The Royal Commission into National Natural Disaster Arrangements has started its hearings with a focus on the changing global climate.
Australia faces even more dangerous bushfire conditions in the future, say scientists who warn the devastating 2019-20 blazes are not a one-off event.
The coronavirus pandemic has slowed the recovery from the bushfires and interrupted planning for future fire seasons, the natural disasters royal commission noted as its public hearings started.
The Bureau of Meteorology says Australia is experiencing longer bushfire seasons with more extreme fire danger days.
Large fire events like the 'Black Summer' 2019-20 bushfires are occurring more frequently, its head of climate monitoring Dr Karl Braganza said.
"This isn't a one-off event that we're looking at here," he told the royal commission on Monday.
"Really, since the Canberra 2003 fires, every jurisdiction in Australia have seen some really significant fire events that have challenged what we do to respond to them and have really challenged what we thought fire weather looked like preceding this period.
"The frequency of these events, if we look at the historical record, seems to be increasing."
Dr Braganza said fire weather will intensify into the future.
Research by the bureau and the CSIRO shows the fire danger is very likely to increase in the future for many regions of Australia, exacerbated by the increased occurrence of extreme heat events.
"These dangerous weather conditions for bushfires are likely to occur at least in part due to increasing greenhouse gas emissions," senior CSIRO scientist Dr Helen Cleugh said.
Fires burning in heavily-forested areas also generated their own weather and thunderstorms - called pyroconvection - which Dr Cleugh said can provide an ignition source and also affects the spread of fires.
"The risk of fire danger is both due to the long-term drying and warming which is conditioning the landscape but also the extreme fire weather that is observed partly due to climate change," she said.
The 'Black Summer' bushfires killed 33 people, destroyed more than 3000 homes and burnt about 12 million hectares across Australia.
Royal Commission into National Natural Disaster Arrangements chair Mark Binskin said many bushfire-affected communities are still grieving.
"The tragic loss of life, the destruction of homes, the significant loss of livestock and millions of hectares of forest has been devastating and continues to deeply affect people and their recovery."
Mr Binskin said in many cases, the ongoing effects of the bushfire season are being further compounded by the measures necessary to address the coronavirus pandemic.
Senior counsel assisting the commission Dominique Hogan-Doran SC said the ongoing impact of the pandemic has been profound.
"As the evidence will show, the recovery from the devastating impacts of the 2019-20 bushfire season has been slowed and fragmented," she said.
"Planning for future seasons appears to have been interrupted."