangered species because they are caught for the food industry the flesh and the eggs are considered fine dining. They skin is also valuable.

… And others ….
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The gases greenhouse gas emissions are:
· Carbon Dioxide (CO2) - Combustion of fossil fuels: oil, natural gas, coal, deforestation (release CO2 when burned or cut).
· Chlorofluorocarbons (CFCs) - are used in sprays, aircraft engines, plastics and solvents used in the electronics industry. Responsible for the destruction of the ozone layer
· Methane (CH4) - Produced by fields, and cattle and the dumps.
· Nitric acid (HNO3) - Produced by the combustion of wood and fossil fuels, by decomposition of chemical fertilizers and by microbes
· Ozone (O3)-It is caused by soil pollution caused by factories, oil refineries and automobiles

The gases responsible for global warming of the Earth are in the combustion of fossil fuels such as oil and its derivatives.
-Cars are responsible for the release of carbon monoxide (CO) and carbon dioxide (CO2), nitrogen oxides (NOx), sulfur dioxide (SO2), derived from lead and oil.
-The industries also account for this since emit sulfur, lead and other heavy materials and solid wastes that are suspended in the air, turn the concentration of oxygen is being increasingly less what is going to cause serious illness in the system nervous, cancer, respiratory problems.
-In agriculture, the substances are originated from the cultivation of rice in the burning of agricultural waste and forests. -The incineration of waste and disposal of solid waste on the land are other sources of greenhouse gases.

The action of human beings in nature has made increasing the amount of carbon dioxide in the atmosphere, through an intensive and uncontrolled burning of fossil fuels and deforestation. The felling causes the increase in the amount of carbon dioxide in the atmosphere by burning and also by natural decomposition. A smaller number of trees also means less carbon dioxide being absorbed.

EFFECTS CAUSED
Global warming could lead to the occurrence of climatic variations such as changes in precipitation, increase the level of the oceans (melting), heat waves. Thus it is natural to register to an increase in cases of flooding which will consequently increase the mortality rate on earth. A profound change of climate will have a disastrous impact on societies affecting agricultural production and reserves of water, resulting in economic and social change.
The climate change will probably increase the frequency of days of intense heat, which is an increase in the number of deaths.
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Greenhouse Effect

The solar energy is captured by the Earth's surface and absorbed, another part is irradiated to the atmosphere. Natural gases that exist in the atmosphere acts as a protective cover that prevents the spread of total heat into outer space, preventing them from getting lost in the night heat. So the planet remains hot.
The greenhouse effect is a natural process responsible for global warming.
Some gases such as carbon dioxide create a kind of roof, like a stove, leaving the earth on the sun come and not letting the heat out. The greenhouse effect caused by nature is essential for the maintenance of life on Earth.

· The solar radiation through the atmosphere. Some part of the radiation is absorbed by surface of the earth, heating it to;
· Some sunlight is reflected by the Earth and atmosphere, returning to space;
· Part of infrared radiation is reflected by the Earth's surface, but not returning to space as it is reflected and absorbed by the new layer of gases surrounding the planet;

The climate has naturally evolved over time, however in recent times the great man is responsible because the world population has increased and hence carbon dioxide (CO2) increases in the atmosphere.
This increase is due especially to the burning of fossil fuels, deforestation, the growing number of industries and the inordinate consumerism.
The greenhouse effect causes an imbalance in the Earth's natural and it is urgent to reduce emissions of harmful gases.

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Global warming


Energy from the Sun reaching the Earth drives almost every known phisical and biological cycle in The Earth system the energy that keeps the earth's surface warm originates from the sun. the primary source of energy to drive our global climate system (incluiding atmospheric and, to a lesser extent, oceanic circulation) is the heat we recieve from the Sun, termed solar insolation. The amount of insolation which reaches the Earth's surface depends on site latitude and season. The insolation into a surface is largest when the surface directly faces the sun. As the angle increases between the normal directionl to surface and the direction of the rays of sunlight, the insolation is reduced in proportion to the cosine of the angle.
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