Climate Change in Australia

A

Adaptation 

In human systems, the process of adjustment to actual or expected climate and its effects, in order to moderate harm or exploit beneficial opportunities. In natural systems, the process of adjustment to actual climate and its effects; human intervention may facilitate adjustment to expected climate and its effects¹

Adaptive capacity

The ability of systems, institutions, humans and other organisms to adjust to potential damage, to take advantage of opportunities, or to respond to consequences.¹

Adaptation options 

The array of strategies and measures that are available and appropriate for addressing adaptation. They include a wide range of actions that can be categorised as structural, institutional, ecological or behavioural.¹

Australian Energy Market Operator (AEMO) 

AEMO manages electricity and gas systems and markets across Australia, helping to ensure Australians have access to affordable, secure and reliable energy. Australian Energy Market Commission (AEMC) AEMC is the rule- maker for Australian electricity and gas markets. 

 Australian Energy Regulator (AER) 

The AER regulates wholesale and retail energy markets, and energy networks, under national energy legislation and rules. Their functions mostly relate to energy markets in eastern and southern Australia.

B

Baseload 

Electricity usage that is constant through a specified time period. Also used to refer to the generating units that run all 24 hours of the day to serve a system's baseload demand.²

Best practice 

Best practice is a feature of accredited management standards such as ISO 31000. Best practice is a method or technique that has been generally accepted as superior to any alternatives because it produces results that are superior to those achieved by other means or because it has become a standard way of doing things, for example a standard way of complying with legal or ethical requirements.

C

Capacity

The maximum electric power output of a generating unit (measured in MW) or the maximum amount of power that lines or equipment can safely carry.²

Carbon dioxide

A naturally occurring gas, carbon dioxide is also a by-product of burning fossil fuels (such as oil, gas and coal), of burning biomass, of land-use changes and of industrial processes (e.g. cement production). It is the principal anthropogenic greenhouse gas that affects the Earth’s radiative balance.¹

Climate

Climate 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 for averaging these variables is 30 years, as defined by the World Meteorological Organization. The relevant quantities are most often surface variables such as temperature, precipitation and wind.¹

Climate change

Climate change refers to a change in the state of the climate that can be identified by changes in the mean and/or the variability of its properties and that persists for an extended period, typically decades or longer. Climate change may be due to natural internal processes or external forcings such as modulations of the solar cycles, volcanic eruptions and persistent anthropogenic changes in the composition of the atmosphere or in land use.¹

Climate extreme

The occurrence of a value of a weather or climate variable above (or below) a threshold value near the upper (or lower) ends of the range of observed values of the variable. For simplicity, both extreme weather events and extreme climate events are referred to collectively as ‘climate extremes’.¹

Climate impact assessment

The practice of identifying, analysing and evaluating, in monetary and/or non-monetary terms, the effects of climate change on natural and human systems.¹

Climate model

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 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 spectrum or 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. There is an evolution towards more complex models with interactive chemistry and biology. Climate models are applied as a research tool to study and simulate the climate and for operational purposes, including monthly, seasonal and interannual climate predictions.¹

Climate model ensemble

A group of climate model simulations characterising historical climate conditions, seasonal climate predictions, or multi-decadal climate projections. Variation of the results across the ensemble members may give an estimate of model-based uncertainty. Ensembles made with the same model but different initial conditions only characterise the uncertainty associated with internal climate variability, whereas multi-model ensembles including simulations by several models also include the impact of model differences. Perturbed parameter ensembles, in which model parameters are varied in a systematic manner, aim to assess the uncertainty resulting from internal model specifications within a single model. Remaining sources of uncertainty unaddressed with model ensembles are related to systematic model errors or biases, which may be assessed from systematic comparisons of model simulations with observations wherever available.¹

Climate projection

The simulated response of the climate system to a scenario of future emission or concentration of greenhouse gases and aerosols, generally derived using climate models.¹

Climate risk assessment framework

Risk assessment frameworks provide a consistent, structured and pragmatic approach to minimising harm and seizing opportunities.³ The process starts with establishing the context, followed by assessing impacts, planning, implementation, monitoring, evaluation and reporting. 

The ESCI Climate Risk Assessment Framework is described in Guidance Module 2 and includes relevant information from:

1. International Standard ISO 31000 Risk Managemenwhich provides a general framework that is widely used around the world.
2. ISO Standard 14090 which is consistent with ISO 31000 and well aligned with climate risk assessment for the electricity sector.
3. Australian Standard AS 5334 Climate change adaptation for settlements and infrastructure.
4. The Australian Climate Compass which is also consistent with ISO 31000, with a focus on climate risk assessment in Australia.
5. Australia's Natural Disaster Risk Reduction Framework

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 assessments. Climate projections often serve as the raw material for constructing climate scenarios, but climate scenarios usually require additional information such as the observed current climate. ESCI climate scenario generation is described in Guidance Module 4.1. Scenarios quantify three main sources of uncertainty: greenhouse gas emission pathways, regional climate responses to each emission pathway, and random weather and climate variability.

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 on 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).¹

Compound extreme events

Extreme weather and climate events and their impacts can occur in complex combinations, an interaction shaped by physical drivers and societal forces. Compound weather events are a combination of multiple drivers and/or hazards that contribute to societal or environmental risk. Compound event impacts are often substantially and non-linearly influenced by non-physical factors such as exposure and vulnerability, cutting across sectors and scales.⁴

Confidence

The robustness of a finding based on the type, amount, quality and consistency of evidence (e.g. mechanistic understanding, theory, data, models, expert judgment) and on the degree of agreement across multiple lines of evidence.¹

Coupled Model Intercomparison Project (CMIP)

A climate modelling activity from the World Climate Research Programme which coordinates and archives climate model simulations based on shared model inputs by modelling groups from around the world. The CMIP5 data set includes projections using representative concentration pathways.¹

D

Demand- and supply-side measures 

Demand-side measures are policies and programmes for influencing the demand for goods and/ or services. In the energy sector, demand-side management aims at reducing the demand for electricity and other forms of energy required to deliver energy services. Supply-side measures are policies and programmes for influencing how a certain demand for goods and/or services is met. In the energy sector, supply-side mitigation measures aim at reducing the amount of greenhouse gas emissions emitted per unit of energy produced.¹

Distribution network service providers (DNSPs)

Distributed Network Service Provider are organisations that own and control the hardware of the distributed energy network such as power poles, wires, transformers and substations that move electricity around the grid. Companies that own the poles and wires, and deliver electricity to consumers.⁵

Distributed energy resources (DER)

Smaller generation units located at an end-use customer's facility. These can include rooftop solar units and battery storage.

Distribution

One of the three parts that makes up the electric grid. The delivery of electricity over medium- and low-voltage lines to end-use consumers. Distribution is owned and represented by the consumer's local distribution network service provider. ²

Downscaling

Downscaling is a method that derives local- to regional-scale (up to 100 km) information from larger-scale models or data analyses. Two main methods exist: dynamical downscaling and empirical/statistical downscaling. The dynamical method uses the output of regional climate models, global models with variable spatial resolution, or high-resolution global models. The empirical/statistical methods are based on observations and develop statistical relationships that link the large-scale atmospheric variables with local/regional climate variables. In all cases, the quality of the driving (host) model remains an important limitation on quality of the downscaled information. The two methods can be combined, for example applying empirical/statistical downscaling to the output of a regional climate model, consisting of a dynamical downscaling of a global climate model.¹

E

El Niño – Southern Oscillation (ENSO)

A coupled ocean-atmosphere process in the Pacific Ocean that affects global climate variability. El Niño and La Niña events represent the extreme phases of this natural oscillation, and these events occur every four to seven years on average. During El Niño conditions, rainfall is often below average over much of eastern Australia, tropical cyclones are less likely in the Coral Sea, and the frequency and amplitude of heatwaves increases across most of northern and eastern Australia. The opposite pattern occurs during La Niña conditions.⁶

Energy Networks Australia (ENA)

ENA is the national industry body representing Australia’s electricity transmission and distribution and gas distribution networks. ENA works with networks, regulators and industry partners to develop research and advice on issues including national and state government policy and regulation relevant to energy networks and how they must operate and key technical issues such as network safety and security of supply, reliability and power quality, the management of peak energy demand, energy efficiency and sustainable energy. 

Extreme weather event 

An extreme weather event is an event that is rare at a particular place and time of year. Definitions of rare vary, but an extreme weather event would normally be as rare as or rarer than the 10^th or 90^th percentile of a probability density function estimated from observations. By definition, the characteristics of what is called extreme weather may vary from place to place in an absolute sense,¹ for example number of days over 40 °C.

F

Fire weather 

Weather conditions conducive to triggering and sustaining wild fires, usually based on a set of indicators and combinations of indicators including temperature, soil moisture, humidity, and wind. Fire weather does not include the presence or absence of fuel load. 

Forest Fire Danger Index (FFDI) 

An indicator of how readily a fire could start, and how intense and fast-moving the fire is likely to be once it gets going. The index represents a combination of temperature, humidity, windspeed and drought factor. The index does not include the contribution from fuel load, ignition sources (such as lightning) or management practices.

G

Generation 

One of the three parts that make up the electric grid.² Also see Transmission and Distribution. 

Generator 

Used synonymously with the term power plant (although technically, the generator is the part of the power plant that converts the mechanical power of a spinning shaft to electricity).²

Greenhouse gas 

Gaseous constituents of the atmosphere, both natural and anthropogenic, that absorb and emit radiation at specific wavelengths within the spectrum of terrestrial radiation emitted by the Earth’s surface, the atmosphere itself and by clouds. This property causes the greenhouse effect. Water vapour, carbon dioxide, nitrous oxide, methane and ozone are the primary greenhouse gases. There are a number of entirely human-made greenhouse gases, such as the halocarbons and other chlorine- and bromine-containing substances, dealt with under the Montreal Protocol. The Kyoto Protocol also deals with the sulphur hexafluoride, hydrofluorocarbons and perfluorocarbons.¹

H

Hazard 

The potential occurrence of a natural or human-induced physical event or trend that may cause loss of life, injury, or other health impacts, as well as damage and loss to property, infrastructure, livelihoods, service provision, ecosystems and environmental resources. See also Exposure, Risk and Vulnerability.¹

Hydro power 

Power that is derived from the weight or motion of water, used as a force to drive a turbine or other machinery.²

I

Impacts

The consequences of realised risks on natural and human systems, where risks result from the interactions of climate-related hazards (including extreme weather and climate events), exposure, and vulnerability.¹

Indian Ocean Dipole (IOD)

Large-scale mode of interannual variability of sea surface temperature in the Indian Ocean. This pattern manifests through a zonal gradient of tropical sea surface temperature, which in its positive phase in September to November shows cooling off Sumatra and warming off Somalia in the west, combined with anomalous easterlies along the Equator.⁶

A positive IOD can lead to below average rainfall in winter and spring over central and southern Australia. In Victoria, particularly spring, a positive IOD contributes to lower rainfall and higher temperatures, exacerbating dry conditions and increasing the fuel load leading into summer. There are interactions between the IOD and ENSO. Positive IOD events are more likely during El Niño years and negative IOD events are more likely during La Niña years.

Intergovernmental Panel on Climate Change (IPCC)

United Nations body that provides objective, scientific information relevant to understanding the scientific basis of the risk of human-induced climate change, its natural, political, and economic impacts and risks, and response options.

L

Likelihood

The chance of a specific outcome occurring, where this might be estimated probabilistically.¹

N

The National Electricity Market (NEM) 

Wholesale market through which generators and retailers trade electricity in Australia. It interconnects the six eastern and southern states and territories and delivers around 80% of all electricity consumption in Australia. The NEM incorporates around 40,000 km of transmission lines and cables. 

National Energy Retail Objective 

The objective is ‘to promote efficient investment in, and efficient operation and use of, energy services for the long term interests of consumers of energy with respect to price, quality, safety, reliability and security of supply of energy’.

P

Paris Agreement 

The Paris Agreement under the United Nations Framework Convention on Climate Change (UNFCCC) was adopted in 2015. The agreement, adopted by 196 Parties to the UNFCCC, entered into force on 4 November 2016 and as of May 2018 had 195 Signatories and was ratified by 177 Parties. One of the goals of the Paris Agreement is ‘holding the increase in the global average temperature to well below 2 °C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5 °C above pre-industrial levels’, recognising that this would significantly reduce the risks and impacts of climate change. Additionally, the Agreement aims to strengthen the ability of countries to deal with the impacts of climate change.¹

Percentile 

A percentile is a value on a scale of one hundred100 that indicates the percentage of the data set values that is equal to, or below it. The percentile is often used to estimate the extremes of a distribution. For example, the 90^th (or 10^th) percentile may be used to refer to the threshold for the upper (or lower) extremes.⁶

Projection 

A projection is a potential future evolution of a quantity or set of quantities, often computed with the aid of a model. Unlike predictions, projections are conditional on assumptions concerning, for example, future socio-economic and technological developments that may or may not be realised.¹

R

Radiative forcing 

Radiative forcing is the change in the net, downward minus upward, radiative flux (expressed in W m^-2) at the tropopause or top of atmosphere due to a change in a driver of climate change, such as a change in the concentration of carbon dioxide or the output of the Sun.¹

Regulatory investment test for distribution 

Designed to establish consistent, clear and efficient planning processes for distribution network investments in the national electricity market. Administered by the Australian Energy Regulator. 

Regulatory investment test for transmission 

Designed to identify the transmission investment option that maximises net economic benefits and, where applicable, meets the relevant jurisdictional or National Electricity Rule-based reliability standards. Administered by the Australian Energy Regulator. 

Renewable energy 

Energy that is naturally replenished such as wind or solar. 

Reliability 

A measure of how often electrical service is interrupted. The National Electricity Rules state that ‘a reliable power system has enough generation, demand response and network capacity to supply customers with the energy that they demand with a very high degree of confidence’. 

Representative concentration pathways (RCP) 

Time-series of emissions and concentrations of the full suite of greenhouse gases and aerosols and chemically active gases, as well as land use/land cover. Each RCP provides only one of many possible scenarios that would lead to the specific radiative forcing characteristics. RCPs were used to develop climate projections in CMIP5.

1. RCP2.6: a low emission pathway where radiative forcing peaks at approximately 3 W m^-2 and then declines to be limited at 2.6 W m^-2 in 2100. RCP2.6 has a two-thirds chance of staying below 2 °C global warming by the end of the century relative to the pre-industrial period (1850–1900) 
2. RCP4.5 and RCP6.0: intermediate stabilization pathways in which radiative forcing is either 4.5 W m^-2 or 6.0 W m^-2 in 2100. RCP4.5 leads to a global warming of 1.7–3.3 °C by the end of the century relative to the pre-industrial period, while RCP6.0 gives a global warming of 2.0–3.8 °C 
3. RCP8.5: a high emission pathway with > 8.5 W m^-2 in 2100. RCP8.5 leads to a global warming of 3–5 °C by the end of the century relative to the pre-industrial period.¹,⁵

Resilience 

Resilience is an attribute of a system. Power system resilience metrics are generally based on the performance of power systems and the consequence of outages, as opposed to relying on attributes of power systems.⁷ Some useful references: 

1. 'The capacity of social, economic and environmental systems to cope with a hazardous event or trend or disturbance, responding or reorganising in ways that maintain their essential function, identity and structure while also maintaining the capacity for adaptation, learning and transformation.'¹
2. 'The ability of a system, community or society exposed to hazards to resist, absorb, accommodate to and recover from the effects of a hazard in a timely and efficient manner, including through the preservation and restoration of its essential basic structures and functions', United Nations Office for Disaster Risk Reduction (UNISDR), '2009 UNISDR Terminology on Disaster Risk Reduction', Geneva, May 2009 United Nations Office for Disaster Risk Reduction  
3. AEMO has adopted the CIGRE definition of resilience as 'the ability to limit the extent, severity, and duration of system degradation following an extreme event'.⁸

Risk 

The potential for adverse consequences where something of value is at stake and where the outcome is uncertain, recognizing the diversity of values. In the context of climate impacts, risk is often used to refer to the potential for adverse consequences of a climate-related hazard, or of adaptation or mitigation responses to such a hazard, on lives, livelihoods, health and well-being, ecosystems and species, economic, social and cultural assets, services (including ecosystem services), and infrastructure. Risk results from the interaction of vulnerability (of the affected system), its exposure over time (to the hazard), as well as the (climate-related) hazard and the likelihood of its occurrence.¹

Risk analysis 

Risk analysis is undertaken after risk identification and before risk evaluation. Risk analysis is a process that is used to understand the nature, sources and causes of the identified risks and to estimate the level of risk. It is also used to study impacts and consequences and to examine the controls that currently exist. The level of detail depends on the risk, the purpose of the analysis, the information available, and the resources allocated. It generally involves the assignment of an overall risk rating to each of the risk events identified by following these steps: 

1. Analyse inherent risk—what is the likelihood and consequence of a risk event if it were to occur in an uncontrolled environment? 
2. Analyse controls—what existing controls are in place to address the identified risk and how effective are these controls in design and operation? 
3. Analyse residual risk—what is the likelihood and consequence of a risk event if it were to occur in the current control environment?⁹ 

Risk assessment 

The qualitative and/or quantitative scientific estimation of risks.¹

Risk evaluation 

Risk evaluation is undertaken after risk identification and risk analysis. It is a process that is used to compare risk analysis results with risk criteria in order to determine whether or not a specified level of risk is acceptable or tolerable.⁹

Risk identification 

Risk identification precedes risk analysis and risk evaluation. Risk identification explores sources of risk, areas of impacts, events (including changes in circumstances) and their causes and potential consequences. The aim of this step is to generate a comprehensive list of material risks based on those events that might create, enhance, prevent, degrade, accelerate, or delay the achievement of objectives. It is important to identify the risks associated with not pursuing an opportunity. Comprehensive identification is critical, because a risk that is not identified at this stage will not be included in further analysis. 

Risk management (or risk treatment) 

Plans, actions, strategies or policies to reduce the likelihood and/or consequences of risks or to respond to consequences.¹

Risk mitigation 

Action taken to reduce the impact of a risk event. Climate change risk mitigation describes efforts to reduce greenhouse gas emissions. 

Risk treatment (or risk management) 

Risk treatment is the process of selecting and implementing of measures to modify risk. Risk treatment measures can include avoiding, optimizing, transferring or retaining risk. Used interchangeably with risk management.

S

Scenario

A plausible 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 technological change, prices) and relationships. Scenarios are neither predictions nor forecasts but are used to provide a view of the implications of developments and actions.¹

Southern Annular Mode (SAM)

The Southern Annular Mode (SAM) is a large-scale alternation of atmospheric pressure between the middle latitudes and high latitudes. During a positive phase of the SAM, there is a southward shift of the westerly-wind belt that circles Antarctica, leading to more rainfall in eastern Australia with more east coast lows, and less rainfall in the south, with the opposite effect during a negative phase. Positive SAM is associated with a decreased likelihood of extreme heat during the spring, but correlations are more mixed during summer. The La Niña phase of ENSO increases global mean temperature and contributes to a negative phase of the SAM. The record hot and dry conditions in 2019 that led to the massive fires in southern and eastern Australia were associated with a positive IOD, negative SAM and global warming.⁵

Supply

Generation of energy in the national electricity market and made available to end users. Generation of electricity can result from:

1. traditional high voltage large-scale generators, such as thermal coal or commercial wind farms
2. a wide variety of smaller distributed generation or embedded generation units including smaller generation units on the consumer's side of the meter such as rooftop photovoltaic solar panels

T

Task Force on Climate-Related Financial Disclosures (TCFD) 

Body created by the Financial Stability Board (an international organisation that monitors and makes recommendations about the global financial system) to develop consistent climate-related financial risk disclosures for use by companies, banks, and investors in providing information to stakeholders. 

Transmission 

The transport of electricity over high-voltage power lines from generations to the interconnection with the distribution system. Transmission is under the jurisdiction of Transmission Network Service Providers. 

Transmission Network Service Provider (TNSP) 

Transmission network service providers are network businesses in the national electricity market (NEM). There are five state-based TNSPs servicing each of the states in the NEM, with crossborder interconnectors linking the grid at state borders to allow electricity to flow from one state to another. TNSPs link generators to the 13 major distribution networks that supply electricity to end use customers.

U

Uncertainty 

A state of incomplete knowledge that can result from a lack of information or from disagreement about what is known or even knowable. It may have many types of sources, from imprecision in the data to ambiguously defined concepts or terminology, incomplete understanding of critical processes, or uncertain projections of human behaviour. Uncertainty can therefore be represented by quantitative measures (e.g. a probability density function) or by qualitative statements (e.g. reflecting the judgment of a team of experts).

V

Vulnerability 

 The propensity or predisposition to be adversely affected. Vulnerability encompasses a variety of concepts and elements including sensitivity or susceptibility to harm and lack of capacity to cope and adapt.

Notes

¹ IPCC (2018) Global warming of 1.5 ^oC. Annex 1 Glossary. 

² Power2Switch Electricity Glossary

³ ISO 14090 (2019) Adaptation to climate change  

⁴ Zscheischler J, Martius O, Westra S, et al. 'A typology of compound and climate events' (2020) 1 Nature Reviews, Earth and Environment 333  A typology of compound weather and climate events  Raymond C, Horton RM,  Zscheischler J, et al. 'Understanding and managing connected extreme events' (2020) 10 Nature Climate Change 611 Understanding and managing connected extreme events

⁵ Solar Victoria: Distributors

⁶ CMSI (2020). Scenario analysis of climate-related physical risks for buildings and infrastructure: climate science guidance Appendix 2. CMSI

⁷ Sandia Report. SAND217-1493 February 2017, Resilience Metrics for the Electric Power System: A Performance-Based Approach. 

⁸ E-cigre.org, WG C4.47 Defining Power System Resilience, RP_306_1 2019 

⁹ ISO 31000 Risk Management