The man who commanded California’s response to the state’s worst ever bushfire, in which 86 people were killed and 14,000 homes were lost last year, says Australians and Americans must accept that climate change has caused a dangerous “new normal” in bushfire behaviour.

“These are the future fires,” said Ken Pimlott, who retired in December after 30 years as a firefighter and eight years as chief of the California Department of Forestry and Fire Protection, known as Cal Fire.

Where once it was abnormal for the fire season in southern and northern California to overlap, now it was overlapping in the southern and northern hemispheres, he said on Tuesday.

Just last week in California Mr Pimlott met with former Fire and Rescue NSW commissioner Greg Mullins in his role as a councillor on the Climate Council, to discuss the impact of climate change on wildfires in both states. He said the two agreed that their experience was nearly identical.