Published works

Australia is subject to significant impacts from natural hazards, the risk of which is increasing due to population growth and climate change (e.g. Newman et al., 2017).

The state of Victoria already has a long history of catastrophic bushfires, amongst which the Black Saturday bushfires of 2009 and the Black Summer bushfires of 2019-2020 stand out in terms of severity and impact in recent history. Expectations for the future are even worse with climate change resulting in a hotter and dryer climate with longer fire seasons. Likewise, climate change is expected to result in substantial sea level rise, putting communities on the coast at risk. In addition to the climate change impacts, the State is expecting a large increase in population, of which part is likely to live in the areas prone to bushfire and coastal inundation.

If we could, it would be cheaper, and cause less harm, to deal with some of these threats in advance to make our communities more resilient. The difficulty is knowing how to prioritize what to plan for, and how to make best use of available resources, which are generally scarce. This difficulty can be addressed by developing a risk reduction strategy, which requires a good understanding of current and future risks.

The projected increase in risk, together with the awareness of the complexity of the underlying dynamics affecting this risk, has led to the recognition that there is an urgent need to better understand the components of disaster risk and their dynamics. In response, over the past ten years, the University of Adelaide and the Research Institute for Knowledge Systems, supported and funded by the Bushfire & Natural Hazard Cooperative Research Centre (BNHCRC), have developed a decision support system (UNHaRMED - Unified Natural Hazard Risk Mitigation Exploratory Decision Support System) to assist government agencies to better understand how risks arising from multiple natural  hazards change over space and time under different plausible future conditions (e.g. climate change, population growth, economic development), as well as the relative effectiveness of different risk reduction strategies (e.g. structural measures, land use planning, land management, building code changes etc.). The development of UNHaRMED has been supported by the inputs of many stakeholders around Australia, including Victorian State Government agencies such as CFA, EMV and DELWP (now DEECA), shaping what the tool should be able to do and what it should look like.

This report demonstrates the use potential of UNHaRMED in a strategic risk assessment and risk reduction context, exemplified using the application developed for Greater and Peri-Urban Melbourne (GPUM), focusing on the following objectives:

1. To develop an approach for exploratory scenario risk assessment that combines narrative storylines with quantitative modelling from UNHaRMED.
2. To apply the approach to Greater and Peri-Urban Melbourne and develop a set of scenarios to obtain a better understanding of future risk across multiple hazards, in particular bushfire and coastal inundation, under changing socio-economic and climate conditions.
3. To reflect on the role of UNHaRMED in supporting risk assessment and risk reduction.

This report first introduces the UNHaRMED system (Section 2), the study area (Section 3) and the application of UNHaRMED to the GPUM case study (Section 4), followed by the scenario risk assessment approach (Section 5) and the results obtained (Section 6). The report concludes with the main findings, lessons learnt and suggestions for further work (Section 7).