New Research Finds Climate Emergency the 'Overwhelming Factor' Behind Australian Bushfires

New research finds "a robust and multi-evidence link" between the climate crisis and Australia's trend of worsening wildfires.

"We need to be ready for more Black Summers--and worse."

Published Friday in Nature, the study was led by researchers at Commonwealth Scientific and Industrial Research Organization (CSIRO), Australia's national science agency, and was based on over 30 years of satellite data as well as nine decades of ground-based climate and weather data.

The trend of worsening fires is clear, the scientists said, noting that bushfires are creating a greater burn area. The study noted as an example that 10 out of 11 fire years that scorched at least 5,000 square kilometers (about 1,930 square miles) have occurred since 2001. The amount of time since the last fire, meanwhile, is decreasing.

Assessing a range of eight wildfire drivers factors including fuel accumulation and prescribed burns, researchers found the key culprit to be climate-related factors such as soil moisture, mean precipitation, and temperature increase.

"While all eight drivers of fire activity played varying roles in influencing forest fires," CSIRO scientist and co-author Pep Canadell said in a statement, "climate was the overwhelming factor driving fire activity."

Canadell said the findings "also suggest the frequency of forest megafires are likely to continue under future projected climate change."

The time period studied included the catastrophic 2019-20 fire season during which 10 million hectares, about 24.7 million acres, burned and over 1 billion animals likely died. In that fire year, according to the researchers, three times the area of any previous year in the 32-year record burned. But even without looking at the year, that trend is clear.

"Forests in Australia experienced an annual average increase of 350% in burned area between the first (1988-2001) and second (2002-2018) half of the record, and an increase of 800% when including 2019," the researchers wrote.

In addition, Canadell and his co-authors wrote at The Conversation:

We are seeing fires growing the most in areas once less likely to be affected by fire, such as cool wet Tasmanian forests unaccustomed to large fires as well as the warmest forests in Queensland previously kept safe from fire by rainfall and a humid microclimate. This includes ancient Gondwanan rainforests not adapted for fire...

Spring and summer used to be the time most forest fires would start. That's no longer guaranteed. Since 2001 winter fires have soared five-fold compared to 1988-2001 and autumn fires three-fold.

Overall, fires in the cooler months of March to August are growing exponentially at 14% a year.

The forest fires of 2019-20--the so-called Black Summer--the researchers added, should not be seen as an "aberration."

"It is now clear that human-induced climate change is creating ever more dangerous conditions for fires in Australia," they wrote. "We need to be ready for more Black Summers--and worse."