Guide content
NB 5
3. The greenhouse effect
Earth's atmosphere is composed of many gases. The most abundant are nitrogen and oxygen (the latter is the need to breathe). The rest, less than one hundredth part, are gases called "greenhouse." We can not see or smell, but they are there. Some of them are carbon dioxide, methane and nitrogen dioxide.
In small concentrations of greenhouse gases are vital to our survival. When sunlight reaches the Earth, some of this energy is reflected in the clouds, the rest passes through the atmosphere and reaches the ground. Thanks to this energy, for example, plants can grow and develop
A: Absorption of radiation emitted by the Sun in the atmospheric layers.
B: Reflection of solar radiation absorbed (about 30%).
C: Uptake of solar radiation reflected by greenhouse gases.
D: Delivery of solar radiation into space.
But not all the sun's energy is harnessed on Earth, a part is "returned" to space. Since Earth is much colder than the Sun, can not return the energy as heat and light. So send it in a different way, called "infrared." An example of infrared energy is the heat emanating from a stove before the bars begin to turn red.
Greenhouse gases absorb this infrared energy like a sponge, thus warming Earth's surface as the surrounding air. If there were no greenhouse gases, the planet would be about 30 degrees colder than it is now! Under these conditions, life probably never could develop. This is what happens, for example, on Mars.
Implications: We know the consequences of the greenhouse effect we can expect for the next century, if not return to lower values:
• Increase in average global temperature.
• Increased drought in some areas and flooding in others.
• Increased frequency of hurricane formation.
• Progressive melting of polar ice caps, resulting in rising sea levels.
• Increased rainfall at the global level but fewer days and more rain in torrents.
• Increased number of hot days resulted in heat waves.
4. Deterioration of the ozone layer
Ozone is a special form of oxygen that is above the earth's crust.
The land is surrounded, to between fifteen and fifty miles high, a layer of stratospheric ozone.
The maximum ozone concentration is located between 25 and 30 kilometers high and is vital for life on the surface, which acts as a shield against harmful ultraviolet rays.
increase the amount of ultraviolet radiation received by the earth's surface, would increase sharply the number of cases of herpes (Rash accompanied by itching), cataract (clouding of the eye) and, especially, the skin cancers in humans.
But the damage to other organisms, especially bacteria, algae and marine plankton, could be much worse. Phytoplankton die plants (blue-green algae), which also disappeared determine zooplankton (bacteria, krill, etc.) Exposing to an eventual extinction of most animals that feed on them in the seas and lakes.
In light of these risks, it is understandable concern in the scientific community about the deterioration detected in the ozone layer, especially in the area Antarctic, where there is a considerable reduction of such gas every spring, a phenomenon known as the ozone hole.
This hole is caused by the deterioration of the ozone layer, which is the result of the transformation of pollutants in the air. Ozone is formed naturally in the upper atmosphere and protects the planet from direct sunlight because it absorbs more than ninety percent of it from UV (ozone beneficial).
Due to a natural process of destruction and regeneration, its concentration remains constant in normal circumstances. However, chlorofluorocarbons (CFCs) used in aerosols and refrigeration technology, and other chemicals in the atmosphere, accelerating the decomposition of ozone and prevent their regeneration.
Increases in UV-B radiation have been observed not only under the ozone hole in Antarctica but in other places like the Alps (Europe) and Canada (North America).
1. Effects on human health. 1.1
skin cancer.
Today it is estimated that skin cancer rates increased due to stratospheric ozone depletion (ozone layer). The most common type of skin cancer, the so-called non-melanoma, is due to exposure to UV-B radiation for several years. There and people who have received doses of UV-B can cause this type of cancer.
Programme United Nations Environment Programme (UNEP) predicts that at an annual rate of 10 percent loss of ozone over several decades, the increase in skin cancer cases will be about 250,000 per year
. Even taking into account the current arrangements for the disposal of ozone depleting substances (ODS), a realistic model indicate that the skin cancer would increase to 25 percent above the 1980 level by 2050, to along the 50 ° north latitude. The most deadly skin cancer called melanoma, may also increase their frequency.
1.2 The immune system of a person's defenses to fight infection depends on the strength of their immune system. It is known that exposure to ultraviolet light reduces the effectiveness of the immune system, not only related with skin infections but also with those observed in other parts of the body.
Exposure to UV-B radiation may well make the immune system to tolerate the disease rather than fighting it. This could mean the usefulness of vaccination programs in both industrialized and developing countries.
5. Accumulation
Garbage Garbage is anything considered as waste and we need to eliminate. Litter is a product of human activities which is considered worthless, disgusting and undesirable which would normally be incinerated or placed in locations for the collection predestined to be channeled to dumps or landfills, landfills or other location .
Normally, when you throw something that is not used, goes to the trash can. Then pass the tanker truck, empty the jar and did not hear from her return. Does finished the problem? Does it go away in the trash? No, do not believe it! What do you think happens next with her?
Now you answer these and other questions ...
Every week our garbage (see glossary) ends mostly buried in large pits. This means that large areas of land are unusable, in addition, the decomposition of material causes diseases and emits unpleasant odors.
But do you think those are the only problems?
Well ... there are no others, is that many of the things we normally throw away materials are not recycled, meaning that they are not taken to nature, such as plastics.
Here ...
If you leave a plastic bag, a glass bottle or aluminum can in the open, they will remain there without submitting changes for hundreds of years. This is because the plastic, glass and metal are not biodegradable (see glossary) will take a long time to decompose to return to earth useful substances.
Certainly it is important that some materials have the status of non-biodegradable, allowing buildings and artifacts that remain intact with the passage of time, however, when these materials are no longer needed is very difficult to get rid of them because their condition.
also possible that some items are dumped into toxic landfills and eventually poison the soil and water, like lead and compounds containing batteries.
addition, we are producing so much garbage that in many places and no place to bury. Landfills also are occupying places that could be used for agriculture, livestock, or to preserve nature. Types of landfills
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• Landfill secret: It is a place where no environmental considerations, is elected by a group of people to deposit their solid waste. Are serious source of pollution, disease and other problems.
• municipal or city landfill: A landfill that under certain assumptions and studies of economic, social and environmental, is assigned by municipal governments or city dwellers. Also known as "landfill" or "landfills."
A landfill is a place for waste disposal or garbage, which will take multiple measures to reduce the problems generated by another method of treatment of waste such as landfills, these measures are, for example, meticulous study of environmental, economic and social development from planning and site selection to monitoring and study of place in the life of the landfill.
In a landfill, as will placing the trash, it is compacted with machinery and covered with a layer of soil and other materials for later covered with a layer of earth is around 40cm thick and another layer is deposited garbage and so on until the landfill is taken for saturated.
Use, exploitation and efficient use of
materials Types of waste that we generate
we eliminate waste are two types of organic and inorganic. Organic waste is mainly food waste that are biodegradable, ie they can be quickly decomposed by microorganisms. Inorganic wastes are wastes from non-living things and take a long time to decompose. The following materials are part of the inorganic wastes once they are discarded.
Plastics Glass Metals
Fuels Detergents
Wastes listed below can take to biodegrade following:
- organic waste .............. ............. 3 weeks to 4 months
- linen or cotton cloth and / or linen ...... 1 to 5 months
- a pair of wool socks .................... 1 year
- leather shoe .................................. 3 to 5 years
-paper
.............................................. .... 3 weeks to 2 months
- cellophane ......................................... ...... 1 to 2 years
- fabric cloth ....................................... 2 to 3 months
- wooden stake .............................. 2 to 3 years
- painted wooden stake ................. 12 to 15 years
- bamboo .......................................... ..... 1 to 3 years
- tin container ................................... 10 to 100 years
- aluminum container ........................... 350 to 400 years
- plastic materials ........................ 500 years
- Glass ................................................ .
decompose indefinite
How to solve the problem of waste
The best solution to the problem of solid waste accumulation and integrating them into a cycle that do reduce their production and take advantage in some materials efficiently.
This process is known as the 3
The three R's: reduce, reuse, recycle
Reduce the amount of waste generated at home, at school or at work. For example, we buy in bulk, avoid buying products with packaging that generate a lot of waste. In addition, we use our power as consumers to encourage companies to manufacture or supply products with less packaging, use reusable containers or buy only products made with recycled material and also durable as steel. For example, a rule of this material lasts much longer than a plastic one.
Reuse waste that can be reused in its original form. This is to lengthen the life of the product / packaging, for example, using jars of milk, coffee and cookies as planters or to hold pencils, thread, trimmings. Another form of reuse is to buy products in returnable containers.
Recycling means to use waste as feedstock for transformed into another product. A common example is the recycling of paper, but on a large scale, steel is the most recycled material worldwide. 45% of new stainless steel comes from recycling old or scrap. The old cars can be recycled into raw material to manufacture washing machines, trains, nails, wire, among thousands of other products.
It is therefore necessary primarily for the support of the entire community, which is achieved through massive awareness campaigns. Internationally he has given the responsibility of recovering industrial waste from product packaging, which has led to the application, almost spontaneously, multiple types of economic instruments that encourage waste minimization, such as selling at a price lower returnable packaging products.
Recycling Recycling Steps
separation at source. The waste is separated at home to start a path different from the rest of the RSD. In the metropolitan area people who decide to separate their trash can take to the supermarket or facilities where companies or charities to collect deposits have enabled plastic, paper and cardboard, newspapers, glass and metals. On the other hand, the municipalities of La Reina, Maipú, La Florida and Providencia have recycling programs that remove waste from homes separated by the neighbors.
collection centers. Facilities used to store and sort recyclable materials, then sell them directly to recycling companies or industries.
recycler. Receives waste collection centers or directly from collectors, transforming raw material from which to build new products or selling them to manufacturing.
Industry. The companies buy the raw material recycling companies and develop new products.
process recycling of certain materials
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