CSIRO scientist talks bushfires, fuel loads and climate change

Eric Barker, 29/11/2021

NEW research by the CSIRO has found a significant increase in bushfire activity over the past three decades, with the fire season taking up a larger part of the year.

The findings were based on putting 32 years of satellite data and 90 years of ground-based data against weather observations to determine areas of burnt forests. No data was used to track fuel loads, with the group making models in its place.

Pep Canadell

CSIRO’s Dr Pep Canadell said the study found a significant uptick in forest-fires since 2000, with climate being the main catalyst.

“We have a forest fire danger index, which brings together moisture, soil moisture, winds and temperature,” Dr Canadell said.

“The trend shows we are having more extreme fire danger days, where fire can burn so quickly and so hard that trees become part of the fuel load.”

Dr Canadell said the group was looking at fires which had altered the landscape enough to be detected on the satellite.

“Our interest was to look at the trend and how it related to climate, so we were looking at big fires driven by big forces of nature or humans,” he said.

“Understanding these trends will help to inform emergency management, health, infrastructure, natural resource management and conservation.”

More work needed on fuel loads

Management of fuel loads in National Parks has been a hot topic in recent years, with many landholders neighbouring parks blaming them for fuelling damaging fires.

This year was no exception, with a landholder in Central Queensland telling Beef Central fuel loads in the Bulburin National Park had accelerated a fire in the area, causing him to lose some grazing land. He said it was a yearly problem.

Dr Canadell said with the group studying such large areas of land, accurate measurements of the fuel loads were hard to find.

“No one has systematically collected fuel load data across Australia and it is hard to see exactly what is on the ground from satellites – especially with forests,” he said.

“There is some work from the Australian National University using remote sensing to determine fuel loads, especially the dryness of fuel loads. Eventually that will be used to inform emergency services about what might coming in-terms of fire.

“But for our study there was no information, so our only option was to make models of fuel loads.”

Dr Canadell said data given to the researchers by fire services and National Parks had shown no trend towards a reduction in prescribed burning.

“The amount of prescribed burning has not changed in 40 years, which means we are still burning about one percent of all forests,” he said.

“There is a lot of discussion about whether we need to do more prescribed burning than we were before.

“Some of the enquiries after the black summer bushfires found we needed to have five times more prescribed burning than what we are already doing – that is the very minimum of what is needed.”

La Nina could bring more fire

Conditions across most of the eastern seaboard this year are very different to the devastating fires of 2019, with widespread rain and formation of a La Nina weather pattern. Recent rain has downgraded the summer fire outlook for a large part of the east coast.

Dr Canadell said the formation of the rain-bearing weather pattern has traditionally been followed by major fire years.

“In 2011, after the biggest La Nina in 100 years, we had the biggest fires recorded in the 32 years of the study,” he said.

“Most of this area was in the rangelands because there was so much gras, even close to Alice Springs where fires are rare. It’s hard to prepare for fires like that.”











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  1. Bob Harris, 01/12/2021

    I would expect a balanced report from the CSIRO.
    I absolutely reject this report.
    The reason for more and hotter fires is mismanagement/no management.
    NSW,VIC,SA have locked forests up for the last 30 years,with very little fuel reduction,hence,major hot fires.
    WA is the exception.They attempt to cool burn 30% of the forest area in south west WA,every year.Works well.
    Another problem is City beauracrats interfering with Rural Firefighters decisions.

  2. Roger Crook, 30/11/2021

    Hector is right, livestock should be allowed to reduce the fuel load in many areas of bush.
    As for climate change, considering that the flash point of eucalyptus oil is ~50c , bit more bit less, how can a small rise in temps have caused more fires?
    There are studies on the fuel loads so we can calculate how much oil is in a forest, frankly uncontrolled they are just a bomb waiting to go off.
    We now encourage people to live in the forest, so in a bomb.

  3. John Gray, 30/11/2021

    How about this for a concept, It is better to have multiple small controllable fires every year than one big uncontrollable fire every 5/10 years. The above comments come from real time experience as of 14 fire seasons flying on fire fighting work as a rotary wing pilot across NSW &Tasmania. For those who just cannot grasp that idea, let me put it simply, its called good land management, fire is one of the best management tools used correctly at the right time of the year regardless of where it is, Npws, forestry or private. Unfortunately, those who do have actual experience in this and exercise “Common sense” are battling an uphill battle against the Government dept ideology.

  4. Hector Goss, 30/11/2021

    Climate change is a reality and a factor in the frequency of these larger fires.
    There was no mention of livestock as a tool in fuel-load reduction. Greater than 250 years ago controlled burns was all that was followed. After livestock was brought in to the country, bushland grazing would have had an impact on fuel-loads, especially as the national herd increased. In recent times bushland grazing on public lands (national parks etc.) has been out of favour. Has there been any consideration of this in the CSIRO study?

  5. Garry Core, 29/11/2021

    The only thing that’s changed is human population, once areas could be burnt on a regular safe basis but now houses and other infrastructure are scattered throughout forests making it hard to do reduction burning so the fuel load thickens, this is happening everywhere even in open grasslands where people are scared to burn for fear of damage to other property, so the fuel load thickens until Bang lightning strike whatever and up it goes, nothing to do with climate change just management

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