Move On Over Mr Polar Bear, Corals are Now The New Poster Child of Global Warming Alarmism



The day has come. Scientists are heartbroken. Corals are as good as dead. RIP beautiful coral reefs. (sniff, sniff, *reaches for Kleenex*)

It must be grim; it’s not like Eric Holthaus to get all emotional and fatalistic about yet another global warming catastrophe. So, I thought I’d lend support and give him a shoulder to cry on:

Then I thought I would do some digging and see what all the fuss was about. First the paper itself:

Spatial and temporal patterns of mass bleaching of corals in the Anthropocene

Not enough time for recovery

Coral bleaching occurs when stressful conditions result in the expulsion of the algal partner from the coral. Before anthropogenic climate warming, such events were relatively rare, allowing for recovery of the reef between events. Hughes et al. looked at 100 reefs globally and found that the average interval between bleaching events is now less than half what it was before. Such narrow recovery windows do not allow for full recovery. Furthermore, warming events such as El Niño are warmer than previously, as are general ocean conditions. Such changes are likely to make it more and more difficult for reefs to recover between stressful events.


Tropical reef systems are transitioning to a new era in which the interval between recurrent bouts of coral bleaching is too short for a full recovery of mature assemblages. We analyzed bleaching records at 100 globally distributed reef locations from 1980 to 2016. The median return time between pairs of severe bleaching events has diminished steadily since 1980 and is now only 6 years. As global warming has progressed, tropical sea surface temperatures are warmer now during current La Niña conditions than they were during El Niño events three decades ago. Consequently, as we transition to the Anthropocene, coral bleaching is occurring more frequently in all El Niño–Southern Oscillation phases, increasing the likelihood of annual bleaching in the coming decades.


The title alone is enough to warn you that what comes after is not necessarily going to be unbiased, hard-nosed science, but ideology. The Anthropocene is an idea, not a formally recognised geological period. Its adoption is being pushed by people like Mark Maslin, for obvious reasons, not without resistance from actual geologists. Thus its use without qualification in a ‘scientific’ study should ring alarm bells.

Unfortunately, the paper is pay-walled, so I’ll have to rely upon second hand reports as to what is actually in it, but the general gist seems clear. The authors analysed 100 coral reefs between 1980-2016, looking at coral bleaching events. They concluded that not only have bleaching events become more common since 1980, they have become global in scope, whereas apparently, before then, bleaching events were localised. In the words of Prof Terry Hughes, lead author of the study:

Before the 1980s, mass bleaching of corals was unheard of, even during strong El Niño conditions, but now repeated bouts of regional-scale bleaching and mass mortality of corals has become the new normal around the world as temperatures continue to rise.

The articles continues:

The study establishes a transition from a period before the 1980s when bleaching only occurred locally, to an intermediate stage in the 1980s and 1990s when mass bleaching was first recorded during warmer than average El Niño conditions, and finally to the current era when climate-driven bleaching is now occurring throughout ENSO (El Niño-Southern Oscillation) cycles.

So, they took their data from the 1980s onwards and claim that before then coral bleaching events were localised only, not global. I don’t know if there was any consistent worldwide monitoring of the state of coral reefs prior to 1980, but here’s a thing. El Nino and La Nina instrumental records only go back to 1950. Guess what? There have only been three recorded “very strong” or super El Nino events since 1950 – all after 1980, namely 1982-83, 1997-98 and 2014-16 (NOAA keep messing with the 0.5C 3-monthly mean thresholds for these events, making it difficult to know when exactly they started and ended. Twice now: once when they updated to ERSSTv4, then again when they updated to ERSSTv5).

Yebbut, we should expect more super El Ninos because the oceans are warming, right? No, it doesn’t work like that. El Nino and La Nina events are defined by anomalies or departures from a 30 year mean and CPC have now adopted a system where this mean period changes every 5 years in order to account for warmer oceans, so the strength of El Ninos is intrinsic, not relative, and consistently defined throughout the record.

Which means that the authors of this study have (cherry?) picked a period in history where very strong El Ninos have been unique and frequent and by no means at all can this fact be unequivocally attributed to climate change. Indeed, it is more likely to be related to the Great Pacific Climate Shift of 1976, whose cause is still something of a mystery. Which means that the global mass bleaching events which the authors identify and which Hughes tells us were “unheard of” before 1980 might be rather more related to super El Ninos than actual generalised warming of the oceans. If so, GHG warming, even supposing it is the main contributor to the rise in tropical ocean temperatures since 1980 (very debatable) is not the principal cause of widespread coral bleaching events; El Ninos are and these events are naturally caused and have been ongoing for centuries. Oh bugger.

But wait, is it just El Nino events that cause mass coral bleaching? Apparently not . The Guardian says:

Friday’s paper also determined the link between El Niño and mass bleaching events has diminished as global warming continues.

Prior to the 1980s mass coral bleaching on a regional scale was “exceedingly rare or absent” and occurred in localised areas stretching tens of kilometres, not the hundreds of kilometres affected in recent times, the paper said.

These local bleaching events were largely caused by small-scale stressors like unusually hot or cold weather, freshwater inundation or sedimentation.

Then global warming increased the thermal stress of strong El Niño events, the paper said, widening the impact of individual bleaching events. Now, they are occurring at any time.

“Any time”? That would imply that mass coral bleaching is occurring randomly regardless of El Nino events. This is clearly double Dutch from the Guardian. The paper itself says coral bleaching is occurring more frequently in all El Niño–Southern Oscillation phases. It should come as no surprise then that there have been three mass coral bleaching events since 1980 associated with very strong El Ninos (1983, 1998 and 2016). There is also a fourth mass bleaching event associated with the “moderate” Modoki (Central Pacific) El Nino of 2010. So in that respect yes, there is evidence that even the moderate El Nino in 2010 bleached corals across the world because tropical sea surface temperatures were already elevated. You might say this was because of GHG global warming occurring since 1980. You might also say that it was due to an enhanced release of ocean heat via two very strong El Ninos in 1982-83 and 1997-98. Where did that ‘extra heat’ come from though? Climate scientists will tell you it was prevented from escaping from the planet by demonic CO2. Others might tell you it arose via enhanced direct solar short wave heating of the tropics due to the decrease in tropical cloud cover that occurred from the early 1980s to 2000, remaining stable thereafter.


Who knows for sure. Climate scientists just think they know. Climate change activists and warmist politicians don’t think, but they know. What is certain is that the huge El Nino of 2014-16 resulted in yet another  major global coral bleaching event in 2016. Warmists freaked out and still are freaking out. The Great Barrier Reef was reportedly dead, then it started to recover, but alas, warmists have not recovered their senses and now tell us that coral everywhere will never recover – ever (unless of course we – but not the Chinese or the Indians – decarbonise yesterday).

I’m not sure how the authors did their analysis, not being privy to the paper itself, but here’s what the Guardian says about the increase in frequency of mass bleaching events:

The study found that time between bleaching events had diminished five-fold in the past 30 to 40 years, and was now too short to allow for a full recovery and was approaching unsustainable levels.

While mass bleaching events used to occur about once every 27 years, by 2016 the median time between them had shrunk to 5.9 years. Only six of the 100 sites had escaped bleaching.

Just like the shrinking Arctic sea-ice measured over 36 years which was supposed to be the death knell for polar bears, corals are now deemed to be in imminent danger of extinction using 36 years of coral bleaching observations and only 4 recorded instances of mass bleaching – in 1983, 1998, 2010 and 2016. Yes, the time between events has shortened dramatically – but they only have 4 data points to work with! However, this appears to be sufficient to pronounce gravely upon the future survivability of corals in the dreaded Anthropocene, i.e. corals which survived the extinction of the dinosaurs, which survived the rapid 4C global warming of the PETM, which have survived millions of years on a hotter Earth when no ice existed at either pole, are done for because the planet warmed 0.6C after 1980 and we had a few very powerful El Ninos which bleached them.





37 thoughts on “Move On Over Mr Polar Bear, Corals are Now The New Poster Child of Global Warming Alarmism

  1. It doesn’t matter what, but when I read or hear about a study where cyclic events are involved, covers only a fraction of time and the rest are disregarded, I hear loud warning bells.

    Anyone with basic skills in statistics understand the problem and knows that making conclutions that way is a no no.

    In this case, corals have been around for at least 500 million years, so a single window of 30-ish years is relevant how?

    Liked by 1 person

  2. Thing is, “death warrant for coral reefs as we know them.” is not at all the same as the extinction (or lack of) that you refer to with your guff about 250 million years. I’m sure the faithful will lap it up though.


  3. Len Martinez says: “I’m sure the faithful will lap it up though.”

    Indeed, it is bread-and-butter to the Guardian.


  4. Jaime. I haven’t read all of your post yet because I was stopped short by a major mistake in the first sentence of the paper you quote from. The photosynthetic symbiotes within modern corals are not algae but dynoflagelates, a quite separate phylum. Anyone writing a speculative scientific paper upon coral reef futures who gets something so basic wrong is already on my low credibility plate. I then read through the abstract looking for something specific – does it mention and attempt to explain why there are no significant developments of tropical coral reefs during most interglacials. This is important because during most interglacials conditions were in some perfectly natural but unknown way unsuitable for massive tropical reefs. The possibility exists that if reefs today begin to decline it could also be for the same subtle reasons that prevented reefs in earlier times. As I expected, nothing in the paper on this subject. So I’m already highly prejudiced against the paper.
    I happen to believe/know that many reefs are in trouble and probably, in many (or most) cases because of human activities (over fishing, use as building materials, pollution (including high nutrient runoff from fertilizers) and tourism), but probably not from climate change.
    Going back to the post.


  5. Jaime. First you should not use the argument that corals have survived for hundreds of millions of years, because they haven’t. There is no species, genus, family or even group of corals that have survived for so long. Modern corals evolved in the Triassic after the extinction of all Tabulate and Rugose corals. We don’t even know if these older reef builders are related to modern corals nor whether they had zooxanthellae symbiotes.
    A better factoid to emphasize the resilience of modern tropical reefs is their survival through multiple glaciation episodes when sea levels dropped precipitously killing off 100% of all tropical reefs , not to mention large sea temperature falls.
    When anyone tries to browbeat you about heating events causing reef death, ask them what the temperature range along the length of the Great Barrier Reef is and whether bleaching events are more prevalent in the much hotter north (they aren’t).
    Will not even bother getting the paper. Nevertheless it probably does have some truth within it. Sometime in the 1980s there was a significant bleaching event in Florida and I saw the results of research being done (I don’t know if it ever was published) to find preservable evidence of this event – which they found. They then went to cores taken through the entire reefs looking for this same evidence. They found only a single horizon in the entire Holocene record where they could infer the existence of a significant bleaching event. If the paper under consideration had examined the preserved record, as was done in Florida, then they might have been more convincing.


  6. OK, I’m no expert on corals, but I believed them to have first appeared IN THEIR CURRENT FORM around 250 million years ago, at the end of the Triassic. Alan confirms this: “Modern corals evolved in the Triassic after the extinction of all Tabulate and Rugose corals”.

    ‘Corals’, in the very widest biological sense of the word, have been around for BILLIONS of years.

    “Reefs, in some shape or form, have been around for a very long time. Approximately 3.5 billion (3,500,000,000) years ago microbialites (calcareous organo-sedimentary deposits) begin to appear in the fossil record.

    Since the Triassic (i.e., over the last 220 million years), scleractinian corals have become increasingly dominant as reef-builders. Diverse (molecular, stable isotopic, ecological) evidence suggests scleractinian corals formed symbioses with algae soon after their appearance in the fossil record.

    Holocene (Recent) reefs probably represent the most developed scleractinian reefs in geological history.”

    So bar quibbling about technical details regarding which species, genus, family have donated their DNA to modern coral communities, I feel I’m generally correct in saying that “corals have been around for 250 million years and survived several major global extinction events”.


  7. You raise some pertinent points Alan with regard to other ecological pressures on modern coral reefs, as does Hunter re. super low tides (which combined with extra sunlight after 1980 might also have severely impacted corals). All of this appears to have been ignored by the authors in favour of declaring man-made climate change to be the single greatest threat to coral reefs.


  8. Jaime. To me the argument about corals is similar to that made by someone who says “don’t worry about the survival of the lowland gorilla, Hominids have lasted 6 million years”. Some of the same coral species survived the last glacial low sea stand, when all modern reefs would have been killed off for many tens of thousands of years, making the argument I suggested the more forceful. But each to their own.

    Corals in reefs have been climate poster animals, but theories suggesting they are in peril from CO2 (by causing heat stress or ocean acidification) can easily be rubbished. Nevertheless I expect a new push on acidification soon as cold winters distract punters from the Holy Warming Grail.


  9. Lots of food for thought. One point of Alan’s is particularly thought provoking – about the rapid changes at the end of the last ice age. Any local species that inhabits an area that was totally different at the height of the ice age isn’t in it’s ‘natural’ location and to get there must have survived very rapid climate change. Corals are probably the best example. Corals set up where they do because they need those conditions. The right distance below sea level, something to stand on and food. So long as the bleached areas haven’t fundamentally changed, there are queues of baby corals waiting for vacant possession. One of the guys connected to the report said the other day that the faster corals took about 10 years to recolonise. He didn’t say what the timescale was for the slow ones. It may be that they could speed the process up by hoovering up coral babies at a spawning event and depositing them directly on a bleached reef, even if it was just done for the slow movers.

    The other thing would be to create artificial reef bases in ‘better’ areas, although the corals may argue about what is better and stubbornly ignore the scientists’ version.


  10. SCUBA diving got going in the 1970s, as kit, training and travel became more accessible. Warm tropical waters were far more popular with sports divers and marine biologists, and Australia discovered a whole new industry, drawing in tourist and science research money from all over the world.

    Australia has done very nicely out of every fresh GBR scare story.

    The post heading is correct, except that the polar bear death spiral nonsense was falling to pieces a decade ago. Ocean acidification and coral bleaching were far better, as they were more photogenic, and better for generating tourism money.

    Tourists can be taken to carefully selected dive sites, to take their own underwater colour photographs, as evidence, but based on a “snapshot” in time, of a continuous process.


  11. Alan, thank you for your review of the essay.
    Your point about the proper ageing, correct identification of the symbiote, etc. are appreciated.
    If I understand the process of bleaching in general, it is that unusual low tides expose parts of the impacted reef to the air or to such shallow water that the coral is heated up and either way goes into shock.
    Is this correct, or are there other mechanisms to cause bleaching?


  12. Hunter, dead coral is calcium carbonate. It is white (ish).

    Those that have tried (I haven’t) to keep marine aquariums, with live corals, know that they are susceptible to dying, if conditions vary. Marine biologists have known this since before the Aqualung was invented.

    Seawater is full of embryonic coral looking for a starter home. Dead coral is ideal.

    Forest fires occur naturally, and are part of the natural lifecycle and regeneration. They are devastating, but after a few years, fresh growth thrives. Nature can clear deadwood, BioScience can’t.


  13. Hunter based on memory alone I believe reefs are built from real goldilocks organisms – conditions must not be too hot or too cold over the long term, or the short term, waters must not be too saline or too brackish, they don’t like excess sediment (although in Thailand they may inhabit muddy delta estuaries) or nutrients. Almost any environmental change and they can throw their zooxanthellae and pigments out of their prams and sulk in glorious white nakedness. It has been shown that this is an environmental response and the bleached corals are recruiting a different suite of zooxanthellae more adapted to the new conditions. Because the stressors can be short lives, presumably corals get their old symbiots back, with comments like “sorry for the misunderstanding”.
    I found it particularly interesting that the most recent widespread bleaching event was associated with an exceptionally low (and therefore long) tide during the day. Strange there were no first hand observational reports of this event and the old chestnut of climate change was immediately pulled out of the shed, leaving the bloody great bus of a low tide still parked under cover.

    Liked by 1 person

  14. Alan Kendall, I am sure that by Victorian times of plant and animal collection and study, it was realised that keeping coral alive in a laboratory tank or marine aquarium was difficult, with minor changes to temperature pH etc being critical.

    I expect that some of the collectors and marine biologists realised that this was all part of the natural ecology and regeneration, just as a forest fire is.

    The Green Blob are very good at blaming natural phenomena on Global Warming.


  15. GolfCharlie I once spent two weeks at a Marine Observatory in northern Jamaica where I was told that it was exceedingly difficult to maintain an sea aquarium even with permanent access to fresh seawater. Organisms in parts of a reef isolated from the main reef, can also suffer fatally. Another aspect is the huge variation over time and space that occurs in reef health. When I was there, one part of the local reef, which had been closely monitored for decades, was unprecidentally being devastated by a huge group of long-spined Diadema sea urchins, munching away and converting a formerly beautiful coral reef into an area of green algal lunch for the echinoids. No one knew why. Now, of course, we know; it’s the demon dioxide molecule.


  16. Alan Kendall, I remember 30(?) years ago a TV documentary about the Crown of Thorns Starfish that was going to eat it’s way through all living coral and destroy the GBR.

    I expect the Australian economy did quite well out of all the free advertising for the beauty of the GBR.

    For Europeans especially, if they want to scuba dive amongst coral and fish in warm water, the Red Sea is far cheaper to access, with better reliability for good weather, all within easy reach of hotel complexes with mod cons.


  17. The temperature of the Red Sea is subject to seasonal change, but not to the sudden change caused by different ocean currents and weather systems.

    Sharks are encountered in the Mediterranean Sea ( don’t tell tourists) but I think they get there because they are lost, in their search for something big enough to eat.

    I am not surprised that so many scuba diving marine biologists look for a problem to research on the GBR that comes with funding.


  18. Tucked away towards the end of the paper is this:

    “We tested the hypothesis that the number of bleaching events that have occurred so far at each location is positively related to the level of postindustrial warming of sea surface temperatures that has been experienced there (fig. S4). However, we found no significant relationship for any of the four geographic regions, consistent with each bleaching event being caused by a short-lived episode of extreme heat (12, 19, 20) that is superimposed on much smaller long-term warming trends. Hence, the long-term predictions of future average warming of sea surface temperatures (13) are also unlikely to provide an accurate projection of bleaching risk or the location of spatial refuges over the next century.”

    Liked by 1 person

  19. WWF could do money raising TV adverts to adopt a coral, to save it from bleaching. This could “highlight” some confusion amongst the fashion conscious.


  20. Thanks to Paul for digging out the actual paper, which reveals no correlation between general warming and bleaching events. So the emphasis has to be almost entirely upon El Nino as the causative agent.


  21. Jaime. I believe the accepted story has for some time been that El Nino become superimposed upon a longer term gradual warming trend, so that over time El Nino events become ever more extreme and damaging. Bleaching occurred during short term episodes of even warmer events superimposed on the already hotter El Ninos. A short term warming might cause bleaching but if over a few degrees Celsius can cause wholesale mortality. That is why exposed corals during the recent low tides were so devastating -they exposed the corals to unsurvivable heat stress.


  22. Alan,

    There appears to be no correlation between generalised post industrial ocean warming and bleaching which, even if El Ninos were vital to give that ‘extra push’, one would expect there to be. I suspect that coral communities are able to adapt to gradually warming oceans, but are ‘knocked out’ by extreme, short-lived warming events. As I pointed out, all of the really extreme El Nino episodes (“very strong”) occurred after 1980 and after the Great Pacific Climate Shift of 1976 which appears to have initiated a period of very rapid warming of global ocean basins in conjunction with ever more extreme El Nino events.
    With regard to very low tides, I believe it is not aquatic thermal stress which kills corals, but a combination of desiccation and exposure to very strong sunlight which bleaches them.

    “We argue that extreme low-tide, high-irradiance events are important structuring forces of intertidal coral reef communities, and can be as damaging as thermal stress events.”


  23. Storms are more likely to break and damage coral at lower tides (very photogenic). They will also stir up more silts and sediments, whilst drawing colder water up from depth at the edge of reefs.

    Underwater photography meant putting a conventional camera into a water and pressure proof case. This was bulky, fragile, high maintenance etc, and expensive. Digital cameras made sub aqua photography far cheaper, less bulky etc

    Breathing compressed air down to 30 feet is relatively free of health problems, which is where most of the colourful marine life exists Things then get progressively more complicated, and at about 100 feet nitrogen narcosis is a significant risk.


  24. Jaime. I was trying to convey what the accepted link was between ElNinos, global warming and coral reef bleaching and mortality events. Not what I believe.

    With regard to the last bleaching event and low tides, the stressor cannot have been desiccation because similar prolonged low tides previously occurred at night and caused no damage. Emphasis has been placed upon the fact that these unusually low tides occurred during the day. Irradiance might be a stressor, but I doubt it. In tropical seas almost all of the incident radiation becomes refracted into the sea so there is unlikely to be much difference above or below the water surface. Since the coral polyps will have retracted into their skeletons upon exposure, I fail to see how irradiance levels can be important.
    The most important difference between coral reef scientists relates to whether they support AGW or not. Supporters spread doom like there’s no tomorrow and cover up past failed predictions. Are these the symptoms of some hitherto unrecognized mental disease that especially afflicts scientists?


  25. Paul Matthews, that Advert should be reported to the ASA. It does not show claws or jaws.


  26. Paul. Do you think The Guardian has any idea what the world’s largest predator can do? It’s like them using a disneyfied boa constrictor with it’s coils around an infant being used to advertising nanny services.


  27. Is there a go-to contrarian for corals in the same way that Crockford is the go-to contrarian for polar bears; an Australian scientist who claims that the great barrier reef is not endangered, for example?


  28. I’ve never heard of Ridd. I had heard of Crockford and was following her on Twitter before the ghastly paper was published that sought to discredit her, of which all of science should be ashamed for a decade at least. But defenders of the Konsensus are no doubt moving on, the blood stains left in the snow no concern of theirs.


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