An arrangement that has worked well for decades is at risk of coming unstuck

Longer bushfire seasons in Australia and the US threaten to disrupt the sharing of vital personnel and equipment between the two countries, fire experts and coordinators have revealed.

At least 50 people have lost their lives in California’s deadliest wildfires, which continue to rage. Fire authorities and scientists say climate change has made the conditions worse.

In July the US requested help from Australia and New Zealand, which sent 188 personnel to help fight the blazes. That group has now returned.

For about 20 years, Australia and the US have exchanged personnel and equipment during major fires. But there are fears that, as climate change drives more severe blazes and lengthens fire seasons, those arrangements could be strained.

A fleet of aircraft, including six adapted helicopters and two Hercules water bombers, are also shared – spending the Australian winter fighting fires in the northern hemisphere before being contracted to fight bushfires in Australia’s summer months.

Facebook Twitter Pinterest Firefighters fight flames close to homes in Wattle Grove in Sydney in mid-April. Photograph: Brendan Esposito/AAP

“It’s an issue for us,” said Stuart Ellis, the chief executive at the Australasian Fire and Emergency Service Authorities Council – the group responsible for coordinating with other countries to share firefighting personnel and equipment.

The problem had “arisen in discussions between ourselves and the US”, he said. “In the US there’s less and less talk of a ‘fire season’ and more a consideration that fire impacts them all through the year.”

The arrangement to contract and share the specialist aircraft, which supplement a fleet owned by Australian authorities, had “worked well for many years”. “There’s no question [the aircraft] make a very positive contribution [to fighting fires],” Ellis said.

But he said the arrangement “could be challenged in the future and we are considering alternatives – whether that’s using more local aircraft or sourcing others”.

I think there’s no other plausible explanation than climate change Stuart Ellis

This year’s deployment of 188 Australian and New Zealand firefighters followed a group of 240 who crossed the Pacific in 2017.

Most of the Australian team is made up of “incident management specialists” – staff trained in a common system used to coordinate and deploy firefighting units.

“In California there are about 4,500 firefighters deployed or available and, at the height of the fires in the western US, there were about 29,000,” Ellis said. “Where we can help is that they tend to have large numbers of firefighters but they run out of incident management specialists.”

Ellis has been in the US and Canada during recent deployments and said the intensity of this year’s fires and the conditions that fed them were “unprecedented”.

Facebook Twitter Pinterest Firefighters work to keep flames from spreading through Paradise, California, last week. Photograph: Noah Berger/AP

“I think there’s no other plausible explanation than climate change,” he said. “It’s not up to the fire services to say what the cause of that is, but the issue of climate change is one we are applying our minds to because it can have an impact on our resources.”

Dr Richard Thornton, the chief executive of the Melbourne-based Bushfire and Natural Hazards Cooperative Research Centre, said there was already an overlap in the times spent fighting major fires in the US and Australia.

“We are now seeing regular fires in the United States – and in California – running into November, and there were fires last year in December that led to mudslides and deaths. In Australia, it appears there’s more fires occurring outside of what we would call the fire season. Clearly then, there’s already an overlap.”

The Bureau of Meteorology says Australia’s bushfire season has lengthened, and increasing temperatures and drier conditions have increased the risk of blazes.

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Thornton said the sorts of conditions that led to catastrophic fire events such as the 2009 Black Saturday fires were “becoming more likely due to climate change”.

The lengthening of fire seasons also meant there was less time to carry out controlled burning, he said.

He called the loss of life in the California fires “truly tragic” and said there were important lessons to be learned for other parts of the world, including Australia.

Facebook Twitter Pinterest Some of the more than 70 houses and businesses destroyed by a bushfire in the coastal NSW town of Tathra in late March. Photograph: Carly Earl/The Guardian

“We have a lot of people living in that rural-urban interface,” he said. “Some people have lived there for a long time and others have moved there, and we see urban planning schemes that open up those areas for new dwellings.

“Then we see very high fuel loads close to those populated areas and changes in demographics, with more vulnerable people there, or getting older there.

“Combined with all that, we see conditions for fires occurring more frequently. There’s an increase in the risk, an increase in the exposure to the risk and all that leads to a challenge that countries need to grapple with.”