Read also the new edition
2013 IPCC Assessment Report on Climate Change

Climate Change 2007 Update


Glossary over Climate Change


Adjustment in natural or human systems to a new or changing environment.

Various types of adaptation can be distinguished, including anticipatory and reactive adaptation, private and public adaptation, and autonomous and planned adaptation. (Source: Millennium Ecosystem Assessment
 Glossary )


An aerosol is a collection of microscopic particles, solid or liquid, suspended in a gas.

In the context of air pollution, an aerosol refers to fine particulate matter, that is larger than a molecule, but small enough to remain suspended in the atmosphere for at least several hours.

The term aerosol is also commonly used for a pressurized container (aerosol can) which is designed to release a fine spray of a material such as paint. It has also come to be associated, erroneously, with the gas (propellant) used to expel materials from an aerosol can. (Source: GreenFacts )



The establishment of a forest through tree planting or seeding on land that has lacked forest cover for a very long time or has never been forested. (Source: GreenFacts)

Alliance of Communicators for Sustainable Development

"Com+ is a partnership of international organizations and communications professionals from diverse sectors committed to using communications to advance a vision of sustainable development that integrates its three pillars: economic, social and environmental.

By offering a platform to share expertise, develop best practice and create synergies, Com+ hopes to actively support creative and inspiring communications across the world."

"Com+ envisions societies that advance and strengthen the three pillars of sustainable development — economic development, social equity and environmental conservation — at local, national, regional, and global levels." (Source: Com+ website  )


Originating from the activity of humans. (Source: GreenFacts )


Breeding and rearing of fish, shellfish, or plants in ponds, enclosures, or other forms of confinement in fresh or marine waters for the direct harvest of the product. (Source: MA   Glossary )


The mass of air surrounding the Earth.

The atmosphere consists of nitrogen (78%), oxygen (21%), and traces of other gases such as argon, helium, carbon dioxide, and ozone.

The atmosphere plays an important role in the protection of life on Earth; it absorbs ultraviolet solar radiation and reduces temperature extremes between day and night. (Source: GreenFacts)



Biodiversity is a contraction of biological diversity. Biodiversity reflects the number, variety and variability of living organisms.

It includes diversity within species (genetic diversity), between species (species diversity), and between ecosystems (ecosystem diversity). (Source: GreenFacts)



The total quantity or mass of organic material produced by living organisms in a particular area, at a given time. (Source: GreenFacts)


Carbon dioxide (CO2)

A colorless, odorless, non-combustible gas, present in low concentrations in the air we breathe (about three hundredths of one percent by volume).

Carbon dioxide is produced when any substance containing carbon is burned. It is also a product of breathing and fermentation. Plants absorb carbon dioxide through photosynthesis. (Source: The Pacific Forest Trust Glossary )


Carbon sequestration

The removal and storage of carbon from the atmosphere in carbon sinks (such as oceans, forests or soils) through physical or biological processes, such as photosynthesis.

Humans have tried to increase carbon sequestration by growing new forests. (Source: GreenFacts)


Climate change

The long-term fluctuations in temperature, precipitation, wind, and all other aspects of the Earth's climate.

It is also defined by the United Nations Convention on Climate Change as “change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods” (Source: CoRIS glossary  )


When referring to humans, a community is defined as:

A collection of human beings who have something in common.

A local community is a fairly small group of people who share a common place of residence and a set of institutions based on this fact, but the word ‘community’ is also used to refer to larger collections of people who have something else in common (e.g., national community, donor community).

When referring to other living organisms, a community is defined as:

An assemblage of species occurring in the same space or time, often linked by biotic interactions such as competition or predation. (Source: Millennium Ecosystem Assessment  Glossary )


The conversion of forested land to non-forested land as a direct result of human activities. (Source: Forest Carbon Accounting Definitions  )



Land degradation in drylands resulting from various factors, including climatic variations and human activities.

Land degradation in drylands resulting from various factors, including climatic variations and human activities. (Source: MA  Glossary )



Any natural or human-induced factor that directly or indirectly causes a change. (Source: MA  Glossary )



The complex system of plant, animal, fungal, and microorganism communities and their associated non-living environment interacting as an ecological unit.

Ecosystems have no fixed boundaries; instead their parameters are set to the scientific, management, or policy question being examined. Depending upon the purpose of analysis, a single lake, a watershed, or an entire region could be considered an ecosystem. (Source: US EPA Glossary of Climate Change Terms   )

EurActiv is the leading internet portal fully dedicated to European public affairs. It brings together daily EU news, weekly "Update" e-mails, in-depth analysis of selected policy topics, and a directory of 10,000 names of names of people and organizations acting on the EU level, the "Guide". All content is free of charge.

EurActiv aims to "facilitate efficiency and transparency (...) by providing news monitoring, policy positions, discussion forums and contacts on selected EU affairs topics, complementing the existing institutional websites."

(Source: EurActiv website )

European Environmental Agency

The European Environmental Agency (EEA) is one of the 15 specialised agencies of the European Union, which handle specific technical, scientific or management tasks. Operational since 1994, the EEA is based in Copenhagen.

"Its mission is to collect, prepare and disseminate timely, targeted, relevant and reliable information on the state and trends of the environment at European level. The founding regulation of EEA stipulates that it is open to countries that do not belong to the European Union but share its concern for the environment. Iceland, Liechtenstein and Norway have been members from the start, and 12 out of 13 candidate countries have joined in 2002 (...)." (Source: EEA website )


Contact of the cells of an organism with a substance, micro-organism or radiation. In the case of humans, this may involve contact with a substance or agent by swallowing, breathing, or through the skin or eyes. Exposure may be short-term [acute exposure], of intermediate duration, or long-term [chronic exposure].

Exposure can be divided into external and internal.

External exposure refers to the whole dose to which an organism is exposed.

Internal exposure refers only to that fraction of the initial chemical dose that is absorbed and distributed throughout the body via systemic circulation. (Source: GreenFacts)



The process by which a system responds to a disturbance that makes it deviate from its initial state. (Source: GreenFacts)



A particular kind of fishing activity, e.g., a trawl fishery or a particular species targeted, e.g., a cod fishery or salmon fishery. (Source: MA  Glossary )

Fossil fuel(s)

A general term for buried combustible geologic deposits of organic materials, formed from decayed plants and animals that have been converted to crude oil, coal, natural gas, or heavy oils by exposure to heat and pressure in the Earth's crust over hundreds of millions of years. (Source: US EPA Glossary of Climate Change terms  )


Water that is not salty, for instance water found in lakes, streams, and rivers, but not the ocean. Also used to refer to things living in or related to freshwater (e.g., "freshwater fish"). (Source: GreenFacts)



A moving body of ice that forms on land from the accumulation and compaction of snow, and that flows downslope or outward due to gravity and the pressure of its own weight. (Source: Alcwin Dictionary of Geology  )


Global warming potential

The global warming potential of a gas refers to the total contribution to global warming resulting from the emission of one unit of that gas relative to one unit of the reference gas, carbon dioxide, which is assigned a value of 1.

For example, if methane has a global warming potential of 21, it means that 1 kg of methane has the same impact on climate change as 21 kg of carbon dioxide and thus 1 kg of methane would count as 21 kg of carbon dioxide equivalent. (Source: based on American College & University Presidents Climate Commitment  Implementation Guide )


Greenhouse gas

Greenhouse gases are those gaseous constituents of the atmosphere, both natural and anthropogenic, that absorb and emit radiation at specific wavelengths within the spectrum of infrared radiation emitted by the Earth’s surface, the atmosphere and clouds.

This property causes the greenhouse effect.

Water vapour (H2O), carbon dioxide (CO2), nitrous oxide (N2O), methane (CH4), and ozone (O3) are the primary greenhouse gases in the Earth’s atmosphere. Moreover there are a number of entirely human-made greenhouse gases in the atmosphere, such as the halocarbons and other chlorine and bromine containing substances, dealt with under the Montreal Protocol. Beside CO2, N2O and CH4, the Kyoto Protocol deals with the greenhouse gases sulphur hexafluoride (SF6), hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs). (Source: IPCC Glossary  )

Greenland Ice Sheet

The Greenland Ice Sheet is a vast body of ice covering roughly 80% of the surface of Greenland. It is the second largest ice body in the world, after the Antarctic Ice Sheet.

Part of the top layer of ice of this ice sheet is melting during summer and the area where this is happening increased by about 16% between 1979 and 2002, an area roughly the size of Sweden. (Source: GreenFacts Digest on based onACIA )


Gross Domestic Product

The total market value of goods and services produced within a nation during a given period (usually 1 year).



Water beneath the Earth's surface in the spaces between soil particles and between rock surfaces. (Source: ATSDR Glossary of Terms  )

Gulf Stream

Current of warm ocean water that flows from the Gulf of Mexico to the coasts of Europe, providing the heat that keeps Europe warmer in winter than regions of North America at the same latitude. (Source: GreenFacts Digest on based on ACIA )

Ice cap, ice sheet, polar ice cap

An ice cap is a dome-shaped mass of glacier ice that spreads out in all directions; usually larger than an icefield but less than 50 000 km2.

An ice sheet is a dome-shaped mass of glacier ice that covers surrounding terrain and is greater than 50 000 km2, such as the Greenland and Antarctic ice sheets.

A polar ice cap, also called polar ice sheet, is a high-latitude region of land or water covered in ice-


Intergovernmental Panel on Climate Change

The Intergovernmental Panel on Climate Change (IPCC) has been established by WMO and UNEP to assess scientific, technical and socio- economic information relevant for the understanding of climate change, its potential impacts and options for adaptation and mitigation.

IPCC publications are prepared by three Working Groups (WG I, II and III) composed of hundreds of scientists from many countries. The IPCC's Fourth Assessment Report (4AR), published in 2007, is available at .

The "Summaries for Policymakers" by the three Working Groups, which were used as the source for the GreenFacts Digest on Climate Change (2007), can be found below:

The IPCC's previous report on climate change, the 2001 Third Assessment Report (TAR), was also summarised by GreenFacts (click here for the Digest).

In 2007, the IPCC shared the Nobel Peace Prize with Al Gore "for their efforts to build up and disseminate greater knowledge about man-made climate change, and to lay the foundations for the measures that are needed to counteract such change". (Source: IPCC website  )

Land use

The human use of a piece of land for a certain purpose (such as irrigated agriculture or recreation). Influenced by, but not synonymous with, land cover. (Source: MA  Glossary )


A site where household and industrial waste can be disposed of. It is generally spread in thin layers which are then covered with soil. (Source: GreenFacts)



A state of bad nourishment.

Malnutrition refers both to undernutrition and overnutrition, as well as to conditions arising from dietary imbalances leading to diet-related noncommunicable diseases. (Source: Millennium Ecosystem Assessment  Glossary )


A general name for several species of halophyte (plant that grows in soils that have a high content of various salts) belonging to different families of plants (including trees, shrubs, a palm tree and a ground fern) occurring in intertidal zones of tropical and subtropical sheltered coastlines and exceeding one half meter in height.

The term is applied to both the individual and the ecosystem, the latter of which is termed mangal. (Source: CoRIS glossary  )


Mass (weight) Units

The Metric System of Measurements uses the mass units: gram (g), kilogram (kg) and tonne (t).

1000 g = 1 kg
1000 kg = 1 tonne

Adding prefixes of the International System of Units (SI) allows to express weight as multiples or fractions of 1 gram:

1 gigatonne (Gt) =1 000 000 000 000 000 g
1 megatonne (Mt) =1 000 000 000 000 g
1 tonne (t) =1 000 000 g
1 kilogram (kg) =1 000 g
1 gram (g) =1 g
1 milligram (mg) =0.001 g
1 microgram (µg) =0.000 001 g
1 nanogram (ng) =0.000 000 001 g
1 picogram (pg) =0.000 000 000 001g

Imperial and US weight units can also be expressed as metric units:

Metric units
1 US ton (ton) =0.907 tonne
1 UK ton (ton) =1.016 tonne
1 lb (pound) =453.59 g
1 oz (ounce) =28.35g

Further information on the International System of Units (SI) is provided by the International Bureau of Weights and Measures (BIPM) 


Methane is a colorless, flammable, nontoxic gas with the chemical formula CH4.

This gas is formed naturally by the decomposition of organic matter. Wetlands, livestock and energy are the main sources of methane emissions to the atmosphere, where it acts as a greenhouse gas.

Methane is also a major component of natural gas. It is mainly extracted from geological deposits for fuel and industrial uses (Source: GreenFacts )

Millennium Development Goals

The Millennium Development Goals (MDGs), endorsed by governments at the United Nations in September 2000, aim to improve human well-being by reducing poverty, hunger, child and maternal mortality, ensuring education for all, controlling and managing diseases, tackling gender disparity, ensuring sustainable development and pursuing global partnerships.

The eight MDGs are:

Goal 1: Eradicate extreme poverty and hunger
Goal 2: Achieve universal primary education
Goal 3: Promote gender equality and empower women
Goal 4: Reduce child mortality
Goal 5: Improve maternal health
Goal 6: Combat HIV/AIDS, malaria and other disease
Goal 7: Ensure environmental sustainability
Goal 8: Develop a global partnership for development (Source: GreenFacts, based on the Millennium Ecosystem Assessment )


Nitrous oxide

Nitrous oxide is a colourless non-flammable gas with the chemical formula N2O.

This gas is naturally emitted by bacteria. The livestock sector and industry are the main anthropogenic sources of nitrous oxide emissions.

When released into the atmosphere it acts as a powerful greenhouse gas. (Source: GreenFacts)


Ozone is a form of oxygen having the molecular form of O3. It is a bluish, unstable gas with a pungent odour, found in two parts of the atmosphere: the stratosphere and the troposphere.

The ozone layer: The stratosphere contains a layer in which the concentration of ozone is greatest, the so called ozone layer. The layer extends from about 12 to 40 km. It shields the Earth from ultraviolet radiation's harmful health effects on humans and the environment. This layer is being depleted by human emissions of chlorine- and bromine-containing compounds.

Ground-level ozone: At ground level (in the troposphere), ozone is considered an air pollutant that can seriously affect the human respiratory system. It is a chemical oxidant and a major component of photochemical smog. (Source: GreenFacts)


Parts per million

A weight to weight ratio used to describe concentrations. Parts per million (ppm) is the number of units of mass of a contaminant per million units of total mass. (Source: GreenFacts)



A layer of soil or bedrock at a variable depth beneath the surface of the earth in which the temperature has been below freezing continuously from a few to several thousands of years.



pH is a measure of the concentration of protons (H+) in a solution and, therefore, its acidity or alkalinity. The concept was introduced by S.P.L. Sørensen in 1909. The p stands for the German "Potenz", meaning power or concentration, and the H for the hydrogen ion (H+). In layman's terms , the "pH" value is an approximate number between 0 and 14 that indicates whether a solution is acidic (pH < 7), basic (pH > 7) or neither (pH = 7) [neutral]. (Source: GreenFacts )



A group or number of people living within a specified area or sharing similar characteristics (such as occupation or age). (Source: ATSDR Glossary of Terms  )



The pronounced deprivation of well-being.

Income poverty refers to a particular formulation expressed solely in terms of per capita or household income. (Source: Millennium Ecosystem Assessment  Glossary )

Production / Productivity

Production is the process of creating, growing, manufacturing, or improving goods and services. It also refers to the quantity produced.

In economics, productivity is used to measure the efficiency or rate of production. It is the amount of output (e.g. number of goods produced) per unit of input (e.g. labor, equipment, and capital).

In biology, productivity is a measure of the efficiency with which a biological system converts energy into growth. (Source: GreenFacts)

Radiative Forcing

In the context of the IPCC assessments, radiative forcing refers to an external perturbation in the radiative energy budget of the Earth’s climate system, which may lead to changes in climate parameters.

A positive forcing (more incoming energy) tends to warm the system, while a negative forcing (more outgoing energy) tends to cool it. This is due to changes in drivers of climate change such as the concentration of carbon dioxide or the output of the Sun.

In the IPCC reports, changes in radiative forcing are relative to the year 1750. (Source: GreenFacts)


Planting of forests on lands that have previously contained forest but have since been converted to some other use. (Source: Millennium Ecosystem Assessment  Glossary )


A measure of the salt concentration of water. (Source: CoRIS Glossary  )


The buildup of salts in soils. (Source: Millennium Ecosystem Assessment  Glossary )



A plausible and often simplified description of how the future may develop, based on a coherent and internally consistent set of assumptions about key driving forces (e.g., rate of technology change, prices) and relationships.

Scenarios are neither predictions nor projections and sometimes may be based on a “narrative storyline.”

Scenarios may include projections but are often based on additional information from other sources. (Source: Millennium Ecosystem Assessment  Glossary )


Sea ice

Sea ice is frozen ocean water.

It occurs in both the Arctic and Antarctic and can cover large extents of water.

It grows during the winter months and melts during the summer months, but some sea ice remains all year in certain regions.

About 15 percent of the world's oceans are covered by sea ice during part of the year.

The freezing temperature of salt water is lower than fresh water; ocean temperatures must reach -1.8° C Celsius (28.8°F) to freeze. (Source: GreenFacts based on NSIDC All about sea ice )



A group of organisms that differ from all other groups of organisms and that are capable of breeding and producing fertile offspring. This is the smallest unit of classification for plants and animals. (Source: OceanLink Glossary of Common Terms and Definitions in Marine Biology  )


Storm surge

Storm surge is a rise in coastal water level caused by a regional low pressure area and water pushed toward coastal shores by prolonged wind forces.

A storm surge can significantly raise the mean water level if combined with astronomical high tides. This rise in water level can cause severe flooding on coastal areas, particularly along shallow slopes along the shoreline. (Source: British Columbia Flood Hazard Definitions   )



Financial assistance (often from governmental bodies) to businesses, citizens, or institutions to encourage a desired activity deemed beneficial. (Source: GreenFacts)



A characteristic or state whereby the needs of the present and local population can be met without compromising the ability of future generations or populations in other locations to meet their needs.


Swiss Agency for Development and Cooperation

"Poverty reduction and sustainable development are the principal tasks of the SDC. To facilitate the achievement of these goals, the SDC focuses on various thematic priorities. In each thematic domain, a sub-goal is targeted while ever keeping in mind the fact that the priority themes are intimately linked to one another." (Source: SDC website )


When the combined effect of several forces operating is greater than the sum of the separate effects of the forces. (Source: Millennium Ecosystem Assessment  Glossary )


"The mission of GRID-Arendal is to provide environmental information, communications and capacity building services for information management and assessment. Established to strengthen the United Nations through its Environment Programme (UNEP), our focus is to make credible, science-based knowledge understandable to the public and to decision-making for sustainable development.

GRID-Arendal provides analysis and supports communication on issues such as climate change, environment and poverty, environment and security, the urban environment and sustainable development through education." (Source: UNEP/GRID-Arendal website )

United Nations

"The United Nations was established on 24 October 1945 by 51 countries committed to preserving peace through international cooperation and collective security. Today, nearly every nation in the world belongs to the UN: membership totals 191 countries*.

When States become Members of the United Nations, they agree to accept the obligations of the UN Charter, an international treaty that sets out basic principles of international relations. According to the Charter, the UN has four purposes: to maintain international peace and security; to develop friendly relations among nations; to cooperate in solving international problems and in promoting respect for human rights; and to be a centre for harmonizing the actions of nations." (Source: UN website )

United Nations Environment Programme

"The United Nations Environment Programme (UNEP), established in 1972, works to encourage sustainable development through sound environmental practices everywhere. Its activities cover (...) the promotion of environmental science and information, to an early warning and emergency response capacity to deal with environmental disasters and emergencies."

See also UNEP.Net , which "delivers authoritative environmental information from a broad range of information and data providers (...)". (Source: UNEP website )

US Environment Protection Agency

The Environment Protection Agency's of the USA was founded in 1970. It's "mission is to protect human health and to safeguard the natural environment — air, water, and land — upon which life depends."

The EPA enforces federal environmental protection laws. It registers and regulates pesticides, enforces laws covering outdoor air and drinking water quality and regulates the disposal of hazardous and solid wastes.

It has now grown into a big and powerful administration: "18,000 people in Headquarters program offices, 10 regional offices, and 17 labs across the country, EPA employs a highly educated, technically trained staff, more than half of whom are engineers, scientists, and environmental protection specialists. A large number of employees are legal, public affairs, financial, and computer specialists."

U.S. EPA's scientific publications are widely recognized as reference materials. (Source: US EPA website  )

Water vapor

Water in its gaseous form.

In the atmosphere it acts as a natural greenhouse gas. (Source: GreenFacts)



Symbol: W

Unit of power equivalent to 1 joule of energy per second (1 J/s). (Source: GreenFacts)


World Business Council for Sustainable Development

"The World Business Council for Sustainable Development (WBCSD) is a coalition of 170 international companies united by a shared commitment to sustainable development via the three pillars of economic growth, ecological balance and social progress.

Our members are drawn from more than 35 countries and 20 major industrial sectors. We also benefit from a global network of 45 national and regional business councils and partner organizations located in 40 countries, involving some 1,000 business leaders globally.

The WBCSD's activities reflect our belief that the pursuit of sustainable development is good for business and business is good for sustainable development." (Source: WBCSD website )

World Wide Fund for Nature

The World Wide Fund for Nature (WWF) was founded in 1961 (formerly known as the World Wildlife Fund) and today is the world's largest conservation organization.

"WWF's mission is to stop the degradation of the planet's natural environment and to build a future in which humans live in harmony with nature, by:

  • conserving the world's biological diversity
  • .
  • resources is sustainable
  • promoting the reduction of pollution and wasteful consumption."

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