Global warming is the increase in the temperature of the planet due to accumulation of some gases in the atmosphere, especially gases that retain the solar energy reflected by the planet surface. The main gas that causes the global warming is carbon dioxide, CO2, but other gases act as "warming gases" too, like methane, CH4, and nitrous oxide, N2O. The exaggerated increase of carbon dioxide in the atmosphere has been caused by the burning of fossil fuels (mainly oil and coal) in industrial and urban societies and by forest fires. (It is important to note that the natural warming provided by gases of the atmosphere is fundamental for the maintenance of the planet temperature.)
Predictions of studies sponsored by the United Nations stated that the global warming might cause in the near future life-threatening transformations in the planet. Countries that are the biggest emitters of carbon dioxide, like the United States and China, however, systematically ignore the warnings and continue, largely contribute to the danger.
Global warming is one of the most polemic environmental issues today.
Bioremediation is the use of microorganisms, like bacteria, protists and fungi, to degrade noxious substances turning them into non toxic or less toxic substances. Bioremediation employs microorganisms whose metabolism uses contaminants as reagents.
Bioremediation is used, for example, in the decontamination of environments polluted by oil spill. In this process, bacteria that use hydrocarbons as substrate for their cellular respiration are employed.
Environmental Issues: bioremediation
Biological control is a natural method to control the size of animal, microorganism or plant populations. Biological control is based on the knowledge of inharmonious (negative) ecological interactions between species. Using such knowledge a parasite, competitor or predator species is introduced in an ecosystem in order to attain reduction of the population of another species with which it has inharmonious ecological interaction. The biological control presents the advantage of substituting the use of pesticides and other toxic chemical products in the control of plagues and diseases. It however should be employed with caution under serious previous study to avoid harmful ecological disequilibrium.
A kind of biological control of some species can be done by the introduction of previously sterilized males that do not generate offspring.
Transgenic can be dangerous to the entire biosphere since the transfer of genes between species may have immediate and long-term unpredictable consequences. The creation of new species by nature is a slow process, dependent on causal mutations and natural selection, a relatively safe process for the ecological equilibrium. It is impossible to know how the fast and artificial introduction of transgenic beings in nature affects ecosystems. Pathogenic agents may be involuntarily created in laboratories, spreading unknown diseases; transgenic species may uncontrollably proliferate destroying ecological interactions that have taken thousands of years to be established; the ingestion of transgenic food also has unpredictable effects.
Transgenic beings are animals, microorganisms and plants that contain recombinant DNA, i.e., genes from other plants, microorganisms or animals artificially inserted into their genetic material. Transgenic beings are made for scientific and economic purposes, in this last case with the intention of improving their commercial features. For example, bacteria that produce human insulin are transgenic beings made by biotechnology. The main targets of the transgenic technology are the eatable vegetables, like soy, corn, potato, and tomato.
Environmental Issues: transgenic beings
Plutonium is the highly radioactive chemical element produced from uranium by nuclear plants. Plutonium can be reprocessed and used again in nuclear plants or in other destinations, like the making of nuclear bombs. Plutonium reprocessing nowadays, however, is done only in some countries like France, Russia and Britain and the countries that have nuclear plants, like Japan, Australia, etc., send their atomic waste by ship to those plutonium reprocessing centers. Besides the inherent risks of the storage of nuclear waste, plutonium reprocessing brings the risks of the transport of radioactive material across the oceans. The "nuclear ships" often travel near the coast of many countries posing danger to their populations.
Environmental Issues: plutonium reprocessing
Nuclear pollution consists in radiations emanated from atomic nuclei, these radiations are high injurious for the living beings. They can be originated from the extraction of radioactive minerals, nuclear plant reactors, nuclear research centers, hospitals, and medical centers that use radioisotopes, nuclear bomb explosions, or accidents with transportation, handling, or storage of nuclear material. Nuclear materials remain dangerous for many years, contaminating the environment with radiation that can cause cancer, immune impairment, congenital deficiencies, burns, and even death. The damage is proportional to the intensity of the exposition to the radiation.
Its persistent feature and high aggression power make nuclear pollution one of the major environmental problems of our time.
The mains chemical compounds that destroy the ozone layer are the CFCs, chlorofluorocarbons, or freons, substances used in the past in refrigerators, airconditioners and spray cans.
Chlorofluorocarbons react with ozone in the high atmosphere releasing molecular oxygen and therefore the amount of ozone in the atmosphere is reduced.
Other substance that destroys the ozone layer is methyl bromide, used in agricultural insecticides.
Ozone, O3, is a gas of the atmosphere that filters ultraviolet radiation from the sun disallowing most of that radiation of reaching the surface of the planet. Ultraviolet radiation is harmful for living beings because it is a mutagen and can cause cancer (mainly skin cancer), other DNA mutations, and even burns.
Environmental Issues: ozone layer
Thermal inversion confines at low altitude, layer of pollutants that would have been dispersed by the natural upward move of warm air. The solid particles present in the atmosphere cause health problems, like the exacerbation of asthma and other pulmonary diseases, cough, respiratory unease and ocular discharges; later the pollution can also trigger the appearing of cardiovascular and neoplastic diseases.