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9 Glossary

Adaptation to climate change
Undertaking actions to minimise threats or to maximise opportunities resulting from climate change and its effects.
Adaptive capacity
The ability of a human system or ecosystem to: adjust or respond to climate change (including both variability and extremes); moderate potential damages; take advantage of new opportunities arising from climate change; or cope with and absorb the consequences.
Adaptive responses
See Adaptation to climate change.
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.
Anomaly
A difference from the long-term average climate (eg, of a climate element).  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.
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 the three-volume IPCC Fourth Assessment Report, 2007.
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.
Bruun Rule
A simple mathematical relationship that states: as sea-level rises, the shoreface profile moves up and back while maintaining its original shape.
Carbon dioxide (CO2)
A naturally occurring gas, also a by-product of burning fossil fuels.  It is the principal anthropogenic greenhouse gas.
Carbon dioxide equivalent (CO2-e)
Carbon dioxide equivalent concentration is used to compare the effect from various greenhouse gases.  It is the concentration of CO2 that would cause the same amount of radiative forcing as a given mixture of CO2 and other greenhouse gases.  Source: IPCC 2007a
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) that 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.
Coastal accretion
A long-term trend of shoreline advance and/or gain of beach sediment volume over several decades.  In many cases, accretion is beneficial and creates a buffer against future coastal hazards.
Coastal erosion
A long-term trend of shoreline retreat and/or loss of beach sediment volume over several decades.  ‘Cutback’ is a more suitable term for a dynamically ‘stable’ shoreline to describe the temporary loss of beach volume or shoreline retreat during a storm (before the volume gets replenished over ensuing weeks and months).
Coastal margin
Aquatic and land environments that are potentially affected by coastal hazards, including the long-term impacts of climate change, in which the coast and any dune or cliff system is a significant element or part, and includes the coastal marine area.
Coastal Marine Area (CMA) 
That area of the foreshore and seabed of which the seaward boundary is the outer limits of the territorial sea (12 nautical miles) and the landward boundary is the line of mean high water spring, except where that line crosses a river.  There, the landward boundary is whichever is the lesser of: 1 kilometre upstream from the mouth of the river, or the point upstream that is calculated by multiplying the width of the river mouth by five.  (Resource Management Act 1991).
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.
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.
El Niño
A significant increase in sea surface temperature over the eastern and central equatorial Pacific that occurs at irregular intervals, generally ranging between two and seven 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’.
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.  GCMs 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.  GCMs 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 30oC.  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 infrared (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 coast erosion or inundation.  Note a hazard does not necessarily lead to harm or damage.
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 OECD countries and some others) 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.  Negotiations are now under way on further commitments for developed countries under the Kyoto Protocol.
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.
Limitation adaptations
Adaptations aimed at lessening or minimising the consequences of the most adverse effects of climate change as they arise over time.
Low-regrets adaptations
Low-cost policies, decisions and measures that have potentially large benefits.
LTCCP
Acronym for Long-term Council Community Plan.
Mean High water Spring (MHWS)
Mean high water spring is traditionally the level of the average spring tides just after full or new moon.  In central–eastern regions, a ‘pragmatical’ MHWS or perigean-spring tide level (MHWPS) is a better hazard measure of upper-level high tides than the traditional MHWS, because the spring-neap effect is weak.
Mean Level of the Sea (MLOS)
The actual level of the sea over a certain averaging period (days, weeks, years, decades) after removing the tides (not to be confused with mean sea level or MSL, which usually refers to a set vertical survey datum).
Mean Sea Level (MSL)
Mean sea level survey datum generally set down in the 1930s to 1950s for different regions.  Because of the sea-level rise since then, MSL datum values around New Zealand are usually several centimetres below the current mean level of the sea.
Mitigation (of climate change)
Activities undertaken to reduce the sources or increase the sinks of greenhouse gases.
Natural character
The qualities of the coastal environment that together give the coast of New Zealand recognisable character.  These qualities may be ecological, physical, spiritual, cultural or aesthetic in nature, whether modified or managed or not.
Natural hazard
Any atmospheric or earth- or water-related occurrence (including earthquake, tsunami, erosion, volcanic and geothermal activity, landslip, subsidence, sedimentation, wind, drought, fire or flooding), the action of which adversely affects or may adversely affect human life, property or other aspects of the environment.  (Resource Management Act 1991).
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, or adaptations that at least have no net adverse effects.
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).
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 average time period between repetition of an extreme weather event, 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..  It also has an element of choice by humans.
RPS
Acronym for Regional Policy Statement – a mandatory policy statement prepared under the RMA by a regional or unitary council.
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.
Sea-level rise
Trend of annual mean sea level over timescales of at least three or more decades.  Must be tied to one of the following two types: global – overall rise in absolute sea level in the world’s oceans; or relative – net rise relative to the local landmass (that may be subsiding or being uplifted).
Significant wave height
The average height of the highest one-third of waves during a short recording interval (typically 10–20 minutes).  Generally, considered the height that a trained observer would report for a given sea state.
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’s 2001 Third Assessment Report.
SST 
Acronym for Sea Surface Temperature (see Global surface temperature).
Storm surge 
The temporary 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.
Storm tide
The total elevated sea height at the coast above a datum during a storm combining storm surge and the predicted tide height.  Note that wave set-up and wave run-up need to be added to the storm tide level at any locality to get the final storm inundation level.
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 1987).
TA 
Acronym for Territorial Authority.
Territorial authorities
Constituted under the Local Government Act 2002, comprising city and district councils and (for some functions) unitary authorities.
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.
Wave run-up
The ultimate height reached by waves (storm or tsunami) after running up the beach and coastal barrier (see also wave set-up).
Wave set-up 
The super-elevation in water level across the surf zone caused by energy expended by breaking waves (see also wave run-up).
Weather generator 
Weather generators produce multiple time series of numbers with statistical properties resembling 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).

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