Jack the Insider recently wrote in The Australian of the rising number of people who believe the Earth is flat, among other crazy conspiracy theories. Not so long ago I would have mocked, too. Indeed, I would’ve struggled to conceal my contempt. But now, as I am increasingly asked about such matters by apparently sane people, I politely reply that while I am still sure Neil Armstrong walked on the moon, I understand why people are questioning everything that authority tells them.

There is nothing more likely to produce a nut-case conspiracy theory than a real conspiracy – or something that appears awfully like a conspiracy. Unhappily, there are plenty of examples of these from recent history.

The Great Barrier Reef should be totally dead by now, and I am not talking about climate change bleaching. For 60 years the authorities have been warning us of supposedly devastating plagues of coral-eating starfish. The reef was supposed to have been fully consumed and digested by the 1970s, leaving in its wake a large galaxy of fat and happy starfish. When this failed to happen, the inevitable death of the reef was deferred until the ’80s, then the ’90s, and so on ad nauseam.

But today we have record high coral cover. To the discredit of our scientific institutions, they now claim there is too much coral and it’s apparently the wrong type. Readers should ignore the nonsense of doomsayers and rest assured: record high coral is good.

No Australian under 60 can remember a time when scientists were not predicting the imminent demise of the reef. Can you blame a north Queenslander for losing faith in reef-science institutions when they can see for themselves that the reef is well and quite wonderful? It is but a short step, then, to distrust those other scientists crying wolf – which sometimes seems to be almost all of them.

Yet there are many other cases where hyperbole by authority has bred popular distrust.

Irrespective of the efficacy of Covid-19 vaccinations in preventing serious disease, especially for older people, there now seems little doubt that vaccines are ineffective at preventing the spread of disease. A few months after the vaccination campaign started, there was strong data indicating that vaccination was not preventing transmission. But authorities, to this day, maintain the fiction.

In an answer to a recent parliamentary question from senator Ralph Babet, senator Katy Gallagher, representing the Health and Aged Care Minister, urged everyone to have their fifth dose and characterised this as a “community responsibility”.

It is also becoming clear that lockdowns and mask wearing are inefficient at preventing disease. Scientists such as eminent Stanford University medical professor Jay Bhattacharya, who co-authored the Great Barrington Declaration and argued early in the pandemic that lockdowns were likely to cause more harm than good, no longer are considered total pariahs, even among some of the staunchest pro-lockdown media. Bhattacharya has had his shadow ban on Twitter lifted and is now a widely sought-after guest on podcasts and other platforms.

So, the cat is out of the bag. There may be a problem with freedom of speech at the moment but it is not so bad that many people can’t see they were lied to, to coerce them to vaccinate, wear a mask and lock up their children. Can you blame these people for losing faith in authority or science institutions?

I could go on about the dubious science of bushfires, Murray-Darling water allocations, Queensland tree clearing, numerous commercial fisheries closures and a worrying number of medical issues.

But the problem is not that the institutions got it wrong about aspects of the Great Barrier Reef and Covid. It was right to worry about starfish plagues in the ’60s, when research was in its infancy, and there were good reasons initially to hope that vaccines would drastically reduce transmission.

The problem is that the authorities often have covered up their errors. People excuse mistakes, and certainly excuse a tendency for caution in times of crisis, but a cover-up can make the cancer of distrust metastasise.

The big worry, as Jack the Insider pointed out, is that if people believe the authorities have lied about the lunar landings, “then you will pretty much believe anything, including that the world is run by a cabal of Jewish bankers” or some other dangerous idea. Who cares if they think the Earth is flat – but will they get their children vaccinated against polio and rubella?

To regain trust, science institutions must admit their mistakes, encourage dissenters to speak freely and fund replication studies attempting to disprove the prevailing wisdom. Sadly, in the meantime, the Earth is looking flatter and flatter to many people.