Note: Where available, the PDF/Word icon below is provided to view the complete and fully formatted document
Standing Committee on the Environment and Energy
Vegetation and land management policy relating to bushfires

MAYFIELD, Dr Peter, Executive Director, Environment, Energy and Resources, Commonwealth Scientific and Industrial Research Organisation

METCALFE, Dr Daniel, Deputy Director, Land and Water, Commonwealth Scientific and Industrial Research Organisation

Committee met at 10:40

CHAIR ( Mr Ted O'Brien ): I declare open this public hearing of the House of Representatives Standing Committee on the Environment and Energy for the inquiry into vegetation and land management relating to bushfires. This is the committee's first public hearing for this inquiry. We are pleased to have representatives of Australia's national science agency, the CSIRO, appearing before the committee. We are aware of CSIRO's bushfire research work spanning several decades and we look forward to learning more about it today.

In accordance with the committee's resolution of 24 July 2019, this hearing will be broadcast on the parliament's website. A proof and official transcript of proceedings will be published on the website. Those present here today are advised that filming and recording may be permitted during the hearing. I remind members of the media who may be present or listening online of the need to fairly and accurately report the proceedings of the committee.

I now welcome representatives of the CSIRO to give evidence today. I do so knowing that unfortunately the committee will have to rise probably in about 15 minutes, given that there will be an address in the parliament. However, we are grateful to the CSIRO that you'll also be providing a submission. We would like to have you back again once you have made that submission to come before us. Meanwhile, we didn't want to lose this opportunity to at least get some initial remarks from you about the bushfire season.

Dr Mayfield : Thank you, Chair. I am the Executive Director for environment, energy and resources in CSIRO. We are currently also leading the work around disaster and climate resilience. We have a report on that to go to COAG later this year.

Dr Metcalfe : I am the deputy director of the land and water business unit. I am helping to coordinate CSIRO's response for bushfire science.

Dr Mayfield : We do have an opening statement. As the national science agency, CSIRO provides independent advice based on its research. We do not comment on policy matters. As such, CSIRO's input to the inquiry will be limited to the terms of reference relating to science and research behind activities such as hazard reduction burning, clearing and rehabilitation. CSIRO has a broad vegetation and land management expertise, but the majority of this is not directed towards bushfires and the subsequent risks they create.

Safeguarding our communities, infrastructure and biodiversity through our future increased bushfire risk requires smart thinking around hazard reduction. With close to 70 years of science to understand bushfires and the challenges they pose to the community and firefighters, CSIRO stands ready to support national efforts and to develop smart approaches to the role of hazard reduction in preparing for and managing bushfire risk. Hazard reduction burning is an important tool to prepare for the fire season. It is not intended to stop the spread of wildfires, but it can reduce the intensity of some unplanned fires. However, it is important not to place undue emphasis on hazard reduction. This is because it is a highly contextual and complex issue, and hazard reduction burns are one of a number of tools that are available and that all need to be deployed. Hazard reduction burns also bring risks and consequences of their own, including smoke hazards for traffic and communities.

Hazard reduction burning can also play an important role in parallel with actions such as reducing ignition through fire bans, active suppression measures by fire agencies and the application of decision support and modelling tools to prioritise which fires to actually target, where and when. It is also important to consider the different types of reduction burns and the strategies behind managing fuel loads out in the bush around homes and critical infrastructure. Accessing all our available knowledge and tools and working collaboratively across agencies and jurisdictions will help us to develop more strategic approaches to fire season preparation. CSIRO is currently preparing a report to the Prime Minister advised by a steering committee chaired by Australia's Chief Scientist, Alan Finkel, on practical actions that governments can take.

There is a diverse range of approaches to deciding how and why fuel reduction burns are initiated and how they are delivered. CSIRO has the means to bring together the science community to integrate these decision support processes and to optimise them for the broad spectrum of unknown futures that we face depending on the fuel reduction approach taken. This has never been a more important time than now with the clear trend towards longer fire seasons, which in turn restrict our opportunity to safely conduct hazard reduction burning out of the fire season.

CHAIR: Thank you. Dr Metcalfe, do you wish to make any opening remarks?

Dr Metcalfe : No, thank you.

CHAIR: Let me start with some questions from our end. You mentioned that hazard reduction is but one of several tools. What are the other tools?

Dr Mayfield : The other things that come in there are about understanding where the fuel loads are, early detection—using earth observation means, to do that sort of stuff—and, I guess, measures to prevent ignition, whether that's through natural means or through human interventions.

Dr Metcalfe : That's consideration of fuel loads and ignition. In addition, there's deployment of resources, where and how they're deployed. And the use of tools to prioritise and identify where it's most appropriate to concentrate those resources is also a significant step agencies can take, in terms of maximising their opportunity to achieve suppression early after ignition, which maximises their chance of bringing any wildfires under control early on.

Mr JOSH WILSON: Thank you both for coming here. You referred in your opening statement to increased bushfire risk and a clear trend to a longer fire season. Are both of those things being delivered to us as a result of climate change?

Dr Mayfield : The work that we publish around State of the climate talks about the trend in southern Australia to drier conditions in the long run. That drives that increased bushfire risk as well as the longer seasons. That's the work we referred to there.

Mr JOSH WILSON: So it's being driven by climate change, the drier conditions, the warming conditions?

Dr Mayfield : Climate change is part of the factors working there, yes.

Mr JOSH WILSON: One of the more significant factors?

Dr Mayfield : In terms of relative contribution, it's hard to make those clarifications. But the long-term trend to having less rainfall in those locations impacts the nature of the fuel in the bushfires, so it is a factor.

Mr JOSH WILSON: The fact that it's drier and hotter through climate change contributes to a longer fire season and more intense fires?

Dr Mayfield : In broad terms, but, terms of each specific fire, it's very hard to make those connections for specific fires.

Mr JOSH WILSON: The intensity of fires that we expect—we're told that climate change will deliver more intense and more frequent fires. Is hazard reduction burning less useful when you have a more fierce, more intense fire?

Dr Metcalfe : Hazard reduction burning has a number of benefits, in terms of how you manage fires. Data suggests that in areas where there has been a fuel reduction, through hazard reduction burning, the time from ignition to fires getting to a state where they're beyond suppression is increased. So the opportunity that agencies have to get on the ground and suppress fires is increased in areas where fuel reduction has taken place. Fuel reduction also results in a significant reduction in the amount of bark that's available to produce firebrands, which are the key means by which spot fires are generated. In areas where fire starts, fuel reduction burn has a significant role to play. As the landscape gets drier and fuel loads get drier and the weather gets more extreme, the amount and the type of fuel becomes less important, in terms of how fire is propagated.

Mr JOSH WILSON: When you say extreme, you mean hotter and windier?

Dr Metcalfe : Yes. So the way that what's referred to as fire days is calculated is based on temperature, humidity and wind speed. That drives the relative dryness of the fuel layer, but it also drives the actual propagation of fires. As it gets hotter, dryer and windier, the ability of fire to move between patches of fuel increases and so the relative impact of fuel reduction burns becomes less.

CHAIR: Are you suggesting the issue in the fire season just gone is more to do with the dryness of the fuel and not the volume of the fuel—the load?

Dr Metcalfe : There's quite a lot of discussion about why this fire season is unprecedented—and there's debate around where those metrics might lie—but what's clear is that we're at the end of a long dry period and so the level of dryness in the fuel layers across the landscape is at a significant low layer. That's combined with extreme fire days—so we're talking about the weather—and the climate has delivered us low levels of wetness within the fuel. The weather is giving us extreme dry hot, windy days. Those combined generate significant fires which rapidly get out of control and change the management of those.

Mr RICK WILSON: Dr Metcalfe, you made the comment that we're getting significantly drier. I've got the Bureau of Meteorology southern Australian rainfall anomaly from 1910 which actually doesn't show any particular trend in terms of dryness. In fact, if anything it shows the continent was significantly drier in the twenties and thirties. I'd firstly challenge your assertion—there's no question that we've had a particularly dry period and 2019, according to the data, was one of the driest on record, but we're talking about long-term trends here. Secondly, you made the comment 'unprecedented fires'. Bjorn Lomborg had an article published in The Australian a week or so ago, where he claimed that by this time, 1 February, on average 5.8 per cent of the Australian continent would have burnt—this is from satellite records from 1979. This year, so far, he's claiming only 2.8 per cent. I don't know the veracity of those figures, but if that's the case then this is certainly not unprecedented.

CHAIR: Your response may be on both of those issues, please—on the long-term data trend and the definition of unprecedented.

Mr RICK WILSON: We want to stick to the science here. There's been a lot of emotion, but my preference would be to stick with the science and the facts.

Dr Metcalfe : I think you really need advice from the bureau over interpretation of weather data but my understanding, and I can't see exactly what you're looking at there, but the anomalies relate to—is that annual weather or seasonal weather?

Mr RICK WILSON: It's the rainfall, which is falling across southern Australia. Across Australia the anomaly actually shows a slight increase in weather. In Western Australia, which is part of southern Australia, the rainfall's dropped off the cliff. We've dropped off about 40 per cent since the 1960s. These are all well-known facts.

Dr Metcalfe : I think the bureau are the most appropriate people. That's their data, and they should be commenting on that. The one point I would make is that they are annual rainfall anomalies and what we're experiencing is not necessarily the amount of rain that's fallen in the entire year but how that rain has patterned through the season and consequently the amount of drying that's taken place between those rainfall events.

Mr JOSH WILSON: And temperature is obviously related. You can have—

Mr RICK WILSON: Also a major factor in a fire burning index is humidity. So what's humidity done in recent times? We're aware that the temperature has increased—

Dr Metcalfe : Those are bureau data so I would refer you to our colleagues in the bureau to answer that. In terms of the proportion of the continent that's burnt—I'm not familiar with the detail of those figures and don't dispute them. As I said earlier on, the level of precedent is dependent on the metrics you want to consider—what we're looking at specifically is the amount of fire in southern, and particularly south-eastern Australia, and the data that I think you've just cited are for national data. And so that includes very extensive fires across the northern tropical systems which we haven't been considering in terms of our response to the current bushfires because many of those are—again, I'd have to go back to the data that ERIN'S produced for the Department of Agriculture, Water and the Environment. Their numbers—where they're talking about 10 million hectares of land burnt—are considering those areas which have been burnt which we would not normally have expected to see burnt by this time of year and they're not considering the fires that have happened north of the tropic across northern Queensland, the Northern Territory and northern West Australia.

CHAIR: Unfortunately, I'm going to have to wrap this up because the Prime Minister will be giving a Closing the Gap statement shortly in the chamber. You have whet our appetite for what will be a very important and interesting inquiry. We thank you for your attendance today. We look forward to receiving your submission into the inquiry and then having you back where we can actually have a more thorough conversation. I'm conscious we've only just started. You will, of course, be sent a copy of the transcript of the evidence today. You'll have an opportunity to request corrections. Otherwise I declare this public hearing closed, and the committee is adjourned until 10 am on Wednesday 26 February 2020 in Canberra. Thank you.

Committee adjourned at 10:56