When the river runs dry: megadroughts on the cards in Australia, new report warns

The cracked bed of a water canal between Pooncarie and Menindee (AAP)

The cracked bed of a water canal between Pooncarie and Menindee Source: AAP / DEAN LEWINS

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Australia could soon see megadroughts that last for more than 20 years, new modelling suggests. The bleak research from the Australian National University and the ARC Centre of Excellence for Climate Extremes has found these droughts could be worse than anything else in recent historical experience.


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TRANSCRIPT

For the past 24 years, the south-west region of the United States has been in drought.

Colby Pellegrino is the Deputy General Manager of Resources at the Southern Nevada Water Authority.

“We talk about drought as being the slowest moving freight train as far as natural disasters are concerned... This drought began in 2000, and since that time the water level has dropped about 160 vertical feet. So if you look out here where the water level is today, if you were here in 2000, it'd be about at the bottom of these rocks filling this entire area with water.”

New research is suggesting that these kinds of megadroughts could one day happen here.

Climate modelling from the Australian National University - and the ARC Centre of Excellence for Climate Extremes - says megadroughts are part of the natural variations of Australia's climate - but that climate change is making the prospect of such an extreme event more likely.

Dr Georgina Falster from the ANU is the lead co-author.

“We used a lot of climate models to look into what we can expect from Australian droughts in the future... On the one hand we found the possibility for naturally occurring megadroughts that can last for multiple decades. But then on the other hand we also have climate change which is tending to make droughts longer, particularly in southwestern and eastern Australia - and it's also making droughts more severe, because of the hotter temperatures.”

The ANU report has recommended urgent action be taken to rapidly reduce greenhouse gas emissions, and transition as soon as possible to renewable energy sources.
Prime Minister Anthony Albanese says Australia is already leading the charge on that front.

“A vision for Australia that sees renewable energy powering advanced manufacturing here to produce more in Australia. Powered by clean energy, positioning ourselves to be a renewable energy superpower for the world. That's my Government's vision.”

The research has also found that parts of Australia are already experiencing longer droughts because of climate change -including the Murray-Darling Basin - could expect future rainfall declines.

The report has also recommended Australia be prepared with water storage and management plans.

Environment Minister Tanya Plibersek says that's exactly what the updated Murray Darling Basin plan is for.

“We can't stand by and allow our threatened species, our rivers, our wetlands, and the three million people who rely on this river system for their drinking water to be unprepared for the next dry period.”

Not everyone has agreed that the updated plan will achieve its goals.

The Opposition's Perin Davey says she's not sure it's going to be as effective as it needs to be.

“One thing we know: climate change will see an increase in the extremes; more floods and more droughts. But when there's a drought - when there is no rain - it does not matter how much water you hold in licenses because that water is not there. What has seen us get through droughts in the past, including the Millennium Drought - and we know how devastating that was - but was the ability to capture the minimal inflows at the time in dams and manage the releases. This basin plan does not propose and this amendment does not propose any infrastructure that will help us manage for those extremities.”

Farmers like Barossa Valley grape grower Greg Knight remain concerned about the lack of rainfall, and how water will be allocated.

“We are totally reliant on weather and climate here. We have some supplementary water available via dams, but its only minimal. We may be able to influence it by ten to twenty per cent at the best.”

Indigenous groups are also worried that their knowledge about how to look after the river has not fully been listened to.

Barkindji community leader Owen Whyman has told SBS that the river system in New South Wales has huge cultural significance to them - and it's still not healthy.

“You talk about fish kill. It's becoming a regular thing; it's happening again already. There's a blue algae alert out up at Menindee about the blue green algae.”

But South Australia's Deputy Premier and Climate Minister Susan Close has maintained that the updated Murray Darling Basin plan is going to help everyone.

“This isn’t a matter of political pride... This is about delivery of a sustainable Murray-Darling Basin. Because just as we’ve seen floods we will next see a drought. And if we’re not ready for that drought, all South Australians and all Australians will suffer for that. The only way to ward off the worst effects of drought is to have water allocated to the environment to keep it healthy during tough times.”

Australia has had around 10 severe droughts since the 1860s, including the Millennium Drought, which ran from 2001 to 2009.

Dr Falster says she remembers what that was like - and how much damage it caused to the Murray Darling region.

“I am from South Australia. I grew up through the Millennium Drought, and I remember we had very heavy water restrictions down in Adelaide. The Murray River pretty much stopped flowing by the time it got to the South Australian border. The Murray mouth closed - and they were sort of dredging for almost a decade afterward. And there were a lot of impacts to the native plants and animals that rely on that river, on the rivers through the Murray Darling Basin.”

Dr Falster says her research is accordingly both a warning - and an opportunity.

“It is scary. The word megadrought is concerning. But the reason that we do and publish research like this is that so we know these megadroughts are a possibility - which means that we can be prepared in case one happens.”


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