This video describes how resilience planning can reduce the impact of future disasters and support Australia to bounce back. Building resilience in communities, infrastructure and the natural environment requires an ongoing up-to-date and informed understanding of hazards, vulnerability and exposure. Full transcript available here: csiro.au/CorporateAffairs/Vimeo/CSIRO-Resilience-Planning/video-transcript[Link will open in a new window].
Climate and disaster events have shattering impacts across the nation and the risk of these events occurring is growing.
The horror summer of 2019/20 is a stark example of what Australia faces—a series of consecutive disaster events including bushfires, floods, drought and heat extremes. The effects of these events won’t just be felt in summer and they won’t be from just one type of disaster. There will be an ever-increasing mix of events that further devastates communities, the economy and the environment if we don't plan and prepare.
To do that effectively for these risks means we need to better understand the future we face and ensure a holistic approach to climate and disaster events.
Prime Minister Scott Morrison recently tasked CSIRO to undertake a body of research on climate and disaster resilience. The national science agency drew together a multidisciplinary team of experts: social scientists, economists, fire behaviourists, mathematicians and ecologists. The result is a comprehensive 200+ page report, with practical guidance on how we face future disasters and who can lead these efforts.
Dr Dan Metcalfe, Deputy Director for CSIRO's Land and Water business unit and the science leader of the report, breaks down what it means for Australia’s future.
What caused the 2019/2020 bushfires?
Climate change had a huge impact on the extent of the past bushfire season. But before Metcalfe gets into the nuances of the causes of the catastrophic bushfires, he says the distinction between weather and climate needs to be clear. In short, it’s a matter of time: weather affects today and tomorrow; climate is the longer-term measurement of weather patterns.
“The bushfires this summer were a consequence of compounding weather events—the conditions on the day,” Metcalfe said.
“With a combination of low humidity, high temperatures and high wind speeds, the points of ignition were more easily triggered.”
But, he added, it’s also important to understand that those days, in the context of high fire danger days, were exacerbated by an extended period of drought. The drought is what primed the landscape to burn. Across much of Australia, the vegetation and ground cover were dry from a lack of water. This provided a large amount of fuel for fires to burn widely and rapidly.
Metcalfe says these conditions coupled with the hot, dry weather that preceded the bushfires were all symptoms of climate change. And it was expected.
“Temperatures have increased by an average of 1.5 degrees Celsius since 1850,” Metcalfe said.
“With this, we’ve seen an increase in heat events and less seasonal rainfall across the south of Australia.”
There is no doubt the climate is changing. As warming temperatures, more drying, lower humidity and less soil moisture become longer-term trends, extreme events will become more common.
Metcalfe says the challenge with trends, however, is their high levels of variability. How can the models be correct with their predictions of reduced rainfall if the fires were followed by floods in NSW?
Convergent, consecutive, compounding events
“NSW had extraordinary rainfall events,” Metcalfe said.
“But these are consistent with the climate models—there is still a reduced annual rainfall. The higher variability means the rainfall we get is likely to be more intense at the scales of hourly and daily rates.”
He says the fires burnt and dried the ground. This caused the heavy rainfall to run off the land faster, leading to soil erosion and freshwater contamination.
The compounding effect, with events stacked one on top of the other, meant the country simultaneously faced drought, fire and floods.
“And the consequences of that series didn’t mean the drought broke,” Metcalfe said.
“It wasn’t a slow steady rain that penetrated deep into the soil. The soil wasn’t holding water, the rain wasn’t replenishing stream flows. What we saw, as the events converged and built upon each other, was the magnification of individual impacts.”
In northern Queensland, a layering of different disaster events saw bushfires ignited within tropical cyclone debris.
“The cyclones in northern Australia preceding the fire season resulted in a lot of fallen trees and branches,” Metcalfe said.
“These dried out and became large fuel loads for fires that got into those systems and areas.”
Metcalfe says the fires in Cape York provide a particularly vivid example of a climate-triggered compound event.
Over in Western Australia, the state’s bushfire seasons merged, overwhelming fire and emergency crews.
“Normally, you’d expect to see fire in northern Western Australia in winter, south in summer,” Metcalfe said.
“Those seasons overlapped so we had fires still burning late in the north and early in the south—the state’s resources were split across all jurisdictions at the same time.”
“We need to start thinking of events not just in terms of the hours or days of an actual event, but of their consequences in days, weeks, or even years,” he said.
Learning from the past
As a nation, we’ve already made strong progress on adaptation and resilience in regard to tropical cyclones. Metcalfe says while the impacts on infrastructure were large for Cyclone Tracey in 1974, they were smaller for Larry in 2006 and smaller again for Yasi in 2011.
“That’s because with each event we learned the weak points in building design and then used that to make buildings more resistant and resilient to those pressures,” Metcalfe said.
The 2009 Black Saturday bushfires are another example of where building code reappraisals were implemented. The buildings in bushfire-prone areas now provide more protection from fires, with less of a chance of burning.
But, Metcalfe says, as the climate changes we have to start making buildings resistant to all disasters—cyclones, bushfire and floods. “We need to start approaching disasters in a more holistic manner,” he said.
“As we think about the complexity of events, we then also need to think about climate and disaster resilience as encompassing the diversity of challenges they present.”
The understandings in the report were gathered from more than 40 different partners and agencies. The overarching recommendation is to bring people together and consider the approaches in doing so.
This includes building standards, planners and the insurance industry working together on resilience in the built environment. It means local, state and commonwealth governments coming together with community groups and non-government organisations to explore opportunities, and what actions are appropriate.
“We can’t give a recipe for resilience,” Metcalfe said. “We can only provide advice on where to get the best information and integrate that.”
What about hazard burning?
One intense debate throughout and after the bushfires was whether more bushfire fuel management, through hazard reduction burning, could have helped.
Metcalfe says Australian landcover has evolved to both tolerate and benefit from fire.
“Fire is an entirely natural part of the Australian landscape,” Metcalfe said. “To reduce the risk of fire to lives and property, we need to understand how fire is propagated and what drives it.”
He says there are social, economic, environmental and management considerations when deciding on the most appropriate fuel management techniques. One of the most frequent techniques is hazard reduction burning—a valuable tool to use in conjunction with other tools. But it has its downsides.
“It’s labour intensive, can be costly and can have dis-benefits at the same time as benefits,” Metcalfe said.
“The more we work to understand the role of fire and the causes of it, the more we recognise what we don’t understand.”
Across Australia’s many and varied landscapes, the nature of fires and their fuel loads are entirely different. Fuel reduction methods are different in woodland areas versus grassland areas. Victorian systems are different to those in New South Wales, which are different again to those in the Northern Territory.
The role of cultural burning
Metcalfe says to counter this, different types of fire reduction burning can be more closely aligned with cultural burning protocols.
“Traditional owners have very established practices of actively managing fire across their landscapes,” he said.
“There is an enormous body of knowledge that we could much better acknowledge and work with to inform what is appropriate going forwards.”
CSIRO works closely with traditional fire managers across much of northern Australia. But, while the depths of traditional knowledge remain in place in some areas, there are great interruptions to, and loss of, knowledge due to colonisation in other areas.
The reasons for cultural burning are also varied and complex.
“It’s not just about fuel reduction,” Metcalfe said.
“Cultural burning practices can be about clearing certain parts of the land for tracks or creating a ‘garden’ that six months later is populated by prey animals. Fire is used in many cases for home economics and land management.”
“We can’t just say we want to use a traditional method of burning for hazard management when it’s been developed for a different purpose.”
Looking to the towns that already have great resilience, Metcalfe says it’s more about the community, rather than an individual, approach to disasters.
“When you get extreme fire weather, fire can jump extraordinary distances,” Metcalfe said.
“The radiant heat from burning vegetation alone can burn buildings 30 metres away. Twigs or leaves on fire can catch in an updraft and travel to ignite vegetation 10 kilometres away.”
“You can manage your yard really well, have clear gutters and sprinklers installed on the roof—but those precautions don’t matter if the neighbour’s yard is overgrown.”
In the fire-prone areas of the New South Wales south coast, the communities worked together to make sure they managed the entire bushfire risk this past summer, so no one missed out. This in turn better protected them.
When ensuring how recovery efforts better facilitate resilience, Metcalfe says it’s important to consider what communities need.
“How do we make sure the recovery process actually makes communities stronger, rather than just rebuilding them back to where they were?”
Whether looking at a cyclone-prone area of northern Queensland, or a bushfire-prone area in southern New South Wales, the research on building community resilience must cross jurisdictions, agencies and collaborations. “Otherwise, you’re as weak as the weakest link,” Metcalfe said.
Where to now?
Building the nation’s resilience goes beyond emergency and disaster management. And not approaching and addressing the weakest link causes people to get hurt. Properties are lost, infrastructure fails and the environment is decimated.
Currently, though they are linked, drought and climate-related disasters are dealt with separately by different agencies and sectors. Fires are managed separately across states and territories, which leads to conflicting information on the borders.
“The report recommends we need better integration and coordination. For example, bringing together all the details across individual states and territories, considering the impacts and risks, and integrating that between jurisdictions.”
Metcalfe says the best areas to focus on to improve disaster resilience and preparation are planning, prevention of impact, relief and longer-term recovery.
“There is a lot of work to be done, with many opportunities to address these gaps in knowledge.”
As a direct result of the 2019/2020 bushfire season, there have been up to five state and federal inquiries. CSIRO has been or is involved in these to varying degrees—most notably the Royal Commission into National Natural Disaster Arrangements, providing expert scientific advice on a range of matters including making practical recommendations to build Australia's resilience to natural disasters. For more information, visit CSIRO.au.