"The atmosphere knows
no boundaries and the
winds carry no passport."
-Sir Crispin Tickel
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The Troposphere, Pollution and Climate Change
Acid Rain
The Stratospheric Ozone Layer
What Happens on Earth as a Result of Ozone Depletion
The Good News on Ozone
Seeking Solutions to Combat Smog, Global Warming and Acid Rain
Seeking Solutions To Combat Ozone Depletion
When you consider the size of the Earth and the vastness of space,
the necessary environment for our survival-air-consists of only
a very thin layer. This layer, called the atmosphere, is the collection
of gases, vapour and particulates surrounding the Earth. Eighty
per cent of its mass lies within the lowest layer, the troposphere,
which extends to an altitude of between six and 17 kilometres
above the Earth's surface, depending on the latitude and the season.
The stratosphere above it continues to about 50 kilometres.
In spite of its importance and the relatively small space occupied
by the atmosphere, we humans are now filling it with pollutants
such as chemicals, carbon and smog. Some of these substances,
when amassed in significant quantities, can threaten life on Earth
as we know it. The first part of this chapter presents the issues
related specifically to the troposphere; the second part presents
the problems associated with the destruction of the stratospheric
ozone layer, which shields life on Earth from the dangerous rays
of the sun.
The Troposphere, Pollution and Climate Change
The atmosphere acts as a system for cycling and recycling carbon, nitrogen, oxygen and hydrogen, which are constituents of all living matter on Earth. About 99 per cent of the atmosphere is made up of nitrogen and oxygen. Living things convert these elements into sources of carbohydrates and proteins for nourishment. Our atmosphere also protects us from the threats of meteorites, which for the most part burn up as they go through the atmosphere, and from invisible threats like harmful radiation.
The air we breathe is our basic life support system; we depend on it every minute of our life. Air normally consists of 78 per cent oxygen, 21 per cent nitrogen and one per cent of assorted other gases. What we require from this air is oxygen.
Air pollution comes in many forms, but four are particularly threatening: sulphur oxides, emitted mainly by power stations and industry; nitrogen oxides, emitted by power stations, industry and vehicles; carbon monoxide, emitted mainly by vehicles; and soot and dust, known technically as suspended particulate matter (SPM), found everywhere where fuels are burnt. Industrialized countries produce most of the first three; and developing countries, which use much coal, wood and charcoal for fuel, produce the most SPM.
In large-enough quantities, smog, largely a result of industrialization, poses a severe threat to animal, plant and human life. Smog is a chemical mixture of gases that forms a brownish-yellow haze, primarily over urban areas such as Los Angeles, Bangkok and Mexico City. The airborne pollutant which makes up about 90 per cent of the smog found in many urban areas is groundlevel ozone. Other components of smog include nitrogen oxides and volatile organic compounds, sulphur dioxide, acidic aerosols and gases, and SPM.
Ground-level ozone is a result of a chemical reaction between several distinct forms of pollutants (nitrogen oxides and volatile organic compounds) and sunlight. When stagnant air masses linger over urban areas, the pollutants are held in place for long periods of time. Sunlight interacts with these pollutants, transforming them into ground-level ozone. The ozone remains in the lower atmosphere until weather systems flush out the area and dissipate it. An 'episode' of ground-level ozone can last from several hours to several days. Episodes are particularly severe in cities with high concentrations of nitrogen oxides and volatile organic compounds during periods of warm weather.
These episodes can be very harmful to human health. The health authorities in many large cities issue warnings for people not to jog or to otherwise exert themselves outdoors during these periods. Long-term exposure can affect lung elasticity and the lungs' ability to resist disease, effectively ageing lungs prematurely. Some healthy adults and children begin to experience coughing, painful breathing and temporary loss of some lung function after about an hour or two of exercise during times of peak ozone concentrations.
Air pollution affects more than human health. Monuments such as the Acropolis in Athens, the Coliseum in Rome and the Taj Mahal in India have stood intact for thousands of years-but in this century are crumbling away because of acid rain and air pollution. The blackened buildings of many cities, particularly those in Eastern Europe, stand testimony to our failure to control air pollution and to clean up properly after it.
The good news is that, according to United Nations estimates,
air pollution has improved over the past two decades-in developed
countries. The bad news is that it is deteriorating in many developing
countries. To clean up their act, developed countries have invested
heavily in technology. As a result, emissions of sulphur oxides
in industrialized countries, during the past two decades, fell
from 65 to 40 million tons a year. They have, however, increased
in the rest of the world, which is now slowly industrializing.
UNEP's Global Environment Monitoring System (GEMS) monitors air
pollution at 175 sites in 75 countries. In a recent assessment
of sulphur dioxide pollution in 54 cities, GEMS reported that
air quality is acceptable in 27 cities, marginal in 11 (including
London, New York and Hong Kong) and unacceptable in 16 (including
Rio de Janeiro, Paris and Madrid). Dust and soot levels were acceptable
in eight cities, marginal in 10 (including Toronto and Sydney)
and unacceptable in 23 (including Bangkok, Tehran and Rio de Janeiro).
Climate Change
The weather changes on a fairly regular pattern everywhere on Earth. There is variation, but range of temperatures, the amount of rain and other aspects of the weather such as monsoonal winds are similar from one year to the next. This is what is referred to as climate, which affects all aspects of life. The climate regulates the cycles of plants and animals, affects their growth and vitality, and is a principal factor in determining how they distribute themselves around the globe.
The Earth's climate is influenced by radiant energy from the sun, and by the way that energy is reflected, absorbed and re-radiated by the ground, oceans, and atmosphere. Because of a delicate interplay of numerous planetary forces, a balance is maintained between the solar energy that enters the atmosphere, and the energy that leaves it. Variations in temperature, rainfall, winds and other phenomena are caused by internal and often apparently random workings of Earth's climate system, involving interactions among the atmosphere, snow and ice, oceans and land. Sometimes sudden changes occur in the planet's climate system due to natural circumstances. Major volcanic eruptions are one example of this type of influence on our climate system. Large eruptions emit substances into the stratosphere, which block sunlight and temporarily cool the Earth's surface.
Like a greenhouse, the earth is warmed when sunlight is absorbed by the planet and transformed into heat. Much of that heat eventually escapes into space through the Earth's atmosphere. However, carbon dioxide and some other gases in the atmosphere have the ability to absorb and re-radiate this heat. Studies of the greenhouse effect have given scientists clues as to why surface temperatures of the Earth have changed over geologic time. They also explain the reasons for differences in surface temperatures on Venus, Mars and Earth. Without its natural atmospheric heat trap, the Earth's average surface temperatures would be about 30°C cooler than at present. If that were the case, life on this planet would indeed be very different.
Because climate change is such a complex issue, there is not enough concrete evidence to scientifically prove that it is occurring. However, most of the international scientific community now believes the human-caused buildup of gases in the atmosphere will ultimately lead to an enhanced warming of the Earth's surface and to significant changes in regional climates. For the first time in history, human activities are capable of altering the climate patterns around which societies are built and upon which the economic infrastructures and cultural activities of nation-states so vitally depend.
Emissions of carbon dioxide, methane, chlorofluorocarbons, halons and nitrous oxide are rapidly increasing the concentrations of natural greenhouse gases in the atmosphere, resulting in a human-induced greenhouse effect. Carbon dioxide is the single most influential greenhouse gas and, over the last century, has contributed almost two-thirds of the potential increase in the greenhouse effect. Prior to the Industrial Revolution, the presence in the earth's atmosphere of 280 parts per million (ppm) of carbon dioxide from natural causes, together with water vapour, helped determine the equilibrium temperature of our planet. Human emissions of carbon dioxide and other greenhouse gases were insignificant. Today, however, carbon dioxide levels in the atmosphere have reached over 350 ppm, a 25 per cent increase over pre-industrial times. Half of this buildup has been added in the past 30 years.
On a per-molecule basis, the global warming potential of methane is about 25 to 30 times greater than that of carbon dioxide. Ice core data show that methane concentrations have approximately doubled over the past two centuries, and that concentrations are currently higher than at any time during the past 160,000 years. A large part of the methane increase is related to agriculture. Rice paddies and domestic animals (mainly cattle and sheep) are thought to be the largest sources related to human activity, although natural gas production and delivery, coal production, landfills and biomass combustion also contribute substantially.
Because of these human-caused gases, the changing of the atmospheric processes that determine climate is taking place at a rate that is faster than has ever occurred in the Earth's known history. The level of these emissions is continuing to increase due to the rapid industrialization in many parts of the world.
Because of the uncertainties inherent in climate models and in projecting future emissions levels, predictions of future warming due to greenhouse gases are highly uncertain. Future emission levels will be tied to future population and economic growth, technological developments and government policies, all of which are notoriously difficult to project.
What is fairly well understood is that global warming will cause increased water vapour, and the melting of snow and ice. As temperatures increase, the air will hold more water vapor which in itself contributes to the greenhouse effect. As a result of global warming, climate models predict that the planet could eventually warm by an average of about 0.8 to 2.4 degrees Celsius. The best predictions of the impacts to expect from this tell us that, in addition to warmer global-averaged temperatures, many physical and biological systems will be affected. Some areas of the planet could experience catastrophic consequences. One international scientific assessment concluded that a warming of 1.5 to 4.5 degrees Celsius would cause a rise in global sea levels of 40 to 120 centimetres by the end of the next century. Such a sea-level rise would submerge many small islands, cause flooding in many coastal areas, cause salt water to enter into fresh water aquifers and destroy commercially important fishing areas.
Based on predictions of related climate variables, scientists have suggested that warming could also increase more intense or more frequent storms, including hurricanes (typhoons) and thunderstorms. Maximum sustainable hurricane intensity is a strong function of sea surface temperature and, hence, would increase with global warming. Though few hurricanes reach maximum intensity, some could be much more damaging in a warmer climate. Moreover, the region where hurricanes commonly occur could expand.
While the precise effects of climate change have yet to be determined,
what is certain is that societal stresses resulting from any changes
in natural climate systems will affect the economic, social and
political fabric of nations around the world. What also is certain
is that the productive infrastructure built during the next decade
will determine the kinds and quantities of emissions that are
released during the next sixty to one hundred years. Thus, choices
made in a variety of economic sectors today will shape the character
of the globalclimate for decades to come.
Acid rain is a direct consequence of industrial activity. Sulphur dioxide rises from burning fossil fuels and reacts with water to produce sulfuric acid. As well, the nitrous oxides found in pollution are converted into nitric acid. These substances then fall to Earth as rain and snow. The landing area of acid rain is affected by weather patterns and wind. Acid rain might fall up to 500 kilometres away from where it was actually produced.
Sulfuric and nitric acids are detrimental to all plant life. Acid precipitation burns plants, causing them to turn yellow and die. If this phenomenon occurs in a concentrated area, entire forests, and the life they support, can be killed. Because of acid rain, forests are now dying in several industrialized regions of the world, including Germany, Scandinavia, India, Russia, China, Canada and the United States.
Acid rain also destroys the ecological system of lakes and rivers. In some countries, because of acid rain, there are lakes where no ecological life can exist and where human recreational activities are prohibited. In regions where people depend on fish for survival, acid rain can cause many serious problems.
Aside from killing off entire ecosystems, acid rain also is causing the corrosion of several important national treasures and buildings as well as the weathering of structures vital to transportation systems, such as bridges.
Measurements over large areas of North America and Europe have shown that rain is often ten times more acidic there than normal. Thousands of lakes have been affected in Canada, Scandinavia, Scotland and the United States-and in many of them all fish have been killed. While acid rain used to be a problem only in developed countries, the issue is emerging in countries such as Brazil, China, India, and Jamaica.
The problem of acid rain is an example of the interconnectedness
of all environmental issues. It starts out as a waste problem
(carbon emissions), then turns into an atmospheric problem (carbon
and chemicals in the air), and then finally ends up a forestry
and land-use problem (deforestation and desertification due to
dying forests), as well as a water problem (high acid levels in
lakes).
The subject of ozone is confusing to many people. Those who live in big cities are all too familiar with the warnings of "high ozone" levels in the air. At the same time, we hear about the dangers of losing ozone, or the "hole in the ozone layer" far above us in the stratosphere. One minute scientists are telling us we have too much, the next they are warning us that we are in danger of losing it.
The fact is, there are two "types" of ozone. Their molecules are exactly the same, but their presence in different places brings very different consequences. Ground-level ozone is a pollutant and is harmful to human health. The presence of ozone in the stratosphere, in contrast, blocks most harmful solar radiation from reaching the Earth.
Ozone is a form of oxygen, similar to that which we breathe. The oxygen we breathe is made up of two oxygen molecules (O2), while ozone consists of three atoms of oxygen bound together (O3). Approximately 90 per cent of all ozone is produced naturally in the stratosphere, the greatest concentration occurring at an altitude of about 25 kilometers from the Earth's surface. This band of ozonerich air is known as the "stratospheric ozone layer." Without this layer, it would be very difficult for us to live on Earth. The unique physical properties of ozone allow it to act as our planet's sunscreen, providing an invisible filter to help protect all life forms from the sun's damaging ultraviolet rays.
Based on data collected since the 1950s, scientists have determined that stratospheric ozone levels were relatively stable until the late 1970s, when severe depletion began to appear over the Antarctic. A general downturn in global ozone levels has been observed since the early 1980s.
The primary culprits in the attack on the ozone layer are chlorofluorocarbons (CFCs) and halons. These two elements are complex synthetic compounds that contain carbon and one or more of the halogen elements-fluorine, chlorine, bromine or iodine.
For decades after the development of CFCs by Dow Chemical, they were considered the perfect chemicals. However, it is their very stability that made these substances dangerous to the ozone layer. Such industrial halocarbons are effective ozonedepleters for two reasons. The first is that they are not reactive, which means they survive long enough in the atmosphere to drift up into the stratosphere. The second is that they assist the natural reactions that destroy ozone.
Once they reach the stratosphere, Ultra Violet-C radiation (UVC) breaks up the halocarbons into chlorine (from CFCs, methyl chloroform, carbon tetrachloride) or bromine (from halons, methyl bromide). Each chlorine atom then attaches itself to an ozone molecule, forcing it to break up into an oxygen and a chlorine molecule. The sunlight then breaks this one up, again freeing the chlorine atom to attack more ozone molecules. A single chlorine atom can destroy up to 100,000 ozone molecules before it finally forms a stable compound and diffuses out of the stratosphere. Bromine acts in a similar manner.CFCs
CFCs are widely used as coolants in refrigeration and air conditioners, as solvents in degreasers and cleaners, and as a blowing agent in the production of foam. CFCs also are used for cleaning electrical circuit boards. Today, emissions of CFCs account for roughly 80 per cent of total stratospheric ozone depletion. Methyl bromide
Methyl bromide, which has been used as a pesticide since the 1960s, is said to be responsible for approximately five to 10 per cent of the depletion. Halons, which are used primarily as fire suppressants, account for only about five per cent of global ozone depletion, but the atmospheric concentration of these potent, long-lived ozone destroyers is rising by an estimated 11-15 per cent annually. Another ozone destroyer is carbon tetrachloride, which is used as an industrial solvent, an agricultural fumigant, and in many other industrial processes including petrochemical refining. Methyl chloroform, an industrial solvent used primarily to clean metal and electronic parts, also is yet another substance that threatens the ozone layer.
Unlike most chemicals released into the atmosphere at the Earth's surface, industrial halocarbons are not "washed" back to earth by rain or destroyed in reactions with other chemicals. What's worse, they can remain in the atmosphere for from 20 to 120 years or more, wreaking havoc on the ozone layer every day of their existence.
Debate over the ozone layer first began in 1974, when researchers at the University of California at Irvine identified CFC emissions as the cause for the thinning of the ozone layer. In 1985, a "hole" in the ozone layer was discovered above Antarctica. This created widespread concern. Data provided by NASA and other agencies have showed conclusively that ozone levels fall by more than 60 per cent over the South Pole during the spring months.
This hole is at times as big as the United States, and has been
growing most years since 1979. Similar drops are now being recorded
in the northern hemisphere, and the damage does not stop there:
according to recent data from UNEP, ozone levels have also diminished,
by five per cent, over the middle latitudes, where New York and
Madrid are situated, and may eventually show the greatest degree
of disintegration over the equator.
What Happens on Earth as a Result of Ozone
Depletion
When the stratospheric ozone diminishes, it allows increased UV-B (Ultra Violet-B) radiation to reach the Earth's surface. Life on Earth has evolved to tolerate normal levels of this radiation. However, exposure to UV-B radiation levels beyond the tolerable levels can cause numerous problems and could threaten the very survival of many species of life.
Although fair-skinned, fair-haired individuals are at the highest risk for skin cancer, the risk for all skin types increases with exposure to UV-B radiation. Studies predict that a one per cent drop in ozone could cause a four to six per cent rise in the number of cases of the two most common types of skin cancer. The present situation could place humans living in countries near the South Pole, such as those living in southern Argentina and Chile, in a position of increased risk. If the ozone hole continues to grow, most of the world's population could eventually be subjected to an increased risk of skin cancer.
A related but less understood problem that arises out of increased UV-B radiation exposure is the possible suppression of the human immunity system. The resulting lower immunity could make it difficult for the body to fight off infectious diseases and cancers.
Most agricultural crops are also very sensitive to UV-B radiation. Increased levels of this radiation will break down the leaves of crops, decreasing the efficiency of photosynthesis and water-use. Simulated ozone loss studies show that ozone loss of 25 per cent reduces the crop yield by 25 per cent. In the long-run, ozone depletion could reduce the productivity of many of the world's most important crops, making it difficult to meet the world's food needs.
One type of life shown to be particularly vulnerable to radiation
exposure is phytoplankton. Phytoplankton form the basis for the
entire food chain in the oceans. These aquatic organisms are dependent
on light and must live near the water's surface. Blue whales,
the largest creatures on Earth, exist from digesting phytoplankton,
the smallest creatures on Earth.
The atmospheric growth rates of ozone layer-destroying chemicals such as CFCs, carbon tetrachloride, methyl chloroform and halons are slowing down, in large measure due to the success of companies around the world to find and use alternatives.
In January 1994, for example, the MISR Foam Company in Egypt phased out 150 tonnes of CFC-11 as a blowing agent for its slabstock and molded foam. The substitute technology for the molded foam uses the water-blown system, rather than the previous chemically-based system. Before the new technology was implemented, MISR Foam Company accounted for 14 per cent of CFC consumption in Egypt in the foam sector.
In Sweden, Integralteknik, a manufacturer of polyurethane integral
skinned foams, phased out its use of HCFC, a harmful ozone layer-destroying
chemical. Its products are often used in medical applications,
and sometimes as insulation. As a substitute, the company began
using a pentane-based formula that was developed by a Danish company,
Baxenden Scandinavia. Integralteknik discovered that the new material,
besides being friendlier to the environment, also produced a stronger,
tear-resistant product.
Protect Yourself
While doing everything we can to stop the problem from getting
worse, we need to protect ourselves and our families from the
effects of ultraviolet radiation. A few simple considerations:
Seeking Solutions to Combat Smog, Global Warming
and Acid Rain
It is clear that the manner in which we think of development should be profoundly altered by the realization that our planet's atmosphere is under siege, a major result of which will be, most probably, an unprecedented climate warming and sea-level rise. Avoiding these catastrophes will require a fundamental change in the way development proceeds in both the developed and the developing worlds. Energy efficiency and increased use of renewable sources of energy must be the cornerstones of all economic development.
The solutions to the problems caused by the greenhouse effect centre upon two key areas: the reduction of gaseous emissions and international cooperation and education. Because groundlevel ozone (and smog in general) results from a combination of pollutants, heat and sunlight, the most effective way of combating it is to reduce the emissions of these pollutants (nitrogen oxides and volatile organic compounds). Since the main sources of nitrogen oxides and volatile organic compounds are vapours from hazardous products and the combustion of fossil fuels by vehicles and industry, the best way to reduce smog is to be conservative and efficient in our use of these resources.
The world has taken several steps forward in its attempts to deal with atmospheric pollution problems. Many countries have introduced tougher laws, changed to cleaner fuels and installed pollution control equipment. In this way Bulgaria, for example, managed to reduce emissions of suspended particulate matter by 1.6 million tons a year during 1976-80. Similar reductions have been made in many industrialized countries and in some developing ones, including Singapore. A witness to all this effort is the sales of pollution control equipment, which stood at US $12.7 billion in 1991-more than double the expenditure of ten years previously.
During the 1980s, two new international protocols were signed
which limit emissions of sulphur and nitrogen oxides. At the Earth
Summit in 1992, most countries agreed on a Convention on Climate
Change, to reduce emissions of carbon and other greenhouse gases.
After 14 months of complex negotiations, the Convention was signed
at the Earth Summit by more than 150 governments. This wide acceptance
was a real achievement and represents our best long-term hope
for dealing effectively with the risk of man-made climate change.
Taking Community Action
Governments and international organizations are doing a lot to address smog, global warming and acid rain. Governments, however, can not solve the problems on their own. While much needs to be accomplished at a policy level, real action must take place at the community level.
One of the primary hurdles your organization will have to deal
with in its efforts to address atmospheric problems in your community
is that there is a lack of awareness concerning the issues and
insufficient knowledge of alternative actions for those concerned
about the topic. Organizations could promote awareness of the
issues and facilitate improved education for those concerned about
them. One idea is to organize seminars bringing different sectors
of society together (developed countries, developing countries,
youth, business, scientists and politicians). A few more ideas
include:
Addressing the Individual
Actions at the individual level are important and should be encouraged
by your community organization. Individuals can help reduce smog
formation by reducing activities that cause or require the emission
of nitrogen oxides and volatile organic compounds. The most obvious
opportunities for reducing greenhouse gas emissions are in improving
the efficiency with which we meet our energy needs at home and
at work.
Seeking Solutions To Combat Stratospheric Ozone
Depletion
Ten years after the University of California discovered that stratospheric ozone loss was a problem, the world community agreed in 1985 to protect the ozone layer in the Vienna Convention for the Protection of the Ozone Layer. According to the Montreal Protocol on Substances that Deplete the Ozone Layer, which they signed two years later in 1987, developed countries must phase out CFC production by 1996. Developing countries that have signed the Protocol have a ten-year grace period to give them time to switch technologies and to stop the use of these substances. The Protocol has also set up a special fund to provide technical and financial assistance to these countries.
Replacing CFCs and halons in businesses and industries around
the world has substantial financial implications. But taking this
action is far less costly than the consequences of taking no action
at all. The governments of the world are working hard to make
changes at a policy level, but there may not be enough time for
the process to take its course. Thus, it is again up to the community
to take action and make a difference.
Taking Community Action
Governments and international organizations are doing a lot to address to the problem of the deteriorating stratospheric ozone layer. Governments, however, can not solve the problem on their own. While much needs to be and is being accomplished at a policy level, real action must take place at the community level if the problem is to be stopped.
One of the primary hurdles your organization will have to deal
with in its efforts to address atmospheric problems in your community
is that there is a lack of awareness concerning the ozone layer.
One idea is to organize seminars bringing different sectors of
society together. A few more ideas include:
Addressing the Individual
Actions at the individual level are important and should be encouraged by your community organization. Following are some key areas in which an individual can take action to minimize his or her contribution to the depletion of the stratospheric ozone layer. Some of the tips may be obviously more useful in the developed countries while others are more aptly suited for developing countries.
The best strategy for taking action to combat ozone destruction is to avoid purchasing products that contain ozone depleters. Ask before you purchase fire extinguishers, foam products, refrigerators and air conditioners. Refuse to purchase products containing ozonedepleters if alternatives are available. Write companies still using these chemicals and voice your concerns.
In some cases, however, consumer products containing ozonedepleters
are already in use in our homes and offices and cannot be easily
replaced. It is necessary in this case to take proper care of
this equipment to ensure that the CFCs they contain are never
released to the stratosphere. A few more ideas include:
References
At the Crossroads: the Multilateral Fund of the Montreal Protocol,
Friends of the Earth International, London, 1992 - A Matter
of Degrees: a Primer on Global Warming, Environment Canada,
Ottawa, 1993 - A Primer on Ozone Depletion; Environment
Canada, Ottawa, 1993 - Brundtland Bulletin, No. 9/10, The
Centre for Our Common Future, Switzerland, 1990 - Catching
Our Breath: Next Steps for Reducing Urban Ozone; U.S. Department
of Commerce National Technical Information Service, Washington,
DC: U.S. Government Printing Office, July 1989 - Choices,
the Human Development Magazine, United Nations Development Programme,
New York, April 1992 - Global Warming and Global Development,
Change: Threat or Opportunity?, Obasi, G.O.P, United Nations
Publications, 1992 - Global Warming: The Greenpeace Report;
M. Woodwell; Oxford University Press; 1990 - Global Climate
Change-Resolution and Strategies, Interparliamentary Conference
on the Global Environment, May, 1990 - Third World Guide 91/92;
Instituto del Tercer Mundo; 1990 - The United Nations Framework
Convention on Climate Change, the United Nations Conference
on Environment and Development, Rio de Janeiro, June, 1992. -
Rational Ecology, Basil Blackwell Inc., New York, 1987
- Ozone Depletion Resolution; The Interparliamentary Conference
on the Global Environment, May, 1990 - Lacoste, Beatrice; Saving
our Ozone Shield; Our Planet (UNEP) Volume 4, Number 4 1992
- Mending the Ozone Hole, Gurney, K., Institute for Energy
and Environmental Research. Tacoma, Wash., 1992 - Handbook
for the Montreal Protocol on Substances that Deplete the Ozone
Layer, United Nations Environment Programme, Nairobi, 1991
- Report on the Aerosols Products, Sterilants, Miscellaneous
Uses and Carbon Tetrachloride Technical Options Committee,
United Nations Environment Programme, Nairobi, 1991.
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