African Politics Pdf

depletion of the ozone layer

Description of the cycle of the ozone layer
The cycle of the ozone layer
Three forms (or allotropes) oxygen are involved in the cycle of ozone and oxygen, the oxygen atoms (O or atomic oxygen), oxygen gas (O2 or diatomic oxygen) and ozone (O3 or triatomic oxygen). Ozone is formed in the atmosphere when oxygen molecules photodissociate after absorbing an ultraviolet photon whose wavelength shorter than 240 nm. This produces two oxygen atoms. The oxygen atoms combine with O2 to create O3. Ozone molecules absorb UV light between 310 and 200 nm, after which the ozone layer breaks down into a molecule of O2 and an oxygen atom. The oxygen atom then joins with a molecule oxygen to regenerate the ozone layer. This is an ongoing process that ends when an oxygen atom "recombines" with an ozone molecule to two molecules O2 O2 O3 + O 2
Global monthly average total ozone.
The layers of the atmosphere (not to scale)
The total amount of ozone in the stratosphere is determined a balance between photochemical production and recombination.
Ozone can be destroyed by a series of free radical catalysts, the most important are oxide, hydroxyl radical (OH), nitrate radical (NO), atomic chlorine (Cl) and bromine (Br). These are all natural and artificial, at present, most OH and NO in the stratosphere is of natural origin, but human activity has significantly increased the levels of chlorine and bromine. These elements found in organic compounds stable, especially chlorofluorocarbons (CFCs), which can find their way into the stratosphere without being destroyed in the troposphere due to its low reactivity. Once in the stratosphere, the Cl and Br atoms are released from parent compounds by the action of ultraviolet light, for example ('h' is Planck's constant,''is the frequency of electromagnetic radiation)
CFCl3 + H + Cl CFCl2
Cl and Br atoms can destroy ozone molecules through a variety of catalytic cycles. In the simplest example of such a cycle, a chlorine atom reacts with an ozone molecule, taking an oxygen atom with it (forming ClO) and leaving a normal oxygen molecule. chlorine monoxide (for example, chlorine dioxide) may react with a second molecule of ozone (ie, O3) to another chlorine atom and two oxygen molecules. Direct access of chemical reactions in the gas phase is:
Cl + O3 ClO + O2
Cl + O3 ClO + 2 O2
The overall effect is a reduction in the amount of ozone. more complex mechanisms have been discovered leading to the destruction of ozone in the lower stratosphere as well.
A single chlorine atom is still destroying the ozone layer (and thus a catalyst) to a maximum of two years (the time scale for transport of the lower troposphere) if there were no reactions that remove them from this cycle by forming a species reservoir and hydrochloric acid (HCl) and chlorine nitrate (ClONO2). On a per atom, bromine is more effective than chlorine to destroy the ozone layer, but there is much less bromine in the atmosphere today. As a result, both chlorine and bromine contribute significantly the total ozone depletion. Laboratory studies have shown that fluorine and iodine and participate in catalytic cycles. However, in Earth's stratosphere, fluorine atoms react rapidly with water and methane to form strongly bound HF, while iodine-containing organic molecules react too quickly in the lower atmosphere does not reach the stratosphere in large quantities. In addition, a chlorine atom is capable of reacting with 100,000 ozone molecules. This, plus the amount of chlorine in the atmosphere by chlorofluorocarbons (CFCs), shows how each year the CFC are hazardous to the environment.
quantitative understanding of chemical processes of ozone loss
In 2007, research on the breakdown of a key molecule in these chemicals that deplete the ozone layer chlorine peroxide (Cl2O2) also known as chlorine dioxide dimer, questioned all current models of atmospheric ozone depletion Polar. Dioxide chlorine dimer serves as a reservoir of chlorine in the atmosphere. Since chlorine is bound in the dimer is not available for catalytic destruction of ozone. Dimer photolysis produces two molecules of chlorine dioxide that can participate in the catalytic destruction of ozone. chlorine nitrate (ClONO2) molecule is another important source.
The chemicals in the laboratory of NASA's Jet Propulsion in Pasadena, California, revisited the dimer absorption cross section CIO for those who are accountable to an order of magnitude lower than expected in the region between 300 and 350 nm .. This absorption coefficient is less implies that chlorine is less available for the catalytic destruction of ozone in the stratosphere, since most of it remain locked in the ClO dimer.
This result led to new measured by different methods, resulting in sections that are in agreement with the elders resolve most divergence. The first report by Chen et al., Uses a new method for determining the absorption section by observing the loss of the dimer in a mass spectrometer as a molecular beam is exposed a UV laser. . This method has the weakness that can be used in lengths wavelengths where laser sources are intense.
There was another, even the study latest shows that major revisions in the model the ozone layer are not necessary. In addition to the new measures, Papanastasiou, et al. From the laboratory of the Earth NOAA systems that support groups JPL did not adequately reflect the uncertainty in the modeling of the cross sections, and when done properly, the error of JPL estimates include the results, although the mean estimate is much lower. Other studies are ongoing and should be published shortly. Preliminary results of the group Anderson at the University of Harvard, presented in absorption, 2009 AGU conference support more cross sections. These new experiences, driven by the bottom JPL have significantly improved our understanding of the chlorine dioxide absorption cross section dimer and increased our confidence in models of destruction photochemical ozone.
Observations on the depletion of the ozone layer
The drop is more pronounced in the ozone layer was in the lower stratosphere. No However, the ozone hole is most often measured in terms of ozone concentrations at these levels (typically a few parts per million), but a reduction in total column ozone above a point on the surface of the Earth, which is normally expressed in Dobson units, abbreviated as "DU." Marked declines in column ozone in the austral spring and early summer compared to early 1970 and before have been observed with instruments such as the mapping spectrometer total ozone (TOMS).
lowest value of ozone measured by TOMS each year of the ozone hole.
Discounts up to 70% in the observed ozone column in the austral (southern hemisphere) spring in Antarctica and the first time in 1985 (when Farman et al. 1985) is ongoing. In the 1990s, total ozone column in September and October have continued to be less than 4.050% of the ozone hole before. In the Arctic, the amount lost is more variable from year to year in Antarctica. The The largest decreases up to 30% are in winter and spring, when the stratosphere is colder.
The reactions occur in polar stratospheric clouds (PSC) play an important role in strengthening the ozone layer. SSP more easily in the extreme cold of the Antarctic stratosphere. This is why ozone holes are formed, and are deeper, over Antarctica. Early models did not consider CSP and predicted an overall decrease, which explains why the ozone hole over Antarctica was sudden as a surprise to many scientists. [Citation needed]
In the middle latitudes, it is better to speak of the destruction of the ozone layer, instead of holes. The decrease of about 3% below pre-1980 values 3560N and about 6% for 3560. In the tropics, there are no significant trends. [Citation needed]
Ozone depletion also explains much of the observed reduction in the stratosphere and upper troposphere temperatures. The heat source in the stratosphere is the absorption UV radiation by ozone, ozone reduces performance leads to cooling. Some stratospheric cooling is also provided for the increase in gas emissions greenhouse gases like CO2. However, ozone-induced cooling appears to be dominant [citation needed]
The predictions of ozone levels remain difficult. The World Meteorological Organization Global Ozone Research and Monitoring No. 44 Projecteport strongly in favor of the Montreal Protocol, but noted that UNEP 1994 Assessment overestimated ozone loss for the period 19941997.
Chemicals in the atmosphere
CFCs in the atmosphere
Chlorofluorocarbons (CFCs) were invented by Thomas Midgley in the 1920's. Have been used in air conditioning and refrigeration, as aerosol propellants before the 1980's, and in the process of cleaning delicate electronic equipment. Also present as byproducts of certain chemical processes. No major natural source has been identified for these compounds their presence in the atmosphere is almost entirely attributable to the manufacture of man. As indicated in the cycle of view of the ozone layer above, when these chemicals that deplete the ozone layer reaches the stratosphere, which are dissociated by ultraviolet light to release chlorine atoms. Atoms chlorine act as a catalyst and everyone can break tens of thousands of ozone molecules before being removed from the stratosphere. Given the longevity of the molecules CFC recovery times are measured in decades. It is estimated that a CFC molecule has an average of 15 years to get from the base's upper atmosphere and can remain there for almost a century until the destruction of one hundred thousand ozone molecules during that period.
Audit observations
Scientists have been increasingly able to attribute the observed ozone depletion in human higher halogenated compounds (anthropogenic) of CFCs by the use of complex chemical transport models and its validation with observational data (SlimCat eg clams). These models work by combining satellite measurements of concentrations chemical and meteorological fields with chemical reaction rate constants obtained in laboratory experiments. They are able to identify not only the chemical reactions key, but also the transport processes that bring CFC photolysis products into contact with ozone.
The ozone hole and its causes
The ozone hole America North in 1984 (unusually warm ozone-depleting reduction) and 1997 (caused by abnormally cold seasonal depletion has increased). Source: NASA
The ozone hole over Antarctica is a region of the Antarctic stratosphere, where ozone levels have declined in the past for only 33% of their values before 1975. The ozone hole occurs during the Antarctic spring, from September to early December, strong westerly winds start to circulate around the continent and create a container in the atmosphere. In this polar vortex over 50% of the lower stratospheric ozone is destroyed during the Antarctic spring.
As explained above, the main cause of loss of ozone is the presence of chlorine-containing gas supply (mainly CFCs and related halocarbons). In the presence of ultraviolet light, these gases dissociate releasing chlorine atoms, which in turn catalyze ozone destruction. The depletion of the ozone layer catalyzed by Cl can occur in the gas phase, but is significantly higher in the presence of polar stratospheric clouds (PSC).
These polar stratospheric clouds form during winter in the extreme cold. Polar winters are dark, composed of 3 months without solar radiation (sunlight). The lack of sunlight contributes to a decrease in temperature and pitfalls of the polar vortex and the air chills. Temperatures hover around or below -80 ° C. These low temperatures form cloud particles and are composed by nitric acid (Type I PSC) or ice (Type II PSC). Both types provide surfaces for chemical reactions lead to ozone destruction. [Citation needed]
The photochemical processes are complex, but well understood. The key observation is that, generally, most of the chlorine in the stratosphere is in stable "reservoir" compounds, mainly hydrochloric acid (HCl) and chlorine nitrate (ClONO2). During the Antarctic winter and spring, however, reactions on the surface particle Polar stratospheric clouds convert these "reservoir" in free radical reactive compounds (Cl and ClO). Clouds can also be removed of NO2 in the atmosphere by converting nitric acid, which prevents the newly formed ClO becomes ClONO2.
The role of sunlight in the ozone layer by ozone depletion over Antarctica is the largest in the spring. During the winter, although the PSC are in their abundance, no light over the post to lead chemical reactions. During the spring, however, the sun rises, the supply of energy to drive photochemical reactions, and melt stratospheric clouds polar, the release of trapped compounds. [Citation needed]
Most of the ozone layer is destroyed in the lower stratosphere, unlike depletion much less homogeneous ozone by gas-phase reactions, which occurs mainly in the upper stratosphere. [Citation needed]
Increasing temperatures near At the end of spring break the vortex in mid-December. As the warm air and ozone-rich flow from lower latitudes, the PSC are destroyed, the process to stop the depletion of ozone layer and ozone hole closes. [Citation needed]
Interest in the ozone layer
While the effect of the ozone hole Antarctic ozone loss overall is relatively low, estimated at around 4% per decade, the hole has attracted much interest because:
The decrease ozone layer was expected at the beginning of 1980 to 7% over 60 years. [Citation needed]
The sudden recognition of 1985 there was a large "hole" is widely in the press. Ozone depletion is particularly rapid in Antarctica had been dismissed as a measurement error. [Citation needed]
Many [citation needed] were concerned that ozone holes might start to appear in other regions of the world, but so far the only defeat on a large scale is a thin layer of ozone "Bump" observed in spring in the Arctic North Pole. The mid-latitude ozone has decreased, but to a much lower (approximately 45% decrease).
If conditions become more severe (cooler stratospheric temperatures, more stratospheric clouds, more active chlorine) and Global Ozone can decrease at a rate much higher. The standard theory of global warming predicts that the stratosphere has cooled.
When the Antarctic ozone hole hit ozone depleted air moves surrounding areas. Reductions in the ozone layer by 10% was reported in New Zealand in the month following the rupture of the hole Antarctic ozone.
The consequences of ozone layer depletion
Since the ozone layer absorbs UVB ultraviolet rays of sun depletion, the ozone layer is expected increased levels of surface UVB rays, which could cause damage, including increases in skin cancer. This is the reason for the Montreal Protocol. Although decreases the stratospheric ozone layer CFCs are linked and there are good theoretical reasons to believe that the reduction of the ozone layer increases the surface UVB radiation, there is no direct evidence linking the depletion of the ozone monitoring with a higher incidence of skin cancer in human beings. This is due in part to the fact that UVA has also been implicated in some forms of skin cancer, is not absorbed by ozone, and it is almost impossible to control statistics for lifestyle changes of population.
Increased UV
Ozone, despite being Minorities in the Earth's atmosphere, is responsible for most of the absorption of the rays UVB. The amount of UVB radiation that penetrates through the ozone layer decreases exponentially with the thickness path inclined to density of the layer. Consequently, a decrease atmospheric ozone layer should lead to significantly higher levels of UVB radiation near the surface.
The increase in area due to UVB ozone hole may be partially inferred from radiation transfer model calculations, but can not be calculated from direct measurements because of the lack of reliable data historical (pre-ozone hole) the surface UV data, although the degree of surface UV observation of new programs (for example, Lauder, New Zealand).
Because this is the same UV radiation that creates ozone in the ozone layer of O2 (normal oxygen) Firstly, a reduction of stratospheric ozone which tend to increase photochemical production of ozone in the lower levels (in the troposphere), although the general trends in total column ozone still show a decline, largely due to the ozone layer has led product photochemical lifetime shorter than it is destroyed before the merger could a level that compensates for the high ozone reduction higher up. [Citation needed]
The biological effects
The main public concern about ozone hole has been the effect of UV rays and increasing the surface of microwave radiation on human health. Until now, the layer of ozone in most locations was typically a small percentage and, as noted above, there is no direct evidence of damage to health is available at most latitudes. Has been the high level seen in the ozone hole depletion to be increasingly common worldwide, the effects could be much more dramatic. As the ozone hole over Antarctica has increased in some cases, as important to reach the southern regions of Australia and New Zealand Environmentalists fear that increasing the radiation surface UV could be significant. [Citation needed]
Effects on humans
UVB (Superior UV energy absorbed by ozone) is generally recognized as a factor which contributes to skin cancer. In addition, increased surface UV leads to increased tropospheric ozone, which is a risk to human health. [Citation needed] UV radiation increases the soil is also an increase in the ability to synthesize vitamin D from sunlight.
Cancer preventive effects of vitamin D represent a possible beneficial effect of reducing the ozone layer. In terms of healthcare costs, potential benefits of increased UV radiation can overcome the burden.
1. Basal and squamous cell carcinoma – The most common forms of skin cancer in humans, basal and squamous cell carcinomas, were strongly related exposure to UVB rays. The mechanism by which UVB induces these cancers is, of course, absorbing UVB radiation causes pyrimidine bases in the DNA molecule to form dimers, leading to transcription errors in DNA replication. These cancers are relatively mild and rarely fatal, although the treatment of squamous cell carcinoma sometimes requires major reconstructive surgery. By combining epidemiological data and results animal studies, scientists believed that a reduction of one per cent of the stratospheric ozone layer could increase the incidence of these cancers in 2%.
2. Malignant melanoma Another form of skin cancer, malignant melanoma, is much rarer, but far more dangerous, being lethal in about 1520% of diagnosed cases. The relationship between exposure to UV rays is melanoma is not yet well understood, but it appears that both UVB and UVA rays are involved. Experiments in fish suggest that 90 and 95% of malignant melanomas may be due to UVA and visible radiation while experiments in opossums suggest a larger role for UVB rays. Because of this uncertainty, it is difficult to estimate the impact of ozone depletion on the incidence of melanoma. One study showed an increase of 10% of the radiation UVB is associated with a 19% increase in melanomas in men and 16% for women. A study of people in Punta Arenas at the southern tip of Chile, showed an increase of 56% in melanoma and a 46% increase in nonmelanoma skin cancer over a period of seven years, with the decreased ozone layer and increased UVB rays.
3. Cortical cataracts – Studies suggest an association between ocular cortical cataracts and exposure to UV-B, with crude approximations of exposure and various valuation techniques of cataract. A detailed assessment of exposure to UV-B radiation was performed in a study on the Chesapeake Bay Watermen, where the increase in annual average exposure eyes have been associated with an increased risk of cortical opacity. In this high exposure group of mostly white men, the evidence linking cortical opacities exposure to sunlight is the strongest to date. However, the following data from a population-based study in Beaver Dam, WI suggested the risk may be limited to men. In the Beaver Dam study, the exposure of women were lower than in men, and found no association. In addition, there was no evidence linking sun exposure to the risk of cataracts in African Americans and other eye diseases have different prevalences between different racial groups, and cortical opacity appears to be higher in African Americans compared with whites.
4. Increased tropospheric ozone – UV surface leads to enhanced tropospheric ozone increase. ozone at ground level is generally recognized as a risk to health, ozone is toxic due to its oxidizing properties strong. At that time, ozone at ground level is produced mainly by the action of ultraviolet radiation on combustion gases from the exhaust of vehicles. [Citation needed]
Effect on crops
Increased UV radiation could have an effect on crops. A number of economically important plant species such as rice, depend on cyanobacteria residing on their roots for the retention of nitrogen. Cyanobacteria are sensitive to UV light would be affected by its increase.
Public Policy
NASA projections of the concentrations of ozone in the stratosphere, so that CFCs had been banned.
The magnitude the damage that CFCs have been caused to the ozone layer is not known or not known for decades, but decreased significantly in column ozone have been observed (as explained above).
After a 1976 report by the National Academy of Sciences concluded that credible scientific evidence supported the hypothesis exhaustion Ozone, a small number of countries including USA, Canada, Sweden and Norway, moved to eliminate CFC use in aerosols. At that time it was considered a first step towards a more complete control, but progress in this direction has slowed in subsequent years due to a combination of political factors (the industry resistance continues halocarbons and a general change in attitude toward environmental regulation in the first two years of the Reagan administration) and evolution science (following evaluation of the National Academy indicates that early estimates of the magnitude of the destruction of the ozone layer was too large.) States States banned the use of CFCs in aerosols in 1978. The European Community rejected the proposed ban on CFCs in aerosols, and the United States, SWC remained used as refrigerants and cleaning circuits. CFC production worldwide fell sharply after the ban on aerosols in the United States but in 1986 had returned close to its 1976 level. In 1980, DuPont closed its research program on alternative halocarbons.
The U.S. government's attitude began to change again in 1983, when William Ruckelshaus replaced Anne M. Burford as Administrator of the United States Environmental Protection Agency. Under Ruckelshaus and his successor, Lee Thomas, EPA pushed for an international approach to the regulation of halocarbons. In 1985, 20 nations, including major CFC producers, signed the Vienna Convention for the Protection of the Ozone Layer, which provides a framework for the negotiation of international rules on substances that deplete the ozone layer. This same year of the discovery of the Antarctic ozone hole was announced, causing a renewed public attention to the issue. In 1987, representatives of 43 nations signed the Montreal Protocol. Meanwhile, the halocarbon industry changed its position and began supporting a protocol to limit CFC production. The reasons for this was explained partly by Dr. Mostafa Tolba, former head of the United Nations Environment Programme, which was quoted in the June 30, 1990 issue of The New Scientist "… the chemical industry supported the Montreal Protocol in 1987, where they established a global schedule for the elimination of CFCs, which [is] no longer protected by patents. These companies have provided equal opportunity of commercialization of new compounds that are more profitable. "
In Montreal, the participants agreed to freeze production of CFCs 1986 levels and reduce production by 50% in 1999. After a series of scientific expeditions in Antarctica provided convincing evidence that the ozone hole was actually caused by chlorine and bromine in halogenated organic compounds of human origin, the Montreal Protocol was strengthened in a meeting London, 1990. Participants agreed to phase out CFCs and halons entirely (except for a very small amount marked for certain uses "Core", such as inhalers for asthma) in 2000. At a meeting in Copenhagen in 1992, the date of disposal was taken until 1996.
To some extent, CFCs have been replaced by less harmful hydro-chloro-fluoro-carbons (HCFCs), although concerns remain on HCFCs. In some applications, hydro-fluoro-carbons (HFCs) have been used to replace to CFCs. HFCs, which do not contain chlorine or bromine no contribution to ozone depletion, although these are the emissions of greenhouse gases. The best known of these compounds is probably the HFC-134a (R-134a), the U.S. have largely replaced CFC-12 (R-12) in automobile air conditioners. In the lab (A former "essential" use) The ODS can be replaced by several other solvents.
Ozone Diplomacy by Richard Benedict (Harvard University Press, 1991) gives an overview detailed negotiation process that led to the Montreal Protocol. Pielke and Betsill a thorough review of the first U.S. government response the new science of destruction ozone layer, CFCs.
The outlook for the depletion of the ozone layer
Depleting gas trends.
Since the adoption and strengthening of Protocol Montreal has led to the reduction of CFC emissions, atmospheric concentrations of the most important compounds have been declining. These substances are gradually removed from the atmosphereince peaked in 1994, the effective equivalent chlorine (OATS) level in the atmosphere has declined by 10% in 2008. It is estimated that in 2015, the ozone hole over Antarctica will fall by 1 million km in 25 (Newman et al, 2004.), complete recovery of the ozone layer over Antarctica should not occur before 2050 or later. Work has suggested that recovery detectable (and statistically significant) does not occur until about 2024, with recovery ozone levels to 1980 levels by about 2068. The reduction of chemicals that deplete the ozone layer Ozone has also been seriously affected by a decrease of bromine-containing chemicals. The data suggest that substantial natural sources of methyl bromide in the atmosphere (CH 3 Br) .. The elimination out of CFCs means that nitrous oxide (N2O) not covered by the Montreal Protocol, has become the substance rather than ozone-depleting emissions and should remain so along the 21 st century.
The 2004 ozone hole was completed in November 2004, daily minimum temperatures in the Antarctic stratosphere the lower stratosphere increased to levels that are too hot for the formation of polar stratospheric clouds (PSC) in 2 to 3 weeks earlier than most in recent years years.
The Arctic winter of 2005 was very cold in the stratosphere, CPCs were abundant in high latitude regions clarified many warm-up event large, which began in the upper stratosphere during February and spread to the Arctic stratosphere in March. The size of the Arctic total ozone abnormally low in 2004-2005 was higher than any year since 1997. The predominance of unusually low ozone values of the total area of the Arctic winter of 2004-2005, attributed to the same lower temperatures in the stratosphere and favorable weather conditions for the destruction of the ozone layer and the continued presence of the destruction chemical ozone in the stratosphere.
A summary of the issues of ozone IPCC 2005 concluded that the observations and model calculations indicate that the amount average of the ozone layer has stabilized around. Despite considerable variation in the ozone layer is expected from year to year, including the polar regions, where depletion is larger, the ozone layer should begin to recover in coming decades because the concentration of the substance that deplete the ozone layer decreases, assuming full Montreal Protocol compliance.
Temperatures during the Arctic winter 2006 was fairly close to the long-term average until late January, thresholds often cold enough for private security. During the last week of January, however, a major global event sent temperatures above normal too hot to support PSC. By the time the temperatures return to near normal in March, the seasonal standard was well above the threshold of CPS. Preliminary maps ozone generated by satellite instruments show a seasonal accumulation of the ozone layer slightly below the long-term average for the Northern Hemisphere as a whole although some events produced ozone. In March 2006, the Arctic stratosphere on 60 north pole was free to abnormally low ozone areas, except during the period three days from 17 March 19 when the lid of the total ozone fell below 300 DU over the North Atlantic from Greenland to Scandinavia.
The area where the total ozone column is less than 220 AU (the accepted definition of the boundary of the ozone hole) has been relatively low until about August 20, 2006. From then the area of the ozone hole grew rapidly, peaking at 29 million km on 24 September. In October 2006, NASA said the ozone hole this year established a new record in space with a daily average of 26 million km between 7 and 13 September 10, 2006 total ozone thickness fell as low as 85 AU, 8 October. The two factors combined, in 2006 the lowest level of depletion of the ozone layer in the story. The decline is attributed to temperatures above Antarctica reaching the most down from the record complete records began in 1979.
In October 2008, Ecuador European Space Agency released a report titled Hyperion, a study the last 28 years of data from 10 satellites and ground dozens of instruments around the world including his own, and found that UV radiation reaching latitudes equatorial was much more than expected, climbing some densely populated cities to 24 UVI, WHO considers that the standard UV Index 11 as an index of extreme risk and high health. The report concluded that the depletion of the ozone layer around the middle latitudes of the planet and is in danger of large populations in these areas. More Later, the conidia, Peruvian Space Agency, made its own study, which are almost the same facts that the study Ecuador.
The ozone hole over Antarctica is expected to continue for decades. Ozone concentrations in the lower stratosphere in Antarctica will increase by 5% in 2020 and re-pre-1980 levels of about 20,602,075, 1025 years later than anticipated in previous assessments. Is due to revised estimates of atmospheric concentrations of substances that deplete the ozone layer and higher expected future use in developing countries. Another factor that can exacerbate ozone depletion is the feeder of nitrogen oxides above the stratosphere due to changing wind patterns.
Search History
The basic physical and chemical processes that lead to the formation a layer of ozone in the stratosphere were discovered by Land Sidney Chapman in 1930. These issues are addressed in the ozone layer and the oxygen cycle radiation section briefly UV short wavelength splits an oxygen (O2) into two molecules of oxygen (O) atoms, which then combine with other oxygen molecules to form ozone. Ozone is removed when an oxygen atom and a molecule of ozone "Gathering" to form two molecules of oxygen, ie O + O3-2O2. In the 1950's, David Bates and Marcel Nicolet has presented evidence that a number of free radicals, especially oxide hydroxyl (OH) and nitric oxide (NO) could catalyze the recombination reaction, thus reducing global ozone amounts. These free radicals are known to be present in the stratosphere, and were considered part of the natural balance, it was estimated that in its absence, the ozone layer would be about twice as thick as it is now.
In 1970, Professor Paul Crutzen is that emissions of nitrous oxide (N2O), a stable gas, produced by long-term soil bacteria, the surface of Earth could affect how much nitric oxide (NO) in the stratosphere. Crutzen showed that nitrous oxide live long enough to reach the stratosphere, where it becomes NO. Crutzen then noted that the increasing use of fertilizers could lead to increased emissions of nitrogen oxides in the natural environment, which in turn lead to a greater amount of NO in the stratosphere. Therefore, human activity could have an impact on the stratospheric ozone layer. The following year, and Crutzen (independent) Harold Johnston suggested that emissions of NO by supersonic aircraft flying in the lower stratosphere, also could deplete the ozone layer.
The Rowland-Molina hypothesis
In 1974, Frank Sherwood Rowland Professor of Chemistry at the University of California at Irvine, and his postdoctoral associate Mario J. Molina suggests that long-term organic compounds halogenated such as CFCs, act the same way that Crutzen proposed for nitrous oxide. James Lovelock (more popularly known as the creator of the Gaia hypothesis) was recently discovered during a cruise in the South Atlantic in 1971, almost all CFC compounds manufactured Since its invention in 1930 were still present in the atmosphere. Molina and Rowland concluded that, as N2O, CFCs is expected to reach the stratosphere where they are dissociated by UV light releasing Cl atoms (One year before, Richard Stolarski and Ralph Cicerone of the University of Michigan showed that Cl is more effective than NO to catalyze ozone destruction. Similar conclusions were drawn by Michael McElroy and Steven Wofsy of Harvard University. Neither group, however, understood that CFCs were a potentially important source of stratospheric chlorine in contrast, had investigated the possible effects of HCl emissions from space shuttle, which are much smaller.)
The Rowland-Molina hypothesis was challenged strongly by representatives of the aerosol industry and halocarbons. Chairman of the Board of DuPont was quoted as saying that the theory of ozone depletion is "a story of science fiction … load … Anything! Absolute. "Robert Abplanalp, president of Precision Valve Corporation (and inventor of the aerosol can practice the first valve) wrote to the rector of the University of California Irvine to complain about Rowland's public statements (Rouen, p. 56.) However, within three years most basic assumptions made by Rowland and Molina were confirmed by laboratory measurements and by direct observation in the stratosphere. Concentrations greenhouse gas source (CFCs and other compounds) and the chlorine reservoir species (HCl and ClONO2) were measured in the stratosphere, and demonstrated that CFCs were indeed the main source of chlorine in the stratosphere, and virtually all CFC gave finally reach the stratosphere. Even more convincing was the measurement, by James G. Anderson and colleagues, chlorine monoxide (ClO) in the stratosphere. Chlorine dioxide is produced by the reaction of Cl with ozone and its observation has shown that Cl radicals were present only in the stratosphere, but also actually involved in the destruction of the ozone layer. McElroy and Wofsy extended the work of Rowland and Molina, demonstrating bromine atoms have been even more effective catalysts for ozone loss and chlorine atoms argued that brominated organic compounds known such as halons, widely used in fire extinguishers, were a potentially important source of bromine in the atmosphere. In 1976, the U.S. National Academy of Sciences published a report concluding that the assumption of the ozone layer has been strongly supported by scientific evidence. Scientists have calculated that if CFC production continues increase the rate of 10% annually until 1990 and then remain steady, CFCs, global loss of ozone from 5 to 7% in 1995 and a loss of 30 to 50% in 2050. In response to the U.S., Canada and Norway banned the use of CFCs in aerosols in 1978. However, subsequent research, summarized by the National Academy of reports issued between 1979 and 1984, suggests that previous estimates of global ozone loss was too great.
Crutzen, Molina and Rowland were awarded the 1995 Nobel Prize Chemistry for his work on stratospheric ozone.
The ozone hole
The discovery of the ozone hole over Antarctica, scientists from the British Antarctic Survey Farman, Gardiner and Shanklin (announced in an article in Nature in May 1985) was a shock to the scientific community, because the observed decrease in layer polar ozone is much higher than expected. [Citation needed] Satellite measurements show the depletion of the ozone mass around the South Pole are being made available at the same time. However, it was initially rejected by the algorithms as reasonable quality control data (which are filtered as errors because the values were surprisingly low) the ozone hole was detected only in the satellite data when data is updated after the decline of ozone on-site reviews. When the software run again without the flags, the ozone hole was first observed in 1976.
Susan Solomon, an atmospheric chemist at the National Oceanic and Atmospheric Administration (NOAA), proposed that the chemical reactions of polar stratospheric clouds (PSC) in the cold Antarctic stratosphere caused a massive increase despite localized and seasonal, the amount of chlorine present in active, ozone-destroying forms. polar stratospheric clouds in Antarctica are formed when the temperature is very low, as low as -80 degrees C, and conditions in early spring. Under these conditions, clouds of ice crystals provide a surface for the conversion of compounds into reactive chlorine compounds reactive chlorine can deplete the ozone layer.
In addition, the polar vortex formed over Antarctica is very tight and the reaction having product on the glass surface of the clouds is very different when it occurs in the atmosphere. These conditions led to the formation of the ozone hole in Antarctica. This hypothesis was decisively confirmed, first by laboratory measurements and subsequently by direct measurements of the earth and high-altitude aircraft, very high concentrations of chlorine monoxide (ClO) in the Antarctic stratosphere. [Citation needed]
Other assumptions, that the ozone hole attributed to variations in solar UV radiation or changes in air traffic patterns, was also tested and proved to be unsustainable. [Citation needed]
Meanwhile, analysis of ozone measurements from the worldwide network of ground Dobson led a group of international experts to the conclusion that the ozone layer is being depleted at all latitudes outside the tropics. [Citation needed] These trends were confirmed by satellite measurements. Consequently, the major producing countries halocarbons agreed to eliminate out production of CFCs, halons and related compounds, a process that was completed in 1996.
Since 1981, the United Nations Environment Programme has organized a series of reports on scientific assessment depletion of the ozone layer. The most recent date of 2007, when satellite measurements showed the ozone hole ozone is recovering and is now smaller than it has been for nearly a decade.
depletion of the ozone layer and global warming
There are five areas connection between the ozone layer, global warming and depletion:
The radiative forcing of emissions of greenhouse gases and other different sources.
CO2 radiative forcing that produces the same near the surface is expected to cool down global warming the stratosphere. This cooling, in turn, should produce a relative increase in the polar ozone (O3) depletion and the frequency of ozone holes. [Citation needed]
By contrast, depletion of the ozone layer is radiative forcing of the climate system. There are two opposite effects: the stratospheric ozone layer causes small to absorb less solar radiation, which cools the stratosphere, while warming in the troposphere, the resulting cooling of the stratosphere emits less long-wave radiation downward, thus cooling the troposphere. In general, cooling dominates: the IPCC concludes that "the stratospheric O3 losses observed in the past two decades have led to a negative forcing, the surface-troposphere "0.10 about 0.15 watts per square meter (W / m).
One of the major predictions of the effects of emissions is that the stratosphere has cooled. Despite This cooling has been observed, is not trivial to separate the effects of changes in the concentration of emissions of greenhouse gases and the depletion of the ozone layer for two lead to cooling. However, this can be done by the digital model of the stratosphere. The results of the National Oceanic and Atmospheric Administration Geophysical Fluid Dynamics Laboratory show that above 20 km (12.4 miles), the emissions of greenhouse gases cooling.
chemicals deplete the ozone layer are also greenhouse gases. Increasing concentrations of these chemicals have produced 0.34 0.03 W / m of radiative forcing, which corresponds about 14% of the total radiative forcing increases in concentrations of greenhouse gases well mixed.
Modeling long-term processes, measurement, analysis, design and testing theories for decades to the role, gain wide acceptance, and ultimately, become the paradigm dominant. Several theories about the destruction of the ozone layer hypothesis in the 1980's, published in late 1990 and has now been found. Schindel and Dr. Drew Dr. Paul Newman, NASA Goddard proposed a theory of early 1990, using an SGI Origin 2000 supercomputer, which was modeled ozone depletion have showed 78% of ozone destroyed. The development of this model 89% of ozone destroyed, but postponed the estimated ozone hole 75 years to 150 years. (An important part of this model is the absence of stratospheric flight by fossil fuel depletion.)
Misconceptions about the ozone layer
Some misconceptions common about the ozone layer are discussed briefly, more detailed discussions can be found in the ozone depletion FAQ.
CFCs are "too heavy "to reach the stratosphere
It is sometimes said that since the CFC molecules are much heavier than nitrogen or oxygen can not reach into the stratosphere in large quantities. However, atmospheric gases are not sorted by weight, wind speed (turbulence) are strong enough to mix gases in the atmosphere. CFCs are heavier than air, but as argon, krypton and other heavy gases with a long life, are distributed uniformly in turbosphere and reach the upper atmosphere.
man-made chlorine is insignificant compared to natural sources
Another objection is sometimes done in general accepted that natural sources of tropospheric chlorine (volcanoes, Ocean Spray, etc.) are four to five orders of magnitude more artificial sources. While very true, the tropospheric chlorine is not relevant is stratospheric chlorine that affects the ozone layer. Ocean Spray Chlorine is soluble and therefore washed by rain before reaching the stratosphere. CFC, however, are insoluble and long term, allowing them to reach the stratosphere. Even in the lower atmosphere is now more chlorine in the form of CFCs and haloalkanes Related HCl is in saline mist, and halocarbons in the stratosphere dominate massively. One of these halocarbons, methyl chloride, has a prevalence of natural sources, and is responsible for 20 percent of chlorine in the stratosphere, and the remaining 80% comes from synthetic compounds.
Very large volcanic eruptions can HCl injected directly into the stratosphere, but direct measurements have shown that their contribution is small compared to that of chlorine from CFCs. A misstatement is similar halogenated compounds soluble volcanic plume of Mount Erebus on Ross Island, Antarctica is an important factor in the Antarctic ozone hole. [Citation needed]
An ozone hole was first observed in 1956
GMB Dobson (Exploring the atmosphere 2 nd edition, Oxford, 1968) mentioned that when levels spring ozone over Halley Bay were first measured in 1956, found that they were surprised to ~ 320 AU, about 150 DU below spring levels, ~ 450 DU, in the Arctic. These, however, at that time known normal weather, because there are no data in the Antarctic ozone were available. What Dobson describes is essentially the baseline used to measure the ozone hole: the actual values of the ozone hole are around 150,100 AU.
The gap between the Arctic and Antarctica said Dobson was primarily a question of timing: when the level of ozone in the Arctic Spring worked smoothly, with a peak in April, while in the Antarctic were more or less constant in early spring, rising abruptly in November, when the vortex polar broke.
The behavior seen in the Antarctic ozone hole is completely different. Instead of remaining constant, the ozone levels in early spring suddenly drop their winter values, and low, up to 50%, and normal values are not reached again before December.
If the theory were correct, the hole Ozone must be above the sources of CFC
CFCs are well mixed in the troposphere and stratosphere. The reason the ozone hole over Antarctica occurs because no more than CFCs, but due to low temperatures due to polar vortex allow polar stratospheric clouds to form. Abnormal findings were significant, serious, localized "holes" in other parts of the world.
The "ozone hole" is a hole in the ozone layer
When the "ozone hole" However, most of the lower stratospheric ozone is destroyed. The stratosphere is much less affected, however, that the global ozone amount in the Americas decreased by 50 percent or more. The ozone hole does not go all the way through the layer, however, is not a uniform thinning of the layer is. This is a "hole" in the sense of "a hole in the ground", which is a depression, not in the sense of "a hole in the windshield."
World Ozone Day
In 1994, the United Nations General Assembly voted to designate September 16 as "World Ozone Day" to commemorate the signing of the Montreal Protocol on this date in 1987.
See also
The ozone-oxygen cycle
Montreal Protocol
"The scientific assessment depletion ozone layer, "a series of technical reports compiled under the auspices of the World Meteorological Organization and United Nations Programme on Environment.
CFC
Melanoma, skin cancer
Greenhouse Gases
UV
CLAMS Lagrange model chemistry of the stratosphere
Global Warming ice shelves
Atmospheric window
References
^ "Part III. The science of ozone hole" Http: / /. Www.atm.ch.cam.ac.uk/tour/part3.html Accessed 05/03/2007 ..
^ "The chlorofluorocarbons (CFCs) are heavier than air, so how do scientists suppose that these substances chemical to reach the height of the ozone layer to hurt? "Http: / /. Www.sciam.com / article.cfm? Id = chlorofluorocarbons, CFCs. Accessed on 08/03/2009.
^ Dobson, R. (2005). "Ozone depletion will increase in the number of cataracts." BMJ 331 (7528): 1292. doi: 10.1136/bmj.331.7528.1292-d. PMID 16322012. Edit
^ Newman, A. Paul. "Chapter 5: Section 4.2.8 Stratospheric Photochemistry CLX catalytic reactions." in Todaro, Richard. Stratospheric ozone: an electronic manual. NASA's Goddard Flight Space Center of atmospheric chemistry and dynamics. . []
^ The depletion of stratospheric ozone by chlorofluorocarbons (Nobel Prize) Land ncyclopedia
Schiermeier ^ Q (September 2007). "The chemicals poke holes in the theory of the ozone layer "([dead link]). Nature 449 (7161): 3823. doi: 10.1038/449382a. PMID 17898724. 070924/full/449382a.html.
Francis D. ^ Pope, Jaron C. Hansen, Kyle D. Bayes, Randall R. Friedl, Stanley P. Sander (2007). "Ultraviolet absorption spectrum of chlorine peroxide, ClOOCl. J. Phys. Chem A 111 (20): 432,232. doi: 10.1021/jp067660w. PMID 17474723. http://pubs.acs.org/doi/abs/10.1021/jp067660w.
^ Journal of the Organization Bulletinhe World Weather
^ HY Chen, CY Lien, WY Lin, YT Lee, JJ Lin (May 2009). "UV absorption cross sections of the Cross are consistent with models ClOOCl degradation of the ozone layer "Science 324 (5928): .. 7814 doi: 10.1126/science.1171305 PMID 19423825 http://www.sciencemag.org/cgi/pmidlookup?view=long&pmid=19423825 …
Dimitrios K. ^ Papanastasiou, C. Vassileios Papadimitriou, David W. Fahey, James B. Burkholder (2009). "UV absorption spectrum of the ClO dimer (Cl2O2) between .. 200 and 420 nm J. Phys Chem A 113 (49): .. 1371113726 Doi. 10.1021/jp9065345 Http: / / pubs.acs.org/doi/abs/10.1021/jp9065345.
^ Some of the ozone hole: Part II. recent ozone depletion
^ World Health Organization (WMO)
^ U.S. EPA: Ozone Depletion
Ab ^ "Climate Change 2001: Group Work I:. The Scientific Basis Intergovernmental Panel on Climate Change Working Group I. 2001, p. Chapter 6.4 of http://www.grida.no/climate/ipcc_tar/wg1/223.htm stratospheric ozone …
^
Encyclopedia.com ^, Chlorofluorocarbons
^ Http: / earthobservatory.nasa.gov / / IOTD / view.php Id = 1771?
The hole ozone over Antarctica ^
^ Ozone depletion over Antarctica FAQ, section 7
"Climate Change 2001: Group Work I: The Scientific Basis "^. Intergovernmental Panel on Climate Change Working Group I. 2001. p. Chapter 9.3.2 Climate change models in the future. http://www.grida.no/publications/other/ipcc_tar/?src=/climate/ipcc_tar/wg1/351.htm.
^
Gvozdovskyy I ^, T Orlova, Salkova E, Terenetskaya I, Milinevsky G (August 2005). "Ozone and solar UV-B monitoring the ability to synthesize vitamin D from sunlight in Kiev and Antarctica" Int J Remote Sens 26 (16). 35,559 doi: .. 10.1080/01431160500076863 ~ content = a723976621 ~ db = all.
^ M Norval, AP Cullen, Gruijl FR, et al. (March 2007). "The effects on human health, loss of stratospheric ozone layer and its interactions with climate change" PHOTOCHEM Photobiol Science 6 (3 ):…. 23,251 doi:. 10.1039/b700018a10.1039/b700018a (22.12.2009 inactive). PMID 17344960.
^ Schwartz GG, Skinner HG (January 2007). "Class Vitamin D and cancer: new perspectives "Curr Opin Clin Nutr Metab Care 10 (1):. 611 doi:. PMID 17143048 http://meta.wkhealth.com/pt/pt-core/template-journal/lwwgateway/ 10.1097/MCO.0b013e328011aa60 .. Media / landingpage.htm? ISSN 1363-1950 = AND volume = 10 & issue = 1 & spage = 6.
^ Grant WB, Garland CF, Holick MF (2005). "Comparisons of estimated economic burdens due to solar ultraviolet radiation and vitamin D deficiency and excess radiation U.S. solar UV .. States "PHOTOCHEM Photobiol 81 (6):. 127,686 doi: .. 10.1562/2005-01-24-RA-424 PMID 16159309. = NLM: PubMed ISSN 0031-8655 = & & date = 2005 & volume = 81 & topic = 6 & spage = 1276.
Ab ^ Frank R. de Gruijl (Summer 1995). "Impacts depletion of the ozone layer spray. "Consequences 1 (2). Http://www.gcrio.org/CONSEQUENCES/summer95/impacts.html.
^ Setlow RB, Grist E, K Thompson, EA Woodhead (July 1993). "Wavelengths effective in induction of malignant melanoma. Proc. Natl. Acad. Science. USA 90 (14): 666,670. Doi: 10.1073/pnas.90.14.6666. PMID 8341684.
^ Fears TR, Bird CC, Guerry D, et al. (July 2002). "Midrange mean outdoor ultraviolet radiation flux and time to predict the risk melanoma "Cancer Res 62 (14 ):…. 39,926 http://cancerres.aacrjournals.org/cgi/pmidlookup?view=long&pmid=12124332 PMID 12124332.
^ JF Abarca, Casiccia CC (December 2002). "Skin cancer and ultraviolet-B radiation in the Antarctic ozone hole: southern Chile, 1987-2000." Photodermatol Photoimmunol PhotoME 18 (6): 294302. doi: 10.1034/j.1600-0781.2002.02782.x. PMID 12535025. .
^ West SK, Duncan DD, Munoz B, et al. (August 1998). "Sun exposure and risk of lens opacities in a study based Labour. Salisbury Eye Evaluation Project "JAMA 280 (8): 7148 doi:. 10.1001/jama.280.8.714 PMID 9728643 .. / 280/8/714.
^ Cruickshanks KJ, Klein BE, Klein R (December 1992). "UV exposure opacities and lens: the Beaver Dam Eye Study. Am J Public Health 82 (12): 165,862. Doi: 10.2105/AJPH.82.12.1658. PMID 1456342. PMC 1694542. .
Rubin GS ^ West SK, Munoz B, Schein OD, Duncan DD (December 1998). "Racial differences in lens opacities: the Salisbury Eye Evaluation (SEE) of the" Am J. Epidemiol 148 (11 ):… 10,339 PMID 9850124 Http: /. Aje.oxfordjournals.org / / cgi / view pmidlookup long PMID = = 9,850,124?.
^ Leske MC, Connell AM, Wu SY, Hyman L, Schachat A (January 1997). "The prevalence of lens opacities in the Barbados Eye Study. Arch. Ophthalmol. 115 (1): 10,511. PMID 9006434. http://archopht.ama-assn.org/cgi/pmidlookup?view=long&pmid=9006434.
^ RP Sinha, SC Singh and D.-P. Hder (1999). "Photoecophysiology of cyanobacteria. Journal of Photochemistry and Photobiology 3: 91,101.
^ ab http://archive.greenpeace.org/ozone/greenfreeze/moral97/6dupont.html
^ Use of ozone-depleting substances in laboratories. 516/2003 TemaNord
^ Newman, PA, Nash, ER, Kawa, SR, Montzka, SA, Schauffler, S. M (2006). "When The Antarctic ozone hole recover "Geophysical Research Letters 33:?. L12814 doi:. 10.1029/2005GL025232.
^ World Meteorological Organization World Meteorological Organization (WMO)
^ NOAA study shows that nitrous oxide and Top-depleting emissions, NOAA, August 27, 2009
World ^ From the World Meteorological Organization (WMO)
^ CPCtratosphere: Winter Bulletins
^
^ Annual NCEP data
^ Select Card ozone layer, individual sources
Index of / products/stratosphere/sbuv2to/archive/nh
^ Ozone Hole Watch
http://www.theregister.co.uk/2006/10/03/ozone_depletion ^
^ CNW Group | Canadian Space Agency | SCISAT 2006 explains that Deplete the Ozone
^ Causes and effects of stratospheric ozone reduction: an update. National Academy of Sciences. (1982 and 1983). http://www.nap.edu/openbook.php?isbn=0309032482.
^ Ozone Depletion, history and politics accessed November 18 2007.
Ab ^ Hegerl, Gabriel C., et al .. "Understanding Climate Change" (PDF). Climate Change 2007: The Physical Science Basis. Contribution Working Group I Fourth Assessment Report of the Intergovernmental Panel on Climate Change. Intergovernmental Panel on Climate Change. p. 675. http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter9.pdf. Retrieved 01.02.2008.
^ ab (PDF) of the IPCC / TEAP Special Report on Safeguarding Ozone Layer and the Global Climate System: Issues to hydrofluorocarbons and perfluorocarbons (Summary for Policymakers). Intergovernmental Panel Climate Change and Economic Assessment Panel. 2005. . Retrieved on 04/03/2007.
^ "The role of ozone layer and emissions of greenhouse gases on climate change in the stratosphere. "Geophysical Laboratory of Fluid Dynamics. 29/02/2007. http://www.gfdl.noaa.gov/aboutus/milestones/ozone . html. Retrieved on 04/03/2007.
Phoenix ^ NewsREON EASY
^ Questions, Part I, Section 1.3.
^ Ozone depletion FAQ, Part II, Section 4.3
^ Http: / / www.nature.com/nature/journal/v403/n6767/full/403295a0.html
^ Ozone depletion FAQ, Part II, Section 4.4
^ Exhaustion Questions ozone, Part III, Article 6
^ Ozone depletion FAQ, Antarctica
^ Ozone depletion: Definition and much more Answers.com
books non-technical
Schiff, Harold Dotto, Lydia (1978). The War of the ozone layer. Garden City, NY: Doubleday. ISBN 0-385-12927-0.
Roan, Sharon (1989). Ozone Crisis: The 15-year evolution of a sudden emergency worldwide. New York: Wiley. ISBN 0-471-52823-4.
Dray, Philip Cagin, Seth (1993). Between Earth and Heaven: How CFC changed our world and endangered the ozone layer. New York: Pantheon Books. ISBN 0-679-42052-5.
Books about public policy issues
Richard Benedict Elliot (1991). Ozone Diplomacy: New Directions in safeguarding the planet. Cambridge: Harvard University Press. ISBN 0-674-65001-8. (Ambassador Benedict was the chief negotiator U.S. in meetings that led to the Montreal Protocol.)
Litfin, Karen (1994). Ozone discourses: science and politics of global environmental cooperation. New York: Columbia University Press. ISBN 0-231-08137-5.
Research papers
Newman PA, Kawa, SR and Nash, ER (2004). "For the size of the hole Antarctic ozone "Geophysical Research Letters 31:?. L12814 doi:. 10.1029/2004GL020596.
Weatherhead EC, Andersen SB (2006). "The search for signals recovery in the ozone layer, "Nature 441 (7089):. 3945 doi: 10.1038/nature04746 .. PMID 16672963.
External Links
Ozone in the Open Directory Project
Ozone Unlayering UN Chronicle: A land without sunscreen
NOAA / ESRL ozone depletion
NOAA ozone depleting gas index
EV
The global warming and climate change

Temperatures
Instrumental record Satellite record last 1000 years Since 1880 paleoclimatology geological record Historical climatology

Causes
Anthropogenic
Attribution of recent climate change Aviation biofuels carbon dioxide carbon from fossil fuels to global dimming greenhouse gases global warming potential greenhouse effect of land use and forestry radiative forcing Urban heat island
Natural
Albedo Bond events Cloud forcing Glaciation Global cooling Ocean variability (AMO ENSO IOD PDO) Orbital variations variation orbital solar forcing volcanism
Models
global climate model

Opinion and controversy
Scientific opinion on the scientists Climate change is opposed to the regular assessment

Policy
Policy
United Nations Convention on Climate Change (UNFCCC / FCCC) Group Intergovernmental Panel on Climate Change (IPCC), climate change denial

Potential effects and issues
General
Climate change and agriculture Drought Economics of global warming on fisheries and climate change Glacier retreat Mass extinction depletion Mar ozone season acidification of the sea yield increased levels of the thermohaline circulation
By country
United States India, Australia

Mitigation
Kyoto Protocol
Clean Development Mechanism Joint Implementation Bali roadmap
Government
European Climate Change Programme United Kingdom Climate Change Programme coal removal
Plans
Emissions trading Personal carbon trading Carbon tax sinks carbon offsets carbon dioxide (carbon sequestration) Cap and Share
Energy Conservation
Efficient use of renewable energy renewable energy commercialization of renewable energy development Soft energy path
Other
Roundtable on G8 climate change action individual and political scenarios on climate change mitigation of climate change

proposed adjustments
Strategies
Dammed tolerance glacial lakes to irrigate rain water storage drought sustainable development investments of time control
Programs
Avoid dangerous climate change Decision land allocation system
Category: Global warming Category: Climate change Glossary of climate change Climate Change Section Index
EV
Pollution
air pollution
Acid Rain Air Quality Index global dispersion models for distillation atmospheric chlorofluorocarbons global dimming global warming indoor air quality depletion of the ozone smog particles
Water Pollution
Eutrophication parameters hypoxia environmental monitoring Freshwater Environmental Quality Pollution marine debris ocean acidification Pharmacy oil spills and personal care products anti-ship surface runoff thermal pollution runoff from urban wastewater borne diseases Water Quality Water stagnation
Soil contamination
Bioremediation The electrical heating values herbicide ground reference of pesticides (SGVS)
Radioactive contamination
Actinides in the environment The environment of radioactive fallout products nuclear fission plutonium poisoning radio background radiation in the environment of uranium in the environment
Other types of pollution
Species invasive light pollution Noise pollution &#…
Dr. Scott Johnson – The Spell And Deception Of Barack Obama 1/9

African Politics $277.5 African Politics