Bushfire risk in Australia has increased by at least 30% because of climate change, a group of scientists has concluded in a new study after analysing this season’s fire catastrophe.

According to the study’s co-author, Geert Jan van Oldenborgh from the Royal Netherlands Meteorological Institute, the impact could be higher because the climate models used for the analysis have more variability and lower trends.

“We show that fire weather like that of the last months is now at least 30% more likely due to anthropogenic climate change, but it could be much more,” he told insuranceNEWS.com.au.

“We cannot give a best estimate because the extreme fire weather events and extreme heat events in the climate models we used are not compatible with the observations.

“For the future, the probability of this kind of fire weather keeps increasing as long as we burn fossil fuels and hence increase the greenhouse warming of the earth.”

The study by World Weather Attribution, a partnership of universities and weather research institutes, aimed to determine if human-induced climate change altered the likelihood and intensity of the months-long bushfire catastrophe.

Climate models used for calculating the Fire Weather Index showed “a significant trend towards higher fire weather risk since 1979,” the study says.

“Compared with the climate of 1900, the probability of Fire Weather Index as high as in 2019/20 has increased by more than a factor of four.

“The four climate models investigated show that the probability of a Fire Weather Index this high has increased by at least 30% since 1900 as a result of anthropogenic climate change.

“As the trend in extreme heat is one of the main factors behind this increase and the models underestimate the observed trend in heat, the real increase could be much higher.

“Projected into the future, the models simulate that a Fire Weather Index at the 2019/20 level would be at least four times more likely with a 2ºC temperature rise, compared with 1900.”

Insured losses from the November-declared bushfire catastrophe have risen to at least $1.99 billion, surpassing the $1.76 billion normalised losses from 2009’s Black Saturday.