Bernie, Greta and Hillary call it an example of the global climate crisis.
85% of the fires were started by human action, either accidentally or deliberate. 180 people have been charged with starting fires. Many of them are involved in lighting multiple fires. 24 of them charged with deliberate arson, the rest charged with various offenses related to accidental or negligent use of fire that got out of control.
One fire was started as a backburn to protect a cannabis crop.
Here's a link to the Sydney Morning Herald article on one arrest that mentions much of the ongoing investigation. The culprit in this case is a Rural Fire Service volunteer.
"Arson is not caused by climate change."
--Liberal MP Craig Kelly