Climate change Greenhouse effect
is called greenhouse the phenomenon whereby certain gases, which are components of a planetary atmosphere, they retain some of the energy emitted by the soil having been heated by solar radiation . It affects all planetary bodies endowed with atmosphere. According to the majority of the scientific community, the greenhouse effect is being pointed at the Earth 
by the emission of certain gases, like carbon dioxide and methane due to human economic activity.
This phenomenon prevents energy consistently received solar return immediately to Earth space, producing a planetary scale similar effect to that observed in a greenhouse.
-called greenhouse gases or greenhouse gases, responsible for the effect described, are:
- Water vapor (H 2 O)
- carbon dioxide (CO 2 )
- Methane (CH 4 )
- nitrogen oxides (NO x )
- Ozone (O 3 )
- chlorofluorocarbons (CFCl 3 )
Climate change is happening and humans contribute daily to increase it. In the past 100 years the average global temperature has risen by 0.7 ° C, and since 1975 the temperature increase per decade of about 0.15 ° C. In the remainder of the century, according to the IPCC, global average temperature increase by 2-3 ° C. This temperature rise will mean for the world's largest climate change in the last 10,000 years and will d 
ifícil for people and ecosystems adapt to this sudden change.
In the 400,000 years prior, as we know from records from ice cores, temperature changes were mainly due to changes in Earth's orbit around the Sun in the current weather, temperature changes are caused by changes in carbon dioxide from the atmosphere. In the past 100 years, atmospheric concentrations of CO2 have risen by 30% due to anthropogenic combustion of fossil fuels. The continuing rise in atmospheric CO2 has been responsible for most of the warming. This warming can not be explained by natural causes: satellite measurements show no changes in body energy from the sun in the last 30 years; the three major volcanic eruptions in 1963, 1982 and 1991 have generated aerosols that reflect solar energy, which resulted in short periods of cooling.
Acid Rain
The acid rain is formed when moisture in the air combines with nitrogen oxides and sulfur dioxide emitted by factories, power and electric vehicles that burn coal or petroleum products. Interacting with water vapor, these gases form sulfuric acid and nitric acid. Finally, these chemicals fall to earth accompanied by the precipitation, forming acid rain.
primary air pollutants that give rise to acid rain can travel great distances, the wind moving them hundreds or thousands of miles before precipitating in the form of dew, rain, rain, hail, snow, fog or mist. When precipitation occurs, can cause r 
significant deterioration in the environment.
rain typically has a pH of approximately 5.65 (slightly acidic), due to the presence of CO 2 warming, which forms carbonic acid, H 2 CO 3 . If it is considered acid rain has a pH of less than 5 and can reach the pH of vinegar (pH 3). These pH values \u200b\u200bare achieved by the presence of acids such as sulfuric acid, H 2 SO 4 , and nitric acid, HNO 3 . These acids are formed from sulfur dioxide, SO 2 and nitrogen monoxide are converted into acids.
hydrocarbons and coal as energy source used in large quantities, can also produce sulfur and nitrogen oxides and sulfur dioxide emitted by factories, power plants and vehicles that burn coal or petroleum products.
acid rain formation
- A large p art of 2 SO (sulfur dioxide) emitted into the atmosphere comes from natural emissions produced by the eruptions volcanic phenomena that are irregular. However, a source of SO 2 is the metal industry. The SO 2 can also come from other sources, such as dimethyl sulfide (CH 3 ) 2 S, and other derivatives, or hydrogen sulfide, H 2 S. These compounds are oxidized with atmospheric oxygen to give SO 2 . Finally, the SO 2 is oxidized to SO 3 (intervening in the reaction hydroxyl radicals and oxygen) and the SO 3 can be dissolved in the raindrops, the emissions SO 2 processes of energy production: coal, oil and other fossil fuels containing sulfur in amounts variables (usually more than 1%), and do due to combustion, sulfur is oxidized to sulfur dioxide.
effects of acid rain
- water acidifies lakes, rivers and seas, hindering the development of living aquatic life and destruction of vegetation.
- Acid rain and corrosive nature, corrodes buildings and infrastructure.
- important indirect effect is that protons, H + , from acid rain, soil creep certain ions. For example, cations of iron, calcium, aluminum, lead or zinc. As a result, an impoverishment of certain essential nutrients and called plant stress, which makes them more vulnerable to pests.
- A 2005 study by Vincent Gauci of Open University suggests that relatively small amounts of sulphate present in acid rain have a strong influence in reducing methane gas produced by methanogens in wetlands, which could have an impact, albeit slight, in the greenhouse.
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Destruction of ozone layer
hole is called the ozone layer to the area of \u200b\u200bEarth's atmosphere where reductions occur Abnormal ozone, annual phenomenon observed during the spring in polar regions and is followed by a recovery during the summer.
the measurements made in recent times found significant reductions in ozone concentrations in that layer, with special emphasis on the area of \u200b\u200bAntarctica.
this phenomenon was attributed to increased concentrations of chlorine and bromine in the stratosphere due to emissions of chemical compounds, among which compounds chlorofluorocarbons.
In September 1987, several countries signed the Montreal Protocol, which pledged to halve the production of CFC's over a period of 10 years. Today the problem is considered solved, due to the prohibition of causing products, which have been replaced by others.
Almost 99% of the sun's ultraviolet radiation that reaches the stratosphere is converted into heat through a chemical reaction that continuously recycle ozone molecules (O 3). When ultraviolet radiation strikes an ozone molecule, energy splits the molecule into highly reactive oxygen atoms, almost immediately, these atoms recombine to form ozone again and releasing energy as heat.
Causes of decline Ozone in the stratosphere
Subsequent investigations of variations in the density of ozone and its causes raised fears about the future of the ozone layer, among other things, it found "holes" in the layer on two poles of the planet and a thinning of the layer around the globe. Ozone is a substance whose molecule is composed of 3 atoms of oxygen, which is formed by 3 atoms dissociated gas comprising oxygen. Each oxygen atom binds to another molecule of oxygen to form ozone molecules O3. It is called the Ozone Layer Earth's stratosphere which concentrates more than 90% of all existing ozone on our planet. This layer is very important in our life as it serves to purify the air and mostly serves to filter out ultraviolet rays from space. Without that filter the existence of life on earth would be impossible.
