Growing scientific evidence linking extreme fires to climate change

The group of five scientists reviewed the growing scientific literature, finding more alarming evidence of the link between the two phenomena.

The scientists have launched the Bushfire Response project to make scientific evidence more accessible to the public, and have released their first report.

Griffith University Professor Brendan Mackey said the evidence showed the Black Summer Fires - which burnt more forest area than any previous fire season - were exacerbated by climate change.

Their report found under extreme fire weather conditions the importance of fuel loads decreases significantly and fuel dryness becomes the key factor - a finding that was mirrored in the recent royal commission into the Black Summer Fires.

Immediately before the catastrophic fires, eastern Australia had suffered a severe drought, with much of north-eastern NSW recording the lowest rainfall on record and above average temperatures for six months prior.

"Projected climate change means more extreme fire weather, especially in south-eastern Australia," Prof Mackey said.

"Climate change brings less winter rain in southern Australia, and so the forest is drier at the start of spring.

"Drought results in very dry fuel conditions, eucalyptus trees dropping their leaves, more small fuel for fire, and wet gullies drying out."

The report also revealed last spring, Forest Fire Danger Indexes were at record levels across 60 per cent of the nation.

"Historically, extreme fires have occurred on only a few days per decade," Prof Mackey said.

"But the BOM State of the Climate Report 2020 revealed the number of extreme heat events had increased tenfold from 14 in the 1960s to 141 in the 2010s, with 43 extreme heat events in 2019 alone."

The report also found the worst fires in Australia's history have come after long droughts.

"Fire seasons are projected to start earlier, last longer and be more intense as human-forced climate change continues to heat the planet," Prof Mackey said.

He pointed to a recently peer-reviewed study, which found human-forced climate change made the extreme weather in the 2018 Queensland fires 4.5 times more likely to occur, and the low rainfall conditions which preceded it 1.5 times more likely to occur.

The Bushfire Response project will soon feature data collected by citizen scientists using the free Bushfire Recovery app.

The data will record where animals have been sighted since the Black Summer fires and then displayed it on an interactive map, to help collect information on habitat.