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climate change > glossary
GlossaryAgenda 21: A document accepted by participating nations at UNCED on a wide range of environmental and development issues for the 21st century.
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Anthrogenic effects: Effects which result from human activities such as the burning of fossil fuels or deforestation.
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Atmosphere: The envelope of gases surrounding the Earth and other planets. Many of these gases are involved in chemical cycles such as the nitrogen and carbon cycles that sustain life on Earth and shape the planet's habitability. Nitrogen, oxygen, and water vapour make up more than 99% of the atmosphere, while so-called trace gases including carbon dioxide, methane and other "greenhouse" gases constitute the remainder.
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Atmospheric pressure: The pressure of atmospheric gases on the surface of the planet. High atomspheric pressure generally leads to stable weather conditions, whereas low atmospheric pressure leads to storms such as cyclones.
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Business-as-usual: The scenario for future world patterns or energy consumption and greenhouse gas emissions which assumes that there will be no major changes in attitudes and priorities.
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Carbon cycle: The exchange of carbon in various forms between the atmosphere, the land and the oceans.
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Carbon dioxide (CO2): One of the major greenhouse gases. Human-generated carbon dioxide is caused mainly by the burning of fossil fuels.
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Carbon sink: Repository for carbon dioxide (CO2) removed from the atmosphere. Oceans appear to be major sinks for storage of atmospheric
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Carbon tax: A policy that would tax fossil fuels according to the amount of carbon they contained. This would reduce the demand for fossil fuels in general and cause a realignment away from coal to less polluting natural gas, or renewable sources of energy.
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Celsius: The Temperature scale, sometimes known as centigrade scale. Its fixed points are the freezing point of water (0o and the boiling point of water (100oC).
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CFC�s (Chlorofluorocarbons): A group of chemicals containing chlorine (Cl), fluorine (F) and carbon (C), sometimes referred to by their trade name Freon. These synthetic compounds were used extensively for refrigeration and aerosol sprays until it was realized that they destroy ozone (they are also very powerful greenhouse gases) and have a very long lifetime once in the atmosphere (more than 100 years). The Montreal Protocol agreement of 1987 has resulted in the scaling down of CFC production and use in industrialised countries.
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Climate: Climate the average weather in a particular region.
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Climate models: Elaborate computer programs that simulate the interplay of the sun's energy with the Earth's land surface, oceans, and atmosphere. By changing equations in the program that represent factors such as the mix of gases in the atmosphere or the snow and ice on the Earth's surface, scientists can investigate how the Earth's climate (rainfall and temperature patterns) might change over time in response to human activities.
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Climate sensitivity: The global average temperature rise under doubled carbon dioxide concentrations in the atmosphere.
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Coal: A black or brown combustible material composed of carbon (C), various carbon compounds and other materials such as sulphur (S). The most abundant of the fossil fuels, it was formed through the accumulation of vegetable matter over millions of years in environments (e.g. swamps, deltas) which reduced the rate of decay of the organic material and allowed the preservation of the solar energy to absorbed by it when it was growing. When coal is burned, it is that energy which is released.
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Conservation (nature): Protection against irreversible destruction and other undesirable changes, including the management of human use of organisms or ecosystems to ensure such use is sustainable.
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Coral bleaching: Occurs when coral organisms (polyps) die or migrate away from a coral reef to the extent that it loses colour. Mass-bleaching events have been associated with small increases in sea temperature.
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Deforestation: Cutting down forests; one of the causes of the enhanced greenhouse effect, not only when the wood is burned or decomposes, releasing carbon dioxide, but also because trees previously took carbon dioxide from the atmosphere in the process of photosynthesis.
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Development: A process of economic and social transformation that defies simple definition. Though often viewed as a strictly economic process involving growth and diversification of a country's economy, development is a qualitative concept that entails complex social, cultural, and environmental changes. There are many models of what 'development' should look like and many different standards of what constitutes 'success'.
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Ecology: Originally defined by Ernst Haeckel in 1866, ecology is the study of the relationships that develop among living organisms and between these organisms and the environment.
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Ecosystem: A distinct system of interdependent plants and animals, together with their physical environment.
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El Ni�o/Southern Oscillation (ENSO): El Ni�o is the name originally given by local inhabitants to a weak warm ocean current flowing along the coast of Ecuador and Peru. ENSO is an extensive, intense, atmospheric and oceanic phenomenon affecting the tropical Pacific Ocean. It is associated with major anomalies in atmospheric circulation and rainfall patterns. El Ni�o occurs irregularly, but approximately every four years on average. ENSO events have impacts on fisheries, bird life and mainland weather.
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Environment: A combination of the various physical and biological elements that affect the life of an organism. Although it is common to refer to �the� environment, there are in fact many environments eg, aquatic or terrestrial, microscopic to global, all capable of change in time and place, but all intimately linked and in combination constituting the whole earth/atmosphere system.
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Environmental pollution: The contamination of the physical and biological components of the earth/atmosphere system to such an extent that normal environmental processes are adversely affected.
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Environmental refugees: People forced to leave their homes because of environmental factors such as drought, floods, sea-level rise.
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Environmentally-sound: The maintenance of a healthy environment and the protection of life-sustaining ecological processes. It is based on thorough knowledge and requires or will result in products, manufacturing processes, developments, etc. which are in harmony with essential ecological processes and human health.
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Eutrophication: The occurrence of high nutrient levels in freshwater and marine ecosystems, usually resulting in excessive plant growth and the death of animal and some plant life due to oxygen deprivation.
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Flood: The inundation of normally dry land by water. Flooding causes millions of dollars'-worth of property damage and takes hundreds of lives each year. It is most common in river valleys or along the coastal areas of lakes, seas and oceans. River floods are caused when a river channel is incapable of carrying the volume of water added to it, and the excess spills over on to the adjacent floodplain. Heavy and prolonged precipitation, snowmelt, channel constrictions, dam failures and alterations to drainage basins may produce or contribute to flooding. Global warming through the increased melting of glaciers and ice sheets, and the subsequent rise in sea level, has the potential to increase the frequency and extent of coastal flooding.
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Fossil fuels: Fuels such as coal, oil and gas made by decomposition of ancient animal and plant remains which give of carbon dioxide when burned.
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Fuel cells: Fuel cells are electrochemical devices that convert a fuel�s energy directly to electrical energy through a chemical reaction instead of combustion. Fuel cells operate much like continuous batteries when supplied with fuel to the anode (negative electrode). Fuel cells forego the traditional extraction of energy in the form of combustion heat, conversion of heat energy to mechanical energy (as with a turbine), and finally turning mechanical energy into electricity (e.g. using a dynamo). Instead, fuel cells chemically combine the molecules of a fuel and oxidizer without burning, dispensing with the inefficiencies and pollution of traditional combustion.
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Global warming: The idea that increased greenhouse gases cause the Earth�s temperature to rise globally.
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Greenhouse effect: The cause of global warming. Incoming solar radiation is transmitted by the atmosphere to the Earth�s surface, which it warms. The energy is retransmitted as thermal radiation, but some of it is absorbed by molecules of greenhouse gases instead of being retransmitted out to space, causing the temperature of the atmosphere to rise. The name comes from the ability of greenhouse glass to transmit incoming solar radiation but retain some of the outgoing thermal radiation to warm the interior of the greenhouse. The �natural� greenhouse effect is due to the greenhouse gases present for natural reasons, and is also observed for the neighbouring planets in the solar system. The �enhanced� greenhouse effect is the added effect caused by the greenhouse gases present in the atmosphere due to human activities, such as burning of fossil fuels and deforestation.
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Greenhouse gas emissions: The release of greenhouse gases into the atmosphere, causing global warming.
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Greenhouse gases: Molecules in the Earth�s atmosphere such a carbon dioxide (CO2), methane (CH4) and CFCs which warm the atmosphere because they absorb some of the thermal radiation emitted from the earth's surface.
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Hydrological cycle: The natural cycle by which water evaporates from the oceans and other water bodies, accumulates as water vapour in clouds, and returns to oceans and other water bodies as precipitation. Precipitation over land has two components: runoff and moisture from evapotranspiration.
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Ice cores: Columns of ice, usually up to 100 metres long, removed from ice sheets or glaciers and analysed to provide evidence of past environmental conditions.
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Industrial revolution: A historical transition that began in England in the eighteenth century, when the use of coal both in steam engines and for iron smelting enormously increased industrial output. Industrial technologies and the use of fossil fuels quickly spread to other nations, generated unprecedented industrial growth, and changed fundamentally the human use of resources and impact on the local and global environment.
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Industrialization: A development path based on expanding a country's capacity to process raw materials and manufacture products for consumers, businesses, and export. This approach to development, first seen in northern Europe in the Industrial Revolution typically entails heavy financial investment in factories and power plants and a rapidly growing demand for energy, particularly fossil fuels.
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IPCC: Intergovernmental Panel on Climate Change - the world scientific body assessing global warming.
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Methane: A simple hydrocarbon gas (CH4) produced during the decomposition of organic material under anaerobic conditions. It is the main constituent of natural gas and therefore and important fuel.
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Monsoon: Particular seasonal weather patterns in sub-tropical regions which are connected with particular periods of heavy rainfall.
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Montreal Ozone Agreement: An agreement signed by 24 nations in 1987 (and since then endorsed by more than 30 others), that set a timetable for the reduction of chlorofluocarbon and halon production levels by 50 per cent by the year 2000 to control damage to the ozone layer. The Montreal Ozone Agreement is considered a model of the global environmental diplomacy needed to address the more complex issue of the greenhouse effect.
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Montreal Protocol: The International agreement signed in 1987 to limit the production and emission of substances that deplete the stratospheric ozone.
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OPEC: Organisation of Petroleum Exporting Countries. A group of Middle Eastern, Asian, African and Latin American nations that includes the world�s major petroleum producers and exporters. They came together in 1960, recognising the importance of oil as a source of future development, and with the intention of using their petroleum resources to advance their economic interests.
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Ozone: Form of the element oxygen with three atoms instead of two that characterise normal oxygen molecules. Ozone (O3) is an important greenhouse gas. The stratosphere contains 90 per cent of all the O3 present in the atmosphere that absorbs harmful utltra violet radiation. In the troposphere, O3 is a secondary air pollutant that has adverse impacts on health.
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Ozone: An unstable and chemically-reactive gas containing three oxygen atoms, formed at high altitudes by the action of sunlight on molecular oxygen. Present at low concentration in the stratosphere, ozone absorbs ultraviolet radiation from the sun and reduces the amount of this damaging radiation that reaches the Earth's surface. Ozone is also formed at ground level - by the interaction of sunlight with exhaust gases from automobiles and industry, and by the action of sunlight on nitrogen oxides and hydrocarbons-where it is a primary component of smog that aggravates breathing problems and damages plants.
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Ozone hole: A region of the atmosphere over Antarctica where, during spring in the southern hemisphere, about half the atmospheric ozone disappears. The Ozone layer protects the earth�s surface from the effects of excess ultraviolet radiation. However, the growth in the volume and use of ozone-destroying chemicals, such as CFCs, has depleted the layer, allowing greater amounts of ultraviolet radiation to pass through to the earth�s surface, raising fears of the increased occurrence of skin cancer, eye damage and genetic mutation in terrestrial organisms. (Recently scientists have decreases of 10-20 per cent in ozone over the Arctic).
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Ozone hole: A popular name given to a phenomenon discovered in 1987, when scientists measured unexpectedly low ozone concentrations in the stratosphere above the South Pole during the Antarctic spring. It is now generally accepted that the loss of stratospheric ozone is caused by chemical reactions initiated by chlorofluorocarbons.
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Petrochemicals: Chemicals derived from oil and natural gas � for example, ethylene, propylene, toluene � which act as feedstocks for the manufacture of products such as plastics, pesticides, fertilisers, antiseptics and pharmaceuticals. Petrochemicals play a very important role in modern society, but they also create pollution problems. Plastics are a major component of solid waste, for example, fertilisers contribute to eutrophication of lakes and rivers and pesticide residues in food and water present health problems.
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Petroleum: A mixture of naturally occurring hydrocarbons, that may exist in a solid (e.g. bitumen), liquid (e.g. crude oil) or gaseous state (e.g. natural gas). It commonly contains variable amounts of other chemicals such as sulphur (S) and nitrogen (N). Petroleum is the end-product of the partial decay of living organisms which once inhabited the world�s oceans. As they died they sank to the bottom of the oceans, where the anaerobic conditions allowed them to be preserved.
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Pollution: An undesirable contaminate (gas, liquid, noise, solid) which has been released into, and is now a part of, the environment.
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Precautionary principle: The principle of prevention being better than cure, applied to potential environmental degradation.
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Renewable energy: Energy sources which are not depleted by use, for example, hydro-power; PV solar cells, wind power and coppicing.
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Sequestration: Removal and storage, for example, carbon dioxide taken from the atmosphere into plants via photosynthesis, or the storage of carbon dioxide in old oil or gas wells.
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Smog: Originally a combination of smoke and fog, now used to describe other mixtures of air pollutants, especially ozone and other compounds formed when strong sunlight acts on a mixture of nitrogen oxides and volatile organic compounds from motor vehicle exhaust.
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Solar thermal energy: Energy produced by using the sun's rays to heat a gas or liquid that then performs useful work, such as powering an electrical generator. Electricity from solar thermal power plants is now nearly competitive in cost with electricity from conventinal fossil-fuel power plants.
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Stewardship: The attitude that human beings should see the Earth as a garden to be cultivated not a treasury to be raided.
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Stratosphere: Highly stratified and stable region of the atmosphere above the troposphere extending from about 10km to 50km.
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Sustainable development: Sustainable development has as many definitions as subscribers. In essence, it refers to economic development that meets the needs of all without leaving future generations with fewer natural resources than those we enjoy today. It is widely accepted that achieving sustainable development requires balance between three dimensions of complementary change:
- Economic (towards sustainable patterns of production and consumption)
- Ecological (towards maintenance and restoration of healthy ecosystems)
- Social (towards poverty eradication and sustainable livelihoods)
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Troposphere: Lowest part of the atmosphere (from the earth's surface to about 10km in altitude at mid-latitudes, to about 9km altitude at high-latitudes and to about 6km altitude in the tropics) in which clouds and weather phenomena occur. The troposphere is defined as the region in which temperatures generally decrease with height.
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Ultraviolet radiation: High energy, short-wave radiation lying between visible light and X-rays in the electromagnetic spectrum. It is usually divided into ultraviolet-A (UV-A) with wavelengths of 320-400 nanometres (nm), ultraviolet-B (UV-B) with wavelengths of 280-320nm and ultraviolet-C (UV-C) with wavelengths of 200-280nm. Ultraviolet rays are an important component of solar radiation. At normal levels it is an important germicide and is essential for the synthesis of Vitamin D in humans. At elevated levels, it causes sunburn and skin cancer, and can produce changes in the genetic make-up of organisms. It also has a role in the formation of photochemical smog. Most of the UV radiation which reaches the earth from the sun is absorbed by the ozone layer in the stratosphere. Thinning of the ozone layer, however, has increased the proportion of ultraviolet radiation � particularly UV-B � reaching the earth�s surface, giving rise to fears of an increasing incidence of skin cancer and other radiation-related problems.
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Water vapour: Water in its gaseous state, produced from liquid water by evaporation or by respiration from animals and transpiration from plants. Its presence in the atmosphere contributes to humidity and through subsequent condensation to precipitation. Water vapour is also a greenhouse gas.
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WHO (World Health Organisation): A UN agency created in 1948 to deal with global health issues and to achieve as high a level of physical, mental and social well-being as possible for peoples of the world. It is involved in a variety of environemental studies, including the impact of climate change and ozone depletion on health, in conjunction with other agencies such as the World Meteorological Organisation (WMO) and the United Nations Environment Program(UNEP).
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World Commission on Environment and Development: Established by the United Nations General Assembly in 1983 to examine international and global environmental problems and to propose strategies for sustainable development. Chaired by Norwegian Prime Minister Gro Harlem Brundtland, the independent commission held meetings and public hearing around the world and submitted a report on its inquiry to the General Assembly in 1987.
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World Summit on Sustainable Development (WSSD): The World Summit on Sustainable Development takes place from 26 August - 4 September 2002 in Johannesburg, South Africa. Governments, UN agencies, and civil society organisations will come together to assess progress since the UN Conference on Environment and Development held in Rio in 1992 (hence the title 'Rio + 10' for the Johannesburg meeting). Sustainable development is defined in the report from the Rio meeting as being 'economic progress which meets all of our needs without leaving future generations with fewer resources than those we enjoy'.
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