This page is a full list of terms and their meaning. Click the alphabet links below to jump to sections.
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
A
1.5°C global warming
In 2015, the Paris Agreement set a goal to pursue efforts to limit global warming to 1.5°C compared to pre-industrial levels.
Though the impacts of climate change will still be experienced, halting global warming at 1.5°C means a safer world. For Australia, limiting temperature increase to 1.5°C could halve sea level rise compared to 2°C, reduce the risk of extreme heat events, and prevent further loss of sea-ice, coral reefs, plant species and wildlife.
2°C global warming
The 2015 Paris Agreement set a goal to limit global warming to well below 2°C in addition to pursuing“efforts to limit the temperature increase to 1.5°C” compared to pre-industrial levels.
At 2°C of warming, it is estimated that 37% of the earth’s population will be exposed to severe heatwaves every 5 years. Heavy rainfall, flooding, drought and fire events will also be more common. Sea-ice-free summers in the arctic may occur every 10 years, and biodiversity loss will be 2 – 3 times worse than at 1.5°C. Additionally, exceeding 1.5°C is likely to trigger multiple tipping points: ice sheets in Antarctica and Greenland will melt rapidly and drive enormous sea-level rise; there will be mass deaths of coral reefs, and key ocean currents in the Atlantic will cease to circulate, further disrupting weather patterns across Europe.
ACCESS
The Australian Community Climate and Earth System Simulator, also known as ACCESS, is a state-of-the-art climate and earth system model tailored to Australia’s unique conditions and research needs. Using ocean, atmosphere, ice and land observations, different versions of the model produce forecasts for the season ahead as well as climate projections for future time periods. ACCESS provides key climate data for Australia to inform considerations of climate risk, mitigation pathways, adaptation policy and decision-making.
Adaptation
Adaptation is the process of adjusting to actual or expected changes in climate to reduce or avoid climate impacts or exploit beneficial opportunities.
B
Baseline
A baseline period serves as the reference period from which the current or future change in climate is calculated.
Common baseline periods are pre-industrialisation (1850-1900) or 1961-1990 or 1991-2020 if you’re using Bureau of Meteorology data. Baseline periods are generally around 30 years or more to ensure they’re representing the climate of that period rather than year to year temperatures which can vary.
Using different baseline periods can be one reason you may get different values for future warming projections. The earlier the baseline period the larger the value of the projected change that will be reported.
C
Carbon budget
A ‘Carbon Budget’ refers to the amount of greenhouse gas emissions the global community can produce without pushing the global temperature above 1.5°C or 2°C.
If we exceed this budget, the planet will continue heating up and the impacts of climate change will become more severe. Scientists are responsible for calculating this budget, while countries that are signatories to the UNFCCC aim to ‘spend’ fewer emissions than they’ve been allocated to stay within the budget.
Climate drivers
Climate driver is a term related to shifts in our climate. Most commonly, these are related to shifting ocean temperatures and interactions with the atmosphere. The most well-known climate driver to influence Australia is the El Niño Southern Oscillation (ENSO) where warm water in the Pacific causes global shifts in weather patterns. For Australia this means drier conditions are more likely over much of eastern Australia. The current state of all Australia’s climate drivers can be found with the Bureau of Meteorology.
Climate forcing
Climate forcing is a measure of the heating effect caused by greenhouse gases in the atmosphere which results in an imbalance in radiation received and emitted. It is the net amount of energy that enters the Earth’s atmosphere.
Climate models
Climate models are computer simulations of the Earth’s climate system that replicate key processes in the atmosphere, oceans, land and ice. The models simulate these processes through time, including how they might be influenced by multiple interacting factors, including greenhouse gas concentrations.
Climate projections
Climate projections are simulations of the Earth’s climate using climate models based on scenarios of future greenhouse gas emissions. There have been many different scenarios used to explore our future climate, the most recent set used by the IPCC are called shared socioeconomic pathways or SSPs.
While we know that increasing greenhouse gas emissions will increase our future temperature, we don’t know what our emissions or future atmospheric concentrations will be. Climate projections are used to provide scenarios for our possible futures.
Projections follow emission pathways and allow us to simulate the impact of different emission levels. This allows us to look at the impacts of our changing climate so we can make management, policy and adaptation decisions accordingly.
Climate sensitivity
Climate sensitivity refers to the average change in global mean temperature in response to a change in climate forcing.
CMIP
The Coupled Model Intercomparison Project – delivered in phases (CMIP3, CMIP5 and CMIP6) and coordinated by the World Climate Research Programme. CMIP sees leading modelling groups from around the world share model inputs from their global climate models. The latest CMIP6 includes shared socioeconomic pathways (SSPs) and has been used by the IPCC and in thousands of research papers.
Previous versions of CMIP still in use include, the CMIP3 multi-model dataset includes projections using IPCC’s Special Report on Emissions Scenarios emission scenarios. The CMIP5 dataset includes projections using the Representative Concentration Pathways (RCPs). Read more from CSIRO.
Co-design
Co-design involves designing and delivering something in partnership with those who will use the product.
Confidence
The validity of a finding based on the type, amount, quality, and consistency of evidence available and on the degree of agreement between scientists. For example, something with robust evidence (90-100% certain to be true) scientists agree would have very high confidence.
In IPCC reports the level of confidence is expressed using 5 qualifiers: “very low,” “low,” “medium,” “high,” and “very high”.
COP
Conference of Parties (COP) is the annual meeting of delegates from the 198 countries committed to the United Nations Framework Convention on Climate Change (UNFCCC), more commonly known as the ‘Convention’. The first COP was hosted by Berlin, Germany in 1995, while the Kyoto Protocol was the first international treaty to become legally binding in 2005, followed by the Paris Agreement in 2015.
D
Downscaling
Downscaling is a method that derives local to regional-scale information from larger-scale models or data analyses. Downscaled climate data provide more useful representations of local and regional climate variation that can be influenced by local conditions such as altitude, topography and distance from the coast. As a result, downscaled data can be valuable for local and regional scale assessments of climate hazards and risks. Different methods exist such as dynamical, statistical and empirical downscaling.
E
Ensemble
Ensembles are groupings of model runs that together help us assess the certainty of results. Each model in the ensemble is a mathematical representation of our climate.
Exposure
Exposure refers to the presence of people, assets or other values in places that could be affected by a hazard.
Extreme event attribution
Extreme events attribution (EEA) allows scientists to establish the causes of extreme weather and the role of climate change in altering the frequency, magnitude or intensity of specific extreme weather and climate events. This involves using climate model results to assess the changing probability or magnitude of an extreme weather event with, and without, human-driven climate change.
While we have always had extreme weather events, EEA helps us understand what would have occurred and how extreme events may have changed due to our warming world. There are several different techniques scientists use to find this out.
Extreme weather event
An extreme weather event is one that is rare at a particular place and time of year.
Definitions for such events vary but would normally be as rare as- or rarer than- the 10th or 90th percentile of observed events. For example, it might be in the top 10% of observed events for intensity. Most extreme weather events are increasing in frequency or intensity with climate change.
G
Global warming level
Global warming levels such as 1.5°C, 2°C, 3°C or more, describe the expected change that will be experienced globally when the world reaches particular levels of global warming since the pre-industrial era. The targets described in the Paris Agreement are commonly referred to global warming levels.
Global warming potential
Global warming potential (GWP) provides a way to compare the warming effects of different greenhouse gases in the atmosphere. The warming effect of a greenhouse gas is expressed relative to the effect of carbon dioxide. The GWP of a gas reflects both its effectiveness at radiative forcing and the time it remains in the atmosphere before breaking down. For example, methane has a GWP of 81 over a 20-year period and 28 over a 100-year period reflecting its shorter lifespan in the atmosphere compared to carbon dioxide.
Greatest plausible change
Considering the greatest plausible change means using the upper end or the upper and lower limits of the projected change in a climate variable or hazard, in a risk assessment.
Greenhouse gases (GHGs)
The main greenhouse gases in the Earth’s atmosphere are water vapour (H2O), carbon dioxide (CO2), nitrous oxide (N2O), methane (CH4), ozone (O3) and fluorinated gases. Each of these gasses has a different Global Warming Potential.
These greenhouse gases absorb and emit radiation keeping our atmosphere warm. Human activities are increasing the amounts of greenhouse gases in the atmosphere trapping heat and further warming our air and oceans. These greenhouse gases absorb and emit radiation which means our atmosphere warms. Human activities are increasing the amounts of greenhouse gases in the atmosphere trapping heat which warms our air and oceans.
H
Hazard
A hazard is a natural or human-induced event with the potential to cause harm. Usually, this harm is damage to property, infrastructure, health, livelihoods, service provision or environmental resources.
Climate hazards can be acute, such as extreme weather events (for example, cyclones or bushfires), or chronic, such as sea level rise or shifting climatic zones. It’s important to remember that these climate hazards can overlap in time and/or space to occur as compound or coincident events – for example, severe winds, flash flooding and storm tide inundation can occur together with tropical cyclones.
I
Impact
An impact of climate change refers to the consequences of our changing climate on our world.
This can refer to effects on lives, livelihoods, health, ecosystems, economies, societies, cultures, services or infrastructure. Evaluating specific potential impacts is important in assessing vulnerability and risk.
K
Knowledge brokering
Knowledge brokers sit between information producers and potential users (for example, policy makers, practitioners, other researchers), and enable the exchange and transfer of information between different groups (such as hub scientists and users). They build partnerships to ensure research is co-designed with the people who need it to inform their decisions.
In this context, knowledge brokers help ensure climate science can be designed and for end-user needs and be fit-for-purpose to inform climate decisions and policy.
M
Maladaptation
Maladaptation refers to actions intended to reduce the impacts of climate change that create more risk and vulnerability in the future or for a different place, community or value. For example, building a seawall to protect a house that creates erosion elsewhere.
Mitigation
Climate change mitigation refers to efforts to reduce or prevent emission of greenhouse gases. It includes things like swapping to renewable energy, reducing transport use, minimising emissions from industrial processes, as well as carbon capture technology and carbon sequestration from natural resources such as vegetation and soils.
In disaster management, the term mitigation is used to refer to ways of reducing damage or suffering (such as mitigating risk). This can include building codes to ensure housing can better withstand cyclones, protecting critical infrastructure or community disaster preparedness.
Used in this way, mitigation sounds a lot like adaptation. Disaster mitigation is a form of adaptation, but the use of the words can be confusing. In thinking about climate change, the Climate Systems Hub uses mitigation to refer to reducing emissions.
N
National Partnership for Climate Projections
The National Partnership for Climate Projections (NPCP) is a collaboration guiding a national approach to high quality and consistent climate projections for Australia. The partnership includes Australian, federal, state and territory governments, and peak science organisations.
Net Zero
Net zero refers to an overall balance between the greenhouse gas emissions being released into the atmosphere. and the greenhouse gases taken out of the atmosphere.
P
Paris Agreement
The Paris Agreement is a legally binding international treaty on climate change. It was adopted by 196 countries at COP21 in 2015. The Paris Agreement set a goal to limit global warming below 2°C and pursue efforts to limit the temperature increase to 1.5°C compared to pre-industrial levels. It also includes goals on adaptation.
By 2020, signatory countries were required to outline their Nationally Determined Contributions (NDCs), and by 2024 their success in implementing these plans will be reviewed. The agreement also provides states with support for the financial, technical and capacity-building aspects of reducing greenhouse gas emissions.
R
Representative Concentration Pathways (RCPs)
Representative Concentration Pathways (RCPs) describe possible trajectories for future changes in atmospheric concentrations of greenhouse gases based on assumptions about how different natural processes and human activities may change the rate of emissions.
They were used in the fifth assessment report of the IPCC.
SSPs and global warming levels have been used in more recent IPCC reports, but all describe possible climate futures.
Resilience
Resilience describes how well people or ecosystems cope with climate shocks. Vulnerability focuses on before the shock, while resilience tends to focus on recovery after a shock or trend. Systems’ resilience can be increased by adaptive measures.
Risk
Risk is the potential for consequences where something of value is at stake or where the outcome is uncertain. Climate risk occurs where 3 interacting components overlap: a climate hazard, exposure and vulnerability. Risk is often assessed based on the probability of hazardous events occurring (likelihood) and the impact from this event/s occurring (consequences).
Risk assessment
A systematic process of evaluating the potential risks that may be involved in a projected activity or undertaking. Climate risk assessments focus primarily on the projected changes in climatic conditions, inventory of potentially impacted assets, the likelihood of the impact happening and the resulting consequences.
Risk assessment methodology
A climate risk assessment methodology or framework provides a structured process for estimating the likelihood of future climate hazards and their potential impacts to identify climate-related risks and possible management actions.
A risk assessment methodology provides a way to navigate uncertainty, identify required data and information (climate and non-climate), consider multiple sources of information, and to make appropriate decisions with often imperfect information.
S
Emissions scenario
Climate change projections are based on standardised scenarios describing plausible concentrations of future atmospheric greenhouse gas emissions. Historically, there have been many different scenarios but RCPs and SSPs are the most common examples. See CoastAdapt for more information.
Sensitivity
In the context of a risk or vulnerability assessment, the term sensitivity refers to the degree to which a system is affected by, or responsive to a hazard.
Shared Socio-economic Pathway (SSP)
SSPs are the latest version of ‘what if’ scenarios used to explore the consequences of greenhouse gases accumulating in the atmosphere.
Each SSP outlines ways the world might change in the future, including different types of energy generation, rates of population growth, economic development and land uses. These lead to different levels of greenhouse gas emissions over time.
The SSP ‘names’ consist of two parts. Using SSP1-2.6 as an example, SSP1 is the family code that describes the global socioeconomic settings. The 2.6 refers to the approximate extra energy (2.6 W/m2) that would result at the Earth’s surface by 2100. This is the same concept as the number used for RCPs. SSPs were first used in the IPCC sixth assessment report.
T
Tipping point
A ‘tipping point’ refers to a threshold that will irreversibly and drastically alter our climate systems if surpassed. Think of it like a line of dominoes – tipping over one domino will cause most or all the others to fall.
In the real world, there are nine major tipping points we’re likely to trigger if we reach 1.5-2°C of global warming. This includes ice-melt in the Arctic, Antarctica and Greenland.
Transition risks
Transition risks arise from policy, regulatory and societal changes made to address climate change. These could be changes in values, markets and demand for products and services.
V
Vulnerability
Vulnerability is the predisposition of something to be negatively affected by a hazard. Vulnerability can be thought of as the susceptibility to harm something has (sensitivity) or the capacity (or lack of capacity) to cope and adapt (adaptive capacity).
Vulnerability assessments
Vulnerability assessments emphasise exposure, sensitivity and adaptive capacity of systems, assets and populations. Most adaptation frameworks use an integrated vulnerability – risk assessment.