The NSW Bushfire Risk Management Research Hub undertook work to support the NSW Bushfire Inquiry. This work addressed key themes concerning the 2019/20 fires, namely their; historical and seasonal context; severity and behaviour; impacts on people, property and biodiversity; and influences on risk in the immediate future. The work is summarised in 18 reports spread across these themes, led by researchers from the University of Wollongong, Western Sydney University, University of Tasmania and University of New South Wales.
This work showed that the fires were substantially the outcome of large scale, record-breaking dryness due to an intense and prolonged drought. Sustained periods of adverse weather conditions, including many days of record fire danger across NSW contributed to the unprecedented size of these fires. By contrast, fuel levels in 2019 were estimated to be similar to those in previous decades. Lightning ignited fires resulted in the bulk of area burned and property losses. The fires burned across many areas that had been recently burned as well as areas that were long unburnt.
Prescribed (hazard reduction) burning up to three years prior to 2019 partly reduced the chance of intense fires burning in tree crowns, though such effects were substantially diminished under adverse weather. Recent prescribed burning also partly reduced the chance of house destruction when it was situated close to property (i.e. within about a kilometre) but had little effect on property loss when situated more remotely. Adverse weather (high temperatures, strong winds, low humidity) resulted in high levels of property loss.
Record breaking levels of smoke pollution were recorded across many population centres and these had major health impacts, including an estimated 219 excess deaths and over $1 billion in health impacts in NSW. Some of the most disadvantaged communities in NSW were affected by the fires, including those with high proportions of Aboriginal residents.
The fires affected large areas of all major forest types and other common plant communities in eastern NSW. Significant proportions of these communities burned at high intensity with likely resultant effects on biota that are sensitive to large, intense fires. High proportions of vulnerable plant communities, such as rainforests and alpine vegetation were burned in NSW. Hundreds of rare and vulnerable plant species were also potentially burned and many of these may now be in a state of decline as a result.
Risk to people, property and environmental values in areas affected by the 2019/20 fires will have been reduced in their immediate aftermath but will rapidly increase in the next few years as fuels re-accumulate. Some of this risk can be mitigated through hazard reduction, but cannot be completely eliminated. Risk mitigation potential will be strongly affected by strategic choices, resources, costs and ability to carry out hazard reduction operations, particularly through planned burning. Many other measures, such as planning, building design and community awareness will also contribute to risk mitigation in the future. Cultural burning led by Aboriginal people can provide a significant new dimension to fire management.
Professor Ross Bradstock University of Wollongong; Dr Rachael Nolan, Western Sydney University; Dr Grant Williamson, University of Tasmania; Dr Katharine Haynes, University of Wollongong; Dr Mark Ooi, University of New South Wales.