Hotter Summer Days, More Fires Forecast for Australia

SYDNEY, Australia, January 14, 2004 (ENS) - Last Friday, hundreds of firefighters were battling a bushfire burning out of control in Sydney's north, one of three in the Australian state of New South Wales, including one that charred parts of Kuringai National Park. Each year during the austral summer, fires blaze across the country.

Whether set deliberately or sparked by lightning, the fires are devastating, and government scientists say future summers will have a greater number of very hot days than this summer, creating ideal conditions for more blazes.

The number of very hot summer days in some Australian cities could double by 2030, said Kevin Hennessy today. The senior climate research scientist is associated with the Atmospheric Research Climate Impact Group at the Commonweath Scientific Industrial Research Organization (CSIRO), the government's research branch.

"By the year 2030, we expect most of Australia to become 0.4 to 2.0 C warmer on average, with 10 to 50 percent more summer days over 35C," said Hennessy.

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Bushfire in Western Australia (Photo courtesy CSIRO)
The impacts of changes in climate are widespread, says Hennessy. "Hotter and drier conditions would lead to greater fire risk, more heat stress for humans, crops and livestock, greater energy demand for air conditioning. But there will also be less energy demand for winter heating and less frost damage, so there will be winners and losers."

The CSIRO climate scientist predicts that the average number of summer days over 35C in the Australian capital of Canberra would increase from four days at present to between six and 10 by the year 2030.

In Melbourne the average number of days over 35C increases from eight to between nine and 12, in Adelaide from 10 to between 11 and 16, and in Perth from 15 to between 16 and 22.

In Hobart, Sydney and Brisbane, the averages may double to two, four and six days respectively by 2030, Hennessy says.

The Federal Government's new Bushfire Research Centre was opened on December 9, 2003, and one of the fire ecology experts at the new center says global warming has already started to produce more severe bushfires over recent Australian summers.

Dr. Kevin Tolhurst, a fire ecology expert from the University of Melbourne, says much of the east coast and the southern states can look forward to more frequent and more intense bushfires.

With an increased carbon dioxide concentration in the atmosphere, forests are going to produce more fuel, so they will burn with greater intensity, Dr. Tolhurst said.

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Firefighter addresses a blaze in Queensland. (Photo courtesy Queensland Fire and Rescue Service)
"Combine that with a greater frequency of drought and more severe weather conditions, we would expect fires to not only be more intense because of the greater fuel amounts, but the likelihood of having severe fire weather conditions is likely to increase as well," Dr. Tolhurst told ABC Radio News.

"Instead of talking about a one in a 100 year event, we'd be talking more likely one in 50 or one in 30 year events becoming much more the par for the course," he said.

Australia has already warmed by about 0.8C since 1950. "This doesn't sound like much but it has been associated with an increase in extremely hot days and hot nights, and a decrease in extremely cold days and cold nights," says Hennessy.

The Bureau of Meteorology recently announced that 2003 was Australia's sixth warmest year since 1910, with the global average temperature being the third warmest since 1861. The hottest year, both globally and in Australia, was 1998.

Climate change would also lead to as many as 80 percent fewer frosts, and Australia will experience more droughts too, Hennessy warns. Up to 15 percent less rainfall is expected in the south and east by 2030, especially in winter and spring. In the southwest, rainfall may decline by up to 20 percent.

"With likely increases in evaporation this means drier conditions in future, with reduced water supply and greater water demand. In the southwest, rainfall has already decreased by about 20 percent since the mid-1970s," he says.

He says strategies to adapt to climate change include water demand management such as restrictions and recycling, breeding and selection of heat tolerant and drought tolerant crops, adjusting cropping calendars to take advantage of a longer frost-free period, more shade and water for livestock, and heat-smart buildings.

"However, some animals and plants may be highly vulnerable to climate change, with limited options for adaptation," Hennessy warns. "For example, coral reefs are likely to experience more bleaching, and some Western Australian frogs and east Australian alpine mammals will find their habitats shrinking as the temperature rises."