Extreme heatwaves and bushfires increasingly tempering Australian summers


South Australia and Victoria are bracing for extreme heatwave and bushfire conditions again this week, as the heatwave that assailed Perth and started a fire that has claimed more than 50 homes and one life as it moves across the country. While a power pole is thought to have started the fire that burned through Mundaring in the Perth Hills on Sunday, the influence of climate change on weather extremes and bushfire risk is again being made, as it was with the unprecedentedly early start to the fire season in NSW last October. Australia is no stranger to extreme heat or fire, but as the global climate changes the science tells us that the dice is being loaded for more extreme and frequent heat, and experience is further fortifying the research.


MT @STWorg: #bigAussieHeat yet again, another heatwave http://www.bom.gov.au/australia/heatwave/  Pretty much as predicted by peer-reviewed science decades ago

Key Points

  • Heat and fire is part of the Australian experience, but not in the frequency and extremes that we are currently experiencing. 2013 was the hottest year on record, and severe heatwaves, destructive fires and earlier and extended fire season show that as average global temperatures rise, Australia will suffer increasingly dire impacts from the heat on health, infrastructure, the environment and its economy.
  • As temperatures and fire risks rise, so does the threats to human health. The young and the elderly are particularly at risk during heatwaves, as seen during the 2009 Victorian Black Saturday bushfires where 374 people are estimated to have died from the heat alone – more than double the official death toll of 173 for the fires themselves. Rising temperatures are also damaging Australia’s flora and fauna as climate change collapses ecosystems, as well as creating new stresses on infrastructure and the economy.
  • While Australia is setting heat record after heat record, it is happening at a time when the El Nino-Southern Oscillation phenomenon is in a “neutral” phase, which typically means more mild weather. Climate change is already increasing the length of fire seasons, and very high and extreme fire danger is expected to rise by 30% by 2020, and 100% by 2050 if strong action to reduce carbon emissions is not urgently taken globally.


More than 50 homes and one life have been lost this week as a severe heatwave opened the door for destructive fires in Mundaring in the Perth Hills. Now contained, the fire is yet another example of climate change loading the dice for extreme weather events, and as the heatwave moves across the country South Australia and Victoria are now preparing for their roll of the dice.

Some parts of Victoria are predicted to hit 45DegC today, and temperatures are expected to break 40DegC for the next four days. With wind gusts of up to 100km/h also expected, this will potentially be the longest heatwave to hit Melbourne in 100 years, and one that comes with an extreme fire risk.

The Bureau of Meteorology has recently launched a new pilot heatwave forecast service to provides a measure of the intensity of a heatwave, while other services from ARC and the ABC demonstrate how the current heatwaves are traversing the country.

In Canberra, severe heatwaves were once expected to hit roughly once every 25 years. Severe heatwaves similar to this week’s have been recorded in Canberra in 1952, 1979, 2009 and 2013, showing an increase in frequency that is emphasised by jumps in the number of major bushfires nationally. Environment Minister Greg Hunt was ridiculed in October, 2013 for using Wikipedia to play down the link between climate change and major bushfires, however, as critics have pointed out, even Wikipedia clearly shows an increasing trend.

What is even more concerning, is that the past two summers have been “neutral” phases of the El Nino-Southern Oscillation phenomenon. This means Australia should be enjoying milder conditions, but instead it is relentlessly notching up record temperatures and extreme fire risks.

As temperatures and fire risks rise, so does the threats to human health. The young and the elderly are particularly at risk during heatwaves. For example: the official total death toll after the 2009 Victorian Black Saturday bushfires was 173, however, during the heatwave 374 people are estimated to have died from heat-related causes.

Similarly, rising temperatures are also doing damage to Australia’s flora and fauna, with the heat knocking off thousands of bats in Queensland, and new research showing that numbers of the iconic Gum tree could shrink by 20 percent or more as climate change collapses ecosystems.

The science tells us that extreme heat is turning Australia into an even drier tinderbox. Very high and extreme fire danger is expected to rise by 30% by 2020, and 100% by 2050 if strong action to reduce carbon emissions is not urgently taken.



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Key quotes

  • “What is unusual about this event, which the pilot heatwave forecast shows, is that when high maximum temperatures and above average minimum temperatures are sustained over a number of days, there is a build-up of ‘excess’ heat. When average conditions are exceeded over a period of time by continuously high night-time and day-time temperatures, heat stress becomes a critical factor in human survival and infrastructure resilience.” Assistant Director for Weather Services at the Bureau of Meteorology, Alasdair Hainsworth.
  • “The threat to life from a period of very hot weather should not be underestimated. The official total death toll due to the 2009 Victorian Black Saturday bushfires was 173. However, it was estimated that during the heatwave in south-eastern Australia 17 January to 8 February 2009 some 374 people died from heat-related causes not associated with bushfires. The young and the elderly are particularly at-risk.” Bushfire Safety Researcher at the Bushfire CRC and Adjunct Professor in the School of Psychological Science at La Trobe University, Jim McLennan.
  • “While we do expect to see heat waves over Australia at this time of year, the context in which they are currently occurring is concerning. Australia’s average temperature has warmed by 1°C due to human induced climate change, which is enough to increase the risk of the number and severity of extreme temperature events. While the current heatwave is just a single event, it is yet other link in the chain of a climatological shift towards more extreme temperature events, more often.” Research Associate for the ARC Centre of Excellence for Climate System Science, Dr Sarah Perkins.
  • ”Because the background climate has warmed, when we get the conditions that are just right for very hot weather, the weather is a little bit hotter than it would otherwise be.” Dr Penny Whetton, CSIRO.
  • “The most powerful protection of human health from the ravages of heat is to prevent the world from warming. Governments must recognise their duty of care to current and future generations by turbo boosting the current lacklustre attempts to prevent the greenhouse disaster. Without rapid decarbonising our economy, a global health crisis will inevitably follow, and global conflict will exacerbate as millions seek to secure diminishing food and water supplies, and access to habitable climates zones.” Fellow of the National Centre for Epidemiology & Population Health at the Australian National University, President of the Climate and Health Alliance and Director of the NHMRC Project: Working in the Heat – health risks and adaptation needs, Dr Liz Hanna.

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More tweets

  • MT @TwistedKristy: Help those affected by fires: Support the #Perth Hills Bushfire Appeal: http://t.co/DNDFX5LWaN & https://t.co/urOE9LLFD4
  • RT @p_hannam: #Melbourne just went thru 40C, #Adelaide at 44.2C. And max temperatures may have  some ways to go. #climate #heatwave
  • RT @climatecouncil: How many heat records did we break in 2013? http://t.co/GntiwdujqJ #climate http://t.co/dKNXQpwLnn
  • MT @BurkeKB: CSIRO: installing solar panels on business roofs cld take pressure off electricity grid during heatwaves http://t.co/Iym3RLAJlw