Australian heatwaves more frequent, hotter and longer: Climate Council report

January 16, 2014, 9:11 am

Heatwaves in Australia are becoming more frequent, hotter and are lasting longer because of climate change, a report released today by the Climate Council says.

The interim findings of the report, titled Australian Heatwaves: Hotter, Longer, Earlier and More Often, come as southern Australia swelters through a heatwave, with the temperature in Adelaide today forecast to hit 46 degrees Celsius.

The report says heat records are now happening three times more often than cold records, and that the number of hot days across Australia has “more than doubled”.

It says the duration and frequency of heatwaves increased between 1971 and 2008, and the hottest days have become hotter.

And it predicts that future heatwaves will last up to three days longer on average, they will happen more often, and the highest temperatures will rise further.

“It is clear that climate change is making heatwaves more frequent and severe,” report co-author Professor Will Steffen said in a statement.

“Heatwaves have become hotter and longer and they are starting earlier in the season.”

After notching up two consecutive days over 40C, Melbourne is on track to record its second-longest heatwave since records began in the 1830s.

The temperature is expected to reach 41C today before increasing to 42C tomorrow.

The longest heatwave in Melbourne was in 1908, when there were five consecutive days over 40C.

Temperatures have also regularly surpassed 40C in South Australia and Western Australia recently.

Report co-author Dr Sarah Perkins says the change has occurred mostly in Australia’s south-east and west.

“So particularly areas around Adelaide and Perth that are currently experiencing heatwave conditions,” she said.

“They seem to be the hardest hit in terms of the number of heatwaves, they’ve increased, and also the intensity of heatwaves as well.”

Extreme weather ‘can be attributed to climate change’

Professor Steffen says the extreme weather patterns can be attributed to climate change, with the continued burning of fossil fuels trapping more heat in the lower atmosphere.

Professor Steffen says large population centres of south-east Australia stand out as being “at increased risk from many extreme weather events, including heatwaves”.

“The current heatwave follows on from a year of extreme heat, the hottest summer on record and the hottest year on record,” he said.

The latest temperatures have driven electricity demand to its highest level since the heatwave which preceded the Black Saturday bushfires five years ago.

Regulators say the predicted high temperatures for the rest of the week could see new records set for peak electricity demand in Victoria and South Australia.

About 10,000 homes in Melbourne were without power yesterday afternoon as electricity suppliers struggled with the demand.

The State Government has warned Victorians that up to 100,000 properties could be affected by outages over the next two days.

The South Australian Government has also flagged possible power cuts to ensure the grid copes under pressure, with Adelaide reaching 43.7C yesterday afternoon.