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

Climate Change 2001 Assessment


Glossary over Climate Change


The process of taking in. For a person or an animal, absorption is the process of a substance getting into the body through the eyes, skin, stomach, intestines, or lungs. (Source: ATSDR Glossary of Terms  )



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 )

Adaptive capacity

The general ability of institutions, systems, and individuals to adjust to potential damage, to take advantage of opportunities, or to cope with the consequences. (Source: Millennium Ecosystem Assessment
 Glossary )

Adverse health effect

A change in body function or cell structure that might lead to disease or health problems. (Source: ATSDR Glossary of Terms  )


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 )



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


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)


Background level(s)

Levels of chemical or physical agents that are normally found in the environment.

Two types of background levels may exist for chemical substances or physical agents: (a) Naturally occurring levels: ambient concentrations of substances or agents present in the environment, without human influence; (b) Anthropogenic levels: Concentrations of substances or agents present in the environment due to human-made, non-site sources (e.g., automobiles, industries). (Source: US EPA Glossary of IRIS Terms  )

Base station (in communications)

[A mobile phone base station is] a transmission and reception station in a fixed location, consisting of one or more receive/transmit antenna, microwave dish, and electronic circuitry, used to handle cellular traffic.

It serves as a bridge between all mobile users in a cell and connects mobile calls to the mobile switching center. (Source: Canadian Radio-television and Telecommunications Commission ; Data Collection - Telecommunications Glossary   )



Deviation of results or inferences from the truth, or processes leading to such systematic deviation. Any trend in the collection, analysis, interpretation, publication, or review of data that can lead to conclusions that are systematically different from the truth. (Source: CDC Glossary of Epidemiologic Terms  )


Bioaccumulation is used to describe the increase in concentration of a substance in an organism over time.

Bioaccumulative substances tend to be fat soluble and not to be broken down by the organism. (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)


Biologic uptake

The transfer of substances from the environment to plants, animals, and humans. (Source: ATSDR Glossary of Terms )



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



Ecological communities of living things, such as microorganisms, plants and animals; the communities form as a result of the physical surroundings, including the land, air, and water of an area. For example, deserts, grasslands, and tropical rainforests are biomes. (Source: Exploring the Environment Glossary  )



The part of the Earth and its atmosphere in which living organisms exist or that is capable of supporting life. (Source: NRDC glossary  )

Capacity building

A process of strengthening or developing human resources, institutions, organizations, or networks.

Also referred to as capacity development or capacity enhancement. (Source: MA,  Glossary )

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 monoxide (CO)

An odorless, colorless, and highly poisonous gas.


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)


Carbon stock

The quantity of carbon contained in a “pool”, meaning a reservoir or system which has the capacity to accumulate or release carbon. (Source: FAO Forestry Terms and definitions  )



The basic subunit of any living organism; the simplest unit that can exist as an independent living system. There are many different types of cells in complex organisms such as humans, each with specific characteristics. (Source: GreenFacts)



Cholera is a devastating and, sometimes, lethal disease caused by the bacterium Vibrio cholera.

Cholera usually spreads through contaminated water.

The symptoms are intense vomiting and extreme watery diarrhoea leading to dehydration, which, unless immediately treated, may be fatal.

Cholera can easily be cured by rehydration and administration of salts and electrolytes (Source: WHO, Treatment of Cholera  )


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 )


A material made up of two or more elements combined in a fixed ratio. (Source: CoRIS glossary  )



The amount of a chemical or substance present in a particular quantity of soil, water, air, food, blood, hair, urine, breath, or any other media. (Source: GreenFacts)


Controlled study

An experiment or clinical trial in which two groups are used for comparison purpose.



Very small freshwater crustacean, which moves by means of its larges antennae's, also known as "water flea", due to it specific motion. (Source: GreenFacts)


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


Degradation of ecosystems

A persistent reduction in the capacity to provide ecosystem services. (Source: MA  Glossary )



A delta is a low, watery land formed at the mouth of a river.

It is formed from the silt, sand and small rocks that flow downstream in the river and are deposited in the delta.

A delta is often (but not always) shaped like a triangle. (Source: NY Geography Glossary  )



Dengue is an infectious disease caused by a virus (genus Flavivirus). It is transmitted by mosquitoes in tropical and subtropical regions. It is characterized by high fever, severe headaches, and pain in muscles and joints.

(Source: GreenFacts )



The weight (mass) of a substance in a given volume (of that same substance). Examples of commonly used units are kg/m3 or g/cm3 for solids, and kg/l or g/ml for liquids and gases. Referring to a substance's density is to describe how heavy a substance is for its size. (Source: GreenFacts)


Dental erosion

Dental erosion is the loss of enamel and dentine from the tooth as a result of direct acid attack.

It is caused by excessive exposure to acid substances – such as those present in fruit juices and fizzy drinks – that are different from those produced by bacteria involved in the process of dental caries (decay).

Dental erosion is irreversible.

The most common teeth affected by dental erosion are the upper front teeth, although all teeth can be affected. Teeth that have been eroded look glassy, can appear short, and have uneven tips that are easily chipped away. (Source: GreenFacts, based on The Dental Centre Dental Erosion  )

Developmental effects

Effects in the developing offspring due to exposure before conception (either parent), prenatally, or postnatally to the time of sexual maturation. Developmental effects may be expressed at any time in the life span of the organism. Developmental effects are a subset of reproductive effects. (Source: CSIRO CSIRO biological effects and safety of EMR Glossary  )


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


Dryland systems

Dryland systems are ecosystems characterised by a lack of water. They include cultivated lands, scrublands, shrublands, grasslands, savannas, semi-deserts and true deserts.

The lack of water constrains the production of crops, forage, wood, and other ecosystem services.

Four dryland subtypes are widely recognized: dry sub-humid, semiarid, arid, and hyperarid, showing an increasing level of aridity or moisture deficit. (Source: GreenFacts based on Millennium Ecosystem Assessment  Glossary )


Ecosystem services

The benefits people obtain from ecosystems.

These include provisioning services such as food and water; regulating services such as flood and disease control; cultural services such as spiritual, recreational, and cultural benefits; and supporting services such as nutrient cycling that maintain the conditions for life on Earth. (Source: MA  Summary )



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   )

El Niño

El Niño, in its original sense, is a warm water current which periodically flows along the coast of Ecuador and Peru, disrupting the local fishery.

This oceanic event is associated with a fluctuation of the intertropical surface pressure pattern and circulation in the Indian and Pacific oceans, called the Southern Oscillation. This coupled atmosphere-ocean phenomenon is collectively known as El Niño-Southern Oscillation, or ENSO.

During an El Niño event, the prevailing trade winds weaken and the equatorial countercurrent strengthens, causing warm surface waters in the Indonesian area to flow eastward to overlie the cold waters of the Peru current.

This event has great impact on the wind, sea surface temperature and precipitation patterns in the tropical Pacific. It has climatic effects throughout the Pacific region and in many other parts of the world.

The opposite of an El Niño event is called La Niña. (Source: IPCC Glossary  )


Electromagnetic spectrum

The electromagnetic spectrum is the entire range of wavelengths of all known electromagnetic radiations. It includes:

Gamma rays have the smallest wavelengths and highest frequencies known. They are high energy waves capable of travelling long distances through air and are the most penetrating waves.

X-rays have longer wavelengths than gamma rays but smaller wavelengths and therefore higher energy than ultraviolet radiation. They have been used in various applications in science and industry and are primarily used in medicine for instance in radiography. They are a form of ionizing radiation and as such can be dangerous. X-rays are emitted by electrons outside the nucleus, while gamma rays are emitted by the nucleus.

Ultraviolet (UV) radiation is defined as the portion of the electromagnetic spectrum between X-rays and visible light. More...

Visible light – also known as the visible spectrum – is the portion of the electromagnetic spectrum that human eyes can detect. It covers all colours from blue at 400 nm to red at 700 nm, with blue light having more energy than red light.

Infrared (IR) radiation – also referred to as thermal radiation – is the portion of the electromagnetic spectrum lying between visible light and microwaves. The most important natural source of infrared radiation is the sun.

Radio waves have long wavelengths, ranging from a few centimetres to many thousands of kilometres in length. They are used among other things for television, cell phone and radio communications. (Source: GreenFacts)


Endangered species

Species that face a very high risk of extinction in the wild. (Source: MA  Glossary )


Environmental cycles

A natural process in which elements are continuously cycled in various forms between different compartments of the environment (e.g., air, water, soil, organisms).

Examples include the carbon, nitrogen and phosphorus cycles (nutrient cycles) and the water cycle. (Source: GreenFacts)



The widespread outbreak of a disease, or a large number of cases of a disease in a single community or relatively small area. (Source: CoRIS Glossary  )


Fairness of rights, distribution, and access. Depending on context, this can refer to resources, services, or power. (Source: Millennium Ecosystem Assessment  Glossary )

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)



The process by which micro-organisms break down complex organic substances generally in the absence of oxygen to produce alcohol and carbon dioxide. (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 )


The Food and Agriculture Organization (FAO) defines “forest” as a portion of land bigger than half a hectare (5 000m2) with trees higher than 5 meters and a tree canopy cover of more than 10 %, or with trees that will be able to meet these criteria.

It does not include land that is predominantly under agricultural or urban land use.


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  )


Frequency is the measurement of the number of times that a repeated event occurs per unit of time.

The frequency of wave-like patterns including sound, electromagnetic waves (such as radio or light), electrical signals, or other waves, expresses the number of cycles of the repetitive waveform per second.

In SI units, the result is measured in Hertz (Hz), named after the German physicist, Heinrich Rudolf Hertz. 1 Hz means one cycle (or wave) per second.

Frequency has an inverse relationship to the concept of wavelength (the distance between two peeks) such that the frequency is equal to the velocity divided by the wavelength. (Source: GreenFacts)


Frequency (in the context of sound)

Frequency is the measurement of the number of times that a repeated event occurs per unit of time.

The frequency of wave-like patterns including sound, electromagnetic waves (such as radio or light), electrical signals, or other waves, expresses the number of cycles of the repetitive waveform per second.

In SI units, the result is measured in Hertz (Hz), named after the German physicist, Heinrich Rudolf Hertz. 1 Hz means one cycle (or wave) per second.

Frequency has an inverse relationship to the concept of wavelength (the distance between two peaks) such that the frequency is equal to the velocity divided by the wavelength. (Source: GreenFacts)



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 Change Master Directory

"The mission of NASA's Global Change Master Directory (GCMD) is to assist the scientific community in the discovery of and linkage to Earth science data, as well as to provide data holders a means to advertise their data to the Earth science community."

See their Master Directory 

See also their main Q&A page:  (Source: GCMD website )

Global scale

The geographical realm encompassing all of Earth. (Source: MA  Glossary )

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  )

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  )


The location and environmental conditions in which a particular organism normally lives. (Source: MA  Glossary )

Human health

A state of complete physical, mental, and social well-being and not merely the absence of disease or infirmity.

The health of a whole community or population is reflected in measurements of disease incidence and prevalence, age-specific death rates, and life expectancy. (Source: MA Glossary  )

Hybrid (plant or animal)

In breeding, hybrids are plants or animals produced by the cross-breeding of two genetically different varieties or species. (Source: GreenFacts)



An ice-like compound formed by the reaction of water and carbon dioxide (CO2), methane (CH4) or similar gases. (Source: IPCC   Glossary )

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-



The frequency of a disease may be measured in two (standard) ways:

- Incidence is the number of new cases detected in the population at risk for the disease during a specific period.

- Prevalence (Source: Health canada Diabetes in Canada  )


It is the growth of a parasite within the human body that causes illness. It can be a virus, a bacteria, a fungus or a protozoa. (Source: GreenFacts )

Infrared radiation

Electromagnetic radiation with wavelengths longer than visible light, but shorter than microwave radiation, i.e. from approximately 750nm to 1mm. The name means "below red", red being the color of visible light of longest wavelength. (Source: GreenFacts)


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  )

International Institute for Sustainable Development

"The International Institute for Sustainable Development (... advances) policy recommendations on international trade and investment, economic policy, climate change, measurement and indicators, and natural resource management to make development sustainable. "

See "LINKAGES, an electronic clearing-house for information on past and upcoming international meetings related to environment and development policy": (Source: IISD website )

Land cover

The physical coverage of land, usually expressed in terms of vegetation cover or lack of it. Related to, but not synonymous with, land use. (Source: MA  Glossary )

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)


Macro policy

Macro Policy is policy which affects the whole country [or region].

It is concerned with monetary, fiscal, trade and exchange rate conditions as well as with economic growth, inflation and national employment levels.

It is distinct from micro policy which only affects particular sectors, districts, neighbourhoods or groups. (Source: Livelihoods Connect Glossary   )


Malaria is caused by a parasite called Plasmodium, which is transmitted via the bites of infected [female] mosquitoes. In the human body, the parasites multiply in the liver, and then infect red blood cells.

Symptoms of malaria include fever, headache, and vomiting, and usually appear between 10 and 15 days after the mosquito bite. If not treated, malaria can quickly become life-threatening by disrupting the blood supply to vital organs. In many parts of the world, the parasites have developed resistance to a number of malaria medicines.

Key interventions to control malaria include: prompt and effective treatment with artemisinin-based combination therapies; use of insecticidal nets by people at risk; and indoor residual spraying with insecticide to control the vector mosquitoes. (Source: WHO Malaria  )


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  )


Market-based instruments

Instruments of environmental policies in which a change in technology, behaviour or products is encouraged through financial incentives (either subsidies, taxes, price differentiation or market creation). (Source: Environmental Programme for the Danube River Basin Glossary   )


Mean / Median

In statistics, mean and median both provide an idea of where the “middle” of a sample is.

The mean (or average) is the sum of all scores divided by the number of scores. For instance the sum of individual ages of persons in a group divided by the number of persons in the group, gives the average age.

The median is the number in a range of scores that falls exactly in the middle so that 50% of the cases are above or below. (Source: GreenFacts)



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 )


Mathematical representation or simulation of an actual situation. (Source: GreenFacts)


A disease or the incidence of a disease within a population. (Source: GreenFacts)


Death. Usually the cause (a specific disease, a condition, or an injury) is stated. (Source: ATSDR Glossary of Terms   )

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)


The approximately 20 chemical elements known to be essential for the growth of living organisms, including nitrogen, sulfur, phosphorus, and carbon. (Source: Millennium Ecosystem Assessment Glossary   )


Organic arsenic compounds

Arsenic compounds containing carbon. They are mainly found in sea-living organisms, although some of these compounds have also been found in species living on land. (Source: GreenFacts)

Organization for Economic Co-operation and Development

The Organization for Economic Co-operation and Development (OECD) is "an international organisation helping governments tackle the economic, social and governance challenges of a globalised economy(... It) groups 30 member countries sharing a commitment to democratic government and the market economy."

See their Environment Pages:


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 billion

A weight to weight ratio used to describe concentrations. Parts per billion (ppb) is the number of units of mass of a contaminant per 1000 million units of total mass.

Also µg/L or micrograms per liter. (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.


Persistent organic pollutants

Persistent organic pollutants (POPs) are chemical substances that persist in the environment, bioaccumulate through the food web, and pose a risk of causing adverse effects to human health and the environment. This group of priority pollutants consists of pesticides (such as DDT), industrial chemicals (such as polychlorinated biphenyls, PCBs) and unintentional by-products of industrial processes (such as dioxins and furans).

Persistent Organic Pollutants are transported across international boundaries far from their sources, even to regions where they have never been used or produced. (Source: European Commission Environment DG POPs  )


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 )


The frequency of a disease may be measured in two (standard) ways:

  • Prevalence is the total number of persons known to have had the disease at any time during a specific period. It gives an idea of the importance/burden of disease at a given time, and it is widely used in public health monitoring and planning.
  • Incidence
Primary & secondary particles

Primary particles are directly released into the atmosphere by wind, combustion processes, or human activities.

Secondary particles are those that form in the atmosphere from other gaseous pollutants, particularly sulfur dioxide, nitrogen oxides, ammonia, and volatile organic compounds. (Source: GreenFacts)

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)


Energy moving in the form of particles or waves. Familiar radiations are heat, light, radio waves, and microwaves. Ionizing radiation is a very high-energy form of electromagnetic radiation. (Source: US Center for Disease Control and Prevention Glossary of Radiological Terms   )


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 )

Renewable energy

Energy produced from sources that can be renewed indefinitely, for example, hydro-, solar, geothermal, and wind power, as well as sustainably produced biomass. (Source: FAO  Forests and energy glossary )


Refers to the amount of disturbance or stress that an ecosystem can absorb and still remain capable of returning to its pre- disturbance state. (Source: GreenFacts, based on Millennium Ecosystem Assessment  Glossary )



The probability that something will cause injury or harm. (Source: ATSDR Glossary of Terms  )

Risk assessment

A scientifically based process consisting of four steps:

  • hazard identification,
  • hazard characterization,
  • exposure assessment and
  • risk characterization
(Source:   Official Journal of the European Communities 2002 L 31 )


Risk management

The process, distinct from risk assessment, of weighing policy alternatives in consultation with interested parties, considering risk assessment and other legitimate factors, and, if need be, selecting appropriate prevention and control measure. (Source: Official Journal of the European Communities 2002 L 31   )


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



"The mission of Science@NASA is to help the public understand how exciting NASA research is and to help NASA scientists fulfill their outreach responsibilities." Read the news in their Earth Science pages: 

(Source: Science@NASA website )

Scientific Consensus

The Scientific Consensus represents the position generally agreed upon at a given time by most scientists specialized in a given field. (Source: GreenFacts)


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  )



Anything capable of evoking a response in an organism. Examples of stimuli include irritants, sights, sounds, heat, cold, smells, or other sensations. (Source: Medline Plus Medical Encyclopedia   )

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   )



The highly stratified region of the atmosphere above the troposphere extending from about 10 km (ranging from 9 km in high latitudes to 16 km in the tropics on average) to about 50 km. (Source: Climate Change Glossary)



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



Sulphate is a salt of sulphuric acid. It refers both to the SO42- anion and to any compound that contains this ion.


Sulphur dioxide (SO2)

A corrosive gas produced by the burning of fuels, such as coal and oil, that contain sulphur. It is also produced from sea spray, organic decomposition and volcanic eruptions.

When combined with water in the air, it produces a weak, corrosive sulfuric acid - an ingredient of "acid rain". (Source: GreenFacts)

Surface water

Water on the surface of the Earth, such as in lakes, rivers, streams, ponds, and springs. (Source: ATSDR Glossary of Terms   )


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.



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 )

Temperate zone

The part of the Earth's surface between the Arctic Circle and the Tropic of Cancer or between the Antarctic Circle and the Tropic of Capricorn; characterized by temperate climate [i.e. mild, moderate temperature; neither hot nor cold]. (Source: WordNet Temperate zone )



Measures taken to treat a physical or mental disease.

First-line therapy is the first type of therapy given for a condition or disease.

Second-line therapy is the treatment that is given when initial treatment (first-line therapy) doesn't work, or stops working. (Source: based on St Jude Hospital Medical Terminology & Drug Database )

Thermohaline circulation

Large-scale density-driven circulation in the ocean, caused by differences in temperature and salinity.

In the north Atlantic, the thermohaline circulation consists of warm surface water flowing northward and cold deepwater flowing southward, resulting in a net poleward transport of heat.

The surface water sinks in highly restricted sinking regions located in high latitudes (Source: ACIA  Glossary )



A pattern of change over time, over and above short-term fluctuations. (Source: Millennium Ecosystem Assessment  Glossary )


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. (Source: GreenFacts)



A type of ecosystem dominated by lichens, mosses, grasses, and woody plants.

Tundra is found at high latitudes (arctic tundra) and high altitudes (alpine tundra).

Arctic tundra is underlain by permafrost and is usually [water] saturated. (Source: ACIA  Glossary )



An expression of the degree to which a future condition (e.g., of an ecosystem) is unknown.

Uncertainty can result from lack of information or from disagreement about what is known or even knowable. It may have many types of sources, from quantifiable errors in the data to ambiguously defined terminology or uncertain projections of human behavior. Uncertainty can therefore be represented by quantitative measures (e.g., a range of values calculated by various models) or by qualitative statements (e.g., reflecting the judgment of a team of experts). (Source: Millennium Ecosystem Assessment  Glossary )

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  )

US National Academies of Sciences

"The US National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. (... It) has a mandate that requires it to advise the federal government on scientific and technical matters."

Home page of the National Academy of Sciences: 

Home page of the National Academies: / 

Home page of the National Academy Press:  (Source: US National Academies of Sciences website )

US National Council for Science and the Environment

"The US National Council for Science and the Environment (NCSE) has been working since 1990 to improve the scientific basis for environmental decisionmaking. NCSE is supported by nearly 500 academic, scientific, environmental, and business organizations. (...) As a neutral science-based organization, NCSE promotes science and its relationship with decisionmaking only, and does not take positions on environmental issues themselves." (Source: NCSE website )


Defined by Webster to be the quality of a thing according to which it is thought of as being more or less desirable, useful, estimable or important.

Using this definition the value of an ecosystem might be defined in terms of its beauty, its uniqueness, its irreplacability, its contribution to life support functions or commercial or recreational opportunities, or its role in supporting wildlife or reducing environmental or human health risks, or providing many other services that benefit humans. (Source: Ecosystem Valuation Definition of Terms  )


Vulnerability (in ecosystems)

Exposure to contingencies and stress, and the difficulty in coping with them. (Source: Millennium Ecosystem Assessment  Glossary )


Vulnerability (in health science)

The likelihood of being unusually severely affected by a substance either as a result of susceptibility to the effects of these substances or as a result of a greater than average [exposure]. (Source: WHO Europe  Answers to follow-up questions from CAFE )

Water stress

Water stress occurs when the demand for water exceeds the available amount during a certain period or when poor quality restricts its use.

Water stress causes deterioration of fresh water resources in terms of quantity (aquifer over-exploitation, dry rivers, etc.) and quality (eutrophication, organic matter pollution, saline intrusion, etc.) (Source: UNEP Freshwater in Europe Glossary  )

Water vapor

Water in its gaseous form.

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



Withdrawal refers to the physical and mental symptoms drug-dependent people experience when they stop taking the drug they depend upon or when they drastically reduce its use. (Source: GreenFacts)


Woods Hole Research Center

"The Woods Hole Research Center conducts research, identifies policies, and supports educational activities that advance the well-being of humans and of the environment. Our mission is to understand the causes and consequences of environmental change as a basis for policy solutions for a better world. We specialize in ecological research on land use in the normally forested regions, including the Amazon Basin, Eurasia, the Congo Basin, and North America. We seek to conserve and sustain forests, soils, water, and energy by demonstrating their value to human health and economic prosperity. We work locally and regionally, assisting communities with resource management, and internationally to promote policies that stabilize climate and protect the integrity of the global environment." (Source: WHRC website )

World Health Organization

"The World Health Organization  (WHO) is the directing and coordinating authority on international health within the United Nations’ system. WHO experts produce health guidelines and standards, and help countries to address public health issues. WHO also supports and promotes health research. Through WHO, governments can jointly tackle global health problems and improve people’s well-being.

193 countries and two associate members are WHO’s membership. They meet every year at the World Health Assembly in Geneva to set policy for the Organization, approve the Organization’s budget, and every five years, to appoint the Director-General. Their work is supported by the 34-member Executive Board, which is elected by the Health Assembly. Six regional committees focus on health matters of a regional nature."

WHO's scientific publications are widely recognized as a reference source.

The WHO has a number of regional offices which address the specific issues of those regions.

WHO World Regional Offices
  WHO African Region  (46 countries)
  WHO European Region  (53 countries)
  WHO Eastern Mediterranean Region  (21 countries)
  WHO Region of the Americas  (35 countries)
  WHO South-East Asia Region  (11 countries)
  WHO Western Pacific Region  (27 countries)
World Resource Institute

The World Resource Institute (WRI) is a moderate Green advocacy group. It defines itself as "an environmental think tank that goes beyond research to find practical ways to protect the earth and improve people's lives."

It publishes Earthtrends on the Internet, an excellent environmental database:  (Source: WRI 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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