This Heatwave: Officially Brought To You By Climate Change
By Bernard LaganJanuary 15, 2013
At the weekend — as roads melted in parts of Queensland, trains crawled on heat-buckled tracks and long-standing temperature records disintegrated in the outback — Australia’s climate change agency slipped out a report confirming that the warming of the planet is behind our record-breaking heatwave and severe bushfires.
It is unlike the Climate Commission — headed by Professor Tim Flannery, a scientist notably not unwilling to share his opinion on the doom of climate change — to mask its reports. But no press release announcing the report appears on the commission’s website; unhappily the commission’s report, Off the Charts: Extreme Australian Summer Heat, received only the barest media attention when it was released early on Saturday morning, an odd hour for any attention seeking.
We think it worth a fuller account — especially as another recent study shows that Australia’s media has largely failed to connect the January heatwave to climate change. Simon Divecha is the business manager at the Environment Institute of the University of Adelaide. A week ago the website The Conversation published his study which showed that fewer than 10 of the 800 articles published in the previous five days about the heatwave had mentioned climate change, global warning or greenhouse gas.
It’s perhaps not so surprising then to learn that scepticism about climate change — at least before the grip of the heatwave — remains reasonably high among Australian conservative voters. A study completed late last year by Griffith University found that one’s experience of climate change in Australia was closely allied to which side of politics you supported. Some 75.7 per cent of Green voters and 60 per cent of Labor’s agreed with the statement: “We are already feeling the effects [of climate change].” But only 40 per cent of Nationals voters agreed, and even fewer (32.7 per cent) Liberal voters. Overall, only 4.2 per cent of the study’s 4,300 respondents selected the option “there is no such thing as climate change” and 8.5 per cent could be considered strong sceptics. Some 45 per cent of all respondents reported they’d had direct personal experience with climate change. Perhaps Australia’s January heatwave will shift opinion in the debate.
The Climate Commission’s report lists what it says are four key messages for Australians arising from the heatwave. They are:
1. The length, extent and severity of the current Australian heatwave is unprecedented.
2. Although Australia has always had heatwaves, hot days and bushfires, climate change is increasing the risk of more frequent and longer heatwaves and more extreme hot days, as well as exacerbating bushfire conditions.
3. Climate change has contributed to making the current extreme heat conditions and bushfires worse.
4. Good community understanding of climate change risks is critical to ensuring appropriate action is taken to reduce greenhouse gas emissions and to put measures in place to prepare for, and to respond to, extreme weather.
The report says that as global temperatures rise, very hot days in Australia are increasing in frequency and heatwaves are lengthening. Temperatures above 40°C and 45°C were unprecedented in their extent across Australia this month, records were broken and the duration of the extreme heat was also unprecedented.
January's soaring heat shot off the charts, literally, forcing the Australian Bureau of Meteorology to add two new colour codes on top of black on the official weather maps. Dark purple and magenta now top the map, representing temperatures of 51°C to 54°C.
In seeking to answer the question of how climate change influences Australia’s temperature, the report says that Australia’s average temperature has already risen 0.9°C since 1910, consistent with the global trend of increasing temperature. While the increase might seem modest, small changes in average temperature can have significant effects on the frequency and nature of extreme weather events, the report says.
By way of example, it says that the number of record hot days across Australia has doubled since 1960, despite the average temperature increase of only 0.9°C. Many record hot days are in store for Australians if global warming continues unabated, the report says, adding that the increase in temperature observed around the world is directly connected to the increase in greenhouses gases from human activities. Those gases in the atmosphere trap heat.
Aside from warming, much of eastern, southern and southwestern Australia has become drier over the past 40 years. Tasmania’s total rainfall has reduced, Victoria has experienced a 10-to-20 per cent decline in rainfall in its late autumn-winter season, most of New South Wales has become drier and there has been a stark rainfall decline in South Australia.
Accompanying the trend to a hotter and drier Australia, is an exacerbation of the risk and intensity of bushfires. When fires occur in more extreme weather conditions, they have the potential to be far more intense and difficult to control, the report says. The Forest Fire Danger Index, used to gauge bushfire threats, has significantly increased at 16 of 38 weather stations across Australia since 1973. None of the stations has shown a significant decrease. The increases are most marked in southeastern Australia, and the fire seasons have become longer, reducing the opportunities for fuel reduction burning.
In seeking to explain why the heatwave has been so unusual, the Climate Commission says the period from last September to January was the hottest four-month period ever recorded in Australia. Rainfall has also been below average across the continent and the wet (monsoon onset) season has been notably inactive. This four-month dry period followed two years of record rainfall across southeastern Australia, magnifying the amount of vegetation and, thus, fuel for bushfires.
This month’s searing temperatures have led to records being set across Australia. Among them are:
Australia experiences seven consecutive days with area-average maximum temperatures above 39°C between January 2-8, breaking the previous record of four days in 1973.
NSW: On January 5, the town of Hay reached 47.7°C, breaking its record by 1.7°C.
Northern Territory: Curtin Springs broke its maximum temperature record on January 4, only for it to be broken again on January 8 when the temperature hit 45.7°C.
South Australia: Between January 4-6, temperature records were broken at four weather stations.
Tasmania: On January 4, Hobart reached 41.8°C, breaking the record by 1°C.
Victoria: On January 4, the temperature in the southwestern town of Portland reached a record 42.1°C.
Western Australia: On January 3, the state’s eastern-most town of Eucla broke its record, reaching 48.2°C.
And what of the effect upon humans of these extremes? If core body temperatures exceed 38°C for several hours, the body can suffer heat exhaustion and reduced mental and physical capacity. At 39°C more serious heat stroke and unconsciousness may occur. Serious heat stroke and even death occurs after a relatively short time if body temperatures rise above 42°C.
The commission’s report says Australian heatwaves in recent years have resulted in more deaths than previously. In Melbourne, for instance, during late January 2009, temperatures reached and exceeded 39°C over three days. There were 374 extra deaths over the period, beyond the estimated 606 that would have been expected. That was a rise of 62 per cent. The elderly were the hardest hit. During the Brisbane heatwave of February 2004 when temperatures climbed to 42°C, deaths increased 23 per cent.
The commission’s report concludes that climate change will cause even more deaths if Australia fails to improve the way it forecasts, prepares for and manages the extreme heat events that are to come.
Soon enough we’ll know just how many extra deaths have occurred because of the January heatwave. First, we’ll need it to end.