Great Barrier Reef sees record coral cover, but it is highly vulnerable
…was shocking in its transparent desperation to find a way to convolute good news into a knot tight enough to twist it into a portent of climate doom. It’s as if I gave you a bottle of Port Charlotte, and your response was “Thanks, but I might drop it.”
In fact the headlines about the Great Barrier Reef have quite a history. I picked a couple of classics to use in Denierland, but they really were the tip of the reef. Before warmer ocean temperatures were the main threat, we had Chinese oil freighters crashing into the reef. We had dredging. Port development. Mud. Pollution from agriculture. The good old crown-of-thorns. Acidity. Cyclones smashing stuff up, as they tend to do. Things were grim and getting grimmer. By 2012:
“Australia’s Great Barrier Reef has lost more than half its coral cover since 1985, according to a new study. The loss has been spurred by a combination of factors including hurricanes, coral-eating starfish and coral bleaching.
The paper, in the Proceedings of the National Academy of Sciences, is the most comprehensive survey of a reef system over such a long period. The researchers from the Australian Institute of Marine Science found that reef cover fell from 28 per cent to 13.8 per cent over the past 27 years, with two-thirds of the decline occurring since 1998.
“We are basically losing an ecosystem that is so iconic for Australia and the rest of the world,” said institute scientist Katharina E. Fabricius, one of the paper’s authors.
At the current rate of loss, researchers said, the Great Barrier Reef will lose half of its coral cover again by 2022, putting it on par with the Caribbean. “It will be really very low in 10 to 15 years,” Fabricius said.Independent
On its knees by 2012, unusually warm sea temperatures in 2016 – made “175 times more likely”* by Homo sapiens and his addiction to SUVs – finally finished the Great Barrier Reef off.
Indeed the map from the Toronto Star purported to show that much of the northern reef was in fact dead:
A year later, in 2017, first The Guardian and then the Telegraph were adamant that the reef was beyond saving.
However, by 2018 it became clear that the reef was not yet, in fact, an ex reef.
Thank Science for the experts, eh? What would we do without them? But only two years later they realised that the scientific detachment that had served them so well briefly in 2018 was an outmoded ideal and let themselves get all emotional about the state of the reef:
The surveyors being Hughes and Pratchett of James Cook. Last year Terry Hughes returned to The Conversation with evidence – or at least a scary map – to show that the game was over, so there.
Original caption: Map of the Great Barrier Reef showing the cumulative level of bleaching observed in 2016, 2017 and 2020. The colours represent the intensity of bleaching, ranging from zero (category 1, dark blue) to severe bleaching that affected more than 60% of corals (category 4, red). Author provided
And even this year The Guardian was reporting that 91% of the individual reefs were affected by bleaching:
That was back a hundred years ago, I mean a quarter of a year ago. Now, in August 2022 we have a mote of good news. Except that it isn’t, or at least, we can’t accept that it is, or might be. The narrative is too strong: the reef is doomed. It has to be.
Slamming the brakes on the hype train for a minute: why should we accept that the Great Barrier Reef’s doom is an established fact, even in the face of warmer sea temperatures, which are either baked in or cooked up, according to your preference? This figure illustrates what every schoolkid knows – or once did: coral reefs, or at least the zooxanthellate kind, like it hot.
The 70F isotherm diagram comes from Tom Garrison’s Essentials of Oceanography, though the snip comes from somewhere else (“Redox College,” whatever that is).
The GBR, as the diagrams of its corpse above show, stops half-way down the Queensland coast. Why? Why no reef around Tasmania? Too hot further south? Of course not. It’s too cold further south.
In fact the large majority of the ocean is too cold for coral reefs (the deep water kind, without the symbionts, notwithstanding). This simple and elementary observation means that coral reefs are not in danger as a phenomenon. A trillion SUVs wouldn’t be able to rid the Earth of them. Maybe some seas will one day be too hot for them? As far as I know, the Red Sea is about the hottest, and…
A recent underwater expedition to the Red Sea offshore from Sudan and Eritrea found surface water temperatures 28 °C (82 °F) in winter and up to 34 °C (93 °F) in the summer, but despite that extreme heat, the coral was healthy with much fish life with very little sign of coral bleaching, with only 9% infected by Thalassomonas loyana, the ‘white plague’ agent.Wiki page on the Red Sea
The GBR, meanwhile:
The surface water temperature varies on the south of the sea from 19 °C in August to 24 °C in February. It is rather warm and stable at 27–28 °С in the north all through the year.Wiki page on the Coral Sea
The consensus is that 28 °С is cooler than 34 °С. So there we have it. Apocalyptic headlines notwithstanding, the GBR is not dead, and not doomed. Wait. What about sea level rise? I forgot about sea level rise. The Great Barrier Reef is doomed, I tell ya, doomed!
Bêche de mer, from W. Saville-Kent (1893). The Great Barrier Reef of Australia: its Products and Potentialities. Allen & Co. [Available at Archive.org.]
*Climate central‘s comment about 175 times more likely:
Climate change made it 175 times more likely that the surface waters of the Coral Sea, which off the Queensland coastline is home to Australia’s Great Barrier Reef, would reach the record-breaking temperatures last month that bleached reefs, modeling analysis showed.