Hello and welcome to the August 2024 FMA Monthly Flyer.
Following keen interest during the FMA National Conference in Brisbane
in May this year, FMA was pleased to present two workshops on the new draft Climate Change Considerations for Australian Rainfall and Runoff (ARR) as part of its August Quarterly Meetings in Brisbane and Sydney. At both meetings there were around 40 people attending in person, with another 25 online in Brisbane and 73 online in Sydney.
The 1.5 hour Workshops included (i) an introduction to the new draft Guidelines by Conrad Wasko; (ii) worked examples of the impacts of the new Guideline on probabilities of flood events by Mark Babister and Monique Retallick (WMAwater) and (iii) (Sydney only) a presentation on considerations of climate change for the NSW Floodplain Management Program by Duncan McLuckie (DCCEEW). The workshops also included a Q&A session with our
presenters for in-person and online attendees.
A big thank you to our speakers for making these workshops such a success.
The new ARR Chapter on Climate Change Considerations was released on 27 August 2024 and is now available as part of the latest ARR Version 4.2. As discussed as the Workshop and outlined in the new ARR Guideline, the impact of climate change on design rainfalls is significant.
As with the previous ARR2019 (Version 4.1), the increases in design rainfalls are linked to increases in temperature. The ARR Guideline recommend a 15% increase in design rainfall depth per degree increase in global temperature for storm durations less than one 1 hour and an 8% increase in design rainfall depth per degree increase in global temperature for storm durations greater than 24 hours. For storm durations between 1 hour and
24 hours, increases would be interpolated between 8% and 15%.
The ARR Guideline presents the global mean surface temperature projections from the Sixth Assessment Report (AR6) from the Intergovernmental Panel for Climate Change (IPCC) for various potential future development emissions
pathways (known as Shared Socioeconomic Pathways (SSP)). As an example, for a high emissions pathway (SSP3-7.0), AR6 projects that there will be an increase in global mean surface temperature (relative to the period 1961–1990) of 1.2°C in the current to near-term (2021 to 2040), an increase of 1.8°C in the medium-term (2041 to 2060) and an increase of 3.3°C in the long-term (2081 to 2100).
As you can see from this snap shot from the new ARR Guideline, the potentially significant impacts of climate change will have to be carefully considered in the future assessment of flood risk in Australia.
Here are some useful links:
Please make sure you put the dates for the FMA November Quarterly Meetings and Workshops in your diary now:
QLD Quarterly Meeting — Wednesday 6 November 2024 — Bundaberg (Venue TBC)
NSW/ACT Quarterly Meeting — Thursday 14 November 2024 — Sydney (Mercure Sydney Hotel).
Sue Ribbons
FMA President