An analysis of the the 2019/20 fire season in southeastern Australia by the World Weather Attribution Consortium has warned that anthropogenic climate change has increased the probability of a Fire Weather Index reaching the 2019/20 level by at least 30% since 1900, and under current warming trends coud be much higher.
The study, authored by 17 international climate experts, uses the highest weekly mean Fire Weather Index (FWI) of the fire season for each grid point as a measure of the most intense fire risk, and the Monthly Severity Rating as a measure of the overall seasonal fire risk. These are averaged over the area of most intense bushfires, between the Great Dividing Range and sea in New South Wales (including the Australian Capital Territory) and Victoria.
Projecting into the future, the eight climate models used in the study simulate that a Fire Weather Index at the 2019/20 level would be at least four times more likely with a 2 ºC temperature rise, compared with 1900. Further, the likelihood of a heatwave as extreme as 2019/20 is about 10 times more likely now than it would have been around 1900.
The full study, Attribution of the Australian bushfire risk to anthropogenic climate change, can be downloaded here