础耻蝉迟谤补濒颈补鈥檚 recent devastating bushfires were made more likely by human-made climate change, an international team of scientists has found.
by World Weather Attribution (WWA) discovered that the weather conditions responsible for the fires were made at least 30 per cent more likely because of how humanity has warmed Earth. Two climate phenomena, the Indian Ocean dipole and southern annular mode, were also found to have played a big role.
Debate has raged in Australia over the cause of the fires, with Australian prime minister Scott Morrison calling them 鈥渂usiness as usual鈥� and .
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The WWA team ran climate models of a world with and without human-made climate change to identify any effect on the bushfires. They didn鈥檛 find humanity鈥檚 fingerprint in monthly and annual drought records, but they did find one in a fire weather index, a measure of weather conditions including temperature, wind and humidity that make fire more or less likely.
Friederike Otto at the University of Oxford, part of the WWA team, says: 鈥淏ecause of climate change alone, we find at least a 30 per cent increase in the likelihood of these events to occur.鈥� But the true figure is likely much larger, she says, because the models underestimate the role of temperature rises.
The attribution analysis looked just at south-east Australia where the fires were most intense. The fires burned 19 million hectares and destroyed nearly 6000 buildings, says Sophie Lewis at the University of New South Wales in Australia.
Lewis says her family spent months inside because of smoke around Canberra and had to cancel their annual holiday. Overall, the fires had an 鈥渆normous human and ecological cost鈥�, she says.
The WWA team says the complex nature of the bushfires meant attributing them to human-caused climate change was much harder than with heatwaves. The analysis of those events has become much more rapid and can be done in a week, such as with the European heatwave last summer, which the team found was made five times more likely by climate change.
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