The unprecedented blazes that swept through Australia during the nation’s summer months were so aggressive they destroyed about a fifth of the nation’s forests. The fires have been linked to climate change, as long-term droughts caused by global warming created the perfect environment for flames to burn.
In recent months, scientists have been trying to gauge the exact extent of the wildfires and identify why they were so extreme. Some of their findings have now been reported in a special edition of Nature Climate Change.
One study found that 5.8 million hectares (14.3 million acres) of broadleaf forest were decimated between September 2019 and January 2020 in the hardest-hit states of Victoria and New South Wales, accounting for 21 percent of Australia’s entire forested area. Most of the time, the amount of Australian forest lost to annual wildfires is just 2 percent of the total. The researchers believe they have underestimated the 2019/2020 fire season figure, as they did not include Tasmania in their data.
"Halfway through Spring 2019 we realised that a very large part of the eastern Australian forest could be burned in this single season," Matthias Boer, from the Hawkesbury Institute for the Environment at Western Sydney University, Penrith, told AFP.
"The shock came from realising that this season was off the charts globally in terms of the percentage of the continental section of a forest biome that burned."
The Australian bush is home to many iconic animals found nowhere else on Earth, like koalas and wallabies, and it’s estimated that over a billion animals died in the recent fires. Some of the worst-affected species that you might not have heard of include the glossy black cockatoo, the Hastings River mouse, and the Kangaroo Island dunnart, a little marsupial found solely on the island with which it shares its name. Losing a fifth of Australia’s forest habitat certainly spells bad news for the wildlife that resides there.
So why has this bushfire season been so terrible? For the past few years, the Murray-Darling Basin, a vast area in southeastern Australia home to 2 million people that holds a large system of rivers, and is crucial to much of Australia’s agriculture, has been unusually dry, experiencing the longest period of below-average rainfall since 1900.
The lack of rain is linked to Indian Ocean Dipole (IOD) events, which can bring rain to the region. Negative IOD events, which occur when the waters of the eastern Indian Ocean are warmer than in the west, can up rainfall. But as ocean temperatures rise with global warming, the number of these events has declined, starving southeastern Australia of rain.
"With climate change, there have been projections that there will be more positive IOD events and fewer negative IOD events," Andrew King of the University of Melbourne, lead author of a Nature Climate Change paper, told AFP.
"This would mean that we'd expect more dry seasons in Australia and possibly worse droughts."
And more droughts mean more fires. A dry, arid environment provides lots of fuel for fires in the form of dry vegetation. And once the flames have been extinguished, a drought makes it harder for plant life to recover.
With intense bushfire seasons set to become more normal as the world warms, Australia’s government must swiftly take action against climate change to protect the country in the years to come.