Glossary

  • ACTIVE LAYER

      A part of the soil which usually freezes in winter and thaws in summer, it can also be known as frost zone. 

    ADAPTATION

    Adaptation to climate change refers to nature or humans adjusting themselves to reduce the impact of actual or expected climate changes, or maybe even benefit from them.

    AEROSOLS

    Very small particles in the atmosphere of either natural or man-made origin, which may influence the weather or climate.

    AFFORESTATION

    Planting of new forests on land that has not recently been wooded.

    AIR CONDITIONING

      The cooling of air inside buildings to produce a comfortable temperature and humidity. This can be done using a heat pump, as in a fridge, or using natural means such as passing water through walls.

    ANTHROPOGENIC

    Resulting from human activity, often called “man-made` or “human-caused`.

    ANTHROPOGENIC EMISSIONS

    Emissions of greenhouse gases and other pollutants as a result of human activities such as burning fossil fuels for energy and deforestation.

    ARCHIPELAGO

      A chain, cluster or arc of islands, sometimes formed by volcanic action.

    ATMOSPHERE

    An envelope of gases surrounding the Earth. The main gases are nitrogen and oxygen, with smaller amounts of other gases such as water vapour, carbon dioxide and methane.

    ATTRIBUTION

    The process of assigning causes to changes in climate change which have been detected. These causes may be man-made or natural.
  • B

    BASIN

    The drainage area of a stream, river or lake.

    BIODIVERSITY

      The variation of different life forms in an ecosystem or the planet as a whole.

    BIOFUEL

    A fuel produced from dry organic matter or combustible oils produced by plants, such as alcohol from fermented sugar.

    BIOMASS

    Organic matter, including living organisms, and dead matter such as wood and leaves.

    BIOSPHERE (TERRESTRIAL AND MARINE)

    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).
  • C

    CAPACITY BUILDING

    In the context of climate change, capacity building is a process of developing the technical skills and resources of people and institutions to enable them to participate in all aspects of adaptation to, mitigation of, and research into, climate change.

    CARBON CYCLE

    The term used to describe the flow of carbon through the atmosphere, land, ocean and biospheres.

    CARBON DIOXIDE (CO2)

    A naturally occurring gas, and also a by-product of burning fossil fuels and biomass. It is the principal anthropogenic greenhouse gas that affects the Earth`s climate.

    CARBON FOOTPRINT

      The effect of human activities on the climate in terms of the net quantity of greenhouse gases generated through individual lifestyle choices.

    CLIMATE

    Climate is the description, in terms of the average (mean) and changes on a day-to-day or year-to-year basis, of temperature, precipitation and other elements of the weather, generally taken over a 30 year period.

    CLIMATE CHANGE

    Climate change refers to a significant variation in climate, persisting for decades or longer. Climate change may be due to natural processes (for example volcanoes) or to human-caused emissions of greenhouse gases and other pollutants. However, in the United Nations Framework on Climate Change (UNFCCC), ‘climate change’ means change which can be attributed to human activities.

    CLIMATE CHANGE IMPACTS

    Consequences of climate change on nature and people, such as rising sea-level.

    CLIMATE FEEDBACK

    A climate feedback is an initial process in the climate which leads to a change in another process in the climate, which then influences the initial one. There are many feedback mechanisms in the climate system that can either amplify (increase – ‘positive feedback’) or diminish (decrease – ‘negative feedback’) changes in the Earth’s climate.

    CLIMATE IMPACT ASSESSMENT

    Identifying the consequences of climate change on nature and people, and evaluating how important they are.

    CLIMATE MODEL (HIERARCHY)

    The numbers and equations that describe the climate system, including the physics, chemistry and biology going on within it, how they interact and affect each other. The most comprehensive models include detailed descriptions of atmosphere, land, oceans, snow and ice and the biosphere, and need powerful supercomputers to be able to use them.

    CLIMATE PROJECTION

    A projection of the response of the climate system to emissions of greenhouse gases and other pollutants, based upon calculations made by climate models.

    CLIMATE SYSTEM

    The climate system is made up of five major components: the atmosp

    CLIMATE VARIABILITY

    Climate variability refers to variations in the average climate from year to year and decade to decade. Variations can be due to many things, including volcanic eruptions and events like the El Niño weather event.

    CRYOSPHERE

    All the snow, ice, and permafrost on and beneath the surface of the Earth and oceans, including glaciers and ice-sheets.
  • D

    DEFORESTATION

    Conversion of forest to non-forest.

    DESERTIFICATION

    Reducing the quality and productivity of the land in arid or semi-arid areas. This may be the result of natural climatic variations or human activities.

    DETECTION

    Detection of climate change is the process of demonstrating that climate has changed in some way, without providing a reason for that change.

    DROUGHT

    A drought is said to exist when precipitation (rain or snowfall) has been significantly below normal levels for an extended time.
  • E

    ECOSYSTEM

    A system of interacting living organisms together with their physical environment.

    EL NIÑO

    A natural warming of the tropical Pacific Ocean east of the dateline, that typically occurs every few years. It has effects throughout the Pacific region and in many other parts of the world. At other times, there may be a cool phase called La Niña.

    EMISSIONS

    The human-caused release of greenhouse gases and other pollutants.

    EMISSIONS SCENARIO

    A way in which we think the emissions of greenhouse gases (and other pollutants) from human activities will change over time, based on assumptions about changes in how many people there will be in the world, and where they will live, economic growth, how much energy we will use and how we will produce it, etc.

    EVAPORATION

    The process by which a liquid becomes a gas.

    EXTREME WEATHER EVENT

    An extreme weather event is an event that is rare in a specific area or time; typically only on 10% of occasions. These may include heat waves, floods, droughts, hurricanes etc. Single extreme events cannot be attributed to human-caused climate change, as it is possible that the event in question might have occurred naturally.
  • F

    FOREST

    A vegetation type dominated by trees.

    FOSSIL CO2 EMISSIONS

    Emissions of carbon dioxide resulting from the burning of fossil fuels such as oil, natural gas, and coal.

    FOSSIL FUELS

    Carbon-based fuels from deposits, including coal, oil, and natural gas, which release carbon dioxide when they are burnt.
  • G

    GCM

    Global Climate Model, or General Circulation Model. Please see Climate Model

    GEO-ENGINEERING (ALSO CALLED CLIMATE ENGINEERING)

    Possible solutions to human-caused climate change that do not involve reducing the amount of greenhouse gases we emit. These include ways of reducing the amount of the Sun`s energy that reaches the Earth, or ways of storing the greenhouse gases we produce without releasing them into the atmosphere, or increasing the amount of carbon the biosphere removes from the atmosphere.

    GEOLOGICAL HISTORY

      A timescale linked to the history of the Earth since its origin 4,567 billion years ago.

    GLACIER

    A “river` of ice flowing downhill, often between the sides of a valley or surrounding peaks. A glacier is fed by snowfall at high altitudes; it melts at lower altitudes and (if near the sea) forms icebergs.

    GLOBAL WARMING

    A term frequently used to refer to anthropogenic (human-caused) climate change, characterised by a global increase in temperature.

    GREENHOUSE EFFECT

    Greenhouse gases effectively absorb infrared radiation (heat), emitted by the Earth`s surface. Thus greenhouse gases trap heat at the surface of the Earth and the lower atmosphere, and increase the temperature there.

    GREENHOUSE GAS (GHG)

    Gases in the atmosphere, both natural and anthropogenic, that absorb and release infrared radiation (heat). The main ones are water vapour (H2O), carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O) and ozone (O3).

    GULF STREAM

      A warm ocean current originating in the Gulf of Mexico which flows northward along the southeast coast of the United States before veering northeastward into the Atlantic Ocean, where it splits to form the North Atlantic Drift and the Canary Current. The Gulf Stream is mostly driven by the wind.
  • H

    HEAT WAVE

      A prolonged period of excessively hot weather for the season and the location.

    HYDROSPHERE

    Liquid water in the atmosphere and on the land, such as oceans, seas, rivers, freshwater lakes, etc.
  • I


    ICE CAP

    A dome shaped ice mass covering a highland area that is considerably smaller than an ice sheet.

    ICE SHEET

    A mass of land ice that is deep enough to cover most of the underlying mountains. There are only two ice sheets in the modern world, one on Greenland and two on Antarctica.

    ICE SHELF

    A large, thick, floating sheet of ice attached to a coast. Nearly all ice shelves are in Antarctica.

    INDIAN OCEAN DIPOLE (IOD)

      The IOD involves a periodic oscillation of sea-surface temperatures, between positive, neutral and negative phases. A positive phase sees greater than average sea-surface temperatures and greater precipitation in the western Indian Ocean region, with a corresponding cooling of waters in the eastern Indian Ocean. The negative phase of the IOD brings about the opposite conditions, with warmer water and greater precipitation in the eastern Indian Ocean, and cooler and drier conditions in the west. It can affect the Indian monsoon.

    INERTIA

    The fact that the climate system is slow to respond to things like human-caused emissions of CO2. This means that, even after emissions are reduced, the climate system will continue to change.

    INFRARED RADIATION

    Radiation emitted by the Earth`s surface, the atmosphere and clouds.

    INTERGOVERNMENTAL PANEL ON CLIMATE CHANGE (IPCC)

    Recognising the problem of potential global climate change the World Meteorological Organisation (WMO) and the United Nations Environment Programme (UNEP) established the Intergovernmental Panel on Climate Change (IPCC) in 1988. The IPCC is made up of the world’s leading scientists in the field of climate change. The role of the IPCC is to assess and review scientific, technical and socio-economic information associated with human-caused climate change.
  • K

    KYOTO PROTOCOL

    The Kyoto Protocol is an agreement between 183 countries adopted in 1997, which entered into force on 16 February 2005. Developed countries agreed to reduce their greenhouse gas emissions (carbon dioxide, methane, and others) by at least 5% below 1990 levels by 2012.
  • M

    MID-LATITUDES

    The areas between the tropics and the polar regions, typically between 30° to 60° North or South of the Equator. The weather in the mid-latitudes is different to the weather in the tropics or polar regions, and is dominated by warm and cold fronts.

    MILANKOVITCH CYCLES

      Periodic variations in the Earth’s orbit around the Sun.These cycles combine to affect the distribution of solar energy at the Earth’s surface and subsequently influence the seasons, weather and climate.

    MITIGATION

    Things that can be done to reduce the amount of greenhouse gases in the atmosphere in the future. These can include ways to produce energy without emitting as much greenhouse gas, or to reduce the need for energy.

    MONSOON

    Monsoons happen in the tropics and subtropics, and involve the main wind direction switching and a noticeable increase in rainfall. They are a result of the fact that land tends to heat up, and cool down, more quickly than oceans. Monsoon rains occur mainly over land in the summer.
  • N

    NORTH ATLANTIC OSCILLATION (NAO)

      Westerly winds blowing across the Atlantic bring moist air into Europe. A permanent low-pressure system over Iceland (the Icelandic Low) and a permanent high-pressure system over the Azores (the Azores High) control the direction and strength of the wind. The relative strengths and positions of the Icelandic Low and the Azores High vary from year to year and this variation is known as the NAO. A large difference in the pressure at the two stations leads to strong westerlies and, consequently, cool summers and mild and wet winters. If the difference is small the westerlies are suppressed and the temperature is more extreme in summer and winter leading to heat waves, deep freezes and reduced rainfall.
  • O

    OZONE

    A molecule, which in the upper atmosphere (stratosphere) filters potentially damaging ultraviolet light from the Sun and stops it reaching the Earth’s surface. Human-caused emissions of certain gases drastically reduce the amount of ozone in the stratosphere, allowing much more ultraviolet through to the Earth`s surface, particularly in polar regions. There is some hope that the ozone in the stratosphere will recover in the coming decades. In the lower atmosphere, ozone is a greenhouse gas, and is partly responsible for the poor air quality found in cities such as Mexico City.
  • P

    PERMAFROST

      Permanently frozen subsoil, occurring throughout the Polar Regions and locally in other continuously cold areas.

    PHYTOPLANKTON

      Minute, free floating aquatic plants

    PRECIPITATION

      Any form of water, such as rain, snow, sleet, or hail that falls to the Earth’s surface. The quantity of such water falling in a specific area within a specific period.
  • R

    RELATIVE SEA LEVEL

    Sea level measured relative to the land.

    S

    SEA ICE

    Floating ice created from the freezing of seawater. Sea ice can also freeze onto the land along a coastline.

    SEA LEVEL CHANGE

    A change in the average (mean) level of the sea. This may be because water expands as it gets warmer, or because of the additional water from the melting of land ice (glaciers, ice-sheets, etc) but not sea-ice.

    STABILISATION

    Finding a way to keep the amount of greenhouse gases in the atmosphere constant.

    STORM SURGE

    The temporary increase in the height of the sea, above the level expected from the tides alone, due to extremely low air pressure and/or strong winds blowing the water inland.

    STRATOSPHERE

    The region of the atmosphere between about 10-15 km and 50km, where temperature increases as you go higher.
  • T

    THERMAL EXPANSION

    As water gets warmer, it expands, leading to a rise in sea-level.

    THERMOHALINE CIRCULATION

    The world`s large-scale ocean circulation driven by differences in temperature and salinity.

    TIPPING POINTS

    Tipping points refer to abrupt climate change. An example of abrupt climate change would be the rapid loss of the Greenland ice sheet. However, abrupt changes like this are not likely to occur in the 21st century.

    TOPOGRAPHICAL MAP

      A map showing the relief of an area: That is the height of the land and its steepness. 

    TROPICAL CYCLONES (ALSO KNOWN AS HURRICANES, TYPHOONS)

    Very large, spinning low pressure systems that develop over warm water. Wind speeds are over 120 km/ hr and usually cause substantial damage.

    TROPICS

    The region between the Tropics of Cancer and Capricorn, where, at some point in the year, the Sun is directly overhead.
  • U

    UNITED NATIONS FRAMEWORK CONVENTION ON CLIMATE CHANGE (UNFCCC)

    A Convention signed by more than 150 countries in 1992. Its ultimate objective is the stabilisation of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system.

    URBAN HEAT ISLAND (UHI)

    An urban heat island is a town or city which is significantly warmer than its surrounding rural areas. The temperature difference is usually larger at night than during the day, and is most obvious when the wind is weak. One of the main causes of the urban heat island is the fact that there is little bare earth and vegetation in urban areas. This means that less energy is used up evaporating water, that less of the Sun’s energy is reflected and that more heat is stored by buildings and the ground in urban than in rural areas. The heat generated by heating, cooling, transport and other energy uses also contributes, particularly in winter, as does the complex three dimensional structure of the urban landscape.
  • W

    WEATHER

    Atmospheric processes and conditions occurred in a short period of time (a few minutes to days), such as temperature, rainfall, wind, thunder and lightning and so on. The weather in one place is linked to the weather around the Earth at the same time, and the weather one day is linked to the weather that will be experienced on the next day