“You’ve got to remember the rainfall of Tamworth is about the annual rainfall of Riyadh in Saudi Arabia,” Barnaby Joyce said on ABC Radio National on Tuesday.

“The gum trees are dying.”

Disgraced and out on his bum just months ago, the former Minister for Agriculture and Water Resources was going hard. After last week’s destructive chaos in Canberra, Joyce found himself partly re-appointed as “drought envoy”.

Joyce wasted no time bulldozing back into very complex Murray Darling Basin irrigation issues, suggesting water set aside to keep the river and the countryside alive should instead be diverted to drought assistance.

“If you have a bushfire they don’t knock on your door and say ‘can I borrow your bulldozer?’” Joyce said. “They just take it because it’s a national emergency … now this as far as I’m concerned is a national emergency … we have billions of dollars of environmental water going past the irrigation properties that could grow the fodder to keep the cattle alive.”

Nobody doubts that these are profound issues which need to be addressed. Australia is a very big, dry old continent with a booming population that depends largely on the Murray Darling Basin for food, fodder, fibre, milk and, er, wine.

The next morning, Professor Richard Kingsford, director of ecosystem science at the University of New South Wales, gave Radio National another angle.

“It’s currently not legal to do that,” he said in response to Joyce’s suggestion.

“The Water Act would need to be changed … to give you some idea we’ve got about 10 Sydney Harbours of water sitting in storage, most of which is owned by the irrigation industry … so there’s lots of water there.

“Obviously we’re all concerned about the drought but in fact a lot of this environmental water is actually growing pasture for cattle on flood plains.”

As this drought rubs raw the challenges we face growing the stuff that we need to eat, drink and wear, most Canberra-transfixed media missed last week’s confronting paper in the world’s “leading journal of original scientific research”, Science. In the paper – titled The Paradox of Irrigation Efficiency – 11 scientists and economists from eight countries and seven universities had showed that the attempts of many governments to increase irrigation efficiency “typically reduces the amount of water available for reallocation”.

In other words, we’ve got it all wrong.

This is the sort of science that puts the theories of the Barnabies into a much more scary perspective. This science should be foremost in the national mind.

Quentin Grafton, Global Water Forum executive editor and professor at Australian National University, and his colleague Professor John Williams, spoke on behalf of the paper’s international authors.

“Drought in Eastern Australia, heatwaves in Europe, water riots in India and raging fires in California are a symptom of a planet where water, or the lack of it, is generating a crisis” they summarised in their article Five steps to avoid a global water tragedy.

“Our research responds to the unfolding global water tragedy by demonstrating that increases in irrigation efficiency, in general, reduce surface run-off and groundwater recharge to the detriment of people, the environment, and our future.”

In recent years, Australia has spent billions restoring environmental flows, including a very large stack of money increasing irrigation efficiency to ensure there is less “waste”.

Irrigators, responsible for about 70 per cent of the planet’s freshwater extractions, tend to view any inland water that eventually reaches the ocean as “wasted”.

Grafton and his colleagues found that once public money is given to improve irrigation efficiency, farmers across the world either apply more water to extant crops to increase yields or they change to more lucrative crops that require more water. They then expand the total area of their irrigated regions to use the water they’ve saved. All this simply reduces groundwater replenishment and exhausts return flows of water available for reallocation for use by downstream farmers and the environment.

“Countries that claim to have the world’s best water practice – like Australia – need to stop wasting money by subsidising increases in irrigation efficiency that are reducing, not increasing stream flows,” the summary states.

“But the key here is water accounting,” Grafton said.

Speaking on a podcast with professor Sarah Wheeler of the Centre for Global Food and Resources at the University of Adelaide, Grafton insisted that all five recommendations should be implemented.

“That’s not about balancing numbers on a spreadsheet … it’s about knowing what’s happening to inflows: precipitation, stream flows … extractions by irrigators and others,” he said.

“We have to know what happens to water when it’s used by irrigators – subsoil and subsurface recharge surface run off… and then we need to know where those flows go … some critical parts to that we don’t know in the Murray-Darling Basin.”

Grafton was hopeful that the South Australian Government’s embattled Royal Commission would assist in discovering some of these details.

He said the Australian Government had spent $3.5 to $4 billion so far on off-farm and on-farm irrigation efficiency improvements, among other vast expenditures, and wisely suggested that we stop spending until we know what’s going on.

“We need to account for the change in irrigation efficiencies associated with the subsidies we’ve spent to acquire water entitlements,” he said.

“We don’t have that. We don’t know that information … we’ve got to have an independent comprehensive audit of the Murray Darling Basin … it seems very straightforward to me that you would want to have that if you’ve spent billions of dollars … you’d want to spend a little bit of time and a little bit of effort actually working out what’s happened.”

Whatever side one takes, this entire argument has at its cornerstone the presumption that all this water is used for feeding humans directly or feeding the animals humans eat, shear or milk.

In such troubled and threatening times nobody dare ask how much water, a vital gastronimic item in itself, should go to the production of ethanol, an addictive depressant which adds billions to our national health, crime and traffic accident costs.

We call it wine, which, with a few fine print back label warnings, we often sell for the price of bottled water. Goonbag. Alley juice. It’s like buying the water in two, four, five or 10-litre plastic bladders with some sugar and 12 to 15 per cent ethanol included for free.

While we can’t possibly consume all the wine we grow and refine, government encourages entire communities to depend on us exporting this stuff, each litre of which uses about 1200 litres of water in growth and manufacture.

Recent grape prices show a glimmer of relief, but many growers go for years with barely a cent of profit.

Until last week’s political ructions, South Australia’s Riverland-based Liberal senator Anne Ruston was Assistant Minister for Agriculture and Water Resources.

“I spent two years as his (Joyce’s) Assistant Minister,” she told ABC Radio Adelaide today, defending her disgraced and now resurrected former boss.

“Having seen him operate in rural and regional areas, his understanding, his empathy with the farmers, his ability to sit down in the front bar of the pub and just spin a yarn … people want to talk to Barnaby.”

It might not surprise us that arid land irrigators and broken, drought-baked farmers like a bit of chat and a beer in the pub, especially with a Deputy Prime Minister who shovels out government money and writes revealingly of his own philandering, booziness and blokey-ness. They’d likely prefer spending their time at the pub with him, or maybe reading his book, than struggling to read reports like this scary paper in Science.

They obviously vote for folks like Joyce and their local Ruston, who seems mystified at the new Prime Minister removing her agriculture and irrigation responsibilities to make her Assistant Minister for International Development and the Pacific, a fairly large ocean which contains a helluva lot of that water many regard as wasted.

“It doesn’t matter what portfolio I’m in, the River Murray will always be my number one priority,” she reassured.

Backing her up, Joyce tweeted: “I am so excited about helping further with the drought. This is so important. Let’s combine all that knowledge for a better outcome.”

No doubt the rivers will also remain a priority of Grafton and his colleagues, whose knowledge these two politicians should surely combine.

Kingsford said: “Joyce should have been aware that his simplistic approach, apart from the environmental issues, raises legal equity and economic issues … he talks about eucalypts dying up near Tamworth. There’ve been river red gums dying in their thousands on our river systems because they’re not getting enough water.

“Let’s not forget the millenium drought lasted for six or seven years. We’re nowhere near that sort of drought yet.”

drinkster.blogspot.com