The small Queensland town of Eromanga bills itself as Australia’s town furthest from the sea. But this week, an ocean of freshwater arrived.
Monsoon-like weather has hit the normally arid Channel Country of inland Queensland. Some towns have had two years’ worth of rain in a couple of days. These flat grazing lands now resemble an inland sea.
One New South Wales man is still missing and dozens of people have been evacuated. Others are preparing to be cut off, potentially for weeks. And graziers are reporting major livestock losses – more than 100,000 and climbing. In some areas, the flooding is worse than 1974, the wettest year on record in Australia.
Why so much rain? Tropical, water-laden air has been brought far inland from the oceans to the north and east. This can happen under normal climate variability. But our ocean temperatures are the highest on record, which supercharges the water cycle.
In coming weeks, this huge volume of water will wend its way through the channels perhaps 600 km to fill Kati Thanda-Lake Eyre, the ephemeral lake which appears in the northern reaches of South Australia. It’s likely this will be a Lake Eyre for the ages.
In the first three months of the year, deadly record-breaking floods hit northern Queensland before Cyclone Alfred tracked unusually far south and made landfall in southeast Queensland, bringing widespread winds and rains and leaving expensive repair bills. Now the rain has come inland.
Why so much rain in arid areas?
Some meteorologists have dubbed this event a pseudo-monsoon. That’s because the normal Australian monsoon doesn’t reach this far south – the torrential rains of the monsoonal wet season tend to fall closer to the northern coasts.
Because the Arafura and Timor Seas to the north are unusually warm, evaporation rates have shot up. Once in the air, this water vapour makes for very humid conditions. These air masses are even more humid than normal tropical air, because they have flowed down from the equator. Many Queenslanders can vouch for the intense humidity.
But there’s a second factor at work. At present, Australia’s climate is influenced by a positive Southern Annular Mode. This means the belt of intense westerly winds blowing across the Southern Ocean has been pushed further south, causing a ripple effect which can lead to more summer rain in Australia’s southeast, up to inland Queensland. This natural climate driver has meant easterly winds have blown uninterrupted from as far away as Fiji, carrying yet more humid air inland.
Many inland rivers in Queensland are in major flood (red triangles) as of April 1.Bureau of Meteorology, CC BY
These two streams of converging humid tropical air were driven up into the cooler heights of the atmosphere by upper and surface low pressure troughs, triggering torrential rain over wide areas of the outback
While these humid air masses have now dumped most of their water, more rain is coming in the aftermath of the short-lived Cyclone Dianne off northwest Australia. These rains won’t be as intense but may drive more flood peaks over already saturated catchments.
This is why it has been so wet in what is normally an exceptionally dry part of Australia.
What is this doing to the Channel Country?
Many Australians have never been to the remote Channel Country. It’s a striking landscape, marked by ancient, braided river channels.
Even for an area known for drought-flood cycles, the rainfall totals are extreme. This is a very rare event.
People who live there have to be resilient and self-sufficient. But farmers and graziers are bracing for awful losses of livestock. Livestock can drown in floodwaters, but a common fate is succumbing to pneumonia after spending too long in water. After the water moves down the channels, it will leave behind notoriously boggy and sticky mud. This can be lethal to livestock and native animals, which can find themselves unable to move.
Where will the water go next?
Little of these temporary inland seas will ever reach the ocean.
Some of the rain has fallen in the catchment of the Darling River, where it will flow down and meet the Murray. The Darling is often filled by summer rains, while the Murray gets more water from autumn and winter rains. This water will eventually reach the Southern Ocean.
But most of the rain fell further inland. The waters snaking through the channels will head south, flowing slowly along the flat ground for weeks until it crosses the South Australian border and begins to fill up Kati Thanda-Lake Eyre. Here, the waters will stop, more than 300 km from the nearest ocean at Port Augusta, and fill what is normally a huge, salty depression and Australia’s lowest point, 15 metres below sea level.
When Kati Thanda-Lake Eyre fills, it creates an extraordinary spectacle. Millions of brine shrimp will hatch from eggs in the dry soil. This sudden abundance will draw waterbirds in their millions, while fish carried in the floodwaters will spawn and eat the shrimp. Then there are the remarkable shield shrimps, hibernating inland crabs and salt-adapted hardyhead fish.
It’s rare that Kati Thanda-Lake Eyre fills up – but when it does, life comes to the desert.Mandy Creighton/Shutterstock
The rain event will send enough water to keep Lake Eyre full for many months and it usually takes up to two years for it to dry out again. We can expect to see a huge lake form – the size of a small European country. Birdwatchers and biologists will flock to the area to see the sight of a temporary sea in the desert.
Eventually, the intense sun of the outback will evaporate every last drop of the floodwaters, leaving behind salted ground and shrimp eggs for the next big rains.
As the climate keeps warming, we can expect to see more sudden torrential rain dumps like this one, followed by periods of rapid drying.
Steve Turton has previously received funding from the federal government.
New Zealand’s North Island features a number of geothermal systems, several of which are used to generate some 1,000 MegaWatts of electricity. But deeper down there may be even more potential.
Supercritical geothermal is hotter and deeper than conventional geothermal sources. It targets rocks between 375°C and 500°C, close to – but not within – magma.
Water at these temperatures and depths has three to seven times more energy for conversion to electricity, compared to ordinary geothermal generation at comparatively cooler temperatures of 200°C to 300°C.
The investment is staged, with $5 million earmarked for international consultants to design a super-deep well, and further funds to be released later for drilling to depths of up to six kilometres. Consultation is underway, with resources minister Shane Jones hoping to convince M?ori landowners to collaborate.
New Zealand already produces 1,000MW of electricity from conventional geothermal sources.Shutterstock/Chrispo
GNS Science estimates the central North Island might have about 3,500MW worth of this resource, although actually accessing it might be difficult and expensive. The energy consulting firm Castalia was engaged to predict how much would be worth developing, suggesting between 1,300MW and 2,000MW, starting from 2037.
This would be a lot of extra power. Even better, it would reduce the peaks and troughs in generation that arise from more variable solar and wind sources, which are expected to make up a growing share of electricity generation in the future. Supercritical geothermal is reportedly cost effective, which means the technology deserves serious consideration. But such claims should be subject to scrutiny.
But New Zealand has a healthy geothermal industry. In the past two decades, geothermal companies have invested $2 billion in hundreds of new wells and new power plants. The industry already knows how to drill wells and profit from them. So why is the government stepping in now?
In practice, supercritical geothermal exploration and development faces several research, technical and economic risks. Private enterprise seems unwilling to bear them alone, prompting the government to step in to establish feasibility.
How to crack soft rock
One problem supercritical geothermal might encounter is that drilling deeper might find lots of hot rock, but not much water. Drilling experiments in Japan and Italy have shown that reaching 500°C is possible, but in both cases the rock was so ductile (pliable and easily stretched) because of the high temperatures that it couldn’t keep open the gaps needed for water to flow.
However, the experience was different in Iceland where two wells managed to find water above 400°C. At this stage, it’s not clear whether this is because Iceland has special rocks – particularly basalts, which are less ductile – or because the country is being stretched through tectonic forces at a high rate. New Zealand is less able to count on basalts but it does experience rapid tectonic stretching.
Deep drilling would test this key hypothesis: is there permeability (gaps for water to flow through) at supercritical conditions? The only way to know for sure is to drill down.
If there isn’t permeability, the government could either abandon the investment or look into methods to create it. Multi-stage hydraulic fracturing (“fracking”) is an option which has worked overseas in the North American shale gas industry. It has also recently been demonstrated in some US geothermal systems.
Even if we did find permeability, the water produced in Iceland’s supercritical wells was enormously corrosive. A better option then might be to inject cold water into the well, suppressing the corrosive fluids. The injected water would heat up and rise into the overlying geothermal system – flushing the heat upwards.
However, both water injection and fracking can trigger earthquakes, perhaps a magnitude 4-5 every year or a magnitude 5-6 every few decades. This happened in 2017 in Pohang in South Korea where water injection triggered a magnitude 5.5 earthquake. It resulted in the cancellation of the geothermal project.
But there are many other geothermal projects where injection has not led to concerning earthquake activity.
Fierce competition from solar, wind and batteries
The other risk is economic. Supercritical geothermal might one day be technically feasible, but its potential contribution in New Zealand will be limited if it can’t beat other generation technologies on cost.
Worldwide, the renewable energy sector continues to be disrupted by unprecedented cost decreases driven by innovations in utility-scale battery storage and solar photovoltaics.
But the supply chains are largely overseas, mostly concentrated in China. This adds geopolitical complexity to the energy security calculus. Homegrown solutions are a strength.
Nevertheless, the International Renewable Energy Agency reports cost reductions for solar and battery modules of 89% and 86% between 2010 and 2023. Solar costs drop 33% each time the built amount doubles. Drops in battery cost are enabling large deployments for daily smoothing of the peaks and troughs of intermittent solar and wind generation.
This shifting cost landscape creates financial uncertainty for energy investors. While cost declines might not continue forever, it’s hard to pick when they will level off. Meanwhile, geothermal costs have been flat for a long time. A billion-dollar geothermal investment might quickly become uncompetitive.
Despite all these caveats, we shouldn’t overlook the positive signal of the government taking a bet on New Zealand science and innovation. It will be exciting to see what’s happening at six kilometres of depth underground. And although the plan is not to drill for magma, an accidental strike (as happened in Iceland) would lead to some amazing science.
Lastly, energy security deserves to be taken seriously over the long term. While supercritical geothermal won’t fix our immediate vulnerability to winter scarcity, it could help avoid similar issues in the 2040s.
David Dempsey receives science funding from MBIE for research into geothermal energy.
The north Queensland city of Townsville would “almost certainly” surpass its annual rainfall record this week, just three months into 2025, according to the Bureau of Meteorology’s senior meteorologist, Jonathan How.
In the dusty Queensland channel country, those old enough to remember still talk about the 1974 outback floods. For more than 50 years that has been the ultimate measuring stick for every downpour or trickle to flow through the central desert towards Kati Thanda-Lake Eyre.
On Sunday, in the tiny town of Jundah, in the heart of Queensland’s outback, the flood waters in some places measured 50cm higher than in 1974. Most of the town (including the pub) is still inundated. Surrounding towns are cut-off and could be isolated for weeks.
Anthony Albanese has confirmed the federal environmental protection agency he has promised to establish if elected would not be “the same model” as the one he promised but failed to legislate during this term of government.
In his first public comments about reviving the nature watchdog plan, Albanese confirmed Labor would pursue a different model in consultation with the states, industry and environmental groups.
The operators of Cadia goldmine have been ordered to pay $350,000 in fines and convicted of three offences after a prosecution by the New South Wales Environmental Protection Authority.
Cadia Holdings Limited, trading as Cadia Valley Operations, pleaded guilty to three offences under the environmental protection act relating to breaches of clean air regulations at the mine in central west NSW.
