Failed predictions

Some failed predictions about bleaching

Scientists have been predicting the end of the GBR since the 1960s, but its demise due to climate change/bleaching is a more recent fashion. One of the most spectacular failed predictions[1] occurred in a 2012 paper that was publicised in all the world’s major media outlets. The coral cover was at low levels after a couple of huge cyclones passed across the reef. The waves from the cyclones killed corals in an area bigger than Belgium and Holland – not huge by Australian standards, but still a fair bit of coral. The scientists stated

“ . . coral cover in the central and southern regions of the GBR is likely to decline to 5–10% by 2022. The future of the GBR therefore depends on decisive action.

This has been proven to be a ridiculous prediction. Not just a bit wrong – it is as wrong as it could possibly be. The coral cover in 2022 is roughly four times higher than this, and now at record levels. The only decisive action was by the coral – it grew back like it always does.

Going back further, the bleaching event in 1998 was a turning point in public debate about climate change. Before 1998, catastrophic human-caused climate change was an interesting hypothesis.

In 1999, a paper by a very eminent coral biologist appeared. It predicted, on the basis of climate models, that owing to increases in temperature attributable to climate change, mass coral bleaching would be occurring seven or eight times per decade by 2018 on all parts of the Reef (Hoegh-Guldberg, 1999).[2] The implication was that by 2020, the reef would be totally devastated by these events. But, in 2022, the reef has record high coral cover.

Another very eminent coral reef biologist, Professor Charlie Veron, who has been responsible for discovery of around 20 percent of all the species of coral, was also quoted (20 August 2018) on Australian television for predicting bleaching every year by 2015. He claims that his prediction has come true. The exact transcript of his comments is as follows[3]

PETER GRESTE (reporter): 30 years ago, he started seeing changes to the climate that made him very worried.

Back in the 1990s, you made some pretty dire predictions. What did you say?

CHARLIE VERON: I predicted by 2015, the carbon dioxide levels would be so high, that it would cause bleaching, practically every year.

PETER GRESTE (reporter): How did it feel to be right?

CHARLIE VERON: It felt horrible to be right. Scientists long to be right because that’s what their business is.

But, it’s all happened and the consequences of that, have turned out to be much worse than those predictions.

It’s exactly like me seeing my family slowly dying of something. It’s very grave-like.

The emotion in this comment is telling, and entirely understandable. The GBR is an exquisite and beautiful thing. People fall in love with it. But Veron’s is an extraordinary claim.

The reef has not been devastated by bleaching. And it has turned out much better than his prediction. His family is not dying it is thriving and he should rejoice at the good news.

[1]     De’ath, G., Fabricius, K.E., Sweatman, H. and Puotinen, M. (2012). The 27-year decline of coral cover on the Great Barrier Reef and its causes. Proceedings of the National Academy of Sciences, 109(44), pp.17995–17999.

[2] Hoegh-Guldberg, O. (1999). Climate change, coral bleaching and the future of the world’s coral reefs. Marine and Freshwater Research, 50(8), p.839.

[3] Greste, P. (2018). Can we repair the Great Barrier Reef or is it already too late? ABC 7:30 Report. [online] 20 Aug. Available at:

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