Annex B. Glossary of Terms
This Glossary is based on the glossaries published in the IPCC Third Assessment
Report (IPCC, 2001a,b,c); however, additional work has been undertaken on consistency
and refinement of some of the terms. The terms that are independent entries
in this glossary are highlighted in italics.
The physiological adaptation to climatic variations.
Activities Implemented Jointly (AIJ)
The pilot phase for Joint Implementation, as defined in Article 4.2(a)
of the United Nations Framework Convention on Climate Change, that allows
for project activity among developed countries (and their companies) and between
developed and developing countries (and their companies). AIJ is intended to
allow Parties to the United Nations Framework Convention on Climate Change to
gain experience in jointly implemented project activities. There is no crediting
for AIJ activity during the pilot phase. A decision remains to be taken on the
future of AIJ projects and how they may relate to the Kyoto Mechanisms.
As a simple form of tradable permits, AIJ and other market-based schemes represent
important potential mechanisms for stimulating additional resource flows for
the global environmental good. See also Clean Development Mechanism and emissions
See Adaptive capacity.
Adjustment in natural or human systems to a new or changing environment.
Adaptation to climate change refers to adjustment in natural or human
systems in response to actual or expected climatic stimuli or their effects,
which moderates harm or exploits beneficial opportunities. Various types of
adaptation can be distinguished, including anticipatory and reactive adaptation,
private and public adaptation, and autonomous and planned adaptation.
The practice of identifying options to adapt to climate change and evaluating
them in terms of criteria such as availability, benefits, costs, effectiveness,
efficiency, and feasibility.
The avoided damage costs or the accrued benefits following the adoption and
implementation of adaptation measures.
Costs of planning, preparing for, facilitating, and implementing adaptation
measures, including transition costs.
The ability of a system to adjust to climate change (including climate
variability and extremes) to moderate potential damages, to take advantage
of opportunities, or to cope with the consequences.
Reduction in emissions by sources or enhancement of removals by
sinks that is additional to any that would occur in the absence of a Joint Implementation
or a Clean Development Mechanism project activity as defined in the Kyoto
Protocol Articles on Joint Implementation and the Clean Development
Mechanism. This definition may be further broadened to include financial,
investment, and technology additionality. Under "financial additionality,"
the project activity funding shall be additional to existing Global Environmental
Facility, other financial commitments of Parties included in Annex I, Official
Development Assistance, and other systems of cooperation. Under "investment
additionality," the value of the Emissions Reduction Unit/Certified Emission
Reduction Unit shall significantly improve the financial and/or commercial
viability of the project activity. Under "technology additionality," the technology
used for the project activity shall be the best available for the circumstances
of the host Party.
See Lifetime; see also Response time.
A collection of airborne solid or liquid particles, with a typical size
between 0.01 and 10 µm that reside in the atmosphere for at least
several hours. Aerosols may be of either natural or anthropogenic origin.
Aerosols may influence climate in two ways: directly through scattering and
absorbing radiation, and indirectly through acting as condensation nuclei for
cloud formation or modifying the optical properties and lifetime of clouds.
See indirect aerosol effect.
Planting of new forests on lands that historically have not contained
forests. For a discussion of the term forest and related terms such as afforestation,
reforestation, and deforestation, see the IPCC Special Report
on Land Use, Land- Use Change, and Forestry (IPCC, 2000b).
Total impacts summed up across sectors and/or regions. The aggregation of impacts
requires knowledge of (or assumptions about) the relative importance of impacts
in different sectors and regions. Measures of aggregate impacts include, for
example, the total number of people affected, change in net primary productivity,
number of systems undergoing change, or total economic costs.
The fraction of solar radiation reflected by a surface or object,
often expressed as a percentage. Snow covered surfaces have a high albedo; the
albedo of soils ranges from high to low; vegetation covered surfaces and oceans
have a low albedo. The Earth's albedo varies mainly through varying cloudiness,
snow, ice, leaf area, and land cover changes.
A reproductive explosion of algae in a lake, river, or ocean.
The biogeographic zone made up of slopes above timberline and characterized
by the presence of rosette-forming herbaceous plants and low shrubby slow-growing
Alternative development paths
Refer to a variety of possible scenarios for societal values
and consumption and production patterns in all countries, including, but not
limited to, a continuation of today's trends. In this report, these paths do
not include additional climate initiatives which means that no scenarios
are included that explicitly assume implementation of the United Nations
Framework Convention on Climate Change or the emission targets of the Kyoto
Protocol, but do include assumptions about other policies that influence
greenhouse gas emissions indirectly.
Energy derived from non-fossil-fuel sources.
The ancillary, or side effects, of policies aimed exclusively at climate
change mitigation. Such policies have an impact not only on greenhouse
gas emissions, but also on resource use efficiency, like reduction in emissions
of local and regional air pollutants associated with fossil-fuel use,
and on issues such as transportation, agriculture, land-use practices,
employment, and fuel security. Sometimes these benefits are referred to as "ancillary
impacts" to reflect that in some cases the benefits may be negative. From the
perspective of policies directed at abating local air pollution, greenhouse
gas mitigation may also be considered an ancillary benefit, but these relationships
are not considered in this assessment.
Annex I countries/Parties
Group of countries included in Annex I (as amended in 1998) to the United
Nations Framework Convention on Climate Change, including all the developed
countries in the Organisation for Economic Cooperation and Development, and
economies in transition. By default, the other countries are referred
to as non-Annex I countries. Under Articles 4.2(a) and 4.2(b) of the
Convention, Annex I countries commit themselves specifically to the aim of returning
individually or jointly to their 1990 levels of greenhouse gas emissions
by the year 2000. See also Annex II, Annex B, and non-Annex B countries.
Annex II countries
Group of countries included in Annex II to the United Nations Framework Convention
on Climate Change, including all developed countries in the Organisation
for Economic Cooperation and Development. Under Article 4.2(g) of the Convention,
these countries are expected to provide financial resources to assist developing
countries to comply with their obligations, such as preparing national reports.
Annex II countries are also expected to promote the transfer of environmentally
sound technologies to developing countries. See also Annex I, Annex B,
non-Annex I, and non-Annex B countries/Parties.
Annex B countries/Parties
Group of countries included in Annex B in the Kyoto Protocol that have
agreed to a target for their greenhouse gas emissions, including all
the Annex I countries (as amended in 1998) but Turkey and Belarus. See
also Annex II, non- Annex I, and non-Annex B countries/Parties.
Resulting from or produced by human beings.
Emissions of greenhouse gases, greenhouse gas precursors, and
aerosols associated with human activities. These include burning of fossil
fuels for energy, deforestation, and land-use changes that
result in net increase in emissions.
Breeding and rearing fish, shellfish, etc., or growing plants for food in special
A stratum of permeable rock that bears water. An unconfined aquifer is recharged
directly by local rainfall, rivers, and lakes, and the rate of recharge will
be influenced by the permeability of the overlying rocks and soils. A confined
aquifer is characterized by an overlying bed that is impermeable and the local
rainfall does not influence the aquifer.
Ecosystems with less than 250 mm precipitation per year.
Assigned amounts (AAs)
Under the Kyoto Protocol, the total amount of greenhouse gas emissions
that each Annex B country has agreed that its emissions will not exceed
in the first commitment period (2008 to 2012) is the assigned amount. This is
calculated by multiplying the country's total greenhouse gas emissions in 1990
by five (for the 5-year commitment period) and then by the percentage it agreed
to as listed in Annex B of the Kyoto Protocol (e.g., 92% for the European Union,
93% for the USA).
Assigned amount unit (AAU)
Equal to 1 tonne (metric ton) of CO2-equivalent emissions
calculated using the Global Warming Potential.
The gaseous envelop surrounding the Earth. The dry atmosphere consists almost
entirely of nitrogen (78.1% volume mixing ratio) and oxygen (20.9% volume
mixing ratio), together with a number of trace gases, such as argon (0.93%
volume mixing ratio), helium, and radiatively active greenhouse gases
such as carbon dioxide (0.035% volume mixing ratio) and ozone.
In addition, the atmosphere contains water vapor, whose amount is highly variable
but typically 1% volume mixing ratio. The atmosphere also contains clouds and
See detection and attribution.
According to the Kyoto Protocol [Article 3(13)], Parties included in
Annex I to the United Nations Framework Convention on Climate Change
may save excess emissions allowances or credits from the first commitment
period for use in subsequent commitment periods (post-2012).
The baseline (or reference) is any datum against which change is measured.
It might be a "current baseline," in which case it represents observable, present-day
conditions. It might also be a "future baseline," which is a projected future
set of conditions excluding the driving factor of interest. Alternative interpretations
of the reference conditions can give rise to multiple baselines.
The drainage area of a stream, river, or lake.
The numbers and relative abundances of different genes (genetic diversity),
species, and ecosystems (communities) in a particular area.
A fuel produced from dry organic matter or combustible oils produced by plants.
Examples of biofuel include alcohol (from fermented sugar), black liquor from
the paper manufacturing process, wood, and soybean oil.
The total mass of living organisms in a given area or volume; recently dead
plant material is often included as dead biomass.
A grouping of similar plant and animal communities into broad landscape units
that occur under similar environmental conditions.
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), including derived dead organic matter such as litter, soil
organic matter, and oceanic detritus.
All living organisms of an area; the flora and fauna considered as a unit.
Operationally defined species based on measurement of light absorption and chemical
reactivity and/or thermal stability; consists of soot, charcoal, and/or possible
light-absorbing refractory organic matter (Charlson and Heintzenberg, 1995).
A poorly drained area rich in accumulated plant material, frequently surrounding
a body of open water and having a characteristic flora (such as sedges, heaths,
Forests of pine, spruce, fir, and larch stretching from the east coast
of Canada westward to Alaska and continuing from Siberia westward across the
entire extent of Russia to the European Plain.
A modeling approach that includes technological and engineering details in the
analysis. See also top-down models.
The total mass of a gaseous substance of concern in the atmosphere.
In the context of climate change, capacity building is a process of developing
the technical skills and institutional capability in developing countries and
economies in transition to enable them to participate in all aspects
of adaptation to, mitigation of, and research on climate change,
and the implementation of the Kyoto Mechanisms, etc.
Aerosol consisting predominantly of organic substances and various forms of
black carbon (Charlson and Heintzenberg, 1995).
The term used to describe the flow of carbon (in various forms such as as carbon
dioxide) through the atmosphere, ocean, terrestrial biosphere,
Carbon dioxide (CO2)
A naturally occurring gas, and also a by-product of burning fossil fuels
and biomass, as well as land-use changes and other industrial
processes. It is the principal anthropogenic greenhouse gas that affects
the Earth's radiative balance. It is the reference gas against which
other greenhouse gases are measured and therefore has a Global Warming Potential
Carbon dioxide (CO2) fertilization
The enhancement of the growth of plants as a result of increased atmospheric
carbon dioxide concentration. Depending on their mechanism of photosynthesis,
certain types of plants are more sensitive to changes in atmospheric carbon
dioxide concentration. In particular, plants that produce a three-carbon compound
(C3) during photosynthesis—including most trees and agricultural
crops such as rice, wheat, soybeans, potatoes, and vegetables—generally show
a larger response than plants that produce a four-carbon compound (C4)
during photosynthesis—mainly of tropical origin, including grasses and the agriculturally
important crops maize, sugar cane, millet, and sorghum.
See emissions tax.
An area that collects and drains rainwater.
Certified Emission Reduction (CER) Unit
Equal to 1 tonne (metric ton) of CO2-equivalent emissions
reduced or sequestered through a Clean Development Mechanism project,
calculated using Global Warming Potentials. See also Emissions Reduction
Greenhouse gases covered under the 1987 Montreal Protocol and
used for refrigeration, air conditioning, packaging, insulation, solvents, or
aerosol propellants. Since they are not destroyed in the lower atmosphere,
CFCs drift into the upper atmosphere where, given suitable conditions, they
break down ozone. These gases are being replaced by other compounds,
including hydrochlorofluorocarbons and hydrofluorocarbons, which are
greenhouse gases covered under the Kyoto Protocol.
An intestinal infection that results in frequent watery stools, cramping abdominal
pain, and eventual collapse from dehydration.
Clean Development Mechanism (CDM)
Defined in Article 12 of the Kyoto Protocol, the Clean Development Mechanism
is intended to meet two objectives: (1) to assist Parties not included in Annex
I in achieving sustainable development and in contributing to the
ultimate objective of the convention; and (2) to assist Parties included
in Annex I in achieving compliance with their quantified emission limitation
and reduction commitments. Certified Emission Reduction Units
from Clean Development Mechanism projects undertaken in non-Annex I countries
that limit or reduce greenhouse gas emissions, when certified by operational
entities designated by Conference of the Parties/Meeting of the Parties,
can be accrued to the investor (government or industry) from Parties in Annex
B. A share of the proceeds from the certified project activities is used
to cover administrative expenses as well as to assist developing country Parties
that are particularly vulnerable to the adverse effects of climate change
to meet the costs of adaptation.
Climate in a narrow sense is usually defined as the "average weather" or more
rigorously as the statistical description in terms of the mean and variability
of relevant quantities over a period of time ranging from months to thousands
or millions of years. The classical period is 30 years, as defined by the World
Meteorological Organization (WMO). These relevant quantities are most often
surface variables such as temperature, precipitation, and wind. Climate in a
wider sense is the state, including a statistical description, of the climate
Climate change refers to a statistically significant variation in either the
mean state of the climate or in its variability, persisting for an extended
period (typically decades or longer). Climate change may be due to natural internal
processes or external forcings, or to persistent anthropogenic
changes in the composition of the atmosphere or in land use. Note
that the United Nations Framework Convention on Climate Change (UNFCCC),
in its Article 1, defines "climate change" as: "a 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." The UNFCCC thus makes a distinction
between "climate change" attributable to human activities altering the atmospheric
composition, and "climate variability" attributable to natural causes. See also
An interaction mechanism between processes in the climate system is called
a climate feedback, when the result of an initial process triggers changes in
a second process that in turn influences the initial one. A positive feedback
intensifies the original process, and a negative feedback reduces it.
Climate model (hierarchy)
A numerical representation of the climate system based on the physical,
chemical, and biological properties of its components, their interactions and
feedback processes, and accounting for all or some of its known properties.
The climate system can be represented by models of varying complexity—that is,
for any one component or combination of components a "hierarchy" of models can
be identified, differing in such aspects as the number of spatial dimensions,
the extent to which physical, chemical or biological processes are explicitly
represented, or the level at which empirical parametrizations are involved.
Coupled atmosphere/ocean/sea-ice general circulation models (AOGCMs)
provide a comprehensive representation of the climate system. There is an evolution
towards more complex models with active chemistry and biology. Climate models
are applied, as a research tool, to study and simulate the climate, but also
for operational purposes, including monthly, seasonal, and interannual climate
A climate prediction or climate forecast is the result of an attempt to produce
a most likely description or estimate of the actual evolution of the climate
in the future (e.g., at seasonal, interannual, or long-term time-scales).
See also climate projection and climate (change) scenario.
A projection of the response of the climate system to emission
or concentration scenarios of greenhouse gases and aerosols,
or radiative forcing scenarios, often based upon simulations by climate
models. Climate projections are distinguished from climate predictions
in order to emphasize that climate projections depend upon the emission/concentration/radiative
forcing scenario used, which are based on assumptions, concerning, for example,
future socio-economic and technological developments that may or may not be
realized, and are therefore subject to substantial uncertainty.
A plausible and often simplified representation of the future climate,
based on an internally consistent set of climatological relationships, that
has been constructed for explicit use in investigating the potential consequences
of anthropogenic climate change, often serving as input to impact models.
Climate projections often serve as the raw material for constructing
climate scenarios, but climate scenarios usually require additional information
such as about the observed current climate. A "climate change scenario" is the
difference between a climate scenario and the current climate.
In IPCC assessments, "equilibrium climate sensitivity" refers to the equilibrium
change in global mean surface temperature following a doubling of the atmospheric
(equivalent) CO2 concentration. More generally, equilibrium
climate sensitivity refers to the equilibrium change in surface air temperature
following a unit change in radiative forcing (°C/Wm-2). In
practice, the evaluation of the equilibrium climate sensitivity requires very
long simulations with coupled general circulation models. The "effective
climate sensitivity" is a related measure that circumvents this requirement.
It is evaluated from model output for evolving non-equilibrium conditions. It
is a measure of the strengths of the feedbacks at a particular time and
may vary with forcing history and climate state. See climate model.
The climate system is the highly complex system consisting of five major components:
the atmosphere, the hydrosphere, the cryosphere, the land
surface and the biosphere, and the interactions between them. The climate
system evolves in time under the influence of its own internal dynamics and
because of external forcings such as volcanic eruptions, solar variations, and
human-induced forcings such as the changing composition of the atmosphere and
Climate variability refers to variations in the mean state and other statistics
(such as standard deviations, the occurrence of extremes, etc.) of the climate
on all temporal and spatial scales beyond that of individual weather
events. Variability may be due to natural internal processes within the climate
system (internal variability), or to variations in natural or anthropogenic
external forcing (external variability). See also climate change.
See equivalent CO2.
See carbon dioxide (CO2) fertilization.
The benefits of policies that are implemented for various reasons at the same
time—including climate change mitigation—acknowledging that most policies
designed to address greenhouse gas mitigation also have other, often
at least equally important, rationales (e.g., related to objectives of development,
sustainability, and equity). The term co-impact is also used in a more generic
sense to cover both the positive and negative sides of the benefits. See also
The use of waste heat from electric generation, such as exhaust from gas turbines,
for either industrial purposes or district heating.
Conference of the Parties (COP)
The supreme body of the United Nations Framework Convention on Climate Change
(UNFCCC), comprising countries that have ratified or acceded to the UNFCCC.
The first session of the Conference of the Parties (COP-1) was held in Berlin
in 1995, followed by COP-2 in Geneva 1996, COP-3 in Kyoto 1997, COP-4 in Buenos
Aires 1998, COP-5 in Bonn 1999, COP-6 Part 1 in The Hague 2000, and COP-6 Part
2 in Bonn 2001. COP-7 is scheduled for November 2001 in Marrakech. See also
Meeting of the Parties (MOP).
Cooling degree days
The integral over a day of the temperature above 18°C (e.g., a day with an average
temperature of 20°C counts as 2 cooling degree days). See also heating degree
The variation in climatic stimuli that a system can absorb without producing
The paling in color of corals resulting from a loss of symbiotic algae. Bleaching
occurs in response to physiological shock in response to abrupt changes in temperature,
salinity, and turbidity.
A criterion that specifies that a technology or measure delivers a good
or service at equal or lower cost than current practice, or the least-cost alternative
for the achievement of a given target.
The component of the climate system consisting of all snow, ice, and
permafrost on and beneath the surface of the earth and ocean. See also
glacier and ice sheet.
Occurs when seawater freezes to form sea ice. The local release of salt and
consequent increase in water density leads to the formation of saline coldwater
that sinks to the ocean floor.
Conversion of forest to non-forest. For a discussion of the term forest and
related terms such as afforestation, reforestation, and deforestation,
see the IPCC Special Report on Land Use, Land-Use Change, and Forestry (IPCC,
Policies and programs designed for a specific purpose to influence consumer
demand for goods and/or services. In the energy sector, for instance, it refers
to policies and programs designed to reduce consumer demand for electricity
and other energy sources. It helps to reduce greenhouse gas emissions.
An infectious viral disease spread by mosquitoes often called breakbone fever
because it is characterized by severe pain in joints and back. Subsequent infections
of the virus may lead to dengue haemorrhagic fever (DHF) and dengue shock syndrome
(DSS), which may be fatal.
Combines a deposit or fee (tax) on a commodity with a refund or rebate (subsidy)
for implementation of a specified action. Se also emissions tax.
An ecosystem with less than 100 mm precipitation per year.
Land degradation in arid, semi-arid, and dry sub-humid areas resulting
from various factors, including climatic variations and human activities. Further,
the United Nations Convention to Combat Desertification defines land degradation
as a reduction or loss in arid, semi-arid, and dry sub-humid areas of the biological
or economic productivity and complexity of rain-fed cropland, irrigated cropland,
or range, pasture, forest, and woodlands resulting from land uses
or from a process or combination of processes, including processes arising from
human activities and habitation patterns, such as: (i) soil erosion caused
by wind and/or water; (ii) deterioration of the physical, chemical, and biological
or economic properties of soil; and (iii) long-term loss of natural vegetation.
Detection and attribution
Climate varies continually on all time scales. Detection of climate
change is the process of demonstrating that climate has changed in some
defined statistical sense, without providing a reason for that change. Attribution
of causes of climate change is the process of establishing the most likely causes
for the detected change with some defined level of confidence.
Frequency, intensity, and types of disturbances, such as fires, inspect or pest
outbreaks, floods, and droughts.
Diurnal temperature range
The difference between the maximum and minimum temperature during a day.
The effect that revenue-generating instruments, such as carbon taxes
or auctioned (tradable) carbon emission permits, can (i) limit or reduce greenhouse
gas emissions and (ii) offset at least part of the potential welfare losses
of climate policies through recycling the revenue in the economy to reduce other
taxes likely to be distortionary. In a world with involuntary unemployment,
the climate change policy adopted may have an effect (a positive or negative
"third dividend") on employment. Weak double dividend occurs as long as there
is a revenue recycling effect—that is, as long as revenues are recycled
through reductions in the marginal rates of distortionary taxes. Strong double
dividend requires that the (beneficial) revenue recycling effect more than offset
the combination of the primary cost and, in this case, the net cost of abatement
The phenomenon that exists when precipitation has been significantly below normal
recorded levels, causing serious hydrological imbalances that adversely affect
land resource production systems.
Economic potential is the portion of technological potential for greenhouse
gas emissions reductions or energy efficiency improvements that could
be achieved cost-effectively through the creation of markets, reduction
of market failures, or increased financial and technological transfers. The
achievement of economic potential requires additional policies and
measures to break down market barriers. See also market potential,
socio-economic potential, and technological potential.
Economies in transition (EITs)
Countries with national economies in the process of changing from a planned
economic system to a market economy.
A system of interacting living organisms together with their physical environment.
The boundaries of what could be called an ecosystem are somewhat arbitrary,
depending on the focus of interest or study. Thus, the extent of an ecosystem
may range from very small spatial scales to, ultimately, the entire Earth.
Ecological processes or functions that have value to individuals or society.
El Niño Southern Oscillation (ENSO)
El Niño, in its original sense, is a warmwater current that 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 atmosphereocean 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.
In the climate change context, emissions refer to the release of greenhouse
gases and/or their precursors and aerosols into the atmosphere
over a specified area and period of time.
An emissions permit is the non-transferable or tradable allocation of entitlements
by an administrative authority (intergovernmental organization, central or local
government agency) to a regional (country, sub-national) or a sectoral (an individual
firm) entity to emit a specified amount of a substance.
The portion or share of total allowable emissions assigned to a country
or group of countries within a framework of maximum total emissions and mandatory
allocations of resources.
Emissions Reduction Unit (ERU)
Equal to 1 tonne (metric ton) of carbon dioxide emissions reduced or
sequestered arising from a Joint Implementation (defined in Article 6
of the Kyoto Protocol) project calculated using Global Warming Potential.
See also Certified Emission Reduction Unit and emissions trading.
Levy imposed by a government on each unit of CO2-equivalent
emissions by a source subject to the tax. Since virtually all of
the carbon in fossil fuels is ultimately emitted as carbon dioxide,
a levy on the carbon content of fossil fuels—a carbon tax—is equivalent
to an emissions tax for emissions caused by fossil-fuel combustion. An energy
tax—a levy on the energy content of fuels—reduces demand for energy and
so reduces carbon dioxide emissions from fossil-fuel use. An ecotax is designated
for the purpose of influencing human behavior (specifically economic behavior)
to follow an ecologically benign path. International emissions/carbon/energy
tax is a tax imposed on specified sources in participating countries by an international
agency. The revenue is distributed or used as specified by participating countries
or the international agency.
A market-based approach to achieving environmental objectives that allows, those
reducing greenhouse gas emissions below what is required, to use or trade
the excess reductions to offset emissions at another source inside or outside
the country. In general, trading can occur at the intracompany, domestic, and
international levels. The IPCC Second Assessment Report adopted the convention
of using "permits" for domestic trading systems and "quotas" for international
trading systems. Emissions trading under Article 17 of the Kyoto Protocol
is a tradable quota system based on the assigned amounts calculated from
the emission reduction and limitation commitments listed in Annex B of
the Protocol. See also Certified Emission Reduction Unit and Clean
A plausible representation of the future development of emissions of substances
that are potentially radiatively active (e.g., greenhouse gases, aerosols),
based on a coherent and internally consistent set of assumptions about driving
forces (such as demographic and socio-economic development, technological change)
and their key relationships. Concentration scenarios, derived from emissions
scenarios, are used as input into a climate model to compute climate
projections. In IPCC (1992), a set of emissions scenarios were used as a
basis for the climate projections in IPCC (1996). These emissions scenarios
are referred to as the IS92 scenarios. In the IPCC Special Report on Emissions
Scenarios (Nakicenovic et al., 2000), new emissions scenarios—the so-called
SRES scenarios—were published. For the meaning of some terms related
to these scenarios, see SRES scenarios.
Restricted or peculiar to a locality or region. With regard to human health,
endemic can refer to a disease or agent present or usually prevalent in a population
or geographical area at all times.
Averaged over the globe and over longer time periods, the energy budget of the
climate system must be in balance. Because the climate system derives
all its energy from the Sun, this balance implies that, globally, the amount
of incoming solar radiation must on average be equal to the sum of the
outgoing reflected solar radiation and the outgoing infrared radiation
emitted by the climate system. A perturbation of this global radiation balance,
be it human-induced or natural, is called radiative forcing.
See energy transformation.
Ratio of energy output of a conversion process or of a system to its energy
Energy intensity is the ratio of energy consumption to economic or physical
output. At the national level, energy intensity is the ratio of total domestic
primary energy consumption or final energy consumption to Gross
Domestic Product or physical output.
The application of useful energy to tasks desired by the consumer such as transportation,
a warm room, or light.
See emissions tax.
The change from one form of energy, such as the energy embodied in fossil
fuels, to another, such as electricity.
Environmentally Sound Technologies (ESTs)
Technologies that protect the environment, are less polluting, use all resources
in a more sustainable manner, recycle more of their wastes and products, and
handle residual wastes in a more acceptable manner than the technologies for
which they were substitutes and are compatible with nationally determined socio-economic,
cultural, and environmental priorities. ESTs in this report imply mitigation
and adaptation technologies, hard and soft technologies.
Occurring suddenly in numbers clearly in excess of normal expectancy, said especially
of infectious diseases but applied also to any disease, injury, or other
health-related event occurring in such outbreaks.
Equilibrium and transient climate experiment
An "equilibrium climate experiment" is an experiment in which a climate model
is allowed to fully adjust to a change in radiative forcing. Such experiments
provide information on the difference between the initial and final states of
the model, but not on the time-dependent response. If the forcing is allowed
to evolve gradually according to a prescribed emission scenario, the
time-dependent response of a climate model may be analyzed. Such an experiment
is called a "transient climate experiment." See also climate projection.
Equivalent CO2 (carbon dioxide)
The concentration of carbon dioxide that would cause the same amount
of radiative forcing as a given mixture of carbon dioxide and other greenhouse
The process of removal and transport of soil and rock by weathering, mass wasting,
and the action of streams, glaciers, waves, winds, and underground water.
Eustatic sea-level change
A change in global average sea level brought about by an alteration to the volume
of the world ocean. This may be caused by changes in water density or in the
total mass of water. In discussions of changes on geological time scales, this
term sometimes also includes changes in global average sea level caused by an
alteration to the shape of the ocean basins. In this report, the term is not
used in that sense.
The process by which a body of water (often shallow) becomes (either naturally
or by pollution) rich in dissolved nutrients with a seasonal deficiency in dissolved
The process by which a liquid becomes a gas.
The combined process of evaporation from the Earth's surface and
transpiration from vegetation.
See introduced species.
The nature and degree to which a system is exposed to significant climatic variations.
See external cost.
Used to define the costs arising from any human activity, when the agent responsible
for the activity does not take full account of the impacts on others of his
or her actions. Equally, when the impacts are positive and not accounted for
in the actions of the agent responsible they are referred to as external benefits.
Emissions of particulate pollution from a power station affect the health
of people in the vicinity, but this is not often considered, or is given inadequate
weight, in private decision making and there is no market for such impacts.
Such a phenomenon is referred to as an "externality," and the costs it imposes
are referred to as the external costs.
See climate system.
The complete disappearance of an entire species.
The disappearance of a species from part of its range; local extinction.
Extreme weather event
An extreme weather event is an event that is rare within its statistical reference
distribution at a particular place. Definitions of "rare" vary, but an extreme
weather event would normally be as rare as or rarer than the 10th or 90th percentile.
By definition, the characteristics of what is called extreme weather may vary
from place to place. An extreme climate event is an average of a number
of weather events over a certain period of time, an average which is itself
extreme (e.g., rainfall over a season).
See climate feedback.
Wood, fuelwood (either woody or non-woody).
Energy supplied that is available to the consumer to be converted into usable
energy (e.g., electricity at the wall outlet).
See Kyoto Mechanisms.
To avoid the problem of coupled atmosphere-ocean general circulation models
drifting into some unrealistic climate state, adjustment terms can be applied
to the atmosphere-ocean fluxes of heat and moisture (and sometimes the surface
stresses resulting from the effect of the wind on the ocean surface) before
these fluxes are imposed on the model ocean and atmosphere. Because these adjustments
are pre-computed and therefore independent of the coupled model integration,
they are uncorrelated to the anomalies that develop during the integration.
A situation that exists when people lack secure access to sufficient amounts
of safe and nutritious food for normal growth and development and an active
and healthy life. It may be caused by the unavailability of food, insufficient
purchasing power, inappropriate distribution, or inadequate use of food at the
household level. Food insecurity may be chronic, seasonal, or transitory.
A vegetation type dominated by trees. Many definitions of the term forest are
in use throughout the world, reflecting wide differences in bio-geophysical
conditions, social structure, and economics. For a discussion of the term forest
and related terms such as afforestation, reforestation, and deforestation:
see the IPCC Special Report on Land Use, Land-Use Change, and Forestry (IPCC,
Fossil CO2 (carbon dioxide) emissions
Emissions of carbon dioxide resulting from the combustion of fuels
from fossil carbon deposits such as oil, natural gas, and coal.
Carbon-based fuels from fossil carbon deposits, including coal, oil, and natural
A lenticular fresh groundwater body that underlies an oceanic island. It is
underlain by saline water.
Policy designed to reduce carbon dioxide emissions by switching to lower
carbon-content fuels, such as from coal to natural gas.
The pricing of commercial goods—such as electric power—that includes in the
final prices faced by the end user not only the private costs of inputs, but
also the costs of externalities created by their production and use.
Framework Convention on Climate Change
See United Nations Framework Convention on Climate Change.
The large scale motions of the atmosphere and the ocean as a consequence
of differential heating on a rotating Earth, aiming to restore the energy
balance of the system through transport of heat and momentum.
Model (GCM) See climate model.
Efforts to stabilize the climate system by directly managing the energy balance
of the Earth, thereby overcoming the enhanced greenhouse effect.
A mass of land ice flowing downhill (by internal deformation and sliding at
the base) and constrained by the surrounding topography (e.g., the sides of
a valley or surrounding peaks); the bedrock topography is the major influence
on the dynamics and surface slope of a glacier. A glacier is maintained by accumulation
of snow at high altitudes, balanced by melting at low altitudes or discharge
into the sea.
Global surface temperature
The global surface temperature is the area-weighted global average of (i) the
sea surface temperature over the oceans (i.e., the sub-surface bulk temperature
in the first few meters of the ocean), and (ii) the surface air temperature
over land at 1.5 m above the ground.
Global Warming Potential (GWP)
An index, describing the radiative characteristics of well-mixed greenhouse
gases, that represents the combined effect of the differing times these
gases remain in the atmosphere and their relative effectiveness in absorbing
outgoing infrared radiation. This index approximates the time-integrated
warming effect of a unit mass of a given greenhouse gas in today's atmosphere,
relative to that of carbon dioxide.
Greenhouse gases effectively absorb infrared radiation, emitted
by the Earth's surface, by the atmosphere itself due to the same gases,
and by clouds. Atmospheric radiation is emitted to all sides, including downward
to the Earth's surface. Thus greenhouse gases trap heat within the surface-troposphere
system. This is called the "natural greenhouse effect." Atmospheric radiation
is strongly coupled to the temperature of the level at which it is emitted.
In the troposphere, the temperature generally decreases with height.
Effectively, infrared radiation emitted to space originates from an altitude
with a temperature of, on average, -19°C, in balance with the net incoming solar
radiation, whereas the Earth's surface is kept at a much higher temperature
of, on average, +14°C. An increase in the concentration of greenhouse gases
leads to an increased infrared opacity of the atmosphere, and therefore to an
effective radiation into space from a higher altitude at a lower temperature.
This causes a radiative forcing, an imbalance that can only be compensated
for by an increase of the temperature of the surface-troposphere system. This
is the "enhanced greenhouse effect."
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 vapor (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. Besides CO2, N2O, and
CH4, the Kyoto Protocol deals with the greenhouse gases sulfur hexafluoride
(SF6), hydrofluorocarbons (HFCs), and perfluorocarbons (PFCs).
A low, narrow jetty, usually extending roughly perpendicular to the shoreline,
designed to protect the shore from erosion by currents, tides, or waves,
or to trap sand for the purpose of building up or making a beach.
Gross Domestic Product (GDP)
The sum of gross value added, at purchasers' prices, by all resident
and non-resident producers in the economy, plus any taxes and minus any subsidies
not included in the value of the products in a country or a geographic region
for a given period of time, normally 1 year. It is calculated without deducting
for depreciation of fabricated assets or depletion and degradation of natural
resources. GDP is an often used but incomplete measure of welfare.
Gross Primary Production (GPP)
The amount of carbon fixed from the atmosphere through photosynthesis.
The process by which external water is added to the zone of saturation of an
aquifer, either directly into a formation or indirectly by way of another
The particular environment or place where an organism or species tend to live;
a more locally circumscribed portion of the total environment.
Compounds containing carbon and either chlorine, bromine, or fluorine. Such
compounds can act as powerful greenhouse gases in the atmosphere.
The chlorine- and bromine-containing halocarbons are also involved in the depletion
of the ozone layer.
Harmonized emissions/carbon/energy tax
Commits participating countries to impose a tax at a common rate on the same
sources. Each country can retain the tax revenue it collects. A harmonized
tax would not necessarily require countries to impose a tax at the same rate,
but imposing different rates across countries would not be cost-effective.
See also emissions tax.
An area within an urban area characterized by ambient temperatures higher than
those of the surrounding area because of the absorption of solar energy by materials
Heating degree days
The integral over a day of the temperature below 18°C (e.g., a day with an average
temperature of 16°C counts as 2 heating degree days). See also cooling degree
In the context of climate change mitigation, hedging is defined as balancing
the risks of acting too slowly against acting too quickly, and it depends on
society's attitude towards risks.
The conversion of organic matter to CO2 by organisms other than plants.
A place or area occupied by settlers.
Any system in which human organizations play a major role. Often, but not always,
the term is synonymous with "society" or "social system" (e.g., agricultural
system, political system, technological system, economic system).
Among the six greenhouse gases to be curbed under the Kyoto Protocol.
They are produced commercially as a substitute for chlorofluorocarbons.
HFCs largely are used in refrigeration and semiconductor manufacturing. Their
Global Warming Potentials range from 1,300 to 11,700.
The component of the climate system composed of liquid surface and subterranean
water, such as oceans, seas, rivers, freshwater lakes, underground water, etc.
A dome shaped ice mass covering a highland area that is considerably smaller
in extent than an ice sheet.
A mass of land ice that is sufficiently deep to cover most of the underlying
bedrock topography, so that its shape is mainly determined by its internal dynamics
(the flow of the ice as it deforms internally and slides at its base). An ice
sheet flows outward from a high central plateau with a small average surface
slope. The margins slope steeply, and the ice is discharged through fast-flowing
ice streams or outlet glaciers, in some cases into the sea or into
ice shelves floating on the sea. There are only two large ice sheets in
the modern world, on Greenland and Antarctica, the Antarctic ice sheet being
divided into East and West by the Transantarctic Mountains; during glacial periods
there were others.
A floating ice sheet of considerable thickness attached to a coast (usually
of great horizontal extent with a level or gently undulating surface); often
a seaward extension of ice sheets.
(Climate) Impact assessment
The practice of identifying and evaluating the detrimental and beneficial consequences
of climate change on natural and human systems.
Consequences of climate change on natural and human systems. Depending
on the consideration of adaptation, one can distinguish between potential
impacts and residual impacts.
- Potential impacts: All impacts that may occur given a projected change
in climate, without considering adaptation.
- Residual impacts: The impacts of climate change that would occur after adaptation.
See also aggregate impacts, market impacts, and non-market
Implementation refers to the actions (legislation or regulations, judicial decrees,
or other actions) that governments take to translate international accords into
domestic law and policy. It includes those events and activities that occur
after the issuing of authoritative public policy directives, which include the
effort to administer and the substantive impacts on people and events. It is
important to distinguish between the legal implementation of international commitments
(in national law) and the effective implementation (measures that induce changes
in the behavior of target groups). Compliance is a matter of whether and to
what extent countries do adhere to the provisions of the accord. Compliance
focuses on not only whether implementing measures are in effect, but also on
whether there is compliance with the implementing actions. Compliance measures
the degree to which the actors whose behavior is targeted by the agreement,
whether they are local government units, corporations, organizations, or individuals,
conform to the implementing measures and obligations.
Costs involved in the implementation of mitigation options. These
costs are associated with the necessary institutional changes, information requirements,
market size, opportunities for technology gain and learning, and
economic incentives needed (grants, subsidies, and taxes).
People whose ancestors inhabited a place or a country when persons from another
culture or ethnic background arrived on the scene and dominated them through
conquest, settlement, or other means and who today live more in conformity with
their own social, economic, and cultural customs and traditions than those of
the country of which they now form a part (also referred to as "native," "aboriginal,"
or "tribal" peoples).
Indirect aerosol effect
Aerosols may lead to an indirect radiative forcing of the climate
system through acting as condensation nuclei or modifying the optical properties
and lifetime of clouds. Two indirect effects are distinguished:
- First indirect effect: A radiative forcing induced by an increase in anthropogenic
aerosols which cause an initial increase in droplet concentration and a decrease
in droplet size for fixed liquid water content, leading to an increase of
cloud albedo. This effect is also known as the "Twomey effect." This is sometimes
referred to as the cloud albedo effect. However this is highly misleading
since the second indirect effect also alters cloud albedo.
- Second indirect effect: A radiative forcing induced by an increase in anthropogenic
aerosols which cause a decrease in droplet size, reducing the precipitation
efficiency, thereby modifying the liquid water content, cloud thickness, and
cloud lifetime. This effect is also known as the "cloud lifetime effect" or
A period of rapid industrial growth with far-reaching social and economic consequences,
beginning in England during the second half of the 18th century and spreading
to Europe and later to other countries including the United States. The invention
of the steam engine was an important trigger of this development. The Industrial
Revolution marks the beginning of a strong increase in the use of fossil
fuels and emission of, in particular, fossil carbon dioxide. In this
report, the terms "pre-industrial" and "industrial" refer, somewhat arbitrarily,
to the periods before and after the year 1750, respectively.
Delay, slowness, or resistance in the response of the climate, biological,
or human systems to factors that alter their rate of change, including
continuation of change in the system after the cause of that change has been
Any disease that can be transmitted from one person to another. This may occur
by direct physical contact, by common handling of an object that has picked
up infective organisms, through a disease carrier, or by spread of infected
droplets coughed or exhaled into the air.
Radiation emitted by the Earth's surface, the atmosphere, and clouds.
It is also known as terrestrial or long-wave radiation. Infrared radiation has
a distinctive range of wavelengths ("spectrum") longer than the wavelength of
the red color in the visible part of the spectrum. The spectrum of infrared
radiation is practically distinct from that of solar or short-wave radiation
because of the difference in temperature between the Sun and the Earth-atmosphere
The basic equipment, utilities, productive enterprises, installations, institutions,
and services essential for the development, operation, and growth of an organization,
city, or nation. For example, roads; schools; electric, gas, and water utilities;
transportation; communication; and legal systems would be all considered as
A method of analysis that combines results and models from the physical, biological,
economic, and social sciences, and the interactions between these components,
in a consistent framework, to evaluate the status and the consequences of environmental
change and the policy responses to it.
The result or consequence of the interaction of climate change policy
instruments with existing domestic tax systems, including both cost-increasing
tax interaction and cost-reducing revenue-recycling effect. The former reflects
the impact that greenhouse gas policies can have on the functioning of
labor and capital markets through their effects on real wages and the real return
to capital. By restricting the allowable greenhouse gas emissions, permits,
regulations, or a carbon tax raise the costs of production and the prices
of output, thus reducing the real return to labor and capital. For policies
that raise revenue for the government—carbon taxes and auctioned permits—the
revenues can be recycled to reduce existing distortionary taxes. See also double
See climate variability.
International emissions/carbon/energy tax
See emissions tax.
International Energy Agency (IEA)
Paris-based energy forum established in 1974. It is linked with the Organisation
for Economic Cooperation and Development to enable member countries to take
joint measures to meet oil supply emergencies, to share energy information,
to coordinate their energy policies, and to cooperate in the development of
rational energy programs.
International product and/or technology standards
A species occurring in an area outside its historically known natural range
as a result of accidental dispersal by humans (also referred to as "exotic
species" or "alien species").
An introduced species that invades natural habitats.
Isostatic land movements
Isostasy refers to the way in which the lithosphere and mantle respond
to changes in surface loads. When the loading of the lithosphere is changed
by alterations in land ice mass, ocean mass, sedimentation, erosion, or mountain
building, vertical isostatic adjustment results, in order to balance the new
Joint Implementation (JI)
A market-based implementation mechanism defined in Article 6 of the Kyoto
Protocol, allowing Annex I countries or companies from these countries
to implement projects jointly that limit or reduce emissions, or enhance sinks
, and to share the Emissions Reduction Units. JI activity is also permitted
in Article 4.2(a) of the United Nations Framework Convention on Climate Change.
See also Activities Implemented Jointly and Kyoto Mechanisms.
Known technological options
Refer to technologies that exist in operation or pilot plant stage today. It
does not include any new technologies that will require drastic technological
Economic mechanisms based on market principles that Parties to the Kyoto
Protocol can use in an attempt to lessen the potential economic impacts
of greenhouse gas emission-reduction requirements. They include Joint
Implementation (Article 6), the Clean Development Mechanism (Article
12), and Emissions Trading (Article 17).
The Kyoto Protocol to the United Nations Framework Convention on Climate
Change (UNFCCC) was adopted at the Third Session of the Conference of
the Parties to the UNFCCC in 1997 in Kyoto, Japan. It contains legally binding
commitments, in addition to those included in the UNFCCC. Countries included
in Annex B of the Protocol (most countries in the Organisation for Economic
Cooperation and Development, and countries with economies in transition) agreed
to reduce their anthropogenic greenhouse gas emissions (carbon dioxide, methane,
nitrous oxide, hydrofluorocarbons, perfluorocarbons, and sulfur hexafluoride)
by at least 5% below 1990 levels in the commitment period 2008 to 2012. The
Kyoto Protocol has not yet entered into force (September 2001).
See El Niño Southern Oscillation.
The total of arrangements, activities, and inputs undertaken in a certain land
cover type (a set of human actions). The social and economic purposes for which
land is managed (e.g., grazing, timber extraction, and conservation).
A change in the use or management of land by humans, which may lead to a change
in land cover. Land cover and land-use change may have an impact on the albedo,
evapotranspiration, sources, and sinks of greenhouse gases,
or other properties of the climate system, and may thus have an impact
on climate, locally or globally. See also the IPCC Special Report on
Land Use, Land-Use Change, and Forestry (IPCC, 2000b).
A mass of material that has slipped downhill by gravity, often assisted by water
when the material is saturated; rapid movement of a mass of soil, rock, or debris
down a slope.
The part of emissions reductions in Annex B countries that may
be offset by an increase of the emission in the nonconstrained countries above
their baseline levels. This can occur through (i) relocation of energy-intensive
production in non-constrained regions; (ii) increased consumption of fossil
fuels in these regions through decline in the international price of oil
and gas triggered by lower demand for these energies; and (iii) changes in incomes
(thus in energy demand) because of better terms of trade. Leakage also refers
to the situation in which a carbon sequestration activity (e.g., tree
planting) on one piece of land inadvertently, directly or indirectly, triggers
an activity, which in whole or part, counteracts the carbon effects of the initial
Lifetime is a general term used for various time scales characterizing
the rate of processes affecting the concentration of trace gases. In general,
lifetime denotes the average length of time that an atom or molecule spends
in a given reservoir, such as the atmosphere or oceans. The following
lifetimes may be distinguished:
- "Turnover time" (T) or "atmospheric lifetime" is the ratio of the mass M
of a reservoir (e.g., a gaseous compound in the atmosphere) and the
total rate of removal S from the reservoir: T = M/S. For each removal process
separate turnover times can be defined. In soil carbon biology, this is referred
to as Mean Residence Time.
- "Adjustment time," "response time," or "perturbation lifetime" (Ta)
is the time scale characterizing the decay of an instantaneous pulse input
into the reservoir. The term adjustment time is also used to characterize
the adjustment of the mass of a reservoir following a step change in the source
strength. Halflife or decay constant is used to quantify a first-order exponential
decay process. See response time for a different definition pertinent
to climate variations. The term "lifetime" is sometimes used, for simplicity,
as a surrogate for "adjustment time." In simple cases, where the global removal
of the compound is directly proportional to the total mass of the reservoir,
the adjustment time equals the turnover time: T = Ta. An example
is CFC-11 which is removed from the atmosphere only by photochemical processes
in the stratosphere. In more complicated cases, where several reservoirs
are involved or where the removal is not proportional to the total mass, the
equality T = Ta no longer holds. Carbon dioxide is an extreme
example. Its turnover time is only about 4 years because of the rapid exchange
between atmosphere and the ocean and terrestrial biota. However, a large part
of that CO2 is returned to the atmosphere within a few years. Thus,
the adjustment time of CO2 in the atmosphere is actually determined
by the rate of removal of carbon from the surface layer of the oceans into
its deeper layers. Although an approximate value of 100 years may be given
for the adjustment time of CO2 in the atmosphere, the actual adjustment
is faster initially and slower later on. In the case of methane, the
adjustment time is different from the turnover time, because the removal is
mainly through a chemical reaction with the hydroxyl radical OH, the concentration
of which itself depends on the CH4 concentration. Therefore the
CH4 removal S is not proportional to its total mass M.
The upper layer of the solid Earth, both continental and oceanic, which is composed
of all crustal rocks and the cold, mainly elastic, part of the uppermost mantle.
Volcanic activity, although part of the lithosphere, is not considered as part
of the climate system, but acts as an external forcing factor.
Leapfrogging (or technological leapfrogging) refers to the opportunities in
developing countries to bypass several stages of technology development, historically
observed in industrialized countries, and apply the most advanced presently
available technologies in the energy and other economic sectors, through investments
in technological development and capacity building.
Level of scientific understanding
This is an index on a 4-step scale (High, Medium, Low, and Very Low) designed
to characterize the degree of scientific understanding of the radiative forcing
agents that affect climate change. For each agent, the index represents
a subjective judgement about the reliability of the estimate of its forcing,
involving such factors as the assumptions necessary to evaluate the forcing,
the degree of knowledge of the physical/chemical mechanisms determining the
forcing, and the uncertainties surrounding the quantitative estimate.
Local Agenda 21
Local Agenda 21s are the local plans for environment and development that each
local authority is meant to develop through a consultative process with their
populations, with particular attention paid to involving women and youth. Many
local authorities have developed Local Agenda 21s through consultative processes
as a means of reorienting their policies, plans, and operations towards the
achievement of sustainable development goals. The term comes from Chapter
28 of Agenda 21—the document formally endorsed by all government representatives
attending the United Nations Conference on Environment and Development (also
known as the Earth Summit) in Rio de Janeiro in 1992.
Lock-in technologies and practices
Technologies and practices that have market advantages arising from existing
institutions, services, infrastructure, and available resources; they are very
difficult to change because of their widespread use and the presence of associated
infrastructure and socio-cultural patterns.
Any changes in natural or human systems that inadvertently increase vulnerability
to climatic stimuli; an adaptation that does not succeed in reducing
vulnerability but increases it instead.
Endemic or epidemic parasitic disease caused by species of the
genus Plasmodium (protozoa) and transmitted by mosquitoes of the genus Anopheles;
produces high fever attacks and systemic disorders, and kills approximately
2 million people every year.
Marginal cost pricing
The pricing of commercial goods and services such that the price equals the
additional cost that arises from the expansion of production by one additional
In the context of mitigation of climate change, conditions that
prevent or impede the diffusion of cost-effective technologies or practices
that would mitigate greenhouse gas emissions.
Measures intended to use price mechanisms (e.g., taxes and tradable permits)
to reduce greenhouse gas emissions.
Impacts that are linked to market transactions and directly affect Gross
Domestic Product (a country's national accounts)—for example, changes in
the supply and price of agricultural goods. See also non-market impacts.
Market penetration is the share of a given market that is provided by a particular
good or service at a given time.
The portion of the economic potential for greenhouse gas emissions
reductions or energy-efficiency improvements that could be achieved under forecast
market conditions, assuming no new policies and measures. See also economic
potential, socio-economic potential, and technological potential.
Applies to all unit movements of land material propelled and controlled by gravity.
Mean Sea Level (MSL)
Mean Sea Level is normally defined as the average relative sea level
over a period, such as a month or a year, long enough to average out transients
such as waves. See also sea-level rise.
A hydrocarbon that is a greenhouse gas produced through anaerobic (without
oxygen) decomposition of waste in landfills, animal digestion, decomposition
of animal wastes, production and distribution of natural gas and oil, coal production,
and incomplete fossil-fuel combustion. Methane is one of the six greenhouse
gases to be mitigated under the Kyoto Protocol.
Method by which methane emissions (e.g., from coal mines or waste sites)
are captured and then reused either as a fuel or for some other economic purpose
(e.g., reinjection in oil or gas reserves).
Meeting of the Parties (to the Kyoto Protocol) (MOP)
The Conference of the Parties of the United Nations Framework Convention
on Climate Change will serve as the Meeting of the Parties (MOP),
the supreme body of the Kyoto Protocol, but only Parties to the Kyoto
Protocol may participate in deliberations and make decisions. Until the Protocol
enters into force, MOP cannot meet.
An anthropogenic intervention to reduce the sources or enhance
the sinks of greenhouse gases.
The social, political, and economic structures and conditions that are required
for effective mitigation.
The upper region of the ocean well-mixed by interaction with the overlying atmosphere.
See mole fraction.
See climate model.
Mole fraction, or mixing ratio, is the ratio of the number of moles of a constituent
in a given volume to the total number of moles of all constituents in that volume.
It is usually reported for dry air. Typical values for long-lived greenhouse
gases are in the order of mmol/mol (parts per million: ppm), nmol/mol (parts
per billion: ppb), and fmol/mol (parts per trillion: ppt). Mole fraction differs
from volume mixing ratio, often expressed in ppmv, etc., by the corrections
for non-ideality of gases. This correction is significant relative to measurement
precision for many greenhouse gases (Schwartz and Warneck, 1995).
Wind in the general atmospheric circulation typified by a seasonal persistent
wind direction and by a pronounced change in direction from one season to the
The biogeographic zone made up of relatively moist, cool upland slopes below
timberline and characterized by the presence of large evergreen trees as a dominant
The Montreal Protocol on substances that deplete the ozone layer was
adopted in Montreal in 1987, and subsequently adjusted and amended in London
(1990), Copenhagen (1992), Vienna (1995), Montreal (1997), and Beijing (1999).
It controls the consumption and production of chlorine- and bromine-containing
chemicals that destroy stratospheric ozone, such as chlorofluorocarbons
(CFCs), methyl chloroform, carbon tetrachloride, and many others.
Rate of occurrence of disease or other health disorder within a population,
taking account of the age-specific morbidity rates. Health outcomes include
chronic disease incidence/ prevalence, rates of hospitalization, primary care
consultations, disability-days (i.e., days when absent from work), and prevalence
Rate of occurrence of death within a population within a specified time period;
calculation of mortality takes account of age-specific death rates, and can
thus yield measures of life expectancy and the extent of premature death.
Net Biome Production (NBP)
Net gain or loss of carbon from a region. NBP is equal to the Net Ecosystem
Production minus the carbon lost due to a disturbance (e.g., a forest
fire or a forest harvest).
Net carbon dioxide emissions
Difference between sources and sinks of carbon dioxide in a given period and
specific area or region.
Net Ecosystem Production (NEP)
Net gain or loss of carbon from an ecosystem. NEP is equal to the Net
Primary Production minus the carbon lost through heterotrophic respiration.
Net Primary Production (NPP)
The increase in plant biomass or carbon of a unit of a landscape. NPP
is equal to the Gross Primary Production minus carbon lost through autotrophic
Enhancement of plant growth through the addition of nitrogen compounds. In IPCC
assessments, this typically refers to fertilization from anthropogenic sources
of nitrogen such as human-made fertilizers and nitrogen oxides released
from burning fossil fuels.
Nitrogen oxides (NOx)
Any of several oxides of nitrogen.
Nitrous oxide (N2O)
A powerful greenhouse gas emitted through soil cultivation practices, especially
the use of commercial and organic fertilizers, fossil-fuel combustion, nitric
acid production, and biomass burning. One of the six greenhouse gases
to be curbed under the Kyoto Protocol.
Pollution from sources that cannot be defined as discrete points, such
as areas of crop production, timber, surface mining, disposal of refuse, and
construction. See also point-source pollution.
See no-regrets policy.
See no-regrets policy.
One that would generate net social benefits whether or not there is climate
change. No-regrets opportunities for greenhouse gas emissions reduction
are defined as those options whose benefits such as reduced energy costs and
reduced emissions of local/regional pollutants equal or exceed their costs to
society, excluding the benefits of avoided climate change. No-regrets potential
is defined as the gap between the market potential and the socio-economic
See no-regrets policy.
Non-Annex B countries/Parties
The countries that are not included in Annex B in the Kyoto Protocol.
See also Annex B countries.
Non-Annex I countries/Parties
The countries that have ratified or acceded to the United Nations Framework
Convention on Climate Change that are not included in Annex I of the Climate
Convention. See also Annex I countries.
A process is called "non-linear" when there is no simple proportional relation
between cause and effect. The climate system contains many such non-linear
processes, resulting in a system with a potentially very complex behavior. Such
complexity may lead to rapid climate change.
Impacts that affect ecosystems or human welfare, but that are not directly
linked to market transactions—for example, an increased risk of premature death.
See also market impacts.
North Atlantic Oscillation (NAO)
The North Atlantic Oscillation consists of opposing variations of barometric
pressure near Iceland and near the Azores. On average, a westerly current, between
the Icelandic low pressure area and the Azores high pressure area, carries cyclones
with their associated frontal systems towards Europe. However, the pressure
difference between Iceland and the Azores fluctuates on time scales of
days to decades, and can be reversed at times. It is the dominant mode of winter
climate variability in the North Atlantic region, ranging from central
North America to Europe.
Ocean conveyor belt
The theoretical route by which water circulates around the entire global ocean,
driven by wind and the thermohaline circulation.
An opportunity is a situation or circumstance to decrease the gap between the
market potential of any technology or practice and the economic
potential, socio-economic potential, or technological potential.
The cost of an economic activity forgone by the choice of another activity.
A policy is assumed to be "optimal" if marginal abatement costs are equalized
across countries, thereby minimizing total costs.
Aerosol particles consisting predominantly of organic compounds, mainly
C, H, and O, and lesser amounts of other elements (Charlson and Heintzenberg,
1995). See carbonaceous aerosol.
Ozone, the triatomic form of oxygen (O3), is a gaseous atmospheric
constituent. In the troposphere it is created both naturally and by photochemical
reactions involving gases resulting from human activities (photochemical "smog").
In high concentrations, tropospheric ozone can be harmful to a wide-range of
living organisms. Tropospheric ozone acts as a greenhouse gas. In the
stratosphere, ozone is created by the interaction between solar ultraviolet
radiation and molecular oxygen (O2). Stratospheric ozone plays a
decisive role in the stratospheric radiative balance. Its concentration
is highest in the ozone layer. Depletion of stratospheric ozone, due
to chemical reactions that may be enhanced by climate change, results
in an increased ground-level flux of ultraviolet-B radiation. See also
Montreal Protocol and ozone layer.
See 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. The ozone concentration reaches a maximum between about 20 and 25 km. This
layer is being depleted by human emissions of chlorine and bromine compounds.
Every year, during the Southern Hemisphere spring, a very strong depletion of
the ozone layer takes place over the Antarctic region, also caused by human-made
chlorine and bromine compounds in combination with the specific meteorological
conditions of that region. This phenomenon is called the ozone hole.
In climate models, this term refers to the technique of representing
processes, that cannot be explicitly resolved at the spatial or temporal resolution
of the model (sub-grid scale processes), by relationships between the area-
or timeaveraged effect of such sub-grid-scale processes and the larger scale
Pareto criterion / Pareto optimum
A requirement or status that an individual's welfare could not be further improved
without making others in the society worse off.
Among the six greenhouse gases to be abated under the Kyoto Protocol.
These are by-products of aluminum smelting and uranium enrichment. They also
replace chlorofluorocarbons in manufacturing semiconductors. The Global
Warming Potential of PFCs is 6,500–9,200 times that of carbon dioxide.
Perennially frozen ground that occurs wherever the temperature remains below
0°C for several years.
The process by which plants take carbon dioxide (CO2) from
the air (or bicarbonate in water) to build carbohydrates, releasing oxygen (O2)
in the process. There are several pathways of photosynthesis with different
responses to atmospheric CO2 concentrations. See also carbon dioxide
The plant forms of plankton (e.g., diatoms). Phytoplankton are the dominant
plants in the sea, and are the bast of the entire marine food web. These single-celled
organisms are the principal agents for photosynthetic carbon fixation in the
ocean. See also zooplankton.
Aquatic organisms that drift or swim weakly. See also phytoplankton and
Pollution resulting from any confined, discrete source, such as a pipe, ditch,
tunnel, well, container, concentrated animal-feeding operation, or floating
craft. See also non-point-source pollution.
Policies and measures
In United Nations Framework Convention on Climate Change parlance, "policies"
are actions that can be taken and/or mandated by a government—often in conjunction
with business and industry within its own country, as well as with other countries—to
accelerate the application and use of measures to curb greenhouse gas emissions.
"Measures" are technologies, processes, and practices used to implement policies,
which, if employed, would reduce greenhouse gas emissions below anticipated
future levels. Examples might include carbon or other energy taxes, standardized
fuel-efficiency standards for automobiles, etc. "Common and coordinated"
or "harmonized" policies refer to those adopted jointly by Parties.
The vertical movement of the continents and sea floor following the disappearance
and shrinking of ice sheets—for example, since the Last Glacial Maximum
(21 ky BP). The rebound is an isostatic land movement.
Atmospheric compounds which themselves are not greenhouse gases or aerosols,
but which have an effect on greenhouse gas or aerosol concentrations by taking
part in physical or chemical processes regulating their production or destruction
See Industrial Revolution.
Present value cost
The sum of all costs over all time periods, with future costs discounted.
Energy embodied in natural resources (e.g., coal, crude oil, sunlight,
uranium) that has not undergone any anthropogenic conversion or transformation.
Categories of costs influencing an individual's decision making are referred
to as private costs. See also social cost and total cost.
A smoothly changing set of concentrations representing a possible pathway towards
stabilization. The word "profile"is used to distinguish such pathways from emissions
pathways, which are usually referred to as "scenarios."
A projection is a potential future evolution of a quantity or set of quantities,
often computed with the aid of a model. Projections are distinguished from "predictions"
in order to emphasize that projections involve assumptions concerning, for example,
future socio-economic and technological developments that may or may not be
realized, and are therefore subject to substantial uncertainty. See also
climate projection and climate prediction.
A proxy climate indicator is a local record that is interpreted, using
physical and biophysical principles, to represent some combination of climate-related
variations back in time. Climate-related data derived in this way are referred
to as proxy data. Examples of proxies are tree ring records, characteristics
of corals, and various data derived from ice cores.
Purchasing Power Parity (PPP)
Estimates of Gross Domestic Product based on the purchasing power of
currencies rather than on current exchange rates. Such estimates are a blend
of extrapolated and regression-based numbers, using the results of the International
Comparison Program. PPP estimates tend to lower per capita GDPs in industrialized
countries and raise per capita GDPs in developing countries. PPP is also an
acronym for polluter-pays-principle.
See energy balance.
Radiative forcing is the change in the net vertical irradiance (expressed in
Wm-2) at the tropopause due to an internal change or a change
in the external forcing of the climate system, such as, for example,
a change in the concentration of carbon dioxide or the output of the
Sun. Usually radiative forcing is computed after allowing for stratospheric
temperatures to readjust to radiative equilibrium, but with all tropospheric
properties held fixed at their unperturbed values.
Radiative forcing scenario
A plausible representation of the future development of radiative forcing
associated, for example, with changes in atmospheric composition or land-use
change, or with external factors such as variations in solar activity.Radiative forcing scenarios can be used as input into simplified climate
models to compute climate projections.
Unimproved grasslands, shrublands, savannahs, and tundra.
Rapid climate change
The non-linearity of the climate system may lead to rapid climate
change, sometimes called abrupt events or even surprises. Some such abrupt
events may be imaginable, such as a dramatic reorganization of the thermohaline
circulation, rapid deglaciation, or massive melting of permafrost
leading to fast changes in the carbon cycle. Others may be truly unexpected,
as a consequence of a strong, rapidly changing, forcing of a non-linear system.
Occurs because, for example, an improvement in motor efficiency lowers the cost
per kilometer driven; it has the perverse effect of encouraging more trips.
Planting of forests on lands that have previously contained forests but
that have been converted to some other use. For a discussion of the term forest
and related terms such as afforestation, reforestation, and deforestation,
see the IPCC Special Report on Land Use, Land-Use Change, and Forestry (IPCC,
Rules or codes enacted by governments that mandate product specifications or
process performance characteristics. See also standards.
The transfer of a portion of primary insurance risks to a secondary tier of
insurers (reinsurers); essentially "insurance for insurers."
Relative sea level
Sea level measured by a tide gauge with respect to the land upon which
it is situated. See also Mean Sea Level.
(Relative) Sea level secular change
Long-term changes in relative sea level caused by either eustatic changes (e.g.,
brought about by thermal expansion) or changes in vertical land movements.
Energy sources that are, within a short time frame relative to the Earth's natural
cycles, sustainable, and include noncarbon technologies such as solar energy,
hydropower, and wind, as well as carbon-neutral technologies such as biomass.
Research, development, and demonstration
Scientific and/or technical research and development of new production processes
or products, coupled with analysis and measures that provide information to
potential users regarding the application of the new product or process; demonstration
tests; and feasibility of applying these products processes via pilot plants
and other pre-commercial applications.
Refer to those occurrences that are identified and measured as economically
and technically recoverable with current technologies and prices. See also resources.
A component of the climate system, other than the atmosphere,
which has the capacity to store, accumulate, or release a substance of concern
(e.g., carbon, a greenhouse gas, or a precursor). Oceans, soils,
and forests are examples of reservoirs of carbon. Pool is an equivalent
term (note that the definition of pool often includes the atmosphere). The absolute
quantity of substance of concerns, held within a reservoir at a specified time,
is called the stock. The term also means an artificial or natural storage place
for water, such as a lake, pond, or aquifer, from which the water may
be withdrawn for such purposes as irrigation, water supply, or irrigation.
Amount of change a system can undergo without changing state.
Resource base includes both reserves and resources.
Resources are those occurrences with less certain geological and/or economic
characteristics, but which are considered potentially recoverable with foreseeable
technological and economic developments.
The process whereby living organisms converts organic matter to carbon dioxide,
releasing energy and consuming oxygen.
The response time or adjustment time is the time needed for the climate system
or its components to re-equilibrate to a new state, following a forcing resulting
from external and internal processes or feedbacks. It is very different
for various components of the climate system. The response time of the troposphere
is relatively short, from days to weeks, whereas the stratosphere comes
into equilibrium on a time scale of typically a few months. Due to their
large heat capacity, the oceans have a much longer response time, typically
decades, but up to centuries or millennia. The response time of the strongly
coupled surface-troposphere system is, therefore, slow compared to that of the
stratosphere, and mainly determined by the oceans. The biosphere may
respond fast (e.g., to droughts), but also very slowly to imposed changes.
See lifetime for a different definition of response time pertinent to
the rate of processes affecting the concentration of trace gases.
See interaction effect.
That part of precipitation that does not evaporate. In some countries, runoff
implies surface runoff only.
The carbon dioxide concentration profiles leading to stabilization defined
in the IPCC 1994 assessment (Enting et al., 1994; Schimel et al.,
1995). For any given stabilization level, these profiles span a wide range of
possibilities. The S stands for "Stabilization." See also WRE profiles.
See tolerable windows approach.
The accumulation of salts in soils.
Displacement of fresh surfacewater or groundwater by the advance of saltwater
due to its greater density, usually in coastal and estuarine areas.
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 forecasts and sometimes may be based on a "narrative
storyline." Scenarios may be derived from projections, but are often
based on additional information from other sources. See also SRES scenarios,
climate scenario, and emission scenarios.
An increase in the mean level of the ocean. Eustatic sea-level rise is a change
in global average sea level brought about by an alteration to the volume of
the world ocean. Relative sea-level rise occurs where there is a net
increase in the level of the ocean relative to local land movements. Climate
modelers largely concentrate on estimating eustatic sea-level change. Impact
researchers focus on relative sea-level change.
A human-made wall or embankment along a shore to prevent wave erosion.
Ecosystems that have more than 250 mm precipitation per year but are
not highly productive; usually classified as rangelands.
Sensitivity is the degree to which a system is affected, either adversely or
beneficially, by climate-related stimuli. The effect may be direct (e.g.,
a change in crop yield in response to a change in the mean, range, or variability
of temperature) or indirect (e.g., damages caused by an increase in the frequency
of coastal flooding due to sea-level rise). See also climate sensitivity.
Sequential decision making
Stepwise decision making aiming to identify short-term strategies in the face
of long-term uncertainties, by incorporating additional information over time
and making mid-course corrections.
The process of increasing the carbon content of a carbon reservoir other
than the atmosphere. Biological approaches to sequestration include direct
removal of carbon dioxide from the atmosphere through land-use
change, afforestation, reforestation, and practices that
enhance soil carbon in agriculture. Physical approaches include separation and
disposal of carbon dioxide from flue gases or from processing fossil fuels
to produce hydrogen- and carbon dioxide - rich fractions and long-term storage
in underground in depleted oil and gas reservoirs, coal seams, and saline
aquifers. See also uptake.
Unconsolidated or loose sedimentary material whose constituent rock particles
are finer than grains of sand and larger than clay particles.
Development and care of forests.
Any process, activity or mechanism that removes a greenhouse gas, an
aerosol, or a precursor of a greenhouse gas or aerosol from the
A seasonal accumulation of slow-melting snow.
The social cost of an activity includes the value of all the resources
used in its provision. Some of these are priced and others are not. Non-priced
resources are referred to as externalities. It is the sum of the costs of these
externalities and the priced resources that makes up the social cost. See also
private cost and total cost.
The socio-economic potential represents the level of greenhouse gas mitigation
that would be approached by overcoming social and cultural obstacles to the
use of technologies that are cost-effective. See also economic potential,
market potential, and technology potential.
The Sun exhibits periods of high activity observed in numbers of sunspots,
as well as radiative output, magnetic activity, and emission of high energy
particles. These variations take place on a range of time scales from
millions of years to minutes. See also solar cycle.
Solar ("11 year") cycle
A quasi-regular modulation of solar activity with varying amplitude and
a period of between 9 and 13 years.
Radiation emitted by the Sun. It is also referred to as short-wave radiation.
Solar radiation has a distinctive range of wavelengths (spectrum) determined
by the temperature of the Sun. See also infrared radiation.
Particles formed during the quenching of gases at the outer edge of flames of
organic vapors, consisting predominantly of carbon, with lesser amounts of oxygen
and hydrogen present as carboxyl and phenolic groups and exhibiting an imperfect
graphitic structure (Charlson and Heintzenberg, 1995). See also black carbon.
Any process, activity, or mechanism that releases a greenhouse gas, an
aerosol, or a precursor of a greenhouse gas or aerosol into the atmosphere.
See El Niño Southern Oscillation.
Spatial and temporal scales
Climate may vary on a large range of spatial and temporal scales. Spatial
scales may range from local (less than 100,000 km2), through regional
(100,000 to 10 million km2) to continental (10 to 100 million km2).
Temporal scales may range from seasonal to geological (up to hundreds of millions
The economic effects of domestic or sectoral mitigation measures on other
countries or sectors. In this report, no assessment is made on environmental
spillover effects. Spillover effects can be positive or negative and include
effects on trade, carbon leakage, transfer, and diffusion of environmentally
sound technology and other issues.
SRES scenarios are emissions scenarios developed by Nakicenovic et al.
(2000) and used, among others, as a basis for the climate projections
in the IPCC WGI contribution to the Third Assessment Report (IPCC, 2001a). The
following terms are relevant for a better understanding of the structure and
use of the set of SRES scenarios:
- (Scenario) Family: Scenarios that have a similar demographic,
societal, economic, and technical-change storyline. Four scenario families
comprise the SRES scenario set: A1, A2, B1, and B2.
- (Scenario) Group: Scenarios within a family that reflect a
consistent variation of the storyline. The A1 scenario family includes four
groups designated as A1T, A1C, A1G, and A1B that explore alternative structures
of future energy systems. In the Summary for Policymakers of Nakicenovic et
al. (2000), the A1C and A1G groups have been combined into one "Fossil-Intensive"
A1FI scenario group. The other three scenario families consist of one group
each. The SRES scenario set reflected in the Summary for Policymakers of Nakicenovic
et al. (2000) thus consist of six distinct scenario groups, all of
which are equally sound and together capture the range of uncertainties associated
with driving forces and emissions.
- Illustrative Scenario: A scenario that is illustrative for
each of the six scenario groups reflected in the Summary for Policymakers
of Nakicenovic et al. (2000). They include four revised scenario markers
for the scenario groups A1B, A2, B1, B2, and two additional scenarios
for the A1FI and A1T groups. All scenario groups are equally sound.
- (Scenario) Marker: A scenario that was originally posted in
draft form on the SRES website to represent a given scenario family.
The choice of markers was based on which of the initial quantifications best
reflected the storyline, and the features of specific models. Markers are
no more likely than other scenarios, but are considered by the SRES writing
team as illustrative of a particular storyline. They are included in revised
form in Nakicenovic et al. (2000). These scenarios have received the closest
scrutiny of the entire writing team and via the SRES open process. Scenarios
have also been selected to illustrate the other two scenario groups.
- (Scenario) Storyline: A narrative description of a scenario
(or family of scenarios) highlighting the main scenario characteristics, relationships
between key driving forces, and the dynamics of their evolution.
The achievement of stabilization of atmospheric concentrations of one or more
greenhouse gases (e.g., carbon dioxide or a CO2-equivalent
basket of greenhouse gases).
In this report, this refers to analyses or scenarios that address the
stabilization of the concentration of greenhouse gases.
See stabilization analysis.
Person or entity holding grants, concessions, or any other type of value
that would be affected by a particular action or policy.
Set of rules or codes mandating or defining product performance (e.g., grades,
dimensions, characteristics, test methods, and rules for use). International
product and/or technology or performance standards establish minimum
requirements for affected products and/or technologies in countries where they
are adopted. The standards reduce greenhouse gas emissions associated
with the manufacture or use of the products and/or application of the technology.
See also regulatory measures.
All the elements of climate change, including mean climate characteristics,
climate variability, and the frequency and magnitude of extremes.
The temporary increase, at a particular locality, in the height of the sea due
to extreme meteorological conditions (low atmospheric pressure and/or strong
winds). The storm surge is defined as being the excess above the level expected
from the tidal variation alone at that time and place.
See SRES scenarios.
Water within a river channel, usually expressed in m3 sec-1.
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.
Changes, for example, in the relative share of Gross Domestic Product produced
by the industrial, agricultural, or services sectors of an economy; or more
generally, systems transformations whereby some components are either replaced
or potentially substituted by other ones.
A rise in the water level in relation to the land, so that areas of formerly
dry land become inundated; it results either from a sinking of the land or from
a rise of the water level.
The sudden sinking or gradual downward settling of the Earth's surface
with little or no horizontal motion.
Direct payment from the government to an entity, or a tax reduction to that
entity, for implementing a practice the government wishes to encourage. Greenhouse
gas emissions can be reduced by lowering existing subsidies that have the
effect of raising emissions, such as subsidies to fossil-fuel use, or
by providing subsidies for practices that reduce emissions or enhance sinks
(e.g., for insulation of buildings or planting trees).
Sulfur hexafluoride (SF6)
One of the six greenhouse gases to be curbed under the Kyoto Protocol.
It is largely used in heavy industry to insulate high-voltage equipment and
to assist in the manufacturing of cable-cooling systems. Its Global Warming
Potential is 23,900.
Small dark areas on the Sun. The number of sunspots is higher during periods
of high solar activity, and varies in particular with the solar cycle.
The water that travels over the soil surface to the nearest surface stream;
runoff of a drainage basin that has not passed beneath the surface since
Development that meets the needs of the present without compromising the ability
of future generations to meet their own needs.
Targets and time tables
A target is the reduction of a specific percentage of greenhouse gas emissions
from a baseline date (e.g., "below 1990 levels") to be achieved by a
set date or time table (e.g., 2008 to 2012). For example, under the Kyoto
Protocol's formula, the European Union has agreed to reduce its greenhouse
gas emissions by 8% below 1990 levels by the 2008 to 2012 commitment period.
These targets and time tables are, in effect, an emissions cap on the total
amount of greenhouse gas emissions that can be emitted by a country or region
in a given time period.
See interaction effect.
The amount by which it is possible to reduce greenhouse gas emissions
or improve energy efficiency by implementing a technology or practice
that has already been demonstrated. See also economic potential, market
potential, and socio-economic potential.
A piece of equipment or a technique for performing a particular activity.
Technology or performance standard
The broad set of processes that cover the exchange of knowledge, money, and
goods among different stakeholders that lead to the spreading of technology
for adapting to or mitigating climate change. As a generic concept, the
term is used to encompass both diffusion of technologies and technological cooperation
across and within countries.
The erosion of ice-rich permafrost by the combined thermal and
mechanical action of moving water.
In connection with sea level, this refers to the increase in volume (and decrease
in density) that results from warming water. A warming of the ocean leads to
an expansion of the ocean volume and hence an increase in sea level.
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.
Irregular, hummocky topography in frozen ground caused by melting of ice.
A device at a coastal location (and some deep sea locations) which continuously
measures the level of the sea with respect to the adjacent land. Time-averaging
of the sea level so recorded gives the observed relative sea level secular
Characteristic time for a process to be expressed. Since many processes exibit
most of their effects early, and then have a long period during which they gradually
approach full expression, for the purpose of this report the time scale is numerically
defined as the time required for a perturbation in a process to show at least
half of its final effect.
These approaches analyze greenhouse gas emissions as they would be constrained
by adopting a long-term climate—rather than greenhouse gas concentration
stabilization—target (e.g., expressed in terms of temperature or sea
level changes or the rate of such changes). The main objective of these approaches
is to evaluate the implications of such long-term targets for short- or medium-term
"tolerable" ranges of global greenhouse gas emissions. Also referred
to as safe-landing approaches.
The terms "top" and "bottom" are shorthand for aggregate and disaggregated models.
The top-down label derives from how modelers applied macro-economic theory and
econometric techniques to historical data on consumption, prices, incomes, and
factor costs to model final demand for goods and services, and supply from main
sectors, like the energy sector, transportation, agriculture, and industry.
Therefore, top-down models evaluate the system from aggregate economic variables,
as compared to bottom-up models that consider technological options or
project specific climate change mitigation policies. Some technology
data were, however, integrated into top-down analysis and so the distinction
is not that clear-cut.
All items of cost added together. The total cost to society is made up of both
the external cost and the private cost, which together are defined
as social cost.
Economic impacts of changes in the purchasing power of a bundle of exported
goods of a country for bundles of goods imported from its trade partners. Climate
policies change the relative production costs and may change terms of trade
substantially enough to change the ultimate economic balance.
Transient climate response
The globally averaged surface air temperature increase, averaged over a 20-year
period, centered at the time of CO2 doubling (i.e., at year 70 in
a 1% per year compound CO2 increase experiment with a global coupled
The boundary between the troposphere and the stratosphere.
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.
A treeless, level, or gently undulating plain characteristic of arctic and subarctic
Ultraviolet (UV)-B radiation
Solar radiation within a wavelength range of 280-320 nm, the greater
part of which is absorbed by stratospheric ozone. Enhanced UV-B radiation suppresses
the immune system and can have other adverse effects on living organisms.
An expression of the degree to which a value (e.g., the future state of the
climate system) 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
concepts or 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). See Moss and Schneider (2000).
The result of food intake that is insufficient to meet dietary energy requirements
continuously, poor absorption, and/or poor biological use of nutrients consumed.
Unique and threatened systems
Entities that are confined to a relatively narrow geographical range but can
affect other, often larger entities beyond their range; narrow geographical
range points to sensitivity to environmental variables, including climate,
and therefore attests to potential vulnerability to climate change.
United Nations Framework Convention on Climate Change (UNFCCC)
The Convention was adopted on 9 May 1992 in New York and signed at the 1992
Earth Summit in Rio de Janeiro by more than 150 countries and the European Community.
Its ultimate objective is the "stabilization of greenhouse gas concentrations
in the atmosphere at a level that would prevent dangerous anthropogenic interference
with the climate system." It contains commitments for all Parties. Under the
Convention, Parties included in Annex I aim to return greenhouse gas
emissions not controlled by the Montreal Protocol to 1990 levels
by the year 2000. The Convention entered into force in March 1994. See also
Kyoto Protocol and Conference of the Parties (COP).
The addition of a substance of concern to a reservoir. The uptake of
carbon-containing substances, in particular carbon dioxide, is often
called (carbon) sequestration. See also sequestration.
Transport of deeper water to the surface, usually caused by horizontal movements
of surface water.
The conversion of land from a natural state or managed natural state (such as
agriculture) to cities; a process driven by net rural-to-urban migration through
which an increasing percentage of the population in any nation or region come
to live in settlements that are defined as "urban centres."
The net output of a sector after adding up all outputs and subtracting intermediate
Worth, desirability, or utility based on individual preferences. The total value
of any resource is the sum of the values of the different individuals involved
in the use of the resource. The values, which are the foundation of the estimation
of costs, are measured in terms of the willingness to pay (WTP) by individuals
to receive the resource or by the willingness of individuals to accept payment
(WTA) to part with the resource.
An organism, such as an insect, that transmits a pathogen from one host to another.
See also vector-borne diseases.
Disease that is transmitted between hosts by a vector organism such as
a mosquito or tick (e.g., malaria, dengue fever, and leishmaniasis).
Volume mixing ratio
See mole fraction.
An agreement between a government authority and one or more private parties,
as well as a unilateral commitment that is recognized by the public authority,
to achieve environmental objectives or to improve environmental performance
The degree to which a system is susceptible to, or unable to cope with, adverse
effects of climate change, including climate variability and extremes.
Vulnerability is a function of the character, magnitude, and rate of climate
variation to which a system is exposed, its sensitivity, and its adaptive
A country is water-stressed if the available freshwater supply relative to water
withdrawals acts as an important constraint on development. Withdrawals exceeding
20% of renewable water supply has been used as an indicator of water stress.
Carbon gain in photosynthesis per unit water lost in evapotranspiration.
It can be expressed on a short-term basis as the ratio of photosynthetic carbon
gain per unit transpirational water loss, or on a seasonal basis as the ratio
of net primary production or agricultural yield to the amount of available
Amount of water extracted from water bodies.
The carbon dioxide concentration profiles leading to stabilization defined
by Wigley, Richels, and Edmonds (1996) whose initials provide the acronym. For
any given stabilization level, these profiles span a wide range of possibilities.
See also S profiles.
The animal forms of plankton. They consume phytoplankton or other
zooplankton. See also phytoplankton.
Charlson, R.J., and J. Heintzenberg (eds.), 1995: Aerosol Forcing
of Climate. John Wiley and Sons Limited, Chichester, United Kingdom, pp.
91–108 (reproduced with permission).
Enting, I.G., T.M.L. Wigley, and M. Heimann, 1994: Future emissions and
concentrations of carbon dioxide: key ocean/atmosphere/land analyses . CSIRO
Division of Atmospheric Research Technical Paper 31, Mordialloc, Australia,
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Scientific Assessment [Houghton, J.T., B.A. Callander, and S.K. Varney (eds.)].
Cambridge University Press, Cambridge, UK, xi + 116 pp.
IPCC, 1994: Climate Change 1994: Radiative Forcing of Climate Change
and an Evaluation of the IPCC IS92 Emission Scenarios, [Houghton, J.T.,
L.G. Meira Filho, J. Bruce, Hoesung Lee, B.A. Callander, E. Haites, N. Harris,
and K. Maskell (eds.)]. Cambridge University Press, Cambridge, UK and New York,
NY, USA, 339 pp.
IPCC, 1996: Climate Change 1995: The Science of Climate Change. Contribution
of Working Group I to the Second Assessment Report of the Intergovernmental
Panel on Climate Change [Houghton., J.T., L.G. Meira Filho, B.A. Callander,
N. Harris, A. Kattenberg, and K. Maskell (eds.)]. Cambridge University Press,
Cambridge, United Kingdom and New York, NY, USA, 572 pp.
IPCC, 1997a: IPCC Technical Paper 2: An Introduction to Simple Climate
Models used in the IPCC Second Assessment Report [Houghton, J.T., L.G. Meira
Filho, D.J. Griggs, and K. Maskell (eds.)]. Intergovernmental Panel on Climate
Change, World Meteorological Organization, Geneva, Switzerland, 51 pp.
IPCC, 1997b: Revised 1996 IPCC Guidelines for National Greenhouse
Gas Inventories (3 volumes) [Houghton, J.T., L.G. Meira Filho, B. Lim, K.
Tréanton, I. Mamaty, Y. Bonduki, D.J. Griggs, and B.A. Callander (eds.)]. Intergovernmental
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