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Glossary

Adaptation to climate change
Undertaking actions to minimise threats or to maximise opportunities resulting from climate change and its effects.
Aerosols
A collection of airborne solid or liquid particles, with a typical size between 0.01 and 10 microns, which reside in the atmosphere for at least several hours. Aerosols may be of either natural or anthropogenic origin.
Agenda 21
An outcome of the 1992 United Nations Conference on Environment and Development (the Earth Summit) held in Rio de Janeiro. Agenda 21 provides the philosophy and process for community-led sustainable development.
Aggregated impacts
Total impacts integrated across sectors and/or regions. The aggregation requires assumptions about the relative importance of impacts in different sectors and regions.
Anomaly
A difference from the long-term average (eg, of a climate variable). For example, the El Niño summer rainfall anomaly is the difference between the rainfall averaged over summers when El Niño conditions are present and the rainfall averaged over all summers.
Antarctic Circumpolar Current
The westward flowing ocean current circling Antarctica, also known as the ‘West Wind Drift’. It is the largest ocean current on Earth (with about three times the flow of the Gulf Stream). A branch of it flows north around the Campbell Plateau to the south of New Zealand.
Anthropogenic
Produced by human beings or resulting from human activities.
Anthropogenic emissions
Emissions of greenhouse gases, greenhouse gas precursors and aerosols associated with human activities. These activities include burning fossil fuels for energy, deforestation and land-use changes that result in a net increase in emissions.
AOGCM
Acronym for atmosphere-ocean general circulation model.
AR4
Acronym for IPCCFourth Assessment Report, 2007.
ARI
Acronym for Average Recurrence Interval. Same as return period.
Atmosphere-ocean general circulation model (AOGCM)
A comprehensive climate model containing equations representing the behaviour of the atmosphere, ocean and sea ice and their interactions.
Black carbon aerosol
An aerosol that consists of soot, charcoal or other light-absorbing organic material.
Carbon dioxide (CO2)
A naturally occurring gas, also a by-product of burning fossil fuels. It is the principal anthropogenic greenhouse gas.
CFC
Acronym for chlorofluorocarbon.
Chlorofluorocarbons
Manufactured gases containing chlorine or fluorine that are used in 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. CFCs are also greenhouse gases, but are covered under the 1987 Montreal Protocol and explicitly excluded from the Kyoto Protocol and the United Nations Framework Convention on Climate Change (UNFCCC).
City and district councils
The management bodies of territorial authorities, of either predominantly urban or predominantly rural character.
Climate
The ‘average weather’, over a period of time ranging from months to thousands or millions of years. The classical period for calculating a ‘climate normal’ is 30 years.
Climate change
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 model
A numerical representation (typically a set of equations programmed into a computer) of the climate system. The most complex and complete climate models are known as ‘General Circulation Models’ (below).
Climate prediction
An attempt to provide a most likely description or estimate of the actual future evolution of the climate.
Climate projection
A potential future evolution of the climate in response to an emission or concentration scenario of greenhouse gases and aerosols. Often based on a simulation by a climate model.
Climate system
The interacting system comprising the atmosphere, hydrosphere (liquid water in lakes, rivers, seas, oceans), cryosphere (snow, ice, permafrost), land surface and biosphere (ecosystems and living organisms), which determines the earth’s climate.
Climate variability
Variations of the climate (eg, of the mean state, standard deviations and extremes) on all temporal and spatial scales beyond those of individual weather events.
CLIMPACTS
An integrated assessment model for conducting analyses of the sensitivity of New Zealand’s managed environments to climate variability and change. Both spatial and temporal variations can be examined. For further information, see website: http://www.climsystems.com/../../index.php (3 April 2008).
Consent notice
A condition on a subdivision consent, under section 221 of the Resource Management Act 1991, which must be complied with on a continuing basis by the subdividing owner and any subsequent owner. A consent notice is issued by a territorial authority and is deemed to be an instrument creating an interest in the land and a covenant on the land.
Consequence (or impact)
The outcome (of an event), expressed qualitatively in terms of the level of impact. Consequences can be measured in terms of economic, social, environmental or other impacts.
Discount rate
This is a term used in the IPCC Working Group III report (2007c), and refers to the degree to which consumption now is preferred to consumption 1 year hence, with prices held constant, but average incomes rising in line with GDP per capita.
Diurnal temperature range
The difference between the maximum and minimum temperature during a day.
Downscaling
Deriving estimates of local climate elements (eg, temperature, wind, rainfall), from the coarse resolution output of global climate models. Statistical downscaling uses present relationships between large-scale climate variables and local variables. Nested regional climate modelling uses the coarse resolution output from a global climate model to drive a high resolution regional climate model.
Down-zoning
Reducing the intensity of future development in an area by, for example, increasing minimum lot sizes.
El Niño
A significant increase in sea surface temperature over the eastern and central equatorial Pacific that occurs at irregular intervals, generally ranging between 2 and 7 years. Associated changes occur in atmospheric pressure patterns and wind systems across the Pacific. These can lead to changes in seasonal rainfall and temperature in parts of Australia and New Zealand.
El Niño-Southern Oscillation (ENSO)
Term coined in the early 1980s in recognition of the intimate linkage between El Niño events and the Southern Oscillation, which, prior to the late 1960s, had been viewed as two unrelated phenomena. The interactive global ocean-atmosphere cycle comprising El Niño and La Niña is often called the ‘ENSO cycle’.
Euphotic zone
The upper, illuminated zone of the marine ecosystem where photosynthesis occurs, typically reaching 30 m in coastal waters but extending to 100–200 m in open ocean waters.
Evapotranspiration
The combined process of evaporation from the earth’s surface and transpiration from vegetation.
Event
An incident that is induced or significantly exacerbated by climate change and that occurs in a particular place during a particular interval of time. Examples are floods, very high winds or droughts.
Extreme weather event
An event that is rare at a particular place. ‘Rare’ would normally be defined as rare as or rarer than the 10th or 90th percentile.
ENSO
Acronym for El Niño Southern Oscillation.
General Circulation Model (GCM)
A global, three-dimensional computer model of the climate system, which can be used to simulate the general circulation and climate of the atmosphere and ocean, and particularly human-induced climate change. General Circulation Models are highly complex and they represent the effects of such factors as reflective and absorptive properties of atmospheric water vapour, greenhouse gas concentrations, clouds, annual and daily solar heating, ocean temperatures and ice boundaries. General Circulation Models include global representations of the atmosphere, oceans and land surface.
GCM
Acronym for General Circulation Model or Global Climate Model.
Global Climate Model (GCM)
The same as General Circulation Model.
Global surface temperature

The global surface temperature is the area-weighted global average of:

(i) the sea surface temperature over the oceans (ie, the subsurface bulk temperature in the top few metres of the ocean), and

(ii) the surface-air temperature over land at 1.5 m above the ground.

Global warming

Generally used to refer to the rise of the earth’s surface temperature predicted to occur as a result of increased emissions of greenhouse gases.

Greenhouse effect
An increase in the temperature of the earth’s surface and the lowest 8 km or so of the atmosphere, caused by the trapping of heat by greenhouse gases. Naturally occurring greenhouse gases cause a greenhouse effect at the earth’s surface of about 30°C. Further temperature increases caused by anthropogenic emissions are termed the ‘enhanced greenhouse effect’.
Greenhouse gases
Gases in the earth’s atmosphere that absorb and re-emit infra-red (heat) radiation. Many greenhouse gases occur naturally in the atmosphere, but concentrations of some (such as carbon dioxide, methane and nitrous oxide) have increased above natural levels because of anthropogenic emissions.
Hazard

A source of potential harm to people or property. Examples are erosion or inundation.

Homogenised climate record

A climate record that has been screened and adjusted for errors (because of changes in site, observing location environs, instrumentation and observation methods) to produce a high-quality climate record for the purpose of detecting climate trends and variability.

Hotspots
An integrated assessment model to facilitate risk assessment and management of exotic mosquitoes of public health concern to New Zealand. http://www.waikato.ac.nz/moved.shtml?igci (3 April 2008).
IFD
Acronym for Intensity, Frequency and Duration, relating to extreme rainfall events. Alternatively known as ‘DDF’ (Depth, Duration, Frequency).
Interdecadal Pacific Oscillation (IPO)

A long timescale oscillation in the Pacific Ocean–atmosphere system that shifts climate every one to three decades. The IPO has positive (warm) and negative (cool) phases. Positive phases tend to be associated with an increase in El Niño, and negative phases with an increase in La Niña events.

Intergovernmental Panel on Climate Change (IPCC)
The body established in 1988 by the World Meteorological Organisation (WMO) and the United Nations Environment Programme (UNEP) to objectively assess scientific, technical and socioeconomic information relevant to understanding the scientific basis of risk of human-induced climate change, its potential impacts and options for adaptation and mitigation.
IPCC

Acronym for Intergovernmental Panel on Climate Change.

IPO

Acronym for Interdecadal Pacific Oscillation.

Kaitiakitangi
Stewardship, or the awareness of and care for natural and cultural resources, according to customary principles.
Kyoto Protocol

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 (COP) to the UNFCCC, in 1997 in Kyoto, Japan. It contains legally binding commitments on countries included in Annex B of the Protocol (most Organization for Economic Cooperation and Development countries and other countries with economies in transition) to reduce their anthropogenic greenhouse gas emissions to some (negotiable) value below 1990 levels in the commitment period 2008 to 2012. Different countries have different targets to achieve. New Zealand’s target is to reduce its greenhouse gas emissions to the level they were in 1990, or take responsibility for excess emissions. New Zealand ratified the Kyoto Protocol in December 2002. The Protocol entered into force on 16 February 2005.

La Niña

A significant decrease in sea surface temperature in the central and eastern equatorial Pacific that occurs at irregular intervals, generally ranging between 2 and 7 years. La Niña is the cool counterpart to the El Niño warm event, and its spatial and temporal evolution in the equatorial Pacific is, to a considerable extent, the mirror image of El Niño. Like El Niño, there are associated changes in atmospheric pressures and wind systems across the Pacific, and related changes can occur in temperature and rainfall in parts of Australia and New Zealand.

Lifelines
Key networks for communication and survival during emergency conditions, including connected links and operating facilities in electricity, telecommunications, roading, water supply and wastewater systems. They may also include key emergency services such as ambulance, fire and civil defence services, and facilitates such as hospitals and medical centres.
Likelihood
The probability or chance of something happening (can be a qualitative or quantitative measure).
Limitation adaptations
Those adaptations that are aimed at lessening or minimising the consequences of the most adverse effects of climate change as they arise over time.
Low-regrets adaptations
Those adaptations that are aimed at pro-actively minimising adverse effects that may arise over time from climate change.
Mitigation (of climate change)
Activities undertaken to reduce the sources or increase the sinks of greenhouse gases.
Montreal Protocol
An international agreement adopted in 1987 to control the consumption and production of chemicals such as chlorofluorocarbons that destroy stratospheric ozone.
Natural variability
Non-anthropogenic climate variability that may be irregular or quasi-cyclic. El Niño-Southern Oscillation is probably the best-known example of a natural oscillation of the climate system, but there are many others. Changes caused by volcanic eruptions and solar variations can also be considered ‘natural’.
No-regrets adaptation
Those adaptations that generate net social, economic and environmental benefits whether or not there is anthropogenic climate change climate, or at least have no net adverse effects.
Ozone
The triatomic form of oxygen (O3). It acts as a greenhouse gas in the troposphere. In the stratosphere (about 10–50 km above the ground) it absorbs harmful UV radiation emanating from the sun.
Percentile
Used to give an observed value a ranking within the historical record. For example, only 5% of observations lie below the 5th percentile (ie, the coldest 5% of the temperature record) and 5% of observations lie above the 95th percentile (ie, the warmest 5% of that record).
Precursors
Atmospheric compounds that are not themselves greenhouse gases or aerosols, but which take part in processes regulating their production or destruction.
Radiative forcing
The perturbation to the energy balance of the earth–atmosphere system following, for example, a change in the concentration of carbon dioxide or a change in the output of the sun. The climate system responds to the radiative forcing so as to re-establish the energy balance. A positive radiative forcing tends to warm the earth’s surface and a negative radiative forcing tends to cool the surface.
Regional Climate Model (RCM)
A climate model that is run at high resolution over a ‘region’ (eg, the eastern part of Australia, Tasman Sea plus New Zealand) to describe climate at the regional scale. RCMs are typically driven with data from Global Climate Models, which run at lower resolution and, therefore, do not accurately simulate, for example, the effects of the Southern Alps on New Zealand’s climate.
Regional councils
Constituted under the Local Government Act 2002 with the functions and responsibilities that relate to defined local government regions.
Relative sea level
Sea level measured by a tide gauge with respect to the land upon which it is situated. Mean Sea Level (MSL) is normally defined as the average Relative sea level over a period, such as a month or a year, long enough to average out transient fluctuations such as waves.
Return period
The probable time period between repetition of extreme weather events, such as heavy rainfall or flooding, in a stationary climate (that is, a climate without global warming or other trends). In the case of rainfall, a return period is always related to a specific duration (eg, 50-year return period of 24-hour extreme rainfall).
Risk
The chance of an ‘event’ being induced or significantly exacerbated by climate change, that event having an impact on something of value to the present and/or future community. Risk is measured in terms of consequence and likelihood.
Scenario
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.
Screening assessment
An initial risk assessment that involves identifying current sensitivity to climate and possible future sensitivity to climate change, and the likely duration and extent of effects that may arise as a consequence of climate change.
SOI
Acronym for Southern Oscillation Index.
Southern oscillation
A multi-year low-latitude seesaw in sea level pressure, with one pole in the eastern Pacific and the other in the western Pacific/Indian Ocean region. This pressure seesaw is associated with a global pattern of atmospheric anomalies in circulation, temperature, and precipitation. Its opposite extremes are the El Niño and La Niña events.
Southern Oscillation Index (SOI)
An index calculated from anomalies in the pressure difference between Tahiti and Darwin. Low negative values of this index correspond to El Niño conditions, and high positive SOI values coincide with La Niña episodes.
SRES scenarios
A set of greenhouse gas and aerosol emissions scenarios developed in 2000 by Working Group III of the IPCC and used, among others, as a basis for the climate projections in the IPCC Third Assessment Report (2001a, 2001b).
SST
Acronym for Sea Surface Temperature (see Global surface temperature).
Storm surge
The excess above the level expected from the tidal variation alone at a given time and place. The temporary increase in the height of the sea is caused by extreme meteorological conditions such as low atmospheric pressure and/or strong winds.
Stratosphere
The region of the atmosphere extending from about 10 km to 50 km altitude.
Sustainability
“... development that meets the needs of the present without compromising the ability of future generations to meet their own needs” (Bruntland Report, Our Common Future, Report of the World Commission on Environment and Development, 1978).
Territorial authorities
Constituted under the Local Government Act 2002, comprising city and district councils and (for some functions) unitary authorities.
Troposphere
The lowest part of the atmosphere, which in mid-latitude locations like New Zealand extends from the earth’s surface to about 10 km altitude.
Unitary authorities
Territorial authorities that also have regional council responsibilities.
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 ‘stabilisation 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. The convention entered into force in March 1994. See also Kyoto Protocol.
Weather generator
Weather generators produce multiple time series of numbers with statistical properties that resemble those of historical weather records. The most common weather generators produce output representing daily time series of maximum and minimum temperature, rainfall and solar radiation. The numbers preserve observed characteristics such as persistence of temperature (eg, one hot day is often followed by another), as well as inter-relationships (eg, wet days tend to have lower solar radiation and lower maximum temperature but higher minimum temperature).