Factsheet 3: Definitions and background

CMIP5 and CMIP6 refer to the 5th and 6th phases of the Coupled Model Intercomparison Project (CMIP). The Queensland Future Climate resources present information based on both CMIP5 and CMIP6 projections data.

Please refer to the User Guide for information on how to identify and select which CMIP version is being displayed on the Dashboard. A separate factsheet on this page provides more detailed information on the main differences between these 2 phases of CMIP.

Queensland Future Climate presents projections information using multiple emissions scenarios to provide a picture of alternative, plausible climate futures.

A Representative Concentration Pathway (RCP) is a greenhouse gas (GHG) concentration trajectory used in CMIP5 climate models. These RCPs are based on assumptions about how different human responses may change future emissions of greenhouse gases (not just emissions policy and activities, but other factors including social and economic forces).

The CMIP5 version of the Queensland Future Climate Dashboard presents downscaled data and information for two RCPs:

RCP8.5 - a future with little curbing of emissions with the concentration of GHGs continuing to rise rapidly, reaching 940 ppm by 2100. This scenario represents a very high emissions future that would require greater levels of adaptation.

RCP4.5 - GHG concentrations increase steadily until after mid-century, with GHG concentrations stabilizing around 2060 and reaching 540 ppm by 2100. This scenario represents a future of moderate GHG emissions.

CoastAdapt provides a useful explainer for the RCPs.

Shared Socioeconomic Pathways (SSPs) provide a new way to describe future changes in atmospheric concentrations of GHGs used in CMIP6 models. The SSPs are based on five different narratives that describe the broad trends that could shape global society and economies in the future. These include population growth, economic growth, technological development, education and urbanisation.

The CMIP6 version of the Queensland Future Climate Dashboard presents downscaled data and information for three greenhouse gas scenarios described using SSPs:

SSP1-2.6 - a low emissions scenario in which global emissions are cut but don't reach net zero until after 2050 and warming stabilises at about 1.8°C by 2100.

SSP2-4.5 - a moderate emissions scenarios where emissions remain steady at roughly the same as current levels before starting to fall in the middle of the century and net zero is not reached by 2100, with temperatures rising by about 2.7°C by the end of the century.

SSP3-7.0 - a high emissions scenario where both emissions and temperatures continue to rise, the latter by about 3.6°C by 2100.

Factsheet #6 provides more information on RCPs and SSPs.

The chances of experiencing an extreme event of a certain magnitude are commonly expressed using two different terms.

• The Average Recurrence Interval (ARI) describes the average time period between events equalling or exceeding a given value. (e.g. '1-in-100 years').
• The Annual Exceedance Probability (AEP) describes the probability of an event being equalled or exceeded in any given year, usually expressed as a percentage.

The use of ARIs has been problematic because it suggests a uniform period of time between events. Many people interpret this in a way that reduces their estimate of climate risk. For example, if a location has just experienced a 1-in-100 year event, there is a tendency to believe a similar event won't occur in the foreseeable future.

In contrast, the AEP emphasises there is an equal probability of a specified event occurring in any given year. This description makes it easier to consider events that may be repeated or clustered within relatively short timeframes in response to seasonal drivers, and how the likelihood of events is likely to be influenced by climate change.

The Australian Disaster Resilience Knowledge Hub includes detailed descriptions of these metrics and how to interpret them.

In addition to providing projections data on an annual basis, aggregated data is available for calendar seasons:

• Summer (December, January and February, labelled 'djf' in some data products)
• Autumn (March, April and May, or 'mam')
• Winter (June, July and August, or 'jja')
• Spring (September, October and November, or 'son').

In addition, we also provide aggregated information for wet (November to March) and dry (May to September) periods.

Note that for extreme indices, the wet and dry seasons have five months instead of six because the transition months (April and October) are excluded when averaging to preserve the nature of extreme events within the seasons.

The Queensland Government's future climate simulations are continuous from 1980 to 2099. Data available via the Queensland Future Climate Dashboard is provided for four 20-year time slices in which averaged information is presented as:

• 2030 (2020-2039)
• 2050 (2040-2059)
• 2070 (2060-2079)
• 2090 (2080-2099)

Additional time slices, including for the 1986-2005 reference period, are available in gridded format via the links available on the High Resolution Projections Data pages.

The Dashboard can display data defined by a number of different regional categories. The spatial information for regional projections was spatially aggregated from 10km pixel-size grids to specific regions. The following seven specific regional categories for which regional projections are presented are: Local Government Areas, Regional Plan Areas, Bioregions, Major River Basins, Disaster Districts, Natural Resource Management Areas and Locations.

Users can select the region of interest in a drop-down menu to visualise specific future climate projections at a chosen regional scale. Please refer to the User Guide for more information.

This interactive plot pane presents summarised information for the selected future climate themes (i.e., Mean Climate, Heatwaves, Extreme Temperature Indices, Extreme Precipitation Indices, Drought indices, Wetness indices and Fire weather indices), for the combination of options selected in the drop-down menus (i.e., regions, variable, season and year) and for the selected region in the map.

The top plot (green bars) displays the projected future climate across seasons (Annual, Summer, Autumn, Winter, Spring, Wet and Dry) for the region, variable and year of interest.

The bottom plot (purple bars) demonstrates how future climate is expected to change over time using four time slices - 2030 (2020-2039), 2050 (2040-2059), 2070 (2060-2079) and 2090 (2080-2099) for the region, variable and season of interest.

The plots present change in relation to the reference period (1986-2005 for CMIP5 products and 1995-2014 for CMIP6 products). The vertical bars represent the range or model spread across the ensemble members (11 for CMIP5 and 15 for CMIP6 downscaled products), while the thick horizontal bars indicate the multi-model averages. The thin horizontal bars denote the individual models (see figure below).

Multi-model averages are calculated at grid-cell basis then spatially aggregated for Queensland's regions.

A comprehensive table with summary statistics for all models is displayed when clicking over any plot element.

Plots and underlying data are available for download in different formats using the "PDF", "PNG", "CSV" and "XML" buttons under the plots.

The map panel presents spatial data for the high-resolution climate modelling across Queensland with 10km of spatial resolution. Maps are customisable through climate themes (tabs) and drop-down menus. By changing variables, emission scenarios, seasons and years, a total of nearly 2,000 future climate maps are accessible and can be regionalised across 205 different regions within Queensland.

After selecting the type of region in the drop-down menu (Local Government Areas, Regional Plan Areas, Bioregions, Natural Resource Management regions, Major River Basins, Disaster Districts and Locations), the regional boundaries are displayed on the map. Users can hover over the map to inspect regions by name and select a region of interest. After clicking on a region, the output charts in the right-hand pane of the window will display the summary information for that region.

Each map represents a multi-model ensemble average - i.e., a multi-model average of all the downscaled models with values shown as change relative to the reference period (1986-2005 for CMIP5 products and 1995-2014 for CMIP5 products). The variables Precipitation and Pan Evaporation are also available as percent change (see figure below).

The maps enable user interactivity through a range of action buttons (see figure below). Once a map region is selected, grid-cell values can be inspected within the region when hovering over the selected region. An additional button is also available underneath the map to show/hide centred geographic coordinates after selecting a region. Click and drag to move the map and scroll up and down for zoom in and out respectively.