Australia's 'catastrophic' future laid bare: 50C days, mass livestock deaths

A map showing the increase in dangerous fire weather days across Australia. Graphic / BOM

Regular 50C days in Sydney and Melbourne; once-in-a-century floods every year; mass deaths of livestock; tropical diseases invading Australia's major cities and a quarter of a million homes under water.

Climate scientists have laid out a "catastrophic" future for Australia, with the weather "flipping on its head".

It now looks "virtually impossible" the world will meet a goal of keeping average temperatures to 1.5 per cent above pre-industrial levels, say the authors of a new report.

A far more likely scenario is that global temperatures will soar by up to 3C.

"If we continue on our merry way in terms of substantial greenhouse emissions then we go into a 3C future which looks grim for Australia," said the director of Australian National University's Institute for Climate Energy and Disaster Solutions, Professor Mark Howden.

He is a co-author of the new report from the Australian Academy of Science (AAS) looking at what that a 3C rise could mean for Australia.

Released today, the paper has called on the Australian government to fast-track its move to become a net zero greenhouse gas emitter within the next two decades.

Flooding in Taree, NSW in March. Photo / Supplied

That's a big ask. Coal – one of Australia's biggest carbon emitters – makes up 56 per cent of all domestic energy generation.

Yet the scientists have insisted that Australia can meet its climate goals without seeing a dire economic impact. Better "a planned transition" to a low-carbon Australia, they say, than a "disorderly collapse".

Targets missed

Australia has a target to reduce greenhouse gas emissions to 26–28 per cent below 2005 levels by 2030, and Prime Minister Scott Morrison has said a goal is to achieve net zero emissions "preferably by 2050".

But the country has been consistently criticised for not having enough ambition or taking the necessary steps towards a low-carbon future.

The Paris Agreement, signed by Australia, aims to limit global warming to "well below 2C" compared to pre-industrial levels, with 1.5C a more ambitious goal.

Neither aim is being achieved. Australia's average surface temperatures have actually gone up by 1.44C since records began in 1910, and there's little sign of that rise stopping.

"Limiting greenhouse gases to 1.5C is now virtually impossible and a rapid transition to net zero emission is required of the international community to limit warming to well below 2C," said University of Queensland Professor Ove Hoegh-Guldberg, another of the report's authors.

Grim outlook

The report states that just sticking to current climate commitments by governments worldwide would see temperatures rise by 3C by 2090.

Letting that happen "could have potentially catastrophic impacts", say the authors, who have laid out depressing lists of the consequences of a 3C future.

Australia would be "warmer and drier with more frequent and violent extremes [of weather]".

One-in-100-year floods, like the ones just experienced, would be annual events. Huge bushfires would be frequent occurrences.

"The whole understanding of Australia's climate will flip on its head," Howden said.

"What used to be thought of as extremely hot years will be cool years in the future."

The average number of days each year above 35C in Sydney could quadruple by 2090. In Melbourne, 24 days could be above 35C compared to 11 now, and in Perth hot days could leap from 28 to 63.

But it's Darwin that could cop it the worst. It generally sees 11 days above 35C annually. With 2C of climate change, that could go up by 10 times to 111 days, or as many as 265 days under a 3C scenario.

Heatwaves in Queensland – that being under 1.5C of warming occurring three times a year and lasting for around seven days – would happen seven times annually and last 10 days under a 3C scenario.

The report suggests Melbourne and Sydney could regularly see 50C days. Already, Sydney's west has seen the mercury nearly touch that figure, leading it to be called out by the United Nations.

Wildfires burn in East Grippsland, Victoria state, in December 2019. Photo / AP

In northern Australia, "every day in the future may be a heat stress day", Howden said.

That in turn could lead to "challenging" conditions for livestock, with many perishing in the stifling heat. The humans tending them wouldn't be much better off.

Yields of key crops such as oil seeds, wheat, fruit and vegetables could plummet as they wilt in the sun or get wiped out by floods.

Infectious disease could flourish. The Ross Rover virus, which can lead to flu-like symptoms and linger for months, could find its way further south carried by mosquitoes.

The Great Barrier Reef, which is already suffering, will bleach further in a 3C Australia. Rain forests such as the Kakadu could be "unrecognisable".

An estimated 160,000 to 250,000 Australian properties might be at risk of coastal flooding with a sea level rise of 1 metre by the end of the century. Some homes would become uninsurable and one in 19 property owners will face the prospect of insurance premiums that will be effectively unaffordable by 2030.

"It's not too late to avoid 3C," said Professor Hoegh-Guldberg.

"We should still be aiming for a stable global temperature below 2C but to get that point we must reduce emissions very rapidly."

What should be done

There are 10 actions the report recommends Australia knuckle down on. One of the main ones is a big swerve away from coal and investment in renewables and battery technology to store energy.

Retraining people working in the fossil fuel energy industry, scaling up technologies that have less of an impact on emissions – such as electric vehicles – and preparing food production and supply chains for climate extremes are other recommendations.

Some of the worst aspects of a 3C warmer Australia might also be mitigated. Simply planting trees on suburban streets, for example, can bring surface temperatures down.

And the researchers insists it's not all global warming gloom.

Australia could become a "clean energy exporter and a global renewable energy superpower", adding to the country's coffers.

Indeed, the biggest cost would be to do nothing, states the report, given much of the world is already reducing its reliance on carbon.

"This is the most critical, transformational decade the human race has probably ever faced," said Professor Lesley Hughes of Sydney's Macquarie University.

"We must emphasise to government that delay is as damaging as denial. Just doing things slowly is just as bad as not doing them at all."