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IPCC Coral-apocalypse: 243,000 km² of Great Barrier Reef corals to die in only 20 years.

IPCC Coral-apocalypse: 243,000 km² of Great Barrier Reef corals to die in only 20 years. That’s it for corals. The IPCC have gone full apocalyptic: “Coral reefs would decline by 70 to 90 per cent with warming of 1.5°C…” And this catastrophic prophesy will unfold sometime around 2040. (See the graph). The IPCC are practically holding the Great Barrier Reef Hostage. Things are so dire, the Financial Review has just declared that the next election is the Great Barrier Reef election. In the game of fine-tuning the carrot and stick, it’s all bad, but there is hope. Right now the reef covers 348,700 km². And if we are good boys and girls we might only lose 243,000 km²: Scientists say Australia has a chance to save 30 per cent of the Great Barrier Reef if immediate global changes are made to stop temperature rises.

This news will come as a shock to corals on the Great Barrier Reef which are obliviously living across a range of 2,000 kilometers and a span of five degrees Celsius from 27 to 32°C. But these are magic numbers apparently, and half a degree hotter (which is all we are talking about) it will be 27.5 to 32.5°C which is numerology hell where baby corals go to die.


You and I might think that corals might just emigrate since they shed sperm and eggs in mass spawning events visible from space and have 112 sites known to reseed all damaged areas. But what would we know?


And what would a dumb coral know – possibly something after 200 million years of climate change, most of which was hotter.


Corals survived the rock that killed the dinosaurs. They survived Toba, the super volcano that left a crater 100km long. Corals survived a 125m sea level rise at the end of the last ice age. And they survived the ice age — and the fifteen before it. They also survived the super cyclones that have been hitting the coast of Queensland for the last 5,000 years and there is no sign that storms are getting worse. (see Nott 2001 and Hayne 2001.)Who knows what handy genes corals carry after 200 million years of climate change?


At least one research team says corals already have the genes to survive another 250 years of warming.


Corals survive across a five degree range:
Great Barrier Reef, temperature variation on the reef,
….


The IPCC are going for the full wipe out.


University of New South Wales climate scientist Sarah Perkins-Kirkpatrick says “virtually all” coral reefs would start dying off if global temperatures increased by 2C. — The Australian


…whereas more than 99 per cent would be lost with 2C.”


Corals survive massive sea level change


Sea levels have been falling in Queensland for 3,000 years. (Lewis et al 2012) Currently they are rising globally by about 1mm a year according to 1,000 tide gauges.


However, as the seas return to where they have been scores of times before, apparently corals will be wiped out, just like they never have been.


Sea levels in Queensland, holocene. Graph.


Corals have been around through all this:
We are worried about a half a degree…


Geological time graph. 65 million years.
,,,


Note that these are polar temperatures on the graph. But that’s the thing, if tropical temperatures had this kind of volatility, how could corals have made it this far? Instead, because the tropics have their own evaporative air conditioner they don’t get too hot, and as long as we are not in a Snowball Earth scenario, they don’t get too cold either. Water evaporates quickly above 30C. 


So the tropics expands and shrinks as the climate changes but it doesn’t go away, and nor have corals.


Things the ABC BBC and CBC won’t tell you about coral reefs:
In some places ocean acidification happens every single day. No biggie.
Fish behave better when artificial tanks mimic these natural daily swings.
A bit less alkalinity is good news for hundreds of marine species.


Some coral reefs thrive in a more acidic ocean


There is a big safety margin: farmed fish seem to cope fine with CO2 levels that are even fifty times higher than today.
We only discovered coral bleaching in the 1980s but it’s probably been going on for millions of years. 


REFERENCES:
Hock et al (2017) Connectivity and systemic resilience of the Great Barrier Reef PLOS Biology (doi 10.1371/journal.pbio.2003355)

IPPC, Episode 24, Death and Destruction 2018. aka Special Report 15


Lewis, S.E., et al., Post-glacial sea-level changes around the Australian margin: a review, Quaternary Science
Reviews (2012), http://dx.doi.org/10.1016/j.quascirev.2012.09.006[abstract] (paywalled).


Jonathan Nott1 & Matthew Hayne2 (2001) High frequency of ‘super-cyclones’ along the Great Barrier Reef over the past 5,000 years, Nature 413, 508-512 | doi:10.1038/35097055


Hayne, M. and Chappell, J. (2001) Cyclone frequency during the last 5000 years at Curacoa Island, north Queensland, Australia. Palaeogeography, Palaeoclimatology, Palaeoecology 168: 207-219. [Abstract] [Discussion Hayne and Chappell (2001) ]


Image: Wikimedia, author Wise Hok Wai Lum: Flynn Reef 2014.

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