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• Important terms and definitions
• Abbreviations

Climate model

A numerical representation of the climate system that is based on the physical, chemical, and biological properties of its components, their interactions, and feedback processes, and that accounts for all or some of its known properties (IPCC, 2014).

Climate projection

A projection of the response of the climate system to emissions 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, e.g., future socioeconomic and technological developments that may or may not be realised and are therefore subject to substantial uncertainty (IPCC 2012).

Climate scenario

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 (IPCC 2012).

Climate variability

Climate variability refers to variations in the mean state and other statistics (such as standard deviations, the occurrence of extremes, etc.) of the climate at all spatial and temporal 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) (IPCC 2012).

Drought

A period of abnormally dry weather long enough to cause a serious hydrological imbalance. Drought is a relative term, therefore any discussion in terms of precipitation deficit must refer to the particular precipitation-related activity that is under discussion. A period with an abnormal precipitation deficit is defined as a meteorological drought. A megadrought is a very lengthy and pervasive drought, lasting much longer than normal, usually a decade or more. (IPCC 2012).

El Niño-Southern Oscillation

The term El Niño is a warming of the tropical Pacific Ocean east of the dateline. This oceanic event is associated with a fluctuation of a global-scale tropical and subtropical surface pressure pattern called the Southern Oscillation. This coupled atmosphere-ocean phenomenon, with preferred time scales of 2 to about 7 years, is collectively known as the El Niño-Southern Oscillation. During an El Niño event, the prevailing trade winds weaken, reducing upwelling and altering ocean currents such that the sea surface temperatures warm, further weakening the trade winds. This event has a 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 cold phase of ENSO is called La Niña. (IPCC 2012).

Greenhouse effect

Greenhouse gases effectively absorb thermal 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 greenhouse effect. 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 that leads to an enhancement of the greenhouse effect, the so-called enhanced greenhouse effect. (IPCC 2012).

Greenhouse gas

Greenhouse gases are those gaseous constituents of the atmosphere, both natural and anthropogenic, which absorb and emit radiation at specific wavelengths within the spectrum of thermal infrared radiation emitted by the Earth’s surface, by the atmosphere itself, and by clouds. This property causes the greenhouse effect. Water (H2O), carbon dioxide (CO2), nitrous oxide (N2O), methane (CH4), and ozone (O3) are the primary greenhouse gases in the Earth’s atmosphere. (IPCC 2012).

Heat wave

A period of abnormally hot weather. Heat waves and warm spells have various and in some cases overlapping definitions (IPCC 2012).

Global Climate Model

Global Climate Models, are computer-driven models that are used for projecting weather, understanding climate, projecting seasonal and inter-annual climate and projecting climate change. They are mathematical representations of the real world which simulate processes in the Earth’s atmosphere and oceans. There are only a handful of countries in the world that have developed Global Climate Models. Australia has developed the ACCESS1.0, ACCESS1.3 and CSIROMk3.6.0 models.

Exposure

Relates to the influences or stimuli that impact on a system. Exposure is a measure of the projected changes in the climate for the future scenario assessed.  It includes both direct stressors, such as increased temperature, and indirect stressors or related events, such as increased frequency of wildfire.

Sensitivity

Reflects the responsiveness of a system to climatic stressors or influences, and the degree to which changes in climate might affect that system in its current form.  Sensitive systems are highly responsive to climate and can be significantly affected by small climate changes.

Vulnerability

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 capacity. This plan is focused on the vulnerability of natural assets to climate change.

Resilience

The ability of a social or ecological system to absorb disturbances while retaining the same basic structure and ways of functioning, the capacity for self-organisation, and the capacity to adapt to stress and change (IPCC, 2012).

Adaptation

The IPCC refers to adaptation as ‘the process of adjustment to actual or expected climate and its effects. In human systems, adaptation seeks to moderate or avoid harm or exploit beneficial opportunities. In some natural systems, human intervention may facilitate adjustment to expected climate and its effects’ (IPCC, 2014).

Adaptive capacity

Is 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 (IPCC, 2014b). The adaptive capacity of a system or society describes its ability to modify its characteristics or behaviour, to cope better with changes in external conditions. The more adaptive a system, the less vulnerable it is. For the purposes of this plan, adaptive capacity will be assigned in terms of the ability of an asset to adjust to climate stressors based on its current state, which may vary from pristine to degraded.

Mitigation

The term mitigation refers to making a condition or consequence less severe. By definition, mitigation is an adaptation response to climate change, aiming to reduce hazards and exposure to potential impacts. In the context of climate change and this plan, mitigation is about taking action to reduce human-induced climate change.

Representative Concentration Pathways

Are used to describe greenhouse gas concentration trajectories.  The pathways are used for climate modelling and research. They describe four possible climate futures, all of which are considered possible depending on how much greenhouse gases are emitted in the future. According to the IPCC, the highest RCP (RCP 8.5) assumes a concentration of 1313 ppm CO2-e by 2100. Projected global mean temperatures associated with this scenario range from 2.6-4.8°C above current temperatures. A mid-range scenario assumes 538 ppm CO2-e (RCP 4.5), projected increases range from 1.0-2.6°C by 2090 (IPCC, 2013). Currently, global emissions have consistently tracked at or above the highest emissions scenario (RCP 8.5).

Abbreviations