3R 
Refers to the 3Rs of reduce, reuse and recycle, which classify waste management strategies according to their desirability. The 3Rs are meant to be a hierarchy, in order of importance.
The waste hierarchy has taken many forms over the past decade, but the basic concept has remained the cornerstone of most waste minimisation strategies. The aim of the waste hierarchy is to extract the maximum practical benefits from products and to generate the minimum amount of waste.

A

Acid rain
Acid rain is simply rain with higher than normal acidity. Its main cause is emissions of nitrogen and sulphur compounds from burning fossil fuels to power transport, power stations, forest fires, fertiliser and industry.

Adaptation
Adjustment in natural or human systems to a new or changing environment. Adaptation to climate change refers to adjustment in natural or human systems in response to actual or expected climatic stimuli or their effects, which moderates harm or exploits beneficial opportunities. Various types of adaptation can be distinguished, including anticipatory and reactive adaptation, private and public adaptation, and autonomous and planned adaptation.

Aerosols
A collection of airborne solid or liquid particles, with a typical size between 0.01 and 10 micrometers (µm) and residing in the atmosphere for at least several hours. Aerosols may be of either natural or anthropogenic origin. Aerosols may influence climate in two ways: directly through scattering and absorbing radiation, and indirectly through acting as condensation nuclei for cloud formation or modifying the optical properties and lifetime of clouds. The term has also come to be associated, erroneously, with the propellant used in "aerosol sprays." See climate, particulate matter, sulfate aerosols.

Afforestation
Planting of new forests on lands that historically have not contained forests. For a discussion of the term forest and related terms such as afforestation, reforestation, and deforestation

Agroecology
is the science of sustainable agriculture; the methods of agroecology have as their goal achieving sustainability of agricultural systems balanced in all spheres. This includes the socio-economic and the ecological or environmental.

Alternative energy
Energy derived from nontraditional sources (e.g., compressed natural gas, solar, hydroelectric, wind).

Anthropogenic
Made by people or resulting from human activities. Usually used in the context of emissions that are produced as a result of human activities.

Atmosphere
The gaseous envelope surrounding the Earth. The dry atmosphere consists almost entirely of nitrogen (78.1% volume mixing ratio) and oxygen (20.9% volume mixing ratio), together with a number of trace gases, such as argon (0.93% volume mixing ratio), helium, and radiatively active greenhouse gases such as carbon dioxide (0.035% volume mixing ratio), and ozone. In addition the atmosphere contains water vapour, whose amount is highly variable but typically 1% volume mixing ratio. The atmosphere also contains clouds and aerosols.
The atmosphere changes from the ground up and consists of four distinct layers: troposphere (8-14,5 km), stratosphere (14,5-50 km), mesosphere (50-85 km) and thermosphere (85-600 km). Temperatures are different for each layer. In the troposphere temperatures drop from about 17 to -52 degrees Celcius, in the stratosphere temperatures increase gradually to -3 degrees Celcius, in the mesosphere temperatures fall to -93 degrees Celcius as altitude increases, and in the thermosphere temperatures can be as high as 1727 degrees Celsius (figure 1).  Above the thermosphere, the exosphere starts and continues until it mixes with interplanetary gases or space. This layer primarily consists of low-density particles such as hydrogen and helium.

Allocation
Under an emissions trading scheme, permits to emit can initially either be given away for free, usually under a ‘grandfathering’ approach based on past emissions in a base year or an ‘updating’ approach based on the more recent emissions. The alternative is to auction permits in an initial market offering.

B

Baseline emissions
The emissions that would occur without policy intervention. Baseline estimates are needed to determine the effectiveness of emissions mitigation strategies.

Biodegradable
Organic matter that can break down or decompose rapidly under natural conditions and processes is referred to as biodegradable. Garden and food waste, animal waste, and most paper products, as well as plastics derived from vegetable content, will biodegrade, but not plastic carrier bags and polystyrene cups, for example.

Biodiesel
Biodiesel is fuel generated from vegetable oil that can be used pure or blended with regular diesel (diesel produced by refining crude oil) in conventional, unmodified diesel engines. It is not the same as waste vegetable oil, otherwise known as 'unwashed biodiesel', which requires engine modification.

Biodiversity
life in all its forms, essential to maintain functioning ecosystems that provide services essential for human survival and quality of life.

Biofuel
Biofuel is a general term for fuel, including biodiesel, that is derived from biomass - living or recently dead organic matter. In general it is made from sugar, starch, vegetable oils or animal fats. Examples include bio-ethanol from energy crops such sugar cane, corn, palm oil, and rape seed.

Biomass
The total mass of living organisms in a given area or volume; recently dead plant material is often included as dead biomass.
Total dry weight of all living organisms that can be supported at each tropic level in a food chain. Also, materials that are biological in origin, including organic material (both living and dead) from above and below ground, for example, trees, crops, grasses, tree litter, roots, and animals and animal waste.

Biosphere
The part of the Earth system comprising all ecosystems and living organisms, in the atmosphere, on land (terrestrial biosphere) or in the oceans (marine biosphere), including derived dead organic matter, such as litter, soil organic matter and oceanic detritus.

C

Car Pooling
Car pooling - or lift sharing - is a way of reducing CO2 emissions from private transport, especially commuter travel, by sharing journeys. It can be arranged informally among friends and colleagues or, increasingly, through dedicated websites. Its aim is to have fewer cars on the road with more people in each.

Carbon
Carbon is the fourth most common chemical element in the universe, and carbon compounds - in other words, carbon chemically combined with other elements - are the basis of all known life forms on earth. Pure carbon appears in many apparently diverse forms, from diamond to graphite to charcoal, but it is much more commonly found in substances such as coal, oil, natural gas, wood and peat that we use for fuel. When we burn these substances to provide energy - either directly in our homes as heat, or in power stations to produce electricity - the combustion process produces 'oxides' of carbon, including the gas CO2.

Carbon Capture and Storage
The process of capturing greenhouse gas pollution from coal or gas power plants and storing it underground instead of releasing it into the atmosphere. Could reduce emissions by up to 70-80% from a power plant.

Carbon Credit
Carbon credit is used in emission trading schemes (see emissions trading), where one credit gives the owner the right to emit one tonne of CO2.

Carbon Cycle
All parts (reservoirs) and fluxes of carbon. The cycle is usually thought of as four main reservoirs of carbon interconnected by pathways of exchange. The reservoirs are the atmosphere, terrestrial biosphere (usually includes freshwater systems), oceans, and sediments (includes fossil fuels). The annual movements of carbon, the carbon exchanges between reservoirs, occur because of various chemical, physical, geological, and biological processes. The ocean contains the largest pool of carbon near the surface of the Earth, but most of that pool is not involved with rapid exchange with the atmosphere.

Carbon Dioxide
A naturally occurring colorless, odorless, incombustible gas, also a by-product of burning fossil fuels and biomass, as well as land-use changes and other industrial processes. It is the principal anthropogenic greenhouse gas that affects the earth’s radiative balance. It is the reference gas against which other greenhouse gases are measured and therefore has a Global Warming Potential of 1.
CO2 is a chemical compound composed of one carbon and two oxygen atoms. It is often referred to by its formula CO2. It is present in the Earth's atmosphere at a low concentration and acts as a greenhouse gas. In its solid state, it is called dry ice. It is a major component of the carbon cycle. As of March 2006 CO2 levels now stand at 381 parts per million (ppm) — 100ppm above the pre-industrial average.

Carbon Footprint
A person's carbon footprint (or that of a particular household, business or entire community) refers to the CO2 for which they are responsible - whether directly, via their home energy use, their transport use, or indirectly via the embodied energy in the products and services they buy and use. You can work out your carbon footprint using calculators such as the Government's Act On CO2 Calculator.

Carbon Neutral
where an individual or company's carbon emissions are effectively reduced to zero through a combination of reducing energy consumption, using renewable energy and offsetting the remainder by (for example) planting trees to absorb carbon dioxide from the atmosphere

Carbon offsetting
where an investment is made in a project that will lead to the prevention or removal of carbon dioxide from the atmosphere (for example, planting trees or building renewable energy power stations to avoid the construction of coal ones).

Carbon sequestration
The uptake and storage of carbon. Trees and plants, for example, absorb carbon dioxide, release the oxygen and store the carbon. Fossil fuels were at one time biomass and continue to store the carbon until burned. See sinks.

Carbon sink
is the natural or human activity or mechanism that removes carbon dioxide from the atmosphere, such as the absorption of carbon dioxide by growing trees.

Cavity walls
A wall comprising two layers of brick or block separated by a cavity (gap). This air space acts as an insulator, but does so more effectively if filled with an insulating material, such as plastic foam or natural materials like wool or recycled newspaper.

CFL bulbs
CFLs are compact fluorescent lamps. They operate on the same principle as fluorescent lights but the tube is folded into a more compact design so they are more versatile and can be used in devices designed to take traditional incandescent bulbs. They use about 80% less electricity than traditional bulbs to produce the same light and last considerably longer. Their mercury content means disposal, especially of broken bulbs, requires extra care. Also referred to as low-energy lightbulbs.

Clean Development Mechanism
CDM is one of three market mechanisms established by the Kyoto Protocol, designed to promote emission reduction projects in developing countries.

Climate Change
Climate change refers to any significant change in measures of climate (such as temperature, precipitation, or wind) lasting for an extended period (decades or longer). Climate change may result from:
* natural factors, such as changes in the sun's intensity or slow changes in the Earth's orbit around the sun;
* natural processes within the climate system (e.g. changes in ocean circulation);
* human activities that change the atmosphere's composition (e.g. through burning fossil fuels) and the land surface (e.g. deforestation, reforestation, urbanization, desertification, etc.)
See climate, global warming, greenhouse effect, enhanced greenhouse effect, radiative forcing.

Climatologist
A person who studies climate.

CO2
CO2, or carbon dioxide, is made up of the elements carbon and oxygen. It exists quite naturally in our atmosphere, as part of the carbon cycle. Everyday processes in the plant and animal world both add CO2 to the atmosphere and take it out. However, because it is a greenhouse gas - meaning it affects the temperature of the earth - the exact level of CO2 is important. Burning fossil fuels releases CO2 into the atmosphere, hence the anxiety that extensive use of these fuels is causing climate change.

D

Deforestation

Those practices or processes that result in the conversion of forested lands for non-forest uses.  This is often cited as one of the major causes of the enhanced greenhouse effect for two reasons: 1) the burning or decomposition of the wood releases carbon dioxide; and 2) trees that once removed carbon dioxide from the atmosphere in the process of photosynthesis are no longer present.

DEFRA

The Department for Environment, Food and Rural Affairs (Defra) is the government department responsible for environmental protection, food production and standards, agriculture, fisheries and rural communities in the United Kingdom.  Defra also leads for the UK at the EU on agricultural, fisheries and environment matters and in other international negotiations on sustainable development and climate change, although a new Department of Energy and Climate Change was created on 3 October 2008 to take over the last responsibility.

Desertification
Land degradation in arid, semi-arid, and dry sub-humid areas resulting from various factors, including climatic variations and human activities. Further, the UNCCD (The United Nations Convention to Combat Desertification) defines land degradation as a reduction or loss, in arid, semi-arid, and dry sub-humid areas, of the biological or economic productivity and complexity of rain-fed cropland, irrigated cropland, or range, pasture, forest, and woodlands resulting from land uses or from a process or combination of processes, including processes arising from human activities and habitation patterns, such as: (i) soil erosion caused by wind and/or water; (ii) deterioration of the physical, chemical and biological or economic properties of soil; and (iii) long-term loss of natural vegetation. Conversion of forest to non-forest.

Diesel
Ordinary diesel, like regular petrol, is refined from oil but it is a thicker, heavier liquid with a higher 'energy density' - meaning it offers better fuel economy. On the down side, unless you buy an air filter, diesel exhaust is a significant source of particulates and other sources of air pollution. A type of diesel not derived from petroleum is increasingly widely available, commonly referred to as biodiesel.

Drought
A period of abnormally dry weather long enough to cause serious shortages of water for agriculture and other needs in the affected area.

Dual Fuel
A dual-fuel vehicle is one designed to run on a combination of traditional fuels (petrol or diesel) and alternative fuels (such as liquid petroleum gas or biodiesel). The term is usually applied to cars with separate tanks for each fuel but is sometimes used to describe those diesel engines that accept a blend of traditional fuel and bio-diesel.

E

Eco friendly
Eco-friendly, or environmentally friendly, is a term applied to goods, services, processes or people deemed to do minimal harm to the environment. The term is shorthand for 'ecologically friendly', ecology being the study of the relationships between living organisms and their environment.

Ecosystems
Any natural unit or entity including living and non-living parts that interact to produce a stable system through cyclic exchange of materials.

Efficiency ratings
All white goods and other household appliances sold in the UK are now required by law to carry a rating indicating their energy efficiency. Goods are graded A to G, with A the most efficient. Information on the EU-wide labelling scheme is available from the government's environment department, Defra.

Emission permit
Tradable allocation of entitlements by a government to an individual firm to emit a specific amount of a substance.

Emission standard
An amount of emission that may not be exceeded legally.

Emissions
The release of a substance (usually a gas when referring to the subject of climate change) into the atmosphere.

Emission trading
A scheme that allows companies either reduce emissions or pay for the right to pollute (with the money paid being used to reduce emissions elsewhere – often in developing countries).

Energy efficiency
Energy efficiency is about using less energy to provide the same amount of heating, cooling or other energy service. Usually refers to cutting energy wastage (like turning off unused lights, plant and equipment).

Environment
The complex of physical, chemical, and biotic factors (as climate, soil, and living things) that act upon an organism (a living thing) or an ecological community (a collection of living things) and ultimately determine its form and survival. The circumstances, objects, and conditions that surround each of us.

Evaporation
is the process by which a liquid becomes a gas.

F

Faculae
Bright patches on the Sun. The area covered by faculae is greater during periods of high solar activity.

Farmers market
Farmers' markets are where producers sell fresh, locally grown produce, or food made with local ingredients, direct to the public. As with organic farming, there is no single, fixed definition but producers should be local (within about 25-30 miles of the market) and selling their own produce - i.e. they are the farmer, family member or direct employee. A large fraction of the produce - particularly during the winter - is grown in artificially-heated greenhouses.

Food miles
A product's 'food miles' indicate how far it has travelled to get from where it (or its ingredients) were grown to where you eat them. Food freight - especially by air and road - is very carbon intensive.

Forest
A vegetation type dominated by trees. Many definitions of the term forest are in use throughout the world, reflecting wide differences in bio-geophysical conditions, social structure, and economics. For a discussion of the term forest and related terms such as afforestation, reforestation, and deforestation

Fossil fuel
fuel of biological (plant and animal) origin and largely comprised of carbon and hydrogen. Coal, gas and oil are all fossil fuels.

Fuel duty
Fuel duty is the tax the government levies on fuel used for transportation, imposed at the point of sale.

G

Gaia hypothesis
The Gaia hypothesis states that the temperature and composition of the Earth's surface are actively controlled by life on the planet. It suggests that if changes in the gas composition, temperature or oxidation state of the Earth are induced by astronomical, biological, lithological, or other perturbations, life responds to these changes by growth and metabolism.

Geosphere
The soils, sediments, and rock layers of the Earth's crust, both continental and beneath the ocean floors.

Glacier
A multi-year surplus accumulation of snowfall in excess of snowmelt on land and resulting in a mass of ice at least 0.1 km2 in area that shows some evidence of movement in response to gravity. A glacier may terminate on land or in water. Glacier ice is the largest reservoir of fresh water on Earth, and second only to the oceans as the largest reservoir of total water. Glaciers are found on every continent except Australia.

Global Warming
Global warming is an average increase in the temperature of the atmosphere near the Earth's surface and in the troposphere, which can contribute to changes in global climate patterns. Global warming can occur from a variety of causes, both natural and human induced. In common usage, "global warming" often refers to the warming that can occur as a result of increased emissions of greenhouse gases from human activities. See climate change, greenhouse effect, enhanced greenhouse effect, radiative forcing, troposphere.

Green washing
Advertising by a number of companies now includes a reference to ’green’ issues in order to influence consumers and try to win their business. This is regarded as ‘green washing’ whereby the company is trying to win customers by promoting their ‘green’ credentials.

Greenhouse effect
Trapping and build-up of heat in the atmosphere (troposphere) near the Earth’s surface. Some of the heat flowing back toward space from the Earth's surface is absorbed by water vapor, carbon dioxide, ozone, and several other gases in the atmosphere and then reradiated back toward the Earth’s surface. If the atmospheric concentrations of these greenhouse gases rise, the average temperature of the lower atmosphere will gradually increase. See greenhouse gas, anthropogenic, climate, global warming.

Greenhouse gas (GHG)
Any gas that absorbs infrared radiation in the atmosphere. Greenhouse gases include, but are not limited to, water vapor, carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), ozone (O3 ), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6). See carbon dioxide, methane, nitrous oxide, ozone, chlorofluorocarbons, hydrochlorofluorocarbons, hydrofluorocarbons, perfluorocarbons, sulfur hexafluoride.

H

Hybrid car
A hybrid car is one that has both a petrol engine and an electric motor and switches between them according to the driving conditions. It is different from a dual-fuel vehicle, which uses two types of liquid fuel.

Hydrogen
At standard temperature and pressure it is a colorless, odorless, nonmetallic, univalent, tasteless, highly flammable diatomic gas. Having been used as an ingredient in some rocket fuels for several decades, hydrogen, or more specifically H2, is now widely discussed in the context of energy. Hydrogen is not an energy source, since it is not an abundant natural resource and more energy is used to produce it than can be ultimately extracted from it.

Hydropower
Hydropower (or hydroelectric power) is the generation of electricity using the power of falling water.

Hydrosphere
The component of the climate system comprising liquid surface and subterranean water, such as: oceans, seas, rivers, fresh water lakes, underground water etc.

I

Ice cap
A dome shaped ice mass covering a highland area that is considerably smaller in extent than anice sheet.

Ice sheet
A mass of land ice which is sufficiently deep to cover most of the underlying bedrock topography, so that its shape is mainly determined by its internal dynamics (the flow of the ice as it deforms internally and slides at its base). An ice sheet flows outwards from a high central plateau with a small average surface slope. The margins slope steeply, and the ice is discharged through fast-flowing ice streams or outlet glaciers, in some cases into the sea or into ice-shelves floating on the sea. There are only two large ice sheets in the modern world, on Greenland and Antarctica, the Antarctic ice sheet being divided into East and West by the Transantarctic Mountains; during glacial periods there were others.

Ice shelf
A floating ice sheet of considerable thickness attached to a coast (usually of great horizontal extent with a level or gently undulating surface); often a seaward extension of ice sheets.

Industrial revolution
A period of rapid industrial growth with far-reaching social and economic consequences, beginning in England during the second half of the eighteenth century and spreading to Europe and later to other countries including the United States. The invention of the steam engine was an important trigger of this development. The industrial revolution marks the beginning of a strong increase in the use of fossil fuels and emission of, in particular, fossil carbon dioxide

Intergovernmental Panel on Climate Change (IPCC)
The IPCC was established jointly by the United Nations Environment Programme and the World Meteorological Organization in 1988. The purpose of the IPCC is to assess information in the scientific and technical literature related to all significant components of the issue of climate change. The IPCC draws upon hundreds of the world's expert scientists as authors and thousands as expert reviewers. Leading experts on climate change and environmental, social, and economic sciences from some 60 nations have helped the IPCC to prepare periodic assessments of the scientific underpinnings for understanding global climate change and its consequences. With its capacity for reporting on climate change, its consequences, and the viability of adaptation and mitigation measures, the IPCC is also looked to as the official advisory body to the world's governments on the state of the science of the climate change issue. For example, the IPCC organized the development of internationally accepted methods for conducting national greenhouse gas emission inventories.

IPCC
Intergovernmental Panel on Climate Change, the international organization founded by the United Nations that tries to predict the impact of the greenhouse effect according to existing climate models and literature information. The Panel consists of more than 2500 scientific and technical experts from more than 60 countries all over the world. It is therefore referred to as the largest peer-reviewed scientific cooperation project in history.

J

Joint implementation
Richer countries have the opportunity to achieve their emission reduction goals, formulated in the Kyoto Protocol, by financing energy saving projects for poorer countries that have also signed the treaty.

K

Kyoto Protocol
The Kyoto Protocol to the United Nations Framework Convention on Climate Change (UNFCCC) was adopted at the Third Session of the Conference of the Parties (COP) to the United Nations Framework Convention on Climate Change, in 1997 in Kyoto, Japan. It contains legally binding commitments, in addition to those included in the UNFCCC. Countries included in Annex B of the Protocol (most OECD countries and countries with economies in transition) agreed to reduce their anthropogenic greenhouse gas emissions (CO2, CH4, N2O, HFCs, PFCs, and SF6) by at least 5% below 1990 levels in the commitment period 2008 to 2012. The Kyoto Protocol has not yet entered into force (April 2001).

L

Land use
The total of arrangements, activities and inputs undertaken in a certain land cover type (a set of human actions). The social and economic purposes for which land is managed (e.g., grazing, timber extraction, and conservation).

Landfill
Land waste disposal site in which waste is generally spread in thin layers, compacted, and covered with a fresh layer of soil each day.

LEDs
An LED is a light-emitting diode. Its light is produced by an electrical current passing through a semiconductive material, so it does not require a filament like an incandescent bulb. They have a long life span, are durable, more energy efficient than CFLs, or incandescent bulbs cool to the touch and, while they have traditionally been used as small indicator lights, multiple LEDs are increasingly being used for household lighting.

M

Medieval warm period
Term introduced by the British meteorologist Hubert Lamb in 1965, for a period between the 9th and 13th century during which it was extremely warm on many locations in and around Europe. Wine was grown in Scandinavia and agriculture was possible on Greenland. This was determined by studying snow lines in the mountains and temperatures in deep boreholes and has given us the impression that temperature changes may have occurred before. Geochemist Wallace Broecker thinks that cyclic processes in the oceans cause a warmer period once in every 1500 years.

Methan
A hydrocarbon that is a greenhouse gas with a global warming potential most recently estimated at 23 times that of carbon dioxide (CO2). Methane is produced through anaerobic (without oxygen) decomposition of waste in landfills, animal digestion, decomposition of animal wastes, production and distribution of natural gas and petroleum, coal production, and incomplete fossil fuel combustion. The GWP is from the IPCC's Third Assessment Report (TAR). For more information visit EPA's Methane site.

Mitigation
A human intervention to reduce the sources or enhance the sinks of greenhouse gases.

Monoculture
Monoculture is the practice of planting a single crop, or genetically similar crops, over a wide area. Its advantages to growers are that the crop may thrive in conditions tailored to its success and without competition from other species. However, the practice will also reduce the region's biodiversity by limiting the number of other species for which it is a suitable habitat. Scientists warn that extensive forest clearance to make way for widespread growth of crops such as sugarcane to create biofuels is creating a monoculture harmful to biodiversity. The opposite of a monoculture is a polyculture.

MRET (Mandatory Renewable Energy Target)
A scheme to increase the amount of electricity generated from 'renewable energy' sources.

N

National Grid
The grid, or National Grid, is a privately owned network of electricity supply lines that stretch from the power stations where the electricity is generated to the homes and businesses where it is used. In some parts of the UK, local or domestic microgeneration may make it feasible to live "off grid", while some homes in remote parts of the country have no choice because it does not reach them. In some cases, microgeneration means there is potential for people to sell surplus electricity back to the grid.

Natural Gas
Underground deposits of gases consisting of 50 to 90 percent methane (CH4) and small amounts of heavier gaseous hydrocarbon compounds such as propane (C3H8) and butane (C4H10).

Nitrogen fertilization
Enhancement of plant growth through the addition of nitrogen compounds. In IPCC Reports, this typically refers to fertilisation from anthropogenic sources of nitrogen such as human-made fertilisers and nitrogen oxides released from burning fossil fuels.

O

Offsetting
Offsetting, or carbon offsetting, refers to the (highly contentious) principle that a company or individual can mitigate or even entirely neutralise the effects of their CO2 emissions by investing in programmes that promote energy-efficiency or CO2 absorption, such as providing low-energy lightbulbs or planting trees.

Ofgem
The Office of Gas and Electricity Markets (Ofgem) is the government agency responsible for regulating the energy market in the UK. It describes its purpose as "protecting consumers... by promoting competition... and regulating the monopoly companies which run the gas and electricity networks". Its aims also include curbing climate change by helping energy providers meet environmental goals. There is also a non-governmental equivalent, the consumer watchdog Energywatch.

Organic farming
There is no universally accepted definition of organic farming, and each country regulates what can and cannot be labelled "organic". In general, it describes a form of agriculture that avoids use of synthetic fertilisers, pesticides, growth regulators, and livestock feed additives, and relies instead, as far as possible, on "natural" products and techniques - such as crop rotation and animal manures.

Oxidize
To chemically transform a substance by combining it with oxygen.

Ozone
Ozone, the triatomic form of oxygen (O3), is a gaseous atmospheric constituent. In the troposphere, it is created both naturally and by photochemical reactions involving gases resulting from human activities (photochemical smog). In high concentrations, tropospheric ozone can be harmful to a wide range of living organisms. Tropospheric ozone acts as a greenhouse gas. In the stratosphere, ozone is created by the interaction between solar ultraviolet radiation and molecular oxygen (O2). Stratospheric ozone plays a decisive role in the stratospheric radiative balance. Depletion of stratospheric ozone, due to chemical reactions that may be enhanced by climate change, results in an increased ground-level flux of ultraviolet (UV-) B radiation. See atmosphere, ultraviolet radiation.

Ozone Layer
The layer of ozone that begins approximately 15 km above Earth and thins to an almost negligible amount at about 50 km, shields the Earth from harmful ultraviolet radiation from the sun. The highest natural concentration of ozone (approximately 10 parts per million by volume) occurs in the stratosphere at approximately 25 km above Earth. The stratospheric ozone concentration changes throughout the year as stratospheric circulation changes with the seasons. Natural events such as volcanoes and solar flares can produce changes in ozone concentration, but man-made changes are of the greatest concern. See stratosphere, ultraviolet radiation.

P

Parts Per Billion (ppb)
Number of parts of a chemical found in one billion parts of a particular gas, liquid, or solid mixture. See concentration.

Parts Per Million (ppm)
Number of parts of a chemical found in one million parts of a particular gas, liquid, or solid. See concentration.

Pesticides
A pesticide is a substance used to kill a pest, and in a farming context a pest is anything that attacks or competes with crops. Hence, there are many different types of pesticides: for example, insecticides kill insects, and herbicides kill weeds. The chemicals used in pesticides can sometimes be toxic to humans, however, so organic farming endeavours to use natural rather than synthetic substances as pesticides.

Photosynthesis
The process by which plants take CO2 from the air (or bicarbonate in water) to build carbohydrates, releasing O2 in the process. There are several pathways of photosynthesis with different responses to atmospheric CO2 concentrations. See carbon sequestration, carbon dioxide fertilization.

Photovoltaic cell
'Photovoltaics' are materials that produce electricity from sunlight. A single photovoltaic cell can be used to power small devices such as calculators; combined in solar panels they can be used to power solar water heating. Most cells are manufactured from silicon.

Precursors
Atmospheric compounds which themselves are not greenhouse gases or aerosols, but which have an effect on greenhouse gas or aerosol concentrations by taking part in physical or chemical processes regulating their production or destruction rates.

R

Radiation
Energy transfer in the form of electromagnetic waves or particles that release energy when absorbed by an object. See ultraviolet radiation, infrared radiation, solar radiation, longwave radiation.

Recycling
Collecting and reprocessing a resource so it can be used again. An example is collecting aluminum cans, melting them down, and using the aluminum to make new cans or other aluminum products.

Reforestation
Planting of forests on lands that have previously contained forests but that have been converted to some other use.

Renewable energy
energy derived from the wind, the sun, the tides and other sources that, for all practical purposes, cannot be depleted (unlike fossil fuels, for example).

S

Sea level alteration
A change in global average sea level brought about by volume changes in the world ocean. This may be caused by changes in water density or changes in the total mass of water.

Sequestration

Carbon sequestration is a geoengineering technique for long-term storage of carbon dioxide or other forms of carbon to mitigate global warming. Carbon dioxide is usually captured from the atmosphere through biological, chemical or physical processes.  It has been proposed as a way to mitigate accumulation of greenhouse gases in the atmosphere, which are released by burning fossil fuels.

Sink
Any process, activity or mechanism which removes a greenhouse gas, an aerosol or a precursor of a greenhouse gas or aerosol from the atmosphere.

Smart meter
A smart meter is a more sophisticated version of your normal gas or electricity meter (in fact, a single smart meter may monitor both) that is linked to your energy provider and can also be linked to a computer in your home. Not yet available, it will eliminate the need for estimated bills, and allow you to monitor your own usage: which devices are using the most energy and when. Smart meters will generally also store up to a month of usage data.

Solar activity
The Sun exhibits periods of high activity observed in numbers of sunspots, as well as radiative output, magnetic activity, and emission of high energy particles. These variations take place on a range of time-scales from millions of years to minutes

Solar energy
Energy from the Sun. Also referred to as short-wave radiation. Of importance to the climate system, solar radiation includes ultraviolet radiation, visible radiation, and infrared radiation.

Solar panel
Solar panels, usually roof-mounted, use the energy of the sun to generate electricity for home use, with the potential to sell surplus back to the grid. Light shining on a panel of photovoltaic cells creates an electric field across layers of semiconductive material, causing electricity to flow.

Stratosphere
Region of the atmosphere between the troposphere and mesosphere, having a lower boundary of approximately 8 km at the poles to 15 km at the equator and an upper boundary of approximately 50 km. Depending upon latitude and season, the temperature in the lower stratosphere can increase, be isothermal, or even decrease with altitude, but the temperature in the upper stratosphere generally increases with height due to absorption of solar radiation by ozone.

Standby
Standby, or 'sleep mode', is a mode in which electronic appliances are turned off but still drawing current and ready to activate on command. Although legislation has limited the energy new appliances can use in standby mode, they still use more energy than if they are switched off at the wall.

Stern Report
The Stern report - or the Stern Review on the Economics of Climate Change - is a 700-page report, written by economist Sir Nicholas Stern for the UK government, and published in October 2006. It discusses the effect of climate change and global warming on the world economy and concludes that global warming could shrink the global economy by 20%, but that immediate action to combat it effectively would cost just 1% of global gross domestic product.

Stratosphere
The second lowest level of the atmosphere, extending from about 10km to about 50km altitude. The ozone layer, the part of the earth's atmosphere with the greatest concentration of ozone, forms part of the stratosphere. Because it sits above the troposphere, where most air turbulence occurs, the lower stratosphere is where most commercial airlines set their cruising altitude.

Sustainability
Sustainability - whether applied to energy, technology, industry, agriculture or just consumption of resources in general - refers to the concept of using things at a rate that, while meeting our own needs, does not compromise future generations' ability to meet theirs. In environmental terms, a process or industry is unsustainable when it requires natural resources to be used up faster than they can be replenished.

T

Tide gauge
A device at a coastal location (and some deep sea locations) which continuously measures the level of the sea with respect to the adjacent land. Time-averaging of the sea level so recorded gives the observed Relative Sea Level Secular Changes.

Troposphere
The lowest part of the atmosphere from the surface to about 10 km in altitude in mid-latitudes (ranging from 9 km in high latitudes to 16 km in the tropics on average) where clouds and "weather" phenomena occur. In the troposphere temperatures generally decrease with height. See ozone precursors, stratosphere, atmosphere.

U

Ultraviolet Radiation (UV)
The energy range just beyond the violet end of the visible spectrum. Although ultraviolet radiation constitutes only about 5 percent of the total energy emitted from the sun, it is the major energy source for the stratosphere and mesosphere, playing a dominant role in both energy balance and chemical composition.
Most ultraviolet radiation is blocked by Earth's atmosphere, but some solar ultraviolet penetrates and aids in plant photosynthesis and helps produce vitamin D in humans. Too much ultraviolet radiation can burn the skin, cause skin cancer and cataracts, and damage vegetation.

United Nations Framework Convention on Climate Change (UNFCCC)
The Convention on Climate Change sets an overall framework for intergovernmental efforts to tackle the challenge posed by climate change. It recognizes that the climate system is a shared resource whose stability can be affected by industrial and other emissions of carbon dioxide and other greenhouse gases. The Convention enjoys near universal membership, with 189 countries having ratified.
Under the Convention, governments:
* gather and share information on greenhouse gas emissions, national policies and best practices
* launch national strategies for addressing greenhouse gas emissions and adapting to expected impacts, including the provision of financial and technological support to developing countries
* cooperate in preparing for adaptation to the impacts of climate change
The Convention entered into force on 21 March 1994.

Uptake
The addition of a substance of concern to a reservoir. The uptake of carbon