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Material that, if left to itself will be decomposed by natural processes

The diversity of plant and animal life in a certain habitat; a high level of biodiversity is desirable

A renewable energy source that is derived from biomass (mainly plant) feed stocks

Biomass boiler
Biomass boilers are fired on biological material; in the context of energy production this usually refers to plant based materials such as a wood chip. The biomass is burnt to produce hot water.

The Building Research Establishment Trust Companies, BRE and BRE Global are world leading research, consultancy, training, testing and certification organisations delivering sustainability and innovation across the built environment and beyond.

Carbon capture
Also known as carbon sequestration, this process traps carbon dioxide after it is produced and injects it under ground, so that the gas never enters the atmosphere.

Carbon dioxide
A colourless gas that is a natural part of the atmosphere. It is termed a green house gas and produced when fossil fuels are burnt.

Carbon footprint
Your carbon footprint is the sum of all CO2 emissions that are directly and indirectly associated with your activities over a given time frame (usually a year).

Carbon neutral
A technology is carbon neutral if the net carbon emissions are zero or below; for example, there are CO2 emissions associated with the production of photovoltaic solar panels, but these are negated by the reduction in carbon emissions while using the technology.

Carbon offset
A financial donation or other act that aims to remove a certain amount of carbon dioxide from the atmosphere, to compensate for another carbon dioxide emitting activity, e.g. a flight.

Carbon sink
Forests and other ecosystems are carbon sinks, as they absorb CO2 thereby removing it from the atmosphere. Some forests are planted specifically for this purpose.

Combined Heat and Power (CHP) is the simultaneous generation of usable heat and power in a single process. In its simplest form, the heat produced during power production is recovered and can be used to raise steam or hot water.

Climate change
Changes to temperature and weather patterns linked to human activity, including the burning of fossil fuels

Ecological footprint
An ecological footprint is the total area of productive land and water required to support an organism and can be expressed as the number of planets that would be required to support the global population if everyone lived a certain lifestyle: in the UK this figure is three planets.

Energy efficient
Energy efficiency is the percentage of total energy input to a piece of equipment that is consumed in useful work and not wasted as heat. An energy efficient light bulb is one with a higher conversion rate than standard.

Food miles
A term that refers to the distance food has travelled from its place of production to consumption

Fossil fuels
Any natural occurring organic fuel formed in the Earth’s crust such as coal, oil and natural gas. Carbon dioxide and other greenhouse gases are generated by burning fossil fuels and they are non renewable.

Fuel poverty
The definition of fuel poverty is when a household needs to spend more than 10% of their household income on all domestic fuel use including appliances to heat their home to an adequate level of warmth.

The Greater London Authority is a unique form of strategic citywide government for London. It is made up of a directly elected Mayor - the Mayor of London - and a separately elected Assembly - the London Assembly. There are around 600 staff to help the Mayor and Assembly in their duties.

Global warming
The gradual increase in the average surface temperate of the earth, usually attributed to human activity.

Greenhouse effect
The increasing temperature of the Earth’s surface caused by gases in the atmosphere. These gases allow solar radiation to penetrate, but they absorb the infrared (heat) radiation instead of allowing it to be radiated into space.

Greenhouse gas
An atmospheric gas that contributes to the greenhouse effect by absorbing infra-red radiation in the atmosphere. GHGs include carbon dioxide (CO2), methane (CH4) and water vapour.

Ground source heat pump
A heat pump installation that uses the earth as a heat sink to store heat or as a source of heat.

Kyoto Protocol
The Kyoto Protocol is an international agreement linked to the United Nations Framework Convention on Climate Change. The major feature of the Kyoto Protocol is that it sets binding targets for 37 industrialized countries and the European community for reducing greenhouse gas (GHG) emissions.

Methane is a greenhouse gas emitted from a variety of natural (e.g. flatulent cows) and human influenced (e.g. landfill) sources. It has considerably greater warming effects than CO2.

Micro generation
Micro generation is the stand alone generation of low carbon heat and power by individuals, small businesses and communities. This could be through a wind turbine, or micro CHP.

A natural resource, such as coal or oil, that once consumed cannot be replaced.

Organic food
Organic food is usually used to mean food grown without most artificial fertilisers or pesticides and in a way that emphasises crop rotation, making the most of natural fertilisers and ensuring that the life of the soil is maintained. Animals are kept in ways which minimise the need for medicines and other chemical treatments.

The payback period of a technology refers to the time taken to recoup the initial financial investment. This achieved through a reduction in fuel bills as well as reduced maintenance costs.

Sunlight is converted directly into electricity through solar photovoltaic panels.

Renewable energy is derived from sources that are theoretically inexhaustible, such as the sun or those that can be renewed, such as wood.

Solar thermal
A solar thermal system uses a heat exchanger to collect heat from the sun, and use this to heat water.

Stern Report
The report’s full title is the ‘Stern Review on the Economics of Climate Change’ and was published in 2006. The report suggests that global warming could shrink the global economy by 20%.

Sustainable development
Development that meets present needs without comprising those of future generations.

Travel demand management
Also known as mobility management, this refers to strategies that encourage a more efficient and therefore sustainable use of transport resources.

Travel plan
A plan developed by an organisation which consists of a range of strategies to encourage use of more sustainable forms of transport, and to reduce reliance on the car.

Zero Carbon
Zero carbon activities are those with zero net carbon emissions.

"Carbon Descent’s methodology is really comprehensive and identified for us the most economically viable set of actions which will meet our ambitious carbon targets."

Bob Fiddik, London Borough of Southwark