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Transcript of Environmental problems
3º ESO A Environmental problems Introduction Pollution As we exploit and use natural resources, we produce an effect on the environment. This changes are known as environmental impact, and this impact can be:
Irreversible: This means that the environment will never be able to recover from this impact and return to its initial state.
Reversible: This means that the environment would be able to recover if the activity that produced the changes stopped. Pollution is the introduction of contaminants into the natural environment that cause adverse change, and therefore, a damage. It is the main source of environmental impact.
The three types of pollution are air pollution, water pollution and soil pollution. Main environmental problems Air Pollution The compounds that pollute the atmosphere come mainly from the combustion of fossil fuels and other processes, and they are, mainly: carbon dioxide, methane, nitrous oxide and ozone. This gasses are not bad for the atmosphere by themselves, but if they are released in excessive quantites they can cause damage in the atmosphere, climate change, acid rain... Climate Change The most important climate change that is happening right now, the global warming, is caused by the enhanced greenhouse effect.
This consists in an excesive increase in the greenhouse effect. The natural greenhouse effect keeps the Earth warm by capturing some of the solar radiation reflected by it. Without it, it would be too cold for us to live.
But the increase of carbon dioxide, produced by the combustion of fossil fuels, has increased the greenhouse effect, leading to higher temperatures around the planet. This is the enhanced greenhouse effect. Acid Rain The acid rain is formed by the reaction of water molecules that are in the air with some compounds that are released into the atmosphere, such as sulphur dioxide and nitrogen oxide. The chemicals in acid rain can cause paint to peel, corrosion of steel structures such as bridges, and erosion of stone statues. Reduction of the Ozone layer Ozone is a gas formed by three oxygen molecules that forms a layer (troposphere) in the Earth's atmosphere. Its function is to absorve ultraviolet radiation from the Sun, which is very harmful for all living beings. This layer is being very damaged by gases like nitric oxide (NO), nitrous oxide (N2O), hydroxyl (OH), atomic chlorine (Cl), and atomic bromine (Br), mainly founded in aerosols. Water pollution Water pollution is caused by several types of pollutants:
Various kinds of industrial waste.
Detergents that modify the oxygenation of water. This affects the aquatic organisms.
Pathogenic microorganisms and organic household waste.
Pesticides and fertilisers.
Opaque particles that don't let organisms do the photosynthesis. Soil pollution Soil pollution is typically caused by industrial activity, agricultural chemicals, or improper disposal of waste.
The main reason for the concern over soil contamination are the health risks that it can involve, from direct contact with the contaminated soil, vapors from the contaminants, and from secondary contamination of water supplies within and underlying the soil.
Once it occurs, the soil pollution usually requires a long period of time to clean up. Overexploitation of resources The overexploitation of natural resources not only causes their depletion, but it also results in environmental changes and affects the habitat of living beings. There are many resources that are being overexploited. Water resources Water resources are used for all human activities, but the ones that cause its overexploitation are irrigated agriculture in inappropiate areas, inefficent irrigation systems, uncontrolled household consumption and overexploitation of undergroung water supplies.
The overexploitation of water resources leads to loss of water in naturally wet areas around the world and desertification. Fossil fuels Fossil fuels are non-renewable energy sources. They are fuels formed by natural processes such as anaerobic decomposition of buried dead organisms. The duration of this processes sometimes exceeds 650 million years. Fossil fuels include coal, petroleum, and natural gas. Nowadays, they are the main energetic source for the society. If alternative sources of energy are not used, society may be faced with an energy crisis. Living beings The relationships between species that form an ecosystem are very complex. Any slight changes may cause permanent damage. Ecosystems regulate themselves, but if human beings introduce artificial factors they can cause significant ecological threats. Poaching Poaching is the unlawful or illegal taking of wild plants or animals, such as through hunting, harvesting, fishing, or trapping. It eliminates too vulnerable species at inappropiate time of the year. Uncontrolled fishing Overfishing is the act whereby fish stocks are depleted to unacceptable levels, regardless of water body size. Resource depletion, low biological growth rates, and critical low biomass levels result from overfishing. Destructive logging Logging is the cutting, skidding, on-site processing, and loading of trees or logs. It seriously alters forest ecosystems, which are important for moving atmospheric carbon dioxide and fixing the soils. Soil The main cause of soil overexploitation is anattempt to achieve greater agricultural production. Soil loses its organic substances and minerals, and it becomes bare. Rocks and minerals A mineral is a naturally occurring substance that is solid and stable at room temperature, representable by a chemical formula, and has an ordered atomic structure. a rock is a naturally occurring solid aggregate of one or more minerals. The growing demand of these resources is causing the reserves to be depleted.