OzClim Climate Change Scenario Generator

Please Note: The OzClim Help and Science pages are currently being reviewed and should be regarded as draft. Regards, the OzClim Team.

  1. Can I generate a mean temperature or mean rainfall climate change scenario?
  2. What is the difference between selecting "change from 1990" or "future climate"?
  3. For which years can I generate a scenario?
  4. Can I generate a scenario for a particular season or annual average?
  5. Within the step-by-step section of OzClim, can I select the rate of global warming I wish to see?
  6. Within the step-by-step section of OzClim, can I select the type of regional change I am interested in?
  7. Which impact models are included with OzClim?
  8. Which climate scenario should I use for my impact model?
  9. How can I choose a subset of models that covers a range of uncertainty for more than one variable?
  10. Why can't I export images or other files from OzClim when using Internet Explorer?
  11. How do I use the data that I have exported using the "Export as Excel File" button?
  12. I can't find the answer to my question - where do I go for further help?

Can I generate a mean temperature or mean rainfall climate change scenario?

Yes.

In 'Step by Step' mode, OzClim allows climate scenarios to be generated for mean temperature or mean rainfall.

Choosing mean temperature will produce a map of the mean temperature or mean temperature change for the year, season, global and regional pattern of change selected.

Choosing mean rainfall will produce a map of the mean rainfall or mean rainfall change for the year, season, global and regional pattern of change selected.

In Advanced mode, OzClim can generate scenarios for 11 climate variables:

*Areal Potential Evapotranspiration
*Daily Relative Humidity
*Maximum Temperature
*Mean Temperature
*Minimum Temperature
*Rainfall
*Relative Humidity at 3pm
*Relative Humidity at 9am
*Sea Surface Temperature
*Solar Radiation
*Temperature at 250m Depth
*Wind Speed

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What is the difference between selecting "Show change from base climate" or "Show future climate"?

A climate scenario can be generated as the change in climate compared to the "base climate" (1975 to 2004), or as the actual climate at a year in the future.

Select show change from base climate if you want to see how the climate variable will change from the base climate for your selected year (In Step-by-Step mode, the year is selected in Step 2). For example: how much drier will it be in the north west of Victoria in the year 2030?

Select show future climate if you want to see projected values for a climate variable for a particular year in the future. For example: What will the annual average rainfall be in the north west of Victoria in the year 2030?

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For which years can I generate a scenario?

Climate scenarios can be generated for years 2020 to 2100 in five year increments.

Select the year for which the scenario is to be generated. For example, selecting 2030 will show the mean temperature or mean rainfall for that year dependent on the other scenario parameters selected.

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Can I generate a scenario for a particular season or annual average?

Yes. You can select the Australian (i.e. southern hemisphere) season for which the scenario is to be generated, for the selected year. For example, selecting Summer will show the mean temperature or mean rainfall for the months December, January and February, for the selected year. Selecting Annual will average the results of the scenario across the entire year selected. You can also select May-October and November-April (the northern Australian 'dry' and 'wet' seasons, respectively).

Scenarios can also be generated for individual months.

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Within the Step-by-Step section of OzClim, can I select the rate of global warming I wish to see?

Yes. Global warming projections derived from these scenarios in 5-yearly intervals were sourced from the IPCC (2007) Fourth Assessment Report.

A low rate of global warming is based on a low emissions scenario (the SRES B1 storyline) and the 10th percentile of the IPCC global warming range. B1 describes a convergent world with a global population that peaks mid-century and declines thereafter. It assumes a rapid change in economic structures towards a service and information economy, with reductions in material intensity and the introduction of clean and resource efficient technologies. The emphasis is on global solutions to sustainability.

A medium rate of global warming is based on a medium emissions scenario (the SRES A1B storyline) and the 50th percentile of the IPCC global warming range. A1B describes a future world of very rapid economic growth, a global population that peaks mid-century and declines thereafter, and the rapid introduction of new and more efficient technologies. There is a balance between fossil fuel use and other energy sources. Major underlying themes are convergence amongst regions, capacity building and increased cultural and social interactions, with a substantial reduction in regional differences in per capita income.

A high rate of global warming is based on a high emissions scenario (the SRES A1FI storyline) and the 90th percentile of the IPCC global warming range. A1FI describes a future world of very rapid economic growth, a global population that peaks mid-century and declines thereafter, and the rapid introduction of new and more efficient technologies. There is intensive fossil fuel use with coal, oil, and gas dominating the energy supply for the foreseeable future. Major underlying themes are convergence amongst regions, capacity building, with a substantial reduction in regional differences in per capita income.

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Within the Step-by-Step section of OzClim, can I select the type of regional change I am interested in?

Yes. The global climate models used by OzClim determine regional responses in terms of degrees of global warming. Different global climate models give different regional patterns of change per degree of global warming.

A pattern of change measures the amount of change occurring at a location for each degree of global warming. For example, if at a point the pattern of rainfall change is 5 percent per degree of global warming, then for a global warming of 2 degrees the projected change at that point would be 10 percent.

Mean Temperature:
Selecting Weaker warming will use the MIUB/KMA: ECHO-G global climate model which over Australia as a whole produces a weaker annual warming response compared to other climate models.

Selecting Moderate warming will use the Max Planck: ECHAM5/MPI-OM global climate model which over Australia as a whole produces a moderate annual warming response compared to other climate models.

Selecting Stronger warming will use the GFDL: GFDL 2.1 global climate model which for Australia as a whole produces a stronger annual warming response compared to other climate models.

Mean Rainfall:
Selecting Drier will use the GFDL: GFDL 2.1 global climate model which over Australia as a whole produces a drier annual rainfall response compared to other climate models.

Selecting Moderate will use the Max Planck: ECHAM5/MPI-OM global climate model which over Australia as a whole produces a moderate annual rainfall response compared to other climate models.

Selecting Wetter will use MIUB/KMA: ECHO-G global climate model which over Australia as a whole produces a wetter annual rainfall response compared to other climate models.

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Which impact models are included with OzClim?

None. In this version impact models are not provided. Most researchers prefer to use their own impact models for specific purposes. If your impact model requires input data not available through OzClim please contact us about our tailored data products.

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Which climate scenario should I use for my impact model?

In the "Example" and "Step-by-step" sections of OzClim, results from three different climate models provide scenarios for low, moderate and high temperature change, and dry, moderate and wet rainfall change. These scenarios illustrate the range of potential change for either mean temperature or mean rainfall. In other words, changes in temperature and rainfall are considered independently.

If your impact model or assessment process requires two or more climate variables to be considered in combination, we recommend that you extract the scenarios using OzClim's "Advanced" mode. It is not scientifically valid to combine different climate variables from different global climate model. For internal consistency, select the same climate model, same rate of global warming and same emission scenario when generating the scenarios.

For general assessments considering Australia as a whole, we recommend the following combinations of Global Climate Model, rate of global warming and emission scenario to represent a low, moderate and high impact scenario.

  • Low impact = MUIB/KMA: ECHO-G Global Climate Model with low rate of global warming and B1 emission scenario
  • Moderate impact = Max Planck: ECHAM5/MPI-OM Global Climate Model with moderate rate of global warming and A1B emission scenario
  • High impact = GFDL: GFDL-CM2.1 Global Climate Model with high rate of global warming and A1FI emission scenario

To generate the low impact, moderate impact and high impact scenarios go to the Advanced section.

For regional assessments, it is necessary to objectively select representative climate models from which climate data can be extracted. If you are undertaking regional assessments, please contact us for assistance with model selection.

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How can I choose a subset of models that covers a range of uncertainty for more than one variable?

Because different global and regional climate models display marked differences with respect to future climate projections, multiple models are often used to generate climate scenarios for impact assessment. This enables the uncertainty in future climate conditions to be reflected in estimates of impact and risk assessments, often by identifying potential ‘best’ and ‘worst’ case impact scenarios. Care must be exercised to preserve the internal consistency of a model’s projections of different climate variables. Variables such as temperature, rainfall, evaporation, and humidity are highly interactive, meaning a change in one variable has an effect on other variables. As such, mixing variables from different models in a single scenario may result in physically implausible (or impossible) combinations. In such cases, selecting appropriate models to use is not a trivial exercise and we recommend you contact us for assistance.

For further information see Chapter 6 of the Climate Change In Australia Technical Report.

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Why can't I export images or other files from OzClim when using Internet Explorer?

Internet Explorer's security settings may try to prevent you from exporting images or other files. If this happens you will see a yellow Information Bar near the top of your browser window. You may also see a dialog titled 'Information Bar'.

You can grant temporary permission to download files from www.csiro.au by clicking on the Information Bar and selecting 'Download File...'. Note that this does not actually download the file, but re-displays the page so that you can request the download again. Depending on the page you are on, you may need to re-enter some data.

Alternatively, you can grant permanent permission to download files from www.csiro.au by modifying your Security settings. Note that a dialog will still be displayed for you to confirm whether to open or save the file, or to cancel the download. To do this:

  • Select Internet Options from the Tools menu, and then click the Security tab.
  • Select 'Trusted sites', and then click the Sites button
  • Type http://www.csiro.au in the text box, make sure the checkbox is unchecked, and then click Add
  • Click Close
  • Click 'Custom level...'
  • Ensure 'Automatic prompting for file downloads' is enabled
  • Click OK
  • Click Yes to confirm that you want to change the setting
  • Click OK

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How do I use the data that I have exported using the "Export as Excel File" button?

The data presented in OzClim have a single value for each grid cell which is approximately 25km x 25km. Each grid cell has an associated spatial reference in degrees latitude and degrees longitude (using the WGS84 datum). The value associated with each grid cell depends on the settings you have chosen. When you download the file for Excel, it is in “csv” format which can be opened directly in Excel. The information in the spreadsheet are arranged as follows:

  1. The first three rows of the spreadsheet describe the settings you had selected in OzClim (such as model name, emissions scenario etc.)
  2. Row four simply states the URL to the OzClim website
  3. Row five contains the field names for the projections data that follow. These are:
  • latitude (the latitude in decimal degrees north of the equator – the negative value indicates the grid cell is in the southern hemisphere – e.g. “-17.5” = 17.5°S)
  • longitude (the longitude in decimal degrees east of the International Dateline – e.g. “113.75” = 113.75°E)
  • value (the climate projection value as determined by the settings you had selected to generate the map – note that “-9999” indicates there are no data for that grid cell)
  1. Commencing in row six are the data for each of the above fields – each row represents a single grid cell.

By default, the data for the whole of Australia are provided and it is not possible to change this within OzClim. However you can simply extract the data that correspond to the latitude/longitudes of the area in which you are interested from the spreadsheet. The data are sorted by latitude (lowest to highest) then by longitude (lowest to highest). If you need to, you can use the map interface in OzClim to identify the latitude/longitudes of the area of interest – the values corresponding to the position of the mouse pointer are displayed at the bottom-right of the map display.

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I can't find the answer to my question - where do I go for further help??

  • Have you checked the help pop-ups on the OzClim screen? These are accessed by clicking the "Help" link associated with the various settings.
  • If you still can't find the answer to your question, please send the OzClim team an email at: ozclim@csiro.au

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OzClim Climate Change Scenario Generator

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