Study shows climate change link to devastating 2019/20 Australian bushfire season
There is no way these attribution studies can prove anything. To make judgments of cause and effect you need the same events to be repeated several times but this never happen with climate. It is always changing
One comment below is admirably frank: "We found that climate models struggle to reproduce these extreme events and their trends realistically"
Need I say more?
This bushfire season has been the worst on record, but what elements of it are fact and what has been distorted by myth.
Climate change did play a part in Australia’s devastating 2019 bushfire season as it has increased the chances of extreme temperatures by at least 30 per cent, a new study shows.
The eight-week study from World Weather Attribution (WWA), an international collaboration that analyses the effect of climate change on extreme weather events, found a strong link between climate change and hotter-than-normal conditions in Australia during the time of the 2019/20 fires.
Last year was the warmest and driest year in Australia since temperature and rainfall records began in 1910 and 1900, and it follows two other dry years in large parts of the country.
According to the Bureau of Meteorology’s Annual Climate Statement 2019, these conditions contributed to a more widespread and intense fire season that started earlier in the season than usual. Other factors included a strong Indian Ocean Dipole and the Southern Annual Mode.
The WWA study looked at what caused the high temperatures and prolonged dry conditions between September to February, to see if they could be linked to climate change.
While they couldn’t link climate change to the drought, it did find a 30 per cent increase in the likelihood of high temperatures.
As climate-heating emissions continue to increase, “We will be facing these extreme conditions more often than in the past,” said Maarten van Aalst, a climate scientist and director of the Red Cross Red Crescent Climate Centre. “Should we be worried about this? Yes, very,” he told journalists.
The study also suggested that scientific models may be vastly underestimating the impacts of rising temperatures.
“We found that climate models struggle to reproduce these extreme events and their trends realistically,” Professor Geert Jan van Oldenborgh of the Royal Netherlands Meteorological Institute said.
“However, they always underestimate the increase in chances for extreme fire risks such as Australia saw in the last few months.
“This means we know the effect is likely larger than 30 per cent increase lower bound, which is already a significant influence of global warming.”
The high temperatures and prolonged dry conditions resulted in unprecedented bushfire activity across the states of New South Wales, Victoria, Western Australia, Queensland, South Australia and in the Australian Capital Territory.
The 2019/20 bushfires burned more than 11 million hectares – an area larger than Ireland or South Korea – destroyed nearly 6000 buildings and killed at least 34 people and an estimated 1.5 billion animals.
The economic costs of the fires could reach $100 billion, according to separate analyses.
“Climate change is now part of Australia’s landscape,” Dr Sophie Lewis of the University of New South Wales said.
“Extreme heat is clearly influenced by human-caused climate change, which can influence fire conditions. There is evidence that Australian fire seasons have lengthened and become more intense, and extreme temperatures have played a role in this.
“Climate change contributed to the fires and extreme heat we lived through in southeastern Australia.”
A week of hot temperatures, like that experienced in southeast Australia in December 2019, was 10 times less likely in 1900 than it is now, while heatwaves like the one in Australia in 2019/20 are already hotter by 1-2°C than they were around 1900.
Dr Friederike Otto of Oxford University said the study was not an ultimate answer to the question of how climate change was impacting things like fire but did confirm it was an important driver locally.
“We need to continue to test our models in the real world to improve them so we can provide higher confidence risk information at the scales where people live and make decisions.”
Researchers from Australia, Europe and the United States carried out the analysis under the World Weather Attribution project, which provides rapid scientific evidence on how much climate change is fuelling extreme weather events.
The group has so far conducted more than 230 such studies, linking last year’s record-breaking heatwave in France and extreme rainfall during Tropical Storm Imelda in Texas, for instance, to climate change.
Not all the events analysed show a connection to global warming.
But the researchers said devastating fire seasons will be at least four times more common in Australia than they were in 1900 if global average temperatures rise 2C above pre-industrial times.
Temperatures have already heated up by a little over 1C, and the world is on track for at least 3C of warming even if all countries meet their commitments to cut emissions under the 2015 Paris Agreement on climate change.