Protection of the ozone layer
Friday, September 17, 2010 AT 02:30 PM (IST)
The date 16th Sept. 2010 is known as "World Ozone Day". Kindly read it seriously & try to keep alive the world.
What will happen... if the Ozone layer would vanish from environment?
Protection of the ozone layer
The ozone layer is a layer of gas in the upper atmosphere which protects humans and other living things from the harmful ultraviolet (UV-B) rays of the sun. In the 1970s scientists discovered that certain man-made chemicals could destroy ozone and deplete the ozone layer. Further research found that the growing production and use of chemicals like chlorofluorocarbons (CFCs) in aerosol sprays, refrigeration, insulation and air conditioning was contributing to the accumulation of ozone-depleting substances (ODS) in the atmosphere. They also observed that an ozone hole was developing above the Antarctic.
A thinning ozone layer leads to a number of serious health risks for humans. It causes greater incidences of skin cancer and eye cataracts, with children being particularly vulnerable. There are also serious impacts for biodiversity. Increased UV-B rays reduce levels of plankton in the oceans and subsequently diminish fish stocks. It can also have adverse effects on plant growth, thus reducing agricultural productivity. A direct negative economic impact is the reduced lifespan of certain materials like plastics.
Severe depletion of the Antarctic ozone layer was first observed in the early 1980s. The international response embodied in the Montreal Protocol. Today 196 parties worldwide have signed the Montreal Protocol which is widely regarded as the most successful Multinational Environmental Agreement and it is the first treaty achieving universal ratification.
Furthermore, the phasing out of ozone depleting substances (ODS) has helped to fight climate change since many ODS are also powerful greenhouse gases.
The ozone layer protection policy of the EU and its Member States is even more ambitious than the Montreal Protocol.
While the Montreal Protocol has made great strides in the global effort to protect the ozone layer, the task is far from being complete. Despite all efforts substantial recovery of the ozone layer is not expected before the middle of the 21st century.
Hence there is the need for new impetus on negotiations to fight the challenges still ahead.
The ozone layer
Although ozone (O3) is present in small concentrations throughout the atmosphere, most ozone (about 90%) exists in the stratosphere, in a layer between 10 and 50km above the surface of the earth. This ozone layer performs the essential task of filtering out most of the sun's biologically harmful ultraviolet (UV-B) radiation. Concentrations of ozone in the atmosphere vary naturally according to temperature, weather, latitude and altitude. Furthermore, aerosols and other particles ejected by natural events such as volcanic eruptions can have measurable impacts on ozone levels.
The Ozone Hole
In 1985, scientists identified a thinning of the ozone layer over the Antarctic during the spring months which became known as the "ozone hole". The scientific evidence shows that human-made chemicals are responsible for the creation of the Antarctic ozone hole and are also likely to play a role in global ozone losses. Ozone Depleting Substances (ODS) have been used in many products which take advantage of their physical properties (e.g. chlorofluorocarbons (CFCs) have been used as aerosol propellants and refrigerants).
ODS are broken down by sunlight in the stratosphere, producing halogen (e.g. chlorine or bromine) atoms, which subsequently destroy ozone through a complex catalytic cycle. Ozone destruction is greatest at the South pole where very low stratospheric temperatures in winter create polar stratospheric clouds. Ice crystals formed in these clouds provide a large surface area for chemical reactions, accelerating catalytic cycles. The destruction of ozone also involves sunlight, so the process intensifies during spring time, when the levels of solar radiation at the pole are highest, and polar stratospheric clouds are continually present. Although ozone losses are less radical in the northern hemisphere significant thinning of the ozone layer was also observed over Europe.
While ozone levels vary seasonally, overall stratospheric ozone levels have been decreasing since the 1970s. Mid-latitudes have experienced greater losses than equatorial regions. In October 2006 the largest Antarctic ozone hole observed to date covered 27 million km2. Over the Arctic the ozone loss in the winter 2004/2005 was among the largest ever diagnosed and significant ozone loss was also observed over Europe.
Environmental and Health Effects
The amount of UV reaching the earth's surface has been shown to correlate with the extent of ozone depletion. Increased UV levels at the earth's surface are damaging to human health, air quality, biological life, and certain materials such as plastics. Human health effects include increases in the incidence of certain types of skin cancers, cataracts and immune deficiency disorders. Increased penetration of UV results in additional production of ground level ozone, which causes respiratory illnesses. Biologically, UV affects terrestrial and aquatic ecosystems, altering growth, food chains and biochemical cycles. In particular, aquatic life occurring just below the surface of the water, where plant species forming the basis of the food chain are most abundant, are adversely affected by elevated levels of UV radiation. The tensile properties of certain plastics can be affected by exposure to UV radiation. Depletion of stratospheric ozone also alters the temperature distribution in the atmosphere, resulting in indeterminate environmental and climatic impacts.
Despite existing regulation of ODS, there continues to be severe ozone depletion and maximum stratospheric levels of chlorine and bromine are predicted to occur only during the next decade. Without further measures the ozone hole will continue to exist beyond 2050. However, the success of the Montreal Protocol has already been observed in terms of changes in the concentrations of man-made chlorine-containing chemicals in the troposphere (i.e. the rates of release of ODS to the atmosphere have been reduced). Additional measures are currently being proposed by the European Commission for domestic actions and on international level to accelerate the phase out of various ODS and thereby to provide much-needed additional protection for the ozone layer.
What you can do to protect the Ozone Layer
You have already taken the first steps to help protect the ozone layer by informing yourself of the problem and its causes. Try to find out as much as you can about the problem from publications, schools or public libraries. The only way to mend the ozone hole is to stop the release of ozone depleting substances (ODS) into the atmosphere. European legislation aims to achieve this by phasing out ODS as soon as viable alternatives become available, and where no such alternatives are available, restricting the use of these substances as far as possible. However, there are a number of practical initiatives which can be taken at the individual level to help protect the ozone layer:
1) Make sure that old refrigerators and air conditioners are disposed off safely by giving it to a recycling yard without damaging the cooling circuit
2) Ensure technicians repairing your refrigerator or air conditioner recover and recycle the old ODS so they are not released into the atmosphere.
3) When renovating your house make sure that old insulation foams containing ODS are disposed of as environmentally hazardous waste
4) Suggest school activities to increase awareness of the problem and to initiate local action.
Protecting yourself from UV Radiation
There is a direct link between increased exposure to UV radiation and elevated risk of contracting certain types of skin cancers. Risk factors include skin type, sunburn during childhood, and exposure to intense sunlight. Recent changes in lifestyle, with more people going on holiday and deliberately increasing their exposure to strong sunlight, are partly responsible for an increase in malignant skin cancers. In order to minimise the risk of contracting skin cancer, cover exposed skin with clothing or with a suitable sunscreen or sun cream, wear a hat, and wear UV-certified sunglasses to protect the eyes.
International challenges ahead
Much has changed since the international community first agreed over 20 years ago to take action to control ozone-depleting substances (ODS). Continuing scientific research has further revealed the scale of the problem, which in many cases is bleaker than previously believed. But this has also brought about alternatives and new solutions. The Montreal Protocol will and must continue to adapt in light of new scientific information.
The latest information from the Scientific Assessment Panels report in 2006 found that, even if complying with all present control measures, Antarctic ozone will only return to its previous levels some time between 2060 and 2075, up to 25 years later than earlier estimates. Meanwhile the solutions put in place to combat ozone depletion have created their own set of challenges such as illegal trade which in turn require an international response. In recent years, attention focused more in strengthening the implementation of control measures, a work that will need to be intensified to address various issues that have emerged.
Critical/essential uses: The overall quantity of methyl bromide used globally in soil fumigation has gone down substantially. However, sectors where no technically or economically feasible alternatives are available are still exempt from the rules.
A number of medical applications, for example for treating asthma and other bronchial diseases are still exempt from the rules on CFCs. Alternatives have now been developed in some countries (including almost all EU countries), but incentives must be introduced to make the technology more widespread, particularly in developing countries.
Addressing the alarming growth of HCFCs: Production and consumption of HCFCs in developing countries is set to double from there current levels, despite the already agreed 2016 freeze date and 2040 phase out date. HCFCs represent about 60 percent of the remaining ozone depleting substances in industrialized countries with overall quantities steadily decreasing. The bulk of currently achieved decreases are due to EU regulation which has a use ban in place well ahead of the 2030 phase-out date applying to industrialized countries. To avoid a further delay in the recovery of the ozone layer, there is a need to address this alarming increase by moving forward the current phase out schedules.
Illegal trade : There is evidence of a significant black market in ODS, with a flow of trade from chemical producers in certain emerging market countries to western companies. Currently, there is insufficient sharing of license information between the parties and there remain significant discrepancies between data declared by importing and exporting countries.
Banks : Although the use of chemicals such as CFCs in spray cans, refrigerants and insulation has been largely phased out, there are still vast quantities of these chemicals that can be found in old equipment and buildings. These represent a threat to the timely ozone recovery as well as a significant global warming potential (estimated to amount to about 3.5% of the total greenhouse gases emissions). Action is required to ensure that they are collected and disposed of safely.
Compliance : Although some countries are going beyond their Protocol commitments, compliance is still a major issue in many countries.
Assessment : Action is needed to assess new substances in light of the latest scientific information on their ozone depleting potential and on whether they need to be added to the list of controlled substances.
Exemptions for quarantine/Pre-shipment : To ensure that goods for export are pest free, the numbers of quarantine and pre-shipment (QPS) applications are increasing rapidly in a number of areas. These applications continue to rely heavily on Methyl Bromide although more and more alternatives are becoming available. The EU would like all countries to address this problem.
Linking ozone and climate policies: The link between ozone and climate change must be addressed more fully. There is increasing evidence that changes in climate, ground temperature, levels of greenhouse gases and water vapour in the atmosphere will influence the recovery of the ozone layer.
Increasing synergies across multilateral environmental agreements: Where possible, increased synergies should be pursued between the Montreal Protocol and other international or multilateral environmental agreements (MEAs) such as the Kyoto Protocol on climate change, the Stockholm Convention on Persistent Organic Pollutants (POPs), the Basel Convention on waste, the International Plant Protection Convention (IPPC) and the Rotterdam Convention on chemicals.