Environmental terminology

In the environmental sense, the term "accumulation" usually refers to the accumulation of substances in human or animal tissue or body fat. For example, children who breathe in large quantities of car exhaust fumes may accumulate lead in their blood. The lead comes from the exhaust fumes emitted by cars powered by petrol that contains lead. Similarly, penguins in the Antarctic have been found to have high levels of PCBs (poly-chlorinated biphenyls) in their body fat as a result of high levels of PCBs in the environment. Controls must ensure that poisons and substances that may accumulate in tissue and fat are prevented from entering food chains and are disposed of safely through recycling, destruction or containment.

ACID RAIN

Acid rain or "acid deposition" occurs when sulphur dioxide and nitrogen oxides that are released into the atmosphere by industries, towns and cities, are transported by prevailing winds and combine with water vapour or dust particles to form droplets or particles which fall back to earth. The droplets or particles fall in either a wet or a dry form. The wet form falls as acidic rain, snow, fog or cloud vapour and the dry form as acidic particles. Rain is normally slightly acidic (around pH 5.0-5.6) since it contains carbonic acid from chemical reactions in the atmosphere. However, industrial activity can push the acidity up to pH 3 (the same as that of vinegar) and even as high as 2.3 (the same as that of lemon juice), which can be about 1,000 times higher than in normal rain. Excessive acidic rain can cause environmental damage to plants and soil.
http://www.epa.gov/airmarkets

ADAPTATION

The term "adaptation" refers to the ability of different species with different genetic make-ups to cope with a specific range of circumstances such as climate, food supply, habitat, defense and movement. Specific species are adapted to specific environmental conditions, such as the polar bear that can survive only in cold, icy climates, or the giraffe, that is adapted to feed off the tops of tall trees which other browsers cannot reach. If a species' genetic diversity allows, it can also adapt to far-reaching changes in the environment. Those that cannot do this, will die out and possibly become extinct. Genetic diversity in a species is often much less where only a very small number of individuals survive and the population is re-established from these few individuals. Such a population is often not able to adapt to a changing environment.

AGENDA 21

This is the name given to the global plan of action for sustainable development agreed to at the Earth Summit by the majority of United Nations (UN) member nations in order to achieve more balanced development with a view to minimise negative environmental impacts.
The Agenda 21 document states that local governments should draw up their own Local Agenda 21s aimed at reshaping their policies, laws and regulations to fit in with the ideals of sustainable development. This includes the participation and co-operation of local communities and authorities in addressing local environmental, social and economic problems and solutions. In South Africa, metropolitan Johannesburg, Pretoria, Durban and Cape Town are all developing and running Local Agenda 21 programmes to include sustainable development and environmental management in municipal affairs and to involve the public in environmental decision making. If you live in these cities, contact your municipality to find out more about their Local Agenda 21 programmes and environmental management policies.
To find out more about Agenda 21, go to:
http://www.un.org/esa/sustdev/agenda21.htm
http://www.durban.gov.za/environment/agenda21/index.htm
http://www.cmc.gov.za/peh/soe
http://www.johannesburg.csoe.co.za

AGRICULTURE

Agriculture is the organised activity of growing food in an intensive manner in order to produce sufficient food to feed a country's population. In order to grow food, fertilisers, pesticides, genetically developed species, crop rotation and machinery are needed. Farmers must take care to ensure that their intensive farming methods do not affect the environment negatively. For example, if a farmer puts too much fertiliser onto his land, it may be washed into rivers and streams where it may cause pollution (called eutrophication), which may reduce the quality of water required for other purposes.
For more information on genetically developed species or genetically engineered food, go to:
Kids' site: http://www.oneworld.net/penguin/genetics/home.html
More advanced site: http://www.psrast.org

ALIEN VEGETATION

The term "alien vegetation" refers to plants that have been introduced from outside an area or country. Alien species are neither endemic nor indigenous. Examples of alien vegetation that are invasive include hakea (a prickly shrub or tree introduced from Australia which invades mountain fynbos) and sesbania (an ornamental shrub introduced from South America which invades river-banks, wetlands, wasteland, roadsides and ditches). Alien vegetation will often out-compete and overwhelm local species. The removal of alien vegetation is expensive, labour-intensive work which can take years to complete because of the need to keep returning to remove seedlings that emerge. It is important to plant indigenous species and to control aliens in order to conserve local species diversity and prevent the loss of important indigenous vegetation.
http://www-dwaf.pwv.gov.za/Projects/wfw

ATMOSPHERE

The "atmosphere`" is defined as the envelope of gases that extends upwards to a distance of about 1000 kilometres from the earth's surface. The earth's gravitational field prevents these gases from escaping. Air pressure and density of gas molecules decreases with altitude. At about 700 kilometres above the earth's surface there is almost a perfect vacuum.
Our concern is mainly with layers of air near the ground, called the troposphere. The troposphere has an altitude of about 7 to 9 kilometres in the polar regions and about 16 kilometres in the equatorial regions. In comparison with the lithosphere and the hydrosphere, the atmosphere is extremely dynamic.
Atmospheric air currents are driven by solar energy. The earth's tilt and rate of rotation mean that different parts of the surface receive different amounts of energy. The nature of the surface itself also influences the absorption and reflection of energy. When the air in regions of high solar input heats up, absorbed energy is moved to areas with lower energy input.

ATMOSPHERIC POLLUTION

Atmospheric pollution is caused when pollutants released into the atmosphere disturb the natural balance of atmospheric systems in various ways. These disturbances include ozone depletion, acid rain and climate change. The atmosphere is the earth�s life-support system and needs to be treated carefully. Pollutants originate from sources such as car exhausts, industries and their associated chemical processes and fires. We need to reduce atmospheric pollution as a part of our drive to become more sustainable. Continued pollution of our planet�s life-support system will have severe impacts on the quality of life and the environment of present and future generations. Atmospheric pollution causes imbalances in the atmosphere. Whilst the atmosphere seems to have the capacity for managing these imbalances, it is not known how long this capacity will last. It is important to ensure that atmospheric pollution is reduced through improved waste management and the development of cleaner production methods in industry.

AUDITS

Auditing is a process that is used to measure and evaluate how well people and systems are functioning. Normally a checklist or questionnaire is used to obtain information about the way people are doing their various jobs, whether they are doing them effectively, and whether or not those jobs could be done in a better way. For example, a school can hold a water audit to find out whether it would be possible to reduce the amount of water they are using. A factory might carry out a compliance audit to find out whether the workers are doing their jobs according to their instructions and the procedures manual. An air quality audit in a factory would look at whether the factory is measuring the emission from its stacks (chimneys) correctly, whether staff running the boilers are adequately trained, and whether the emission measurements taken form the stack have been correctly recorded for inspection by the authorities.

BACTERIA

Bacteria are single-cell organisms. They are procaryotic (which means that their genetic material is not enclosed by a nuclear membrane and they do not have mitochondria or plastids). Many are decomposers which obtain nutrients needed for survival by breaking down complex organic compounds in the tissues of living or dead organisms into simpler inorganic nutrient compounds. This is why wounds must be cleaned to prevent these organisms from living off the damaged cells of the wound and causing it to become septic or infected. If a wound is left untreated long enough, gangrene (which is an advanced form of infection) may set in and could result in limb amputation or even death. Bacteria affect humans and domestic animals. The condition known as tetanus is caused by the bacterium Clostridium tetani and is characterised by muscles becoming rigid and inflexible. Anthrax, which affects cattle and sheep, is a bacterial disease that spreads through spores and can result in Septicaemia and death in animals and humans. Some bacteria, such as cyano bacteria (previously known as blue-green algae), use sunlight (photosynthesis) to combine inorganic chemicals to make the organic nutrient compounds they need to live. Whilst in the direct human context, bacteria are often seen as a problem, they form a key part of natural ecosystems' functioning. An example of a direct link to human value is the bacteria that live on oil and hydrocarbons. These are usefull in cleaning up oil spills, especially where oil clean-up detergents cannot be used for fear of causing other environmental damage.

BIODEGRADABLE

Biodegradable substances are those that are easily broken down by living organisms such as microbes and bacteria and absorbed into the environment. Waste products that are biodegradable cause less harm in the environment since, after having been bio-degraded, their constituent parts are used by other organisms and processes in nature. Man produces waste products that can, in some cases, remain unchanged in the environment for decades. The most extreme example of this is radio-active waste which can take tens of thousands of years to break down in the environment (radio-active waste does not biodegrade, but breaks down through radio-active decay). Substances that are not biodegradable should be recycled or reused to promote sustainability.

BIODIVERSITY

Biodiversity, or biological diversity, describes the extraordinary diversity of plant, animal and insect species that exist on earth, the genes they contain, their evolutionary history and the potential they encompass and the ecosystems, ecological processes and landscapes of which they are integral parts. Each grouping of species has a different genetic make-up to cope with a specific range of circumstances such as climate, food supply, habitat, defence and movement.

Biodiversity is made up of three related concepts: genetic diversity, species diversity and ecological diversity. Genetic diversity is the variability of genes within a single species (for example, the different markings on the King Cheetah, which is the same species as the ordinary cheetah, but with a genetic variation). Species diversity is the variety of species on earth and in different parts of the planet (e.g. forests, lakes, oceans). Ecological diversity is the variety of biological communities that interact with one another and with their environments. Landscape diversity is sometimes included as a fourth concept.

To date, scientists have classified almost 2 million different species on earth. However, it is suspected that the actual number may be over 40 million, with insects accounting for as much as three quarters of that total. Diversity of species ensures ecological stability. Any reduction of this diversity directly threatens and weakens ecosystems. This is particularly true in monoculture systems of agriculture where the loss of species opens crops to a greater risk of disease and pest infestations. Loss of biodiversity represents one of the greatest environmental threats to the future of mankind. Whilst it may not be evident for current generations, future generations could be wiped out by disease and pestilence because of our inability to use the earth's natural resources in a sustainable manner and to protect the organisms on which we depend for our survival.

BIOREMEDIATION

Bioremedation is the method of using living organisms as a means of cleaning up or removing pollution from soil or water. Usually this is done using special types of micro-organisms, such as natural or bio-engineered bacteria, which convert the pollution or hazardous waste into harmless substances. Bio-remediation is being used to treat contaminated ground water where the water is pumped from underground, treated with micro-organisms which remove the pollution at the surface and then pumped back underground again. Another example is a new type of bacteria which has been specifically �bred� for the purpose of breaking down oil spills into harmless byproducts such as water, carbon, carbon dioxide and oxygen. This is a new way of dealing with waste and pollution and will probably be developed more extensively in future. Wetlands are a natural bio-remediation process which filter out most pollutants from water.
For further information on wetlands:

Rennies Wetlands Project
http://www.psybergate.com/wetfix/home.htm
South African Wetlands Conservation Programme:
http://www.ccwr.ac.za/wetlands
Wetlands International:
http://www.wetlands.org
For educational material:
http://www.epa.gov/owow/wetlands

BIOSPHERE

The biosphere consists of all living organisms that occur on earth. About 1.7 million species of plants, animals and micro-organisms have been described by scientists and placed in taxonomic lists. The actual total, however, is probably much higher. Estimates range from ten to forty million species.
The biosphere is fundamentally different from the non-living world because life continuously creates new structures and processes. This creativity is the result of the genetic mechanism characteristic of all human organisms. Variety comes from such genetic processes as recombination, chromosome rearrangement and mutation. These genetic properties give cells information on how to function and prescribe how the body is built.
The result of genetic variability and sexual reproduction is that in a population each individual has slightly different capacities to respond to the environment. As individuals interact with each other and the environment, some are better able to survive and reproduce than others. The next generation comes from the survivors and their genetic information is available to be recombined and used to instruct yet another population of individuals. This creates a force that has produced the biotic variety that we see on the earth.

CARBON DIOXIDE

Carbon dioxide is a gas that occurs naturally in the air and is produced when animals breathe, vegetation rots and when materials containing carbon is burnt or broken down. Carbon dioxide is a key component in photosynthesis, which is the major source of food on earth. In photosynthesis, carbon dioxide combines with water and sunlight (energy) to produce sugars, which in turn provide energy for plants from which they live and grow. Millions of years ago, the earth's atmosphere was mainly carbon dioxide, until plants gradually removed the gas and �fixed' the carbon in the fossil fuels, coal, oil and gas. Man is now reversing that process by releasing the carbon again through the excessive burning of fossil fuels.

CARCINOGEN

A carcinogen is any substance that is capable of causing cancer in animal tissues. Doctors and scientists do not fully understand how carcinogens cause cancer, but much is known about the kinds of substances that cause the cancers. The first carcinogenic substance to be discovered was arsenic, but many, many more have been added to the list. Substances such as beryllium, cadmium, cobalt, chromium and asbestos have been identified and the list has grown to include over 300 different major substances. Communication between workers, interested and affected parties and industry is important. In this manner full information on chemical substances being used in the workplace will become freely available. The risk of dealing with carcinogenic substances can be discussed and clearly understood.

CARRYING CAPACITY

This is the maximum number of organisms that can be supported or fed, or is able to survive in any specific habitat or ecosystem without causing the breakdown of that habitat or ecosystem. For example, the carrying capacity of a lift might be 5 people. That would be governed by the weight of those five people. Understanding the limits of an ecosystem is important when considering sustainable development, since you need to know the maximum carrying capacity in order to manage the numbers of organisms and keep those numbers below the maximum to prevent the system from breaking down. We, for example, do not know what the carrying capacity of the earth is with regard to human population, but we do know that we are stretching the limits of some of the resources that the earth needs in order to supply the requirements of mankind.

CLEANER PRODUCTION

Cleaner production refers to a philosophy of improving industrial processes and products to prevent the pollution of air, water and land, to reduce waste at source and to minimize risks to the human population and the environment. This is done by, inter alia, improving housekeeping in factories (cleaning up and tidying waste), training workers, reducing wastage, spills and losses and improving cleaning methods and systems. Cleaner Production was an initiative started by the Industry and Environment section of the United Nations Environment Programme (UNEP). The section has produced a range of publications as well as case studies and contacts to help those who wish to explore Cleaner Production in more detail. A useful website for more information is the International Cleaner Production Information Clearing House (ICPIC) at http://www.unepie.org/icpic/icpic.html The chemical industry is implementing cleaner production approaches and more information on cleaner production can be obtained from the Director of the Chemical and Allied Industries Association (CAIA) or the Manager of the Industrial Environmental Forum.
For more information on the Industrial Environmental Forum, visit:
http://www.ief.co.za

CLIMATE CHANGE

The earth's climate has naturally gone through changes through the ages. However, with the onset of increased atmospheric pollution because of man's activities and the resulting disturbance of the natural balances in the atmosphere, scientists fear that the earth's climate will change rapidly, with widespread consequences for human life. This is sometimes referred to as global warming. The earth's climate will, however, not become uniformly warmer. Some areas will experience more droughts, some areas more floods and some much colder winters. Scientists are still unsure of exactly how this will turn out, but they do agree that continued pollution will have a major impact on our climate and that pollution levels need to be drastically cut.
For more information on climate change, visit:
http://weathersa.co.za/wfacts.climchange.html
For more information on global warming, visit:
http://www.epa.gov/globalwarming
http://www.epa.gov/globalwarming/kids/index.html

COMMUNITIES

The term "communities" is used to describe two types of situations, one relating to man and the other to the natural environment. Communities in the context of man are groups of people living, working and interacting together in a manner that may result in organized activities, views and opinions. In the context of nature, the term is used mainly to describe groups of plant and animal species that live together and interact with each other in the same geographical area, for example a vleiland or wetland community.

COMPOSTING

Composting is the breaking down of organic material (plant and animal). Compost is rich in plant nutrients such as nitrogen, phosphorus and potassium and acts as a sponge to help retain moisture. Adding compost to soil and covering the soil with mulch helps to protect the soil and enable it to produce nutritious food. Using garden and household organic refuse is a way of reducing the amount of waste that has to be dumped in landfill sites and also helps to recycle waste in an environmentally friendly manner. For advice on composting, ask your local nurseryman or any keen gardener, or visit:
http://www.oldgrowth.org/compost/
For more information on urban agriculture, visit:
http://www.cityfarmer.org
http://cityfarmer.org/s.africa.html

CONSUMPTION

Any ecosystem includes both consumers and producers. Plants are 'producers' because they produce food. All animals are consumers, since they consume food in the food chain, produced by the plants. People also fall in the consumer category. This is, however, not what is generally meant by referring to consumerism within the human society. We live in a 'consumer society', which encourages us to buy more 'things' all the time. Advertisements on television, in newspapers and in magazines constantly tell us about bigger, better 'things' that we just 'have to have', but we could really cope quite well without them. The pressures of this consumer society call for huge amounts of energy and valuable resources and also tend to generate vast quantities of waste (packaging, waste from production processes and of the disposal of 'things' we no longer need). In environmental terms, this is an unsustainable approach. All the modern conveniences we use cause us to consume vast quantities of energy and non-renewable, polluting fossil fuels. We need, in the future, to develop alternative, more efficient forms of energy generation and usage and learn to re-use and recycle consumable goods in order to create a more sustainable society.
For more information on consumerism, visit:
http://www.verdant.net
http://www.oneworld.org/guides/consumerism

CONTAMINATED LAND

Contaminated land is land that is polluted or poisoned by toxic or hazardous substances. Land can be contaminated in different ways. It may be through factories being located on it and, at some stage, factory wastes either draining from the factory area into the soil, or toxic wastes being buried around the factory site. It is not only large quantities of toxic substances that contaminate land. Contamination can occur even when small quantities of waste are allowed to seep into the soil over a long period of time. This can occur, for example, when oil is not cleaned up after repeated spills. The oil drains down through the soil and contaminates both the soil and the groundwater. Land can also be contaminated through the excessive use of pesticides and fertilizers which drain off the land into rivers and also seep through the soil into the groundwater.

DEFORESTATION

Deforestation is the chopping down of not only a number of trees, but whole forests, which will never be able to regenerate again. Sustainable forestry practices involve planting at least as many, if not more trees than are removed by logging. In some countries poor people are forced to practise 'slash and burn' agriculture to grow food and in this process they strip whole areas of trees. Often these poor farmers 'overplant' the land, exhausting the soil of nutrients and rendering the land useless. As a result the people are forced to move on and chop down the next forest to start the whole process over again. Since trees absorb large amounts of carbon dioxide and in turn release oxygen, loss of forests also affects the earth's ability to cleanse and freshen the air. Loss of indigenous forests in South Africa also causes loss of biodiversity of species within the forest ecosystem.
For more information on deforestation of rain forests: http://www.ran.org

DESALINATION

Desalination is the process of removing dissolved salts from salt or brackish water to make it fit for human consumption, or for agricultural and other human purposes. Common types of desalination include distillation and reverse osmosis. Some countries in the Middle East have established desalination plants to produce fresh water for human consumption because of the desperate shortage of fresh water. Namibia has also recently announced a project to set up a desalination plant on the coast. Desalination is very expensive and is one of the last resorts to counter drought. There are about 7 500 desalination plants in the world which provide about 0.1% of all the fresh water used by man.

DESERTIFICATION

The term "desertification" is used to describe desert formation or expansion which occurs as a result of climate change, poor land use (e.g. overgrazing and intensive farming of arid land), repeated burning of natural vegetation, aggressive removal of trees, or a combination of all these factors, together with other influences. It also describes the degradation of dry but productive land to the point where the land can no longer produce food or sustain life. The United Nations Environment Programme (UNEP) classifies 90% of South Africa as dry land and extremely vulnerable to land degradation. A recent national survey suggests that 25% of all magisterial districts are already badly degraded.
For more information on desertification:
http://www.wcmc.org.uk/dynamic/desert

DISSOLVED OXYGEN CONTENT

This is an important means of measuring the �health� of a stretch of river or quantity of water by checking the concentration of oxygen. It is usually measured in mg/l (milligrams per litre). The healthier the water body, the higher the dissolved oxygen content will be, so that a level of 8 or 9 could be expected in a normal stream, whereas measurements of 4 and below indicate situations where it is very difficult for organisms to survive owing to the presence of some forms of pollution. The available oxygen is used by fish and other water organisms to survive and the more oxygen available, the better the 'health' of the water.

DONGA

"Donga" is a slang term used to describe a dry, eroded watercourse that channels water flow during heavy rains. Dongas are usually big gaping crevices in the earth which are made wider and deeper by every heavy rainfall. Dongas usually develop and worsen through poor land management practice, lack of erosion control and overgrazing. Once vegetation has disappeared from the land and is no longer able to slow down the water flow, dongas develop and cut deeply into any sloping land, causing the soil to be washed away to the sea.

DRIP IRRIGATION

This is a very economical irrigation system which delivers small quantities of water to crops close to their roots with minimal loss to evaporation or runoff. It consists of thin pipes which are punctured beneath the shadow of each plant to deliver drops of water rather than a stream or flow of water. Drip irrigation was pioneered by the Israelis, who began to grow oranges in the desert with limited water supplies. Their success in growing the world-renowned �Jaffa� oranges has encouraged many others to develop irrigation systems that deliver minimal quantities of water exactly where they are needed.
For more information on drip irrigation: http://www.cropinfo.net/drip.htm

EARTH SUMMIT

The Earth Summit, also called UNCED (United Nations Conference on Environment and Development), was held in June 1992 in Rio de Janeiro in Brazil. It was attended by more than 30 000 people, including 103 heads of state, monarchs and prime ministers.

The purpose of the Earth Summit was to set a series of objectives and establish and sign a number of conventions and treaties to address the deterioration of the global environment. Agenda 21 is one of the action plans that originated from the Earth Summit. The follow-up conference to the Earth Summit, officially known as the World Summit on Sustainable Development and popularly referred to as Earth Summit 2002 or RIO + 10, will be held in Johannesburg in September 2002.
For more information on the Earth Summit 2002:
http://www.environment.gov.za/earthsummit2002
http://www.earthsummit2002.org

ECOCATASTROPHE

The term "ecocatastrophe" describes any major catastrophe that results in a major decline or drop in biodiversity or environmental quality. It can be either natural, or the result of human activity. An example of a natural ecocatastrophe could be a major volcanic eruption resulting in lava flows, ash, clouds of dust and smoke causing serious air, water and soil pollution and destruction of vegetation, land and animals. The eruption of Krakatoa provides a good example of a natural ecocatastrophe. An example of a human-induced ecocatastrophe would be the destruction along the Cape coast caused by oil spills, or the increase in flood levels due to the overgrazing of a river's catchment area.

ECO-EFFICIENCY

The term "eco-efficiency" describes the ecological efficiency of goods and services on the basis of their economic value, which includes their consumer demand and their monetary cost, and checking this against their production or manufacturing successes in reducing environmental impact, improving quality of life and lessening the overall negative environmental impact on the earth. The higher the eco-efficiency ratio of goods and services is, the less the negative environmental impact and the lower the use and abuse of natural resources will be. We must encourage manufacturers to improve their eco-efficiency by using Life Cycle Assessments.

ECOLOGICAL FOOTPRINT

This term is used to describe the ecological impact a company or group of people have on the earth. The bigger the footprint, the worse the impact. It is a complicated measurement which includes information such as population numbers, technology used, energy consumed, water used, use of natural resources, etc. For example, a group of San Bushmen who live off the earth have a very small ecological footprint, whereas a large manufacturing plant in an industrial area would have a much bigger ecological footprint. The principles of sustainable development require of us to make our individual and collective ecological footprints as small as possible. This is not the same as carrying capacity - if an area's carrying capacity is exceeded, making the ecological footprint smaller might help to reduce the environmental impact, but when it is exceeded by too great an extent, even the smallest ecological footprint would not be sustainable.
For more information:
http://www.iisd.ca/linkages/consume/mwfoot.html
http://www.rprogress.org/progsum/nip/ef/ef_main.html

ECOSPHERE

The ecosphere (sometimes called the "biosphere") is that part of the earth's environment in which living organisms are found. The word is normally used to include the atmosphere, hydrosphere and lithosphere, i.e. the air, water and land that supports living things. The most important aspect to remember about the ecosphere is that all organisms live in balance with one another in a system that is continually evolving and changing whilst still maintaining the environment which supports the organisms' survival. This balance is called "ecological equilibrium".

ECO-TAXES

These are taxes, duties and fees that are levied by government to encourage companies and individuals to be more aware of environmental protection requirements and to reduce their level of pollution. A simple example is a compulsory government deposit on a can or bottle, which is refunded when the article is returned to the store. Some governments levy a tax on dirty industries and refund some or all of the payments if such industries implement cleaner technology or reduce their ecological footprint or negative environmental impact. If people and companies ensure that human activities have a limited negative environmental impact, there would be little need for eco-taxes.

EL NIÑO

El Niño meaning, "the boy child" or "the Christ Child" in Spanish, is the name of a warm, Pacific Ocean current which periodically flows southward along the coast of Ecuador. The current begins somewhere between Papua New Guinea and Micronesia and flows across the Pacific to Peru. The current was discovered by fishermen operating from Spanish ports in the Pacific in the 17^th century who called it "El Niño" because although it flowed irregularly, its time of flow tended to be around Christmas. The "El Niño" current may prevent the upwelling of nutrient-rich cold waters, resulting in the death of large quantities of plankton and consequently in a reduction in surface fish populations which depend upon the plankton for food. An El Niño event influences the atmospheric circulation and consequently changes climate patterns globally.

La Niña, Spanish for "the little girl", is the opposite of El Niño and is characterised by unsually warm ocean temperatures in the Equatorial Pacific. South Africa normally recieves below-normal rainfall during El Niño season, while La Niña normally brings normal or above-normal rainfall.
For more information:
http://www.pmel.noaa.gov/toga-tao/el-nino/nino-home.html
http://www.weathersa.co.za/wfacts/elnino.html

ENERGY

Economic growth, population increase and development all result in an increased need for energy. Most of the energy used in the developed and developing world today is derived from energy sources which cause significant local and global environmental impacts. For example, electricity is produced at power stations on the Highveld which burn low-grade coal, causing air pollution impacts in Mpumalanga province due to sulphur dioxide emissions. Thus, the energy is exported to Gauteng and the air pollution problem ends up in Mpumalanga. The solution is not to stop development, but rather to use energy more efficiently and to invest in new technologies for alternative energy development, such as wind and solar powered options. As individuals, we can play a major role in conserving energy by not wasting electricity. (Electricity generation creates air pollution). Recycling also saves energy, since industries often use less energy for recycling products than for creating new products. Energy efficiency can contribute towards a more sustainable society.
For more information on:
Renewable energy:
http://www.dme.gov.za/energy/renewables.htm
Solar energy:
http://www.ases.org
http://edugreen.teri.res.in/explore/renew/solar.htm
Wind energy:
http://www.icon.co.za/~sawea
http://sln.fi.edu/tfi/units/energy/windguide.html

ENDEMICS

Endemics are plant or animal species that occur only in one very specific geographical area and nowhere else on earth. If these species are endangered, they should be considered a conservation priority as they cannot be reintroduced from somewhere else once they have disappeared, but would join the ever-growing list of extinct species.

ENVIRONMENTAL AUDITING

Environmental auditing is a process used mainly in commerce and industry to measure how well environmental policies, programmes and plans are being implemented in practice. The process uses checklists and questionnaires (sometimes called "audit protocols") to understand how successfully environmental measures are being implemented and tries to help to improve systems by constructive criticism. The process depends upon the co-operation of those people being audited and should not be used merely to police their activities. Simple environmental audits can be carried out in all sorts of different situations such as schools, factories, offices and shops. Although specialists may be needed for more formal and compliance-related environmental audits, simple internal environmental audits can raise a large number of issues which can be dealt with internally and relatively easily. All that is needed are environmental policies and programmes against which to audit activities. Then a simple checklist should be drawn up which asks performance and action response questions. In the absence of specific environmental policies, use can be made of such environmental, policy tools as the International Chamber of Commerce Business Charter for Sustainable Development, http://www.iccwbo.org, or the CERES (Coalition for Environmentally Responsible Economies) Principles, http://www.ceres.org/about/principles.htm.

ENVIRONMENTAL ECONOMICS

A major problem of environmental economics has been defined as the selection of a strategy for the management of the environment which best promotes the collective welfare of society. Economists view the environment as a reservoir of natural resources (some renewable and others non-renewable). However, problems arise when the following question is asked: What is of greater value to the community - industrial development, which creates wealth, or unspoiled scenery, which creates and supports high quality of life? The question to be asked is how the private cost (to the manufacturer) of environmental pollution (usually zero) can be reconciled with the public cost (often considerable)? This underlines the inability of traditional market forces to prevent deterioration of the environment. Traditional economics theory struggles to cope with the finer aspects of environmental management because of the difficulties of pricing environmental assets and liabilities.

Economics interfaces with environment in three main areas: the environment is a source of natural resources; the environment provides "natural goods" (landscape, scenic views, wilderness, all species of wildlife), which contribute to the quality of life; and industrialised society interacts with the environment in its use (or abuse) of the atmosphere, land and oceans as dumping areas for wastes.

Numerous tools and techniques have been developed to try to sensitise the market to environmental issues. On a crude level, strategies such as the taxation of the polluter, regulation of emission by legally imposed standards, and the allocation of property rights in amenities, such as clean air and silence, are possible. One of the mechanisms used to evaluate social benefits from pollution abatement and control is the cost benefit analysis. In theory, this mechanism, which aggregates gains and losses, costs and benefits, works well, but in practice the high levels of individual judgmental inputs mean that the analysis is difficult to repeat and cannot guarantee uniformity of approach and conclusion. Elsewhere in the world environmental taxes, such as carbon taxes, are beginning to emerge as a response to the need to reduce carbon dioxide emissions. Some countries are trying to recoup environmental costs by charging licence and permit fees, which not only cover the costs of evaluating the applications, but also have built into them charges which relate to the volumes and concentrations of emissions. This strategy has been used for some time by water authorities who levy "effluent charges".

There are alternative economic theories which suggest that a capitalist approach to environmental management may be inappropriate. Some thinkers complain that "natural capital" (renewable and non-renewable) resources never appear on the balance sheet and the services that they provide are never "paid' for. For example, stack emissions are wastes which, unless there are high fees for disposal (say in the form of permits or licences to release emissions) are dumped into the atmosphere, free of charge. The Department of Environmental Affairs and Tourism has put considerable effort into developing structural bases for environmental resource economics in South Africa.
http://www.econ4env.co.za/
http://www.ranesa.co.za/

ENVIRONMENTAL HEALTH

The term "environmental health" describes those factors of human health that are determined or affected by environmental influences. Typical environmental health concerns would be the health-related aspects of water and air pollution, drinking water quality, sanitation, waste disposal, food quality and the presence of harmful chemicals. Environmental health issues vary in developed and underdeveloped countries. For example, in developed or industrialised countries, concerns relate to lead in drinking water or pesticide residues in food. However, in underdeveloped countries, the concerns would relate to more basic aspects such as conditions causing the spread of tuberculosis or dysentery, or problems relating to malnutrition, or the lack of a safe drinking water supply.

How close the link between health and the environment is, can be appreciated when we consider that the human body is really an extension of the wider environment, in constant interaction with it. For example, in our lungs only two ultra-thin membranes, thinner than one micrometre, separate our bloodstream from the air that we breathe. In the 5^th century BC the Greek doctor Hippocrates stated: "Health is the expression of a harmonious balance between various components of man's nature, the environment and way of life."

ENVIRONMENTAL IMPACT ASSESSMENT (EIA)

EIA is a process that produces a research report which examines the environmental impact (positive and negative) of a project or development on a particular area. It looks at different alternatives to a project to assist the decision makers in deciding which type of project will best suit an area or particular environment while having the least negative environmental impact. The EIA is a planning tool and can only provide guidance to decision makers such as politicians. It will present a set of alternatives indicating the benefits and drawbacks of each alternative. This will then assist the decision maker in deciding whether the project may go ahead and in what form and under which conditions it should go ahead. EIAs are now required by law in South Africa for projects that fall in certain categories. For further information on EIAs, contact your local municipality, the Environmental Affairs Department of your province, or the National Department of Environmental Affairs and Tourism.

ENVIRONMENTAL JUSTICE

Environmental Justice attempts to right the wrongs of past practises which put the poor and disadvantaged next to dirty and polluting industries or on poor and degraded land. Those past wrongs denied the people the political or economic abilities to resist or change their situation. Past apartheid policies often 'dumped' black communities near industrial areas to ensure that a labour supply was close at hand, not realising that the health of those people could be seriously affected by the smoke and effluent emissions from the factories that provided them with work. New environmental legislation will prevent this kind of situation in future.
For more information on the Environmental Justice Network Forum, go to:
http://www.botany.uwc.ac.za/inforeep/EJNF.htm

ENVIRONMENTAL MANAGEMENT SYSTEM (EMS)

Care for the environment includes concerns about how industry manufactures products and the impact that such products and manufacturing processes could have on the environment. In order to control this a documented management system is required so that everyone understands what they must do to protect the environment from pollution. There are many different types of environmental management systems. In 1996, the South African Bureau of Standards (SABS) published a code of practice, ISO 14000 (that replaces SABS Code 0251, originally published in 1993), which provides companies with guidelines and requirements for adopting an environmental policy and implementing an EMS. This code assists companies in formulating their own environmental policies and objectives. (Contact the SABS for more information.)

ENVIRONMENTAL RISK AND LIABILITY

Environmental risk describes the possibility (the technical word is the "probability") of an environmental accident (such as the spill of wastes or chemicals polluting a river) occurring. Environmental liability refers to the exposure of the responsible company or institution to the possibility or risk of an environmental accident or disaster in a given situation. (For example, a factory that has no procedures to deal with spills will have a greater environment liability in the eyes of insurance companies and the authorities than a factory that has taken precautions and made plans.) Environmental risk and liability describe the readiness and preparedness of organisations and individuals to deal with and respond to environmental disasters, problems and accidents.

EXTINCTION

"Extinction" is the term used to describe the total disappearance of a species from the earth. Extinction occurs naturally, and often as a result of environmental changes. For example, it is believed that a rapid change of climate may have been one of the causes of the extinction of the dinosaurs. Changes in the environment are also caused by man. According to certain scientists, 75% of all known mammal extinctions and 66% of all bird extinctions since 1600 can be directly attributed to man or to human activities. Examples of these causes could be destruction or modification of habitat, poisoning by man-made substances or chemicals, hunting, urbanisation or the introduction of an alien species.

FLOOD PLAINS

Flood plains are the areas next to rivers which flood when the rivers overflow their banks in times of heavy rain. Flood plains are normally very fertile areas since flooding deposits silt, which is often rich in nutrients. People like to settle on flood plains since fertile soils and flat land create optimum conditions for farming. However, floods may cause considerable damage to farms and communities living on flood plains. One of the worst examples of flood damage can be seen in Bangladesh. More than 80% of the country consists of flood plains and shifting islands of silt. Flooding during monsoons kill thousands of people every year.

FOSSIL FUELS

Fossil fuels include crude oil, coal, gas or heavy oils, which are all made up of partially or completely decomposed plants and animals. These organisms died millions of years ago and became part of the earth's crust over long periods of time. They were exposed to heat and pressure and through carbon chemistry were turned into fossil fuels and sources of energy for man. Fossil fuels are non-renewable (limited) natural resources, which means that they will run out some time in the future and that alternative energy sources will have to be found. Fossil fuels, when burnt, release gases and particles which may cause pollution if not managed correctly. Carbon dioxide, one of the gases released from burning fossil fuels, contributes towards global warming.

GEOGRAPHICAL INFORMATION SYSTEMS (GIS)

GIS is essentially a set of computer-based software systems (database and mapping techniques combined) which allow managers, decision makers and scientists to look at spatial data (information that often appears on maps) in new ways. It can be used to manage utilities such as water and sewage mains, roads and power lines, or may help to clarify the relationship between different issues 'on the ground', e.g. areas of high population and the location of amenities such as schools and clinics. Different 'sets' of data and information can be 'mixed' to see what types of overlaps or parallels there may be. It also assists in the identification of problems. For example, one set of data may map the flows of smoke from a factory chimney and, superimposed over a land use map, it would be possible to identify which residential areas would be affected by the smoke. Using the mapping capabilities of GIS information, it is possible to represent facts and circumstances in real life and make predictions about the likely outcome of changing events or different circumstances.

GEOTHERMAL ENERGY

Geothermal energy is obtained from heat sources contained within the earth. Water is heated to steam on hot rock located below ground surface and the steam is captured and drives steam turbines which generate electricity. Iceland and New Zealand both make extensive use of geothermal energy for heating and electricity generating purposes. It is regarded as 'clean' energy which does not produce significant pollutants in the form of particulates or noxious gasses. This method does, however, sometimes produce small quantities of hydrogen sulphide ('rotten egg' smell). South Africa does have a number of hot springs, but none are used for significant production of geothermal energy. Geothermal energy is an alternative energy source which conforms to many of the principles of sustainable development.
For more information on geothermal energy:
http://www.solstice.crest.org/renewables/geothermal/grc/

GLASS

Glass is a very useful substance which everybody uses regularly. It is 100% recyclable and the benefits of recycling glass are considerable. Glass manufactured by using recycled glass requires only 10% of the energy required to melt silica sand in order to manufacture virgin glass. It makes sense to recycle as much of it as possible since it will take up valuable space in landfill sites. Glass recycling may help to raise money for schools, non-government organisations and other charitable institutions. You can help to reduce glass waste by recycling it. Find out more about glass recycling by contacting the Glass Recycling Association.
Tel: (011) 827 0338
Fax: (011) 827 6944

GLOBAL WARMING

Global warming is the predicted increased warming of the atmosphere as a result of the increased accumulation of carbon dioxide in the atmosphere. The atmosphere is normally warmed when infrared radiation emitted by the earth (after being received from the sun) is absorbed by carbon dioxide and water vapour in the air. As man's activities, such as the burning of fossil fuels and deforestation (forests absorb carbon dioxide), result in the release of more carbon dioxide, more heat energy is retained by the carbon dioxide, which results in changes in rainfall and wind patterns, possible melting of ice caps and the subsequent rise in sea levels. For more information on globalwarming:
http://www.epa.gov/globalwarming/

HAZARDOUS WASTES

In order to provide for consumable products in today's society, industries often produce hazardous and dangerous byproducts which cannot be used and must be disposed of by being dumped in landfill sites. Responsible companies use properly designed and well-managed licensed landfill sites which minimise the risk of pollution to the environment. Responsible companies also try to reduce their production of hazardous wastes by looking at alternative materials, substances and chemicals which are less hazardous. Hazardous wastes that are dumped into the natural environment not only affect natural ecosystems, but are also a potential human health hazard. Hazardous wastes include substances such as asbestos (which can cause terminal lung cancer). It is an ethical and legal responsibility of industries and the government to inform communities of the hazardous substances that they may be exposed to.
For more information, visit:
http://www.epa.gov/
For educational material on hazardous wastes:
http://www.epa.gov/superfund/students/clas_act/haz-ed/hazindex.htm/

HYDROSPHERE

The hydrosphere consists of the ocean and fresh water. The ocean makes up about 71 percent of the surface area of the earth. Its mean depth is about 3800 metres. Water makes up a larger portion of the southern hemisphere than of the northern hemisphere.
Physical properties of water are dependent upon its temperature and chemistry. As water temperature decreases, its density increases. Denser water moves to the bottom of a water body under the force of gravity. As water temperature declines to 0º C, water becomes solid ice. Because ice is less dense and about 8.5 percent lighter than liquid water, it floats on the surface and the oceans do not freeze from the bottom up. If water continued to increase in density as temperature declines, most of the water on the earth would be locked up as ice. Two principal processes are involved in the movements of the oceans.
First, winds blow across the water surface and produce surface currents. Because of the earth's rotation and the presence of the continents, these currents do not move in the same direction as those of the atmosphere. Rather, they are deflected to the right in the northern hemisphere and to the left in the southern hemisphere, yielding clockwise and anticlockwise movements respectively. This is called the Coriolis effect, after Casper Coriolis (1792 to 1843), who was the first to observe it.
Second, the currents cause the water of the ocean to mix. For example, in the Atlantic Ocean the water is moved north in the surface currents and cools as it reaches the Arctic zone. Large volumes of water sink to their appropriate density level and then return south towards the equator, where they gradually warm and rise.
Seven major elements occur in sea salt, namely sodium, magnesium, calcium, potassium, chlorine, sulfur and carbon. There are 35 grams of salt per litre of water. This salinity of the sea is relatively constant over all oceans, supporting the observation that the various oceans mix. The annual flow of rivers into the oceans represents about 40,000 cubic kilometres of water. Most of the sediment carried by the rivers is deposited near shores in estuaries and coastal plains. Eventually the sand and silt is moved to the ocean by the flow of water or by wind from the land.

INDIGENOUS SPECIES

Indigenous species are plants or animals that are native to a particular area. South Africa has many such species which are found only in this country (endemics). The fynbos region is the sixth flora kingdom of the world and has thousands of endemic plants, particularly in the protea family. We also have some very special fish species, which are found in the southern Cape region and nowhere else in the world. It is important to protect indigenous species because they have evolved to cope with local conditions, circumstances or situations. For example, fynbos has evolved to cope with veld fires and many plants actually, require the heat of the fire to germinate their seeds. Many indigenous plants have been found to contain unique properties which have been used to develop specialised drugs used to save thousands of lives. All endemics are indigenous, but not all indigenous species are endemic. The Ghieliemientjie (a fish species that occurs in the Western Cape) is endemic because it is not found in any other country in the world, but the elephant in indigenous to South Africa, although it also occurs elsewhere in Africa.

INDUSTRIAL ECOLOGY

Industrial ecology is a discipline that looks at the design, development, operation and decommissioning of industrial facilities and in the process tries to imitate the functioning of natural ecosystems. It attempts to copy nature's abilities to use natural resources in the most efficient way possible and therefore reduce negative environmental impacts and encourage the principles of sustainable development. The discipline studies nature's techniques and methods and tries to copy them into man's industrial systems in the hope of lessening negative impacts and harmonising man's activities more closely with nature.

INTEGRATED ENVIRONMENTAL MANAGEMENT (IEM)

IEM is a philosophy that is concerned with finding the right balance between development and environment concerns. It provides a framework of published guidelines to ensure that environmental considerations are taken into account at every stage of the project, process or policy. The difference between IEM and Environmental Impact Assessment (EIA) is that IEM is the entire process of looking at the environment from every angle, whereas EIA is just one analytical tool which gathers the analyses of environmental information for one particular project or situation. IEM forms part of the new White Paper on Environmental Management Policy in South Africa and has also been written into the new National Environmental Management Act (NEMA) (No. 107 of 1998) and is thus formally and legally recognised.

INTEGRATED PEST CONTROL

Integrated pest control is the modern approach to managing all kinds of pests, be they insects, birds or animals. The basis of this approach is to have efficient pest control, whilst minimising the possible damage to the environment. For example, instead of using pesticides, farmers can introduce creatures that are the natural enemies of pests. This is less dangerous, reduces pollution, and makes use of nature's normal population control systems. Other methods would be to remove the nesting areas of the pests in order to encourage them to break up their flocks or move elsewhere and disperse. This approach accepts that there may be circumstances where chemical methods must be used, but such methods will only be introduced after all other methods have been investigated or tried and have failed.

INTEGRATED POLLUTION AND WASTE MANAGEMENT (IP&WM)

Integrated Pollution and Waste Management is an approach adopted by Government to deal with the current problems relating to waste management and pollution. A new framework for legislation, regulations, policies and information is being developed which will simplify pollution control and ensure better management and protection of the environment. The policies include greater transparency and better availability of pollution and environmental information to the public. A White Paper on IP & WM was published in May 2000. For further detailed information about IP & WM, contact the National Department of Environmental Affairs and Tourism, or the Department of Water Affairs & Forestry.

ISO 14000

ISO stands for "International Standards Organisation". This is an international organisation that designs and writes codes of practice (called standards) to ensure that actions and processes are carried out in a correct and uniform manner. This is especially important where operations require that equipment must be made to fit different countries' systems and the tolerance or margin for error is very small. ISO 14000 is an international standard for environmental management, which sets guidelines on how to operate environmental management systems in different companies in different countries.

There are a number of different detailed standards in the ISO 14 000 series, e.g. ISO 14 001 - Environmental Management Systems, ISO 14 010 - Guidelines for Environmental Auditing and ISO 14 040 - Life Cycle Assessment. For more information on ISO 14000 or any other ISO standard, contact the South African Bureau of Standards at 012 - 428 6991 or e-mail: masukugd@sabs.co.za

LANDFILL

Landfill is a method of waste disposal where waste is dumped into a hole, a depression or a valley. It is then compacted and covered with soil or material, such as building rubble, to keep flies away and prevent diseases from developing. Landfill sites must be carefully researched, planned and developed to prevent liquid wastes from leaching (meaning " moving down through") through the landfill site down to the base of the landfill and polluting groundwater resources. Landfill is not a satisfactory method of disposal, but has been traditionally used for many years. We should minimise our wastes, sort and recycle wherever possible, and try and waste as little land as possible on landfill sites. Once full, landfill sites cannot be built on and can only be used as parks or sportsfields.

LAND OWNERSHIP

Land ownership carries with it the very important responsibility to manage and protect the land wisely so that future generations will benefit from the land. Land ownership means respecting the form and shape of the land, preventing erosion, avoiding pollution and managing the land to prevent its loss through over-utilisation and desertification. Read about land use and abuse in articles such as the Tragedy of the Commons by Barry Commoner and books such as The Sand County Almanac and World Without Trees.

LANDSCAPE ARCHITECTURE

Landscape architecture can be described as the science, technique and art of ecological, functional and aesthetic planning and design of exterior and open spaces for human use and enjoyment and for environmental conservation and rehabilitation. In modern society the landscape architect is not only involved in the traditional function of design in relation to the aesthetic environment but also makes an important contribution to environmental planning and impact management.

LAND USE PLANNING

There are many different pressures on the use of land by man. These include the need for housing, the importance of fertile land to grow food, land for industry, land for recreation such as parks, sportsfields and nature and game reserves, and various other land uses. In order to balance the different needs and priorities, land use planning must be undertaken. Although most land use planning is carried out by the various levels of government, commerce and industry must also carry out land use planning, for example, to identify development sites that are near customers. The key to good land use planning is communication between the different land users to achieve a balance of land use and zoning that will satisfy as many people as possible.

LEVEES

Levees are raised embankments alongside the edge of a river channel, showing a gentle slope away from the channel. The levee results from periodic 'over-bank' flooding where coarser sediment is immediately deposited or dumped, while the finer sediments flow over a further distance. Over time, with successive flooding and dumping of deposits, this can result in the river flowing at a level well above the level of the outer, wider flood plain.

LIFE CYCLE ASSESSMENT (LCA)

LCA looks at the entire life cycle of a product, process or activity �from cradle to grave�, or from the first moment it was thought of until its final disposal or destruction. LCA forms a part of the philosophy that encourages holistic thinking and integrated environmental management approaches. ISO 14 040 - 'Environmental management - Life cycle assessment - principles and framework' - contains more detail on LCA. Contact the SABS for further information at 012 428 6911, or e-mail masukugd@sabs.co.za
The purpose of LCA is threefold:

To provide as complete a picture as possible of the product, process or activity and its relatioship to the environment
To add to man�s understanding of the interdependence of human activities and the environment
To provide decision makers with information that clearly defines the direct and indirect, positive and negative environmental impacts of a product, process or activity

LITOSPHERE

The lithosphere consists of the rock and the inner core of the earth below the point where living organisms are active. The lithosphere is made up of the crust and the upper mantle, which is roughly synonymous with the term "plate". The plates rest on a partially melted mantle and core, which together are called the asthenosphere. The core is thought to be made up of iron and nickel, as well as lighter elements such as sulfur and silicon. The core is believed to rotate at a faster rate than the rest of the planet.
Had we been present 300 million years ago, we would have seen the planet with a very different pattern of land and ocean than we see today. The terrestrial surface would have formed a single continent, called Pangea. About 200 million years ago this ancient continent began to break up and move in the direction represented by today's configuration of the earth's surface. Although this movement of the surface took place slowly in human terms, it demonstrates that the earth is a dynamic, ever-changing system. Not even the solid earth beneath our feet is static and unchanging. The mechanism through which lithospheric change occurs is called plate tectonics.

MARINE RESOURCES

The oceans cover over two thirds of our planet and provide many resources. South Africa's eastern, southern and western boundaries consists of coastline and therefore fishing is a major commercial industry in this country. Fish catches are limited by law as overfishing could deplete many different fish species. Many people in South Africa depend on marine resources for basic subsistence. Overutilisation of these resources means that ultimately these people will lose their livelihood. A further cause of the unsustainable use of marine resources is pollution. Hazardous substances that are dumped in oceans either accidentally (oil spills) or on purpose, can cause tremendous damage to marine life. An example of this is the Exxon Valdez oil tanker spill in Alaska in 1989 and closer to home the oil spills along the Cape coast. For more information, see:
Oil spills:
http://www.cutter.com/osir/primer.htm
http://www.oilspill.state.ak.us
http://www.uct.ac.za/depts/stats/adu/oilspill/index.htm
Coral reefs:
http://www.coral.org
General:
http://www.yoto98.noaa.gov/kids.htm
http://www.environment.gov.za/mcm

MEDICINAL HERBS

Traditional medicine and healing has used herbs as medicines for thousands of years. Over 65% of all formal medicines are based on herbal or plant-based structures or formulas. Traditional healers collect their medicinal products from the bark, roots and leaves of plants and seedlings. As a result of the tremendous increase in the demand for traditional medicines, the gatherers of these herbs have sometimes seriously impaired the chances of survival of rare or endangered species. Currently plans and programmes are under way to train and educate traditional healers to harvest their herbs more carefully to avoid wiping out stocks in the areas from which they harvest. Programmes are also under way to try to grow medicinal herbs commercially so that they may become freely available, thereby preventing extinction through overharvesting.

MULCHING

The process of mulching involves putting a layer of organic material around the base of plants or trees or over a bed of soil as a �blanket� in order to protect the soil. This is done to stop the soil from drying out or being blown away by the wind. Mulching also helps to prevent the growth of weeds that will rob plants or trees of valuable nutrients and water. South Africa has limited water resources and every technique possible should be used to save water and ensure that it is used in the best possible way. There are many different types of materials that can be used as mulch. For example, you may use dried leaves, bark chips, straw, hay, compost, shredded newspaper or cardboard (with something heavy placed on top to hold it down), mealie cobs or kraal manure.

NITROGEN

Nitrogen is a colourless, odourless gas that comprises 78% of the atmosphere. It is cycled between air and soil by means of the nitrogen cycle which includes a process known as nitrogen fixation. Nitrogen fixation may take place through either industrial (fertilisers) or natural processes. Natural processes take place when micro-organisms produce nitrogen in a reduced form as ammonia and amino groups of amino acids, which are then absorbed from the soil by plants and are used to make proteins for nutrition. Nitrogen Oxide (N₂O) is a colourless gas with a sweet odour which is used as a weak anaesthetic (�laughing gas'). Nitrogen Dioxide (NO₂) is a reddish-brown toxic gas which is one of the products of vehicle combustion and an active part of smog.

NON-RENEWABLE RESOURCES

Non-renewable resources are environmental resources that cannot be replenished. Once they have been depleted, there will be no more. Most non-renewable resources consist of minerals extracted through mining, for example gold, iron ore and titanium. Coal and oil are known as fossil fuels and although they are technically renewable through natural processes, these processes take place over such long periods that they are for all practical purposes non-renewable. Besides being significant sources of pollution, these fuels will not last forever (some scientists have suggested that the earth has only 200 years of exploitable oil reserves left at current consumption levels) and alternative energy sources will have to be found. Water is also a non-renewable resource that is often classified as renewable.

ONION WEATHERING

Onion weathering or exfoliation is a form of weathering where temperature differences between a rock and its outer layer are such that expansion and contraction cause the outer layer to peel away. This usually occurs where the difference in temperature between day and night is extreme, thereby causing considerable physical pressures during rapid cooling at dusk.

OPENCAST MINING

This is a type of mining where, instead of sinking a shaft and mining underground, the topsoil is stripped away from the surface and materials are mined from an open pit or trench. Opencast mining requires the land to be rehabilitated after mineral extraction in order to be re-used responsibly. Usually when opencast mining is undertaken, topsoil is safely stored away and protected so that when it is replaced, it still contains its seed stock to help re-established lost vegetation for soil stabilisation and aesthetic reasons. A number of mining companies in South Africa successfully rehabilitate their opencast mines to the extent that many of the mining sites can be used once again for high-grade farming purposes.

OZONE (STRATOSPHERIC)

Ozone is an unstable form of oxygen (the molecule contains three oxygen atoms) and is found in the upper atmosphere. The ozone in the stratosphere is more stable than the tropospheric ozone and forms an ozone layer roughly between 15 and 50 km above the earth. The chemistry of the atmosphere is still not fully understood, but it is known that the stratospheric ozone layer protects life on earth from the harmful effects of shortwave (UV) radiation, by absorbing most of the solar UV-B radiation. UV-B radiation in small doses causes sunburn and certain skin cancers in fair-skinned people. Excessive quantities can even cause damage and mutation in plants and other non-human organisms. The stratospheric ozone layer is being destroyed by ozone depleting substances (ODS) which consist of chemicals found in fridges, aerosols and fire extinguishers and are also released through certain industrial processes.
For more information:
http://www.weathersa.co.za/wfacts/ozone.html

OZONE (TROPOSPHERIC)

Ozone in the troposphere (0-15 km above the earth) is produced when volatile organic compounds (VOCs) such as hydrocarbons from vehicle exhausts, combine with nitrogen oxides in sunlight (called a photochemical reaction). The ozone that is formed in this manner is toxic to both animals and plants. The short-term effects of being exposed to this ground level ozone include irritation of the eyes, nose, throat and lungs. Long-term exposure may cause temporary or permanent damage to the lungs and there may be a link between excessive ozone exposure and increasing levels of lung cancer in humans.

PIONEER SPECIES

Pioneer species are the first species to colonise a new or newly denuded area. This could be an island that has emerged from the sea, or an area that has been disturbed by large-scale activity such as a volcanic eruption or man�s clearance of land for development or mining. These species include wind-dispersed microbes, mosses and lichens which grow close to the ground and establish quickly over large areas. Their basic characteristics include rapid growth, the production of copious, small, easily dispersed seed and the ability to germinate and establish themselves quickly and easily on open sites. These species are able to trigger the process of soil formation on bare rock by trapping windblown soil particles and by secreting acids which eventually break down rock. This chemical breakdown is supplemented by physical weathering. Plants that are commonly recognized as weeds are often a form of pioneer species on disturbed soils or newly cleared areas.

PLASTICS

Plastics are usually synthesised from petrochemicals and natural gas, although in South Africa most plastics originate from coal. Plastics are recyclable, but tend to attract negative attention because of their presence in litter. Stretch your imagination to come up with practical uses for used plastic. If you have any questions about plastics and their uses, contact the Plastics Federation in Midrand.

POVERTY

Absolute poverty (defined as a person living on $1 or less per day) affects 1.3 billion people (one fifth of the world�s population) and the pressure of poverty is probably the major cause of environmental degradation and pollution on earth. People who are desperately trying to find their next meal or the next sip of water do not worry about littering or soil erosion or even pollution. By removing poverty and providing potable water, work, shelter, security and good sanitation, we can free people to concentrate on improving themselves through education and awareness of their surroundings.

RADIOCARBON DATING

Carbon-14 is a radioactive isotope of carbon, which is present in minute quantities in the atmosphere. Living things such as wood and the bones of living animals absorb this carbon naturally. But when a tree is cut down or an animal dies, the absorption stops and the level of carbon-14 begins to fall as the isotope decays. Since the level of carbon-14 in living things is known and its rate of decay (its half-life) is also known, the age of the object can be calculated by measuring how much carbon-14 is left and comparing it with the original level.

Carbon-14 has a half-life of 5 700 years, meaning that half of it is converted to non-radioactive carbon in 5 700 years and every 5 700 years thereafter half of the remainder is converted. An object with exactly half as much carbon-14 as its living counterpart, therefore, died exactly 5 700 years ago. The system is accurate to within a few hundred years. But the margin of error increases with the age of the object and carbon-14 dating is not at all reliable for anything that is more than about 40 000 years old. Older fossils are usually dated by means of a similar method known as potassium-argon dating.

REHABILITATION OF LAND

The rehabilitation of land becomes necessary when man�s activities have disturbed it to such a degree that it cannot recover naturally. The best example of the value of rehabilitating land is the rehabilitation of opencast mines and quarries. Before the coal or mineral is removed, the topsoil and subsoil are stripped off and carefully stored in their different layers or horizons. Where possible, the grass or vegetation is mown or vacuumed beforehand to suck up any available seed from the natural plants in the area. After mining, heavy equipment reshapes the landform and the soils are replaced in a way that even allows for drainage and copies the natural shape of the land. The collected seeds are then dispersed over the recovered soil to reseed it. Sometimes additional work is needed to assist the natural plant species to re-establish. Once the plants have re-established, the land is once again suitable for other uses, such as agriculture.

RESPONSIBLE CARE

Responsible Care, an international chemical industry programme operating in 42 countries, promotes continuous improvement in health, safety and environmental performance. Committed companies sign a formal, public pledge which requires them to

operate in a manner which minimises negative environmental impacts;
communicate with neighbours, customers and the public on their activities;
promote the principles of sustainable development; and
provide information about their products and seek to continuously improve their knowledge and performance with regard to health, safety and environment efforts.

Responsible Care is administered in South Africa by the Chemical and Allied Industries Association (CAIA), from whom the first report on the implementation of the Responsible Care Initiative can be obtained.

SEA WATER

About 71% of the globe is covered by sea water, which supports about 250 000 species of marine organisms. By distributing heat through ocean currents, sea water is an important regulator of climate. These currents also mix and dilute human wastes to less harmful levels, provided that the quantities released are controlled. The oceans also help to regulate carbon dioxide which, through the greenhouse effect, affects the earth�s atmospheric temperature.

Evaporation from the sea forms an important part of the hydrological cycle, which supplies the scarce resource called �fresh water�, upon which many organisms on earth depend. Sea water is �salty� and contains many different types of salts. However, the primary dissolved salt in sea water is sodium chloride (table salt), with an average of 35 grams per litre.

The ocean also acts as a giant bio-geological �sink�, or exchange, for minerals and elements which cycle through the global system.

SHEET EROSION

Sheet erosion occurs when sheet flow or sheet wash transports materials in large quantities down hills and slopes. Instead of erosion occurring in flows of channel-like format, vast areas are eroded by a thin sheet of water flowing over the surface. This is made worse when the surface has been stripped of vegetation through overgrazing, erosion, or other human activities. Sheet erosion can cause considerable damage in a short space of time. Sheet erosion can be limited by maintaining vegetation on soil at all times and revegetating cleared areas as quickly as possible when stripping has taken place.

SILT

Silt is the name used to describe very fine particles of soil that are between 0.002 and 0.06 mm in diameter. Silt occurs most commonly in rivers and consists mainly of eroded materials that have been washed down rivers and, through abrasion, have become smaller and smaller. Silt can be very rich in nutrients and form fertile soils. River flood plains in mature river systems such as the Ganges delta have fertile, silty soils which people occupy, in order to farm. When the river floods, bringing with it fresh silt, disaster is inevitable and thousands of people drown or become homeless.

SOIL

Soil is a complex mixture of eroded rock, mineral nutrients, decaying organic material, water, air and millions of microscopic organisms (which form part of the process of rotting and breaking down of dead organic material and re-incorporating their nutrients into the soil). Well-developed or mature soils are arranged in a series of layers called soil horizons, each of which has a distinctive set of features and characteristics. A cross-section through these soil horizons is called a soil profile. The surface layer is called the O horizon and consists mainly of freshly fallen leaf litter, twigs and animal waste. The topsoil or A horizon comes next. The B horizon is called subsoil (this layer is found between developed soil and rocky material with some organic material and water) and the C horizon is called the parent material and consists mainly of rock. An immature soil starts off as mostly rock, which breaks down over thousands and thousands of years and accumulates organic material, is weathered and receives deposited material to eventually form a mature soil consisting of the various horizons.

STRATEGIC ENVIRONMENTAL ASSESSMENT (SEA)

SEA is an environmental assessment that is carried out on a strategic action, policy, plan or programme. Whereas an EIA studies a physical project, the SEA looks at policies, plans, ideas and programmes that are more difficult "to touch and feel". An SEA tends a wider area rather than the focussed site normally covered by an EIA. The SEA is an important planning tool since it assists planners in understanding the effects of different land uses on a specific area. The aim of an SEA is to provide information on and an analysis of the consequences of different actions and their environmental impacts in the short, medium and long terms. It is a new environmental planning tool in South Africa and has not yet been used very widely.

SUSTAINABLE DEVELOPMENT

The World Conservation Strategy ( a global plan to manage the environment) calls for sustainable development, i.e. any prospective development must not permanently damage the functioning of ecological processes or life-support systems. The World Conservation Union, in the book Caring for the Earth, defines sustainable development as "improving the quality of human life while living within the carrying capacity of supporting ecosystems". The problem is that economic systems are often not refined enough to be able to recognise or consider the delicate balances and interrelationships of nature. Ideally, man�s development systems should harmonise with nature, but in practice this is very difficult to achieve without re-organisation, additional funding and raised awareness amongst managers, industrialists and the public who generate the consumer demand. However, a great deal of progress has been made in trying to put industrial activity in line with sustainable development.
To view Caring for the Earth, go to:http://coombs.anu.edu.au/~vern/caring/caring.html
Also visit IUCN's website at: http://www.iucn.org

TERRACING

Terracing is a technique used to allow the cultivation of crops on steep slopes. Normally it is not possible to grow crops on steep slopes because of the difficulties encountered when planting and harvesting on such slopes, and since steep slopes cause erosion or cannot retain sufficient moisture to allow the plants to grow. Terraces are created by developing stepped layers down a hill which follow the contours of the land. From above, terraces look like a series of rings encircling a hill. They create a flat platform on which to grow crops and also allow water retention and an easier working space for farm workers. The most well-known examples of terracing in agriculture are the tea-growing terraces in India and the rice-growing terraces on hills in Asia.

TOBACCO

We are well aware of the health hazards of smoking tobbaco, but there are also ecological and environmental consequences involved in growing tobacco. Tobacco needs much more nutrients than other food crops. It needs over double the amount of potassium needed by coffee plants and almost eight times that needed by maize, while it uses over double the amount of nitrogen needed by the latter.

Its is estimated that between 12 000 and 50 000 square kilometres of forest are cut down annually to fuel tobacco curing barns. (The tobacco leaves are "smoked" in the process of preparing them for use in cigarettes and cigars.) Often tobacco grows best in semi-arid areas with the result that the ecological impacts it causes may also enhance the desertification process. If current trends continue, it is estimated that annual deaths relating to tobacco smoking will reach 10 million by the year 2020.

TOPSOIL AND RUNOFF

Topsoil is the layer of soil that contains organic material and provides growing space for many plants. In technical terms topsoil is described as the "A horizon" of a soil profile. It is a porous (allows water to move through it) mixture of decomposed organic matter (called humus) and some inorganic mineral particles (mostly rock fragments). It is usually darker and looser than lower soil layers and the root systems of most plants and most of the soil�s organic matter are concentrated in the topsoil. Runoff is rain-water that flows across the surface of the soil during and after rainfall. If topsoil is not protected by vegetation cover or other means, heavy rainfall and high runoff can wash away topsoil and reduce the ability of the soil to enable the growth of plants and crops. It is estimated that soil erosion and uncontrolled runoff carry away 20 billion tons of soil per annum.

TORNADO

A tornado is the most violent type of thunderstorm.
For more information on tornadoes:
http://www.weathersa.co.za/wfacts/Tornado.html
http://www.spc.noaa.gov/faq/tornado
http://www.torro.org.uk

TRENCH GARDENING

Trench gardening is a simple method of food gardening which is designed for those who have limited space, water and good soil available, although it can also be used under circumstances where these constraints are not present.

TROPICAL RAIN FOREST

Tropical rain forests appear like a girdle around the equator and occupy approximately 8% of the earth�s land surface, yet they comprise about half of all growing wood on the face of the earth and they provide habitats for at least two fifths of the earth�s total number of species. Scientists have still identified only one in six of the estimated two million species that exist in tropical rain forests. These forests also act as a �green lung� for the earth, producing the vast quantities of oxygen needed for the survival of man. These forests provide an important balance in managing the air quality of the earth we live on. Temperatures in tropical rain forests usually remain between 20 and 35 ºC all year round and rainfall typically varies from 125 to 510 centimetres per year. The soil in tropical rain forests is normally very shallow and low in nutrients. When the canopy cover is therefore removed by, for example, hardwood logging activities, the land becomes seriously degraded in a very short time and is very difficult to rehabilitate.
For more information see http://www.ran.org

VETIVER GRASS

Vetiver grass (Vetiveria zizanioides), sometimes called �Mauritius grass�, is a coarse grass that can be used as a natural barrier to prevent soil erosion. The plant is a native of India and is very versatile, being able to withstand being submerged in water during floods and also having the ability to withstand the severe pressures of drought. When planted in hedges, it acts as an erosion barrier and can prevent terraces on slopes from being damaged by heavy rainfall or mud-slides. The plant is available in South Africa and has been shown not to be invasive or damaging in any way to the soil. It is known to exist in 24 countries in Africa, 13 in Asia and 11 in the Americas. The plant is able to function as a natural engineering resource without causing ecological damage or interference with natural systems. For more information on vetiver grass, contact the Southern African Vetiver Grass Network:
http://www.inr.unp.ac.za/vetiver

VOCs or "volatile organic compounds"

VOCs are primarily the lighter �fractions� of oil or hydrocarbons (i.e., the parts that evaporate easily because they have a low boiling point). Some of these products are used because of their evaporating or �quick-drying� characteristics. Most VOCs are carbon-hydrogen compounds (hydrocarbons) but they also include aldehydes and ketones. Emissions come, for example, from households (cleaners, cosmetics, lacquering), the metal industry (paints and coatings), the printing industry (inks and cleaners), oil refineries (loading, storage and transfer of hydrocarbons products), petrol stations (the pumping of petrol) and the dry-cleaning industry (cleaning solvents). Tropospheric ozone forms as a result of photochemical (sunlight) reactions between nitrous oxides and VOCs and this can be hazardous to health in peak concentrations. Various countries (e.g. the European Union, with the Netherlands in the forefront) are now attempting to control the release of VOCs by setting various reduction targets.

VOLCANO

Apart from releasing varying quantities of lava, volcanoes can be nature�s most visible and drastic �natural� polluters of the atmosphere. In extreme cases, they eject vast quantities of gases such as sulphur and nitrogen oxides and particulate matter, usually soot and mineral ash, high into the troposphere. The tiny droplets of sulphuric acid (acid rain) may stay in the atmosphere for periods of up to three years. One of the most spectacular and devastating volcanoes known to man was Krakatoa, a volcanic island adjoining Indonesia. In August 1883, the climax of a series of blasts over a four-month period was heard 3 500 kilometres away and ash was propelled some 80 kilometres into the air. The surrounding region was plunged into darkness for two and a half days and a fine ash continued to fall around the world for at least two years afterwards. 21 cubic kilometres of rock fragments were spread over an area of 800 000 square kilometres. The blast triggered a tidal wave 40 metres high, which killed 36 000 people in its path.
For more information on Volcanos:http://volcano.und.nodak.edu

WASTE REDUCTION

One of the best ways of solving the problem of excess hazardous and normal waste is to practise waste reduction. This involves changing aspects of manufacturing processes or substituting polluting products with less polluting or non-polluting products. The 3M company in the USA, over a 10-year period, eliminated 10 000 tonnes of water pollutants, 90 000 tonnes of air pollutants and 140 000 tonnes of sludge, saving over $192 million at the same time. In homes, schools and offices, waste reduction can also be done in simple ways, for instances by using both sides of each sheet of paper and sending it for recycling when it is no longer needed. Another idea is to use plastic margarine tubs for storing things instead of throwing them away.

WATER

Water is essential for human survival. Each person needs at least 5 litres per day to meet his minimal physiological needs. A reasonable quality of life requires about 80 litres per person per day, while wealthy Americans use over 500 litres per day. Humans also use water for transporting themselves and their goods, for irrigating crops, cooking food and washing themselves and their clothes. Industries need water as a coolant, a dilutant for pollution, a solvent and a means of transporting wastes away. Fresh water is taken for granted when it comes from a tap. You would appreciate water all the more if you had to fetch what you needed for the day and carry it up to 15 kilometres from the river to your home! Remember that there are still people in South Africa and other countries who do not have access to piped fresh water. Don�t waste it!
For more information on water conservation: http://www.sawac.co.za

WEATHER

The term "weather" is used to describe the condition of the atmosphere at a particular place and time. Atmospheric conditions are expressed and described in terms of temperature, humidity, type and amount of precipitation (rain, snow, hail, drizzle, sleet, etc.), wind (speed, type and direction), air pressure, cloud cover and visibility. By collecting information on all of these, it is possible to analyse and predict future weather conditions. Human activities may affect air quality and weather conditions. For example, heavy pollution may affect the amount of sunlight reaching the ground, increased pollution may affect the acidity of rain, increased urbanisation may create �hot spots� where the concrete of cities absorbs heat and changes the climate within a city by changing the temperature, pressure and humidity condition. By releasing carbon dioxide into the atmosphere, man can increase the mean temperature of the earth through a phenomenon known as global warming.
For more information: http://www.weathersa.co.za

WORLD WIDE FUND FOR NATURE (WWF)

The WWF is the world�s leading non-governmental conservation organisation consisting of 27 national organisations, 6 associate organisations and 22 programme offices. The South African branch of the WWF (which used to be called the Southern African Nature Foundation) was established in 1968 by Dr Anton Rupert. Since that date, it has raised over R260 million for over 830 conservation projects in Southern Africa. The WWF also coordinates the Green Trust Awards, which are aimed at recognising people and projects that support and protect the environment. Contact the WWF to find out how you can help.
For more information about their activities, go to http://www.panda.org.za

ZERO POPULATION GROWTH

The term "zero population growth" describes a situation when a population remains stable because the total number of human births equals the total number of human deaths on earth, or in any given geographical area. Zero population growth will only be achieved if family planning becomes a way of life and the importance of contraception is instilled into the earth�s inhabitants. Zero population growth will not be enough to control and reduce the global environmental crisis. The growing use of resources, as people demand a better quality of life with electricity, household appliances, bigger houses, more goods and more material possessions, puts pressure on the earth.