The scientists examined the probability of extreme heat and drought and a fire weather index as severe as those just experienced compared with Australia's climate of about 1900.
The bushfires drew international attention in part because of the"unprecedented nature of this event",with millions of hectares burned,5900 residential and public structures destroyed and at least 34 people killed directly.
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"It was really scary to see such extreme conditions in such a country as well prepared as Australia,"said Maarten van Aalst,a researcher with the Red Cross Red Crescent Climate Centre in The Hague,Netherlands,and one of the researchers.
Previous studies of Australian heat had identified a clear influence of climate change,including the 2012-13 summer.
The recent heat again offered a clear climate change signal,with temperatures driven higher in heatwaves that are 1-2 degrees hotter than 1900,the researchers found. The record-breaking temperatures during one week in December - which smashed previous Australia-wide daily maximums - were 10 times more likely than a century earlier,they said.
Identifying climate change's role for the drought was more difficult. The scientists did not find an attributable climate change trend in either extreme annual drought or the driest month of the September-February fire season.