The Great Barrier Reef is now dying faster than scientists can document.

Just a month ago, in the prestigious journal Nature, the team from the Australian Research Council Centre of Excellence for Coral Reef Studies published the results of their work, recording the damage from last year’s disastrous coral bleaching of the northern third of the reef.

The journal article makes for frightening reading. More than two-thirds of the coral on one 300-kilometre-long section of the reef is dead. On the worst-affected reefs, mortality was as high as 99 per cent.

In addition, more than a quarter of corals along another 600 kilometres of reef died in 2016. Then, this summer, the reef bleached again.

“That Nature article came out on March 16,” says Professor Terry Hughes, director of the centre and lead author of the article. “That was two days after I had started the new survey of this year’s bleaching. We can’t actually publish our research fast enough before we’re out again measuring the next bleaching event.”

The empirical evidence of more frequent and severe damage to the world’s reefs is overwhelming, as is the evidence that emissions of carbon dioxide from the burning of fossil fuels is the cause of it.

This year it happened further south, although there was some overlap with the areas that bleached last year. From Cooktown down to Townsville, and also around the Whitsunday Islands, at least 60 per cent of the corals on most reefs were bleached.

It’s too early to assess mortality from this summer’s bleaching. It takes months before it can be determined whether bleached corals will recover or die. It won’t be until about this time next year that we get the definitive account of the destructiveness of this year’s event. By which time we may well be in the middle of the next.

We can’t be sure of that, of course. The occurrence of two mass bleachings on the Great Barrier Reef in successive years was unprecedented. Maybe next year the reef will be spared. We can be pretty sure, however, that it will happen again long before the reef can recover.

Not only in Australia but around the world coral reefs are suffering more frequent and more extensive occurrences of bleaching and death. The cause is climate change.

Indeed, the world’s coral reefs provided some of the earliest and most definitive evidence of the risks of a warming climate, and of the need for action.

That’s because corals are extremely sensitive to temperature change. If the water gets just a couple of degrees warmer than usual, they expel the microscopic algae (zooxanthellae) that live in their tissues and give them their colour as well as producing most of the energy they need to survive. The corals turn white.

If the heat stress is not too extreme or protracted, they may regain their zooxanthellae and colour, and resume their symbiotic relationship. If not, they die, with consequent effects on the rest of the reef ecosystem.

Forty years ago, mass coral bleaching was an unknown phenomenon.

“The first mass bleaching – by which I mean bleaching at 1000 kilometres-plus scale – occurred in the early 1980s, predominantly in the Caribbean and eastern Pacific,” Hughes says.

“That event caused a big stir in the reef science community … because no one had ever seen anything like it. It coincided with record-breaking temperatures, and even back then scientists who had been studying reefs for decades said, ‘This is global warming, and we’re likely to see more of these into the future.’ So that awareness goes back to the early 1980s.”

But the enormity of what was happening did not attract the attention of the broader community, particularly the Australian community, until the summer of 1997-98, with the first global, or as the reef scientists say, “pan tropical”, bleaching.

It was a strong El Niño year – the effects of global warming are exacerbated by El Niños – and reefs in many places throughout the world bleached. So did about 50 per cent of the Great Barrier Reef.

There have been two more global mass bleachings since then: one in 2010, and the biggest yet, a rolling series of catastrophic events affecting reefs all around the world from 2014 to this year.

None of these global bleachings affected all reefs at the same time. The 2010 event largely missed the Great Barrier Reef, although the reefs off Western Australia were damaged.

There also have been many more regional instances. The second mass bleaching of the Great Barrier Reef, which affected about 60 per cent of corals in 2002, for example, was not part of a global event.

The empirical evidence of more frequent and severe damage to the world’s reefs is overwhelming, as is the evidence that emissions of carbon dioxide from the burning of fossil fuels is the cause of it.

Our prime minister, Malcolm Turnbull, is well aware of that. In fact, he has been aware of it for a long time. As minister for the environment in the Howard government in 2007 he wrote the foreword to a “Climate Change Action Plan” for the Great Barrier Reef Marine Park Authority, identifying climate change as “the greatest long-term threat to the Great Barrier Reef”.

The crisis has grown more serious since then, even as Turnbull has become a great deal less serious about addressing it. He has reversed his previous support for putting a price on carbon emissions and campaigns opportunistically against renewable energy.

This week Turnbull was in India, negotiating a deal to export billions of tonnes of Australian coal to be burned in power plants there. He met Gautam Adani, founder of the company that wants to build Australia’s biggest coalmine in the Galilee Basin in central Queensland. They discussed Adani’s request for a $1 billion concessional loan from the government so it can build a rail line to Abbot Point and ship 60 million tonnes of coal a year for 60 years through the waters of the reef its business is killing.

That meeting was on Monday, the same day I spoke with Terry Hughes.

“Nearly every other World Heritage property that is a reef – I think there are 26 of them – has bleached in the last three years,” Hughes says.

The trend is obvious, but individual instances of bleaching are unpredictable, because there are many variables.

Last year’s bleaching of the northern reef, for example, was an ecological disaster of unprecedented proportions, but might have been even worse had it not been for the arrival in early March of the remains of cyclone Winston.

“Winston’s wind, cloud cover and rain brought the temperature in the southern part of the reef down 3 degrees Celsius,” Hughes says. “And that’s what rescued the southern part. Without it we would have had bleaching the whole way along the reef.”

A few months later Pauline Hanson and other One Nation senators went diving on that southern, unbleached section of the reef. When they came up, she claimed her tiny personal experience proved the scientists wrong. She pronounced the whole reef to be in good health.

“We can’t have these lies put across by people with their own agendas,” she said.

Whether Hanson is delusional or just cynical is hard to say. The reality is the scientists had explicitly said the southern third of the reef had been spared, and they had explained why. Her pronouncement amounted to the denial of a claim that had never been made.

Hanson is, however, far from the only politician to attempt to mislead the Australian people about the state of the reef and what is being done to protect it.

Before we get to them, however, more of the science. It’s depressing. Even discounting global warming, the Great Barrier Reef has long been stressed by human activity. It has been stressed by sediment from the dredging of ports, by fertilisers and pesticides in the runoff from farms, by commercial and recreational fishing, coastal development and human-induced changes to the ecological balance, such as greater predation by the crown-of-thorns starfish.

When it comes to bleaching, though, Jon Day, a former director of the Great Barrier Reef Marine Park Authority, says the government response is a “con job”.

An example: the same day Pauline Hanson conducted her scuba-diving mission to prove there was no problem, the federal minister for the environment and energy, Josh Frydenberg, was spruiking “joint action” by the federal and Queensland governments to save the reef “through the reef 2050 Plan which involves 151 separate action items”.

Many of these are Band-Aid measures. The one Frydenberg emphasised that day was a $45 million agreement to improve the reef’s water quality by reducing soil erosion.

But the parts of the reef most damaged by the 2016 bleaching were not significantly affected by soil erosion, or fertilisers or dredging or any of those other human activities that had degraded the southern and central sections. They were, Day points out, the most pristine parts of the reef. What is happening to the Great Barrier Reef, says Hughes, amounts to “a gigantic experiment in natural selection”.

He explains: “Already in that northern part of the reef the gene pool of a year ago is very altered, because the more thermally sensitive corals have been thinned out, and the more tolerant ones are more prevalent.”

The fact that the bleaching in the north was not as bad this year is not necessarily a good news story: the likely reason is that “the sensitive corals are already dead”.

Meanwhile, further south, in the central region of the reef, where only about 7 per cent of corals died from the 2016 bleaching, those that remained were more vulnerable when the water got hot again this year.

“When a coral bleaches, even if it survives and regains its colour after a few months, it’s physiologically weakened,” Hughes says. “They don’t reproduce as well and they typically grow more slowly for several years after they’ve been bleached.”

As the Nature article said, even fast-growing coral species that are good colonisers need 10 or 15 years to recover. But when other long-lived corals die from bleaching, their replacement will necessarily take many decades.

Corals have adapted to changes in climate over hundreds of millions of years. In the case of the Great Barrier Reef, says Hughes, “we saw how reefs reassembled themselves at the end of the last Ice Age when water depth changed and corals invaded what had been dry land. We don’t, however, have a very good idea of how long that adaptation takes.”

Self-evidently, though, it takes much longer than the few decades we have allowed the world’s coral reefs, which is why they are dying.

And the knowledge that coral will adapt eventually to human-induced climate change, Hughes says, will not help people or industries dependent on the reef. “We should actually deal with the elephant in the room,” he says, “which is climate change.”

So long as we keep burning fossil fuels and pumping carbon dioxide into the atmosphere, so long as the world keeps getting warmer, reefs will continue to die.

“Yet we have Turnbull in India this week and [Queensland Premier Annastacia] Palaszczuk was there last week. Both the Commonwealth and the state seem hell-bent on promoting the Adani coalmine,” Hughes says.

“That’s hardly a meaningful response to the back-to-back bleachings.”

In India, Turnbull continued to peddle the fiction that the Adani mine would create “tens of thousands of jobs” in Australia.

The true number is far less. Under oath before the Land and Environment Court, Jerome Fahrer of ACIL Allen Consulting, who did the modelling for Adani, said the project would create just 1464 direct and indirect jobs.

That still seems like a fair few, until you compare it with the 69,000 people whose jobs depend directly or indirectly on reef tourism, which also generates about $7 billion annually.

While Malcolm Turnbull was away in India, negotiating with the head of a company with a well-documented history of human rights and environmental abuses, bribery, corruption and tax avoidance, Barnaby Joyce was acting prime minister. He went on a furious round of media interviews, talking up the Adani project.

When asked in one interview about its impact on the reef, Joyce responded: “If you walk out across the grass, you’re going to have some sort of environmental impact. If you build a house where there would have been grass, there’s an environmental impact.”

If you spent too much time worrying about such matters, he said, you got nothing done.

In another interview, he issued an obscure warning to those opposed to further expansion of the fossil fuel industry: “If you live with the butterflies, you will die with the butterflies.”

In both interviews, he made it clear his main consideration was, as he put it, “to make a buck”.

Joyce’s dismissal of an impending tragedy of the commons, the loss of the greatest repository of marine diversity on the planet, really says all you need to know about our government.

As Terry Hughes says: “The coral reef crisis won’t be averted by biologists trying to fix the reef by killing crown-of-thorns starfish, or breeding more resilient corals in aquaria, or various other Band-Aid solutions.

“It’s all about what we can do internationally, institutionally and in terms of legal frameworks and changing people’s behaviour.

“The coral reef crisis is actually a crisis of governance.”